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Department of Defence

RAAF Base Edinburgh Environmental Investigation of PFAS

Detailed Site Investigation - Main Report

11 December 2018

52234/117,720 (Rev 0)

JBS&G

Department of Defence RAAF Base Edinburgh Environmental Investigation of

PFAS

Detailed Site Investigation - Main Report

11 December 2018

52234/117,720 (Rev 0) JBS&G

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Table of Contents

Abbreviations ...................................................................................................................................... x

Executive Summary ........................................................................................................................... xii

1. Introduction .............................................................................................................................. 1

1.1 Background ..................................................................................................................... 1

1.1.1 Legacy AFFF ..................................................................................................... 1

1.2 Project Objectives ........................................................................................................... 2

1.3 Assessment Process ........................................................................................................ 2

1.4 Scope of Work ................................................................................................................ 3

1.5 Legislation, Legislative Instruments and Relevant Contaminated Sites Guidance Documents ..................................................................................................................... 4

2. The Site and Investigation Area ................................................................................................ 6

2.1 Site Identification and Land Use ..................................................................................... 6

2.2 Investigation Area........................................................................................................... 7

2.3 Surrounding Land Use and Zoning ................................................................................. 8

3. Environmental Setting ............................................................................................................ 10

3.1 Geology ......................................................................................................................... 10

3.1.1 Regional Setting ............................................................................................ 10

3.1.2 Quaternary Units........................................................................................... 10

3.1.3 Tertiary Units ................................................................................................ 10

3.2 Hydrogeology ............................................................................................................... 11

3.2.1 Regional Setting ............................................................................................ 11

3.2.2 Quaternary Aged Sediments ......................................................................... 13

3.2.3 Tertiary Aged Sediments ............................................................................... 14

3.2.4 Groundwater Flow Direction ........................................................................ 14

3.2.5 Use of Groundwater within the Investigation Area ...................................... 14

3.2.6 Environmental Values of Groundwater ........................................................ 16

3.3 Topography and Hydrology .......................................................................................... 16

3.4 Climate .......................................................................................................................... 18

3.4.1 Rainfall .......................................................................................................... 18

3.4.2 Wind Conditions ............................................................................................ 18

3.5 Heritage ........................................................................................................................ 20

3.6 Flora and Fauna ............................................................................................................ 20

4. Site History .............................................................................................................................. 22

4.1 Historical Aerial Photographs ....................................................................................... 22

4.1.1 May 2003 ...................................................................................................... 22

4.1.2 October 2009 ................................................................................................ 23

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4.1.3 February 2013 ............................................................................................... 23

4.1.4 February 2018 ............................................................................................... 24

5. Summary of Previous Investigations Relevant to PFAS .......................................................... 25

5.1 RAAF Base Edinburgh Contaminated Sites Register (CSR) ........................................... 26

5.2 CSR Document Reviews ................................................................................................ 29

5.2.1 Stage 2 Environmental Investigations Edinburgh Defence Precinct - SA2232, Part 1 (GHD, 2008) ........................................................................................ 29

5.2.2 AFFF Soil and Surface Water Assessment Edinburgh (URS, 2011) ................ 30

5.2.3 SA 3139 Asbestos and Contaminated Soil Remediation Option Report, RAAF Edinburgh Site SA019 (AEC, 2012) ................................................................ 32

5.2.4 AFFF Infrastructure Assessment (URS, 2012) ............................................... 32

5.2.5 Edinburgh Defence Precinct Groundwater Monitoring, Groundwater Monitoring Event March 2014 (GHD, 2014a) ............................................... 33

5.2.6 SA3787 Edinburgh Defence Precinct Groundwater Well Installation (GHD, 2014b) ........................................................................................................... 33

5.2.7 SA Environmental comments - Defence Estate Legacy PFC Review July 2015 (Defence, 2015) ............................................................................................. 34

5.3 AIR 7000 Project Documents ........................................................................................ 35

5.3.1 Segregation of Soils proposed for Excavation from Areas 1, 2 and 3, AIR 7000 Project Area, RAAF Base Edinburgh (AECOM, 2016a) ......................... 35

5.3.2 In-Situ Waste Soil Characterisation for Northern Runway Extension, AIR 7000 Project, RAAF Base Edinburgh (AECOM, 2016b) .................................. 36

5.3.3 Email correspondence: Air7000 Sites - Boundary Confirmation (Lendlease, 2016) ............................................................................................................. 36

5.4 Base Estate Plans .......................................................................................................... 36

5.4.1 Edinburgh Defence Precinct Base Specific Investigations (Jacobs, 2016a and Jacobs, 2016b) ............................................................................................... 36

5.5 Stormwater – Base Water Quality Assessment, Edinburgh Defence Precinct – Base Engineering Assessment Program (Aurecon, 2012) ..................................................... 37

5.6 Defence Estate Legacy PFC Review - DEHP-ID-022 (CH2M, 2015) ............................... 37

5.7 Timeline for Analysis and Management Actions Regarding PFOS and PFOA within AFFF products at RAAF Edinburgh ................................................................................ 38

5.8 SA Environmental Groundwater Monitoring, Edinburgh Defence Precinct (DRAFT) (GHD, 2016) .................................................................................................................. 40

5.9 Figure Showing Historic AFFF Use Areas Still to be Investigated (Broadspectrum, 2016) ............................................................................................................................. 40

6. Interviews with Site Personnel ............................................................................................... 41

7. Preliminary Conceptual Site Model ........................................................................................ 42

7.1 Contaminant Profile ..................................................................................................... 42

7.2 Sources of Contamination ............................................................................................ 43

7.2.1 Primary Sources ............................................................................................ 43

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7.2.2 Secondary ...................................................................................................... 48

7.3 Off-Site .......................................................................................................................... 48

7.3.1 Primary .......................................................................................................... 48

7.3.2 Secondary ...................................................................................................... 49

7.4 Potentially Affected Media ........................................................................................... 49

7.5 Preliminary Exposure Pathways and Receptors at Risk ............................................... 50

7.6 Initial Uncertainties and Data Gaps .............................................................................. 54

8. Data Quality Objectives .......................................................................................................... 55

8.1 State the Problem ......................................................................................................... 55

8.1.1 Identify the Decision/Goal of the Study........................................................ 56

8.1.2 Identify Inputs to the Decision ...................................................................... 56

8.1.3 Define the Study Boundaries ........................................................................ 57

8.1.4 Develop a Decision Rule ................................................................................ 57

8.1.5 Specify Limits of Decision Error..................................................................... 58

8.1.6 Optimise the Design for Obtaining Data ....................................................... 60

9. Field Investigation Approach and Methodology .................................................................... 61

9.1 Overview ....................................................................................................................... 61

9.2 Preliminary Assessment ............................................................................................... 61

9.3 Stage 2A Investigation Program ................................................................................... 61

9.4 Stage 2B Investigation Program ................................................................................... 62

9.5 Private Property Sampling Program ............................................................................. 64

9.6 Fieldwork Methodology ............................................................................................... 64

9.7 Laboratory Analysis ...................................................................................................... 65

9.7.1 PFAS Analysis ................................................................................................ 65

9.7.2 Laboratory Analytical Methods ..................................................................... 65

9.7.3 Leachable PFAS ............................................................................................. 66

9.7.4 Physical and Physicochemical Properties ..................................................... 66

9.7.5 Non-PFAS Contaminants of Potential Concern ............................................. 66

9.8 Deviations from the SAQP ............................................................................................ 67

9.9 Quality Assurance and Quality Control (QA/QC) .......................................................... 68

10. Assessment Criteria ................................................................................................................ 70

10.1 Overview ....................................................................................................................... 70

10.2 PFAS .............................................................................................................................. 71

10.3 Non-PFAS COPC ............................................................................................................ 75

11. Investigation Results ............................................................................................................... 76

11.1 Preliminary Assessment Results ................................................................................... 76

11.1.1 Field Observations ........................................................................................ 76

11.1.2 Physicochemical Field Parameters ................................................................ 78

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11.1.3 Sediment Observations and Materials Encountered .................................... 78

11.1.4 Analytical Results .......................................................................................... 78

11.2 Climatic Conditions ....................................................................................................... 79

11.2.1 Rainfall .......................................................................................................... 79

11.2.2 Wind Conditions ............................................................................................ 80

11.3 Soil Investigation .......................................................................................................... 82


11.3.2 Soil Analytical Results.................................................................................... 83

11.3.3 Vertical Profiling Results ............................................................................... 86

11.3.4 Leachate Results ........................................................................................... 89

11.3.5 Physical Properties ........................................................................................ 91

11.4 Groundwater Investigation .......................................................................................... 91


11.4.2 Groundwater Levels and Flow Direction....................................................... 94

11.4.3 Groundwater Hydraulic Gradients ................................................................ 94

11.4.4 Physicochemical Field Parameters ................................................................ 95

11.4.5 Groundwater Analytical Results.................................................................... 98

11.4.6 Dominant PFAS in Groundwater ................................................................. 104

11.4.7 Water Chemistry ......................................................................................... 104

11.4.8 Hydraulic Conductivity Testing Results ....................................................... 106

11.5 Surface Water Investigation ....................................................................................... 107

11.5.1 Field Observations ...................................................................................... 107

11.5.2 Physicochemical Field Parameters .............................................................. 108

11.5.3 Surface Water Analytical Results ................................................................ 109

11.6 Sediment Investigation ............................................................................................... 112

11.6.1 Sediment Analytical Results ........................................................................ 112

11.6.2 Vertical Profiling Results ............................................................................. 114

11.6.3 Leachate Results ......................................................................................... 114

11.6.4 Pore Water Results ..................................................................................... 114

11.7 Concrete Investigation Analytical Results .................................................................. 114

11.8 Private Property and Water Supply Bore Investigations ............................................ 117

11.8.1 Water Use Survey Results ........................................................................... 117

11.8.2 Analytical Results ........................................................................................ 120

12. Refined Conceptual Site Model ............................................................................................ 122

12.1 Nature and Extent of Site Contamination .................................................................. 122

12.1.1 Primary Source Areas .................................................................................. 122

12.1.2 Secondary Source Areas .............................................................................. 128

12.1.3 Off-Site ........................................................................................................ 128

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12.2 Contaminant Transport Mechanisms and Migration Pathways ................................. 129

12.3 Exposure Pathways and Receptors at Risk ................................................................. 130

12.4 Remaining Uncertainties and Data Gaps .................................................................... 139

13. Discussion and Conclusions .................................................................................................. 140

13.1 PFAS Contamination Source Areas ............................................................................. 140

13.2 Off-Site Extent of Contamination ............................................................................... 142

13.3 Human and Ecological Receptors ............................................................................... 143

13.4 Potential PFAS Contamination Exposure Pathways ................................................... 144

14. Next Steps ............................................................................................................................. 145

15. Limitations ............................................................................................................................ 146

16. References ............................................................................................................................ 147

List of Tables (in text) Table 2.1: Site Details .......................................................................................................................... 7

Table 3.1: Regional Stratigraphy and Hydrostratigraphy of the Northern Adelaide Plains .............. 12

Table 3.2: Summary of Licensed Water Supply Bores in Current Investigation Area ....................... 15

Table 3.3: Assessment of Protected Environmental Values of Groundwater .................................. 16

Table 3.4: Summary of Mean Climate Data for RAAF Base Edinburgh (BOM, 2018) ....................... 18

Table 3.5: Summary of Monthly Rainfall Data (BOM, 2018) ............................................................ 18

Table 5.1: List of Relevant Documents Provided and/or Requested to Inform Preliminary CSM Development ............................................................................................................. 25

Table 5.2: Relevant Extracts from the RAAF Base Edinburgh CSR .................................................... 27

Table 5.3: Summary of Primary PFOS Sources Identified in URS, 2011 ............................................ 31

Table 5.4: Detectable Concentrations of PFAS in Soil Samples (from GHD, 2014b) ......................... 34

Table 5.5: Summary of Known or Potential AFFF Impacted Sites from CH2M, 2015 ....................... 37

Table 7.1: Chemical and Physical Properties of PFOS, PFOA, and PFHxS ......................................... 42

Table 7.2: Summary of Known and Potential Primary Sources of PFAS Contamination .................. 44

Table 7.3: Summary of Known and Potential Secondary Sources of PFAS Contamination .............. 48

Table 7.4: Summary of Known and Potentially Affected Media Based on Historical Information ... 49

Table 7.5: Preliminary Summary of Potential Receptors and Exposure Pathways – Human Health 51

Table 7.6: Preliminary Summary of Potential Receptors and Exposure Pathways – Ecological ....... 53

Table 8.1: Summary of Decision Rules .............................................................................................. 57

Table 8.2: Summary of Quality Assurance / Quality Control Program ............................................. 59

Table 9.1: Summary of Stage 2A Field Program ................................................................................ 62

Table 9.2: Summary of Stage 2A Field Program ................................................................................ 63

Table 9.3: Summary of Private Property Sampling Works ................................................................ 64

Table 9.4: Standard Minimum PFAS Analytical Suite ........................................................................ 65

Table 9.5: Summary of QA/QC Non-Conformances and Investigation Outcome ............................. 68

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Table 10.1: Summary of Adopted Tier 1 PFAS Screening Criteria..................................................... 72

Table 11.1: Summary of Soil Analytical Results ................................................................................ 84

Table 11.2: Summary of Soil Vertical Profiling Results ..................................................................... 87

Table 11.3: Summary of Aquifer Physical Properties ........................................................................ 91

Table 11.4: Summary of Hydraulic Gradients ................................................................................... 95

Table 11.5: Summary of Groundwater Field Parameters ................................................................. 97

Table 11.6: Updated Assessment of Protected Environmental Values of Groundwater ................. 98

Table 11.7: Summary of Groundwater Analytical Results – Q1 Aquifer ........................................... 99

Table 11.8: Summary of Groundwater Analytical Results – Q2 Aquifer ......................................... 100

Table 11.9: Summary of Groundwater Analytical Results – Q3 Aquifer ......................................... 100

Table 11.10: Summary of Hydraulic Conductivity Testing Results.................................................. 106

Table 11.11: Summary of Surface Water Field Parameters ............................................................ 108

Table 11.12: Summary of Surface Water Analytical Results ........................................................... 111

Table 11.13: Summary of Sediment Analytical Results................................................................... 113

Table 11.14: Summary of Concrete Analytical Results ................................................................... 116

Table 11.15: Summary of Water Use Survey Responses ................................................................ 118

Table 11.16: Summary of Private Property Sampling Results ........................................................ 120

Table 11.17: On-Site T2 Bore Water Level Gauging and Sampling Results .................................... 121

Table 12.1: Summary of Primary Source Area Assessment ............................................................ 124

Table 12.2: Summary of Secondary Source Area Assessment ........................................................ 128

Table 12.3: Updated Summary of Potential Receptors and Exposure Pathways – Human Health 131

Table 12.4: Updated Summary of Potential Receptors and Exposure Pathways – Ecological ....... 137

List of Figures (in text) Figure ES.1: Site and Investigation Area Location ............................................................................. xii

Figure ES.2: Graphical Depiction of the Aquifers within the Investigation Area ............................. xvi

Figure ES.3: Source Areas and Major Stormwater Drainage Features ........................................... xviii

Figure 3.1: 9am Prevailing Wind Direction – All Data 1972 to Present (BOM, 2018) ....................... 19

Figure 3.2: 3pm Prevailing Wind Direction – All Data 1972 to Present (BOM, 2018) ...................... 20

Figure 11.1: Summary of Climatic Conditions During Preliminary On-Site Sampling Program ........ 77

Figure 11.2: Summary of Climatic Conditions During Preliminary Off-Site Sampling Program ........ 77

Figure 11.3: DSI Rainfall Versus Long-term Average (sourced from BOM, 2018) ............................ 79

Figure 11.4: Rainfall Conditions – Surface Water Sampling Event 1 ................................................ 80

Figure 11.5: Rainfall Conditions – Surface Water Sampling Event 2 ................................................ 80

Figure 11.6: Prevailing Wind Direction – Stage 2A Sampling Program ............................................. 81

Figure 11.7: Prevailing Wind Direction – Stage 2B Sampling Program ............................................. 81

Figure 11.8: Comparison of Dry Weight Versus Soil Leachate Results - PFOS .................................. 89

Figure 11.9: Comparison of Dry Weight Versus Soil Leachate Results - PFHxS ................................ 90

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Figure 11.10: Comparison of Dry Weight Versus Soil Leachate Results - PFOA ............................... 90

Figure 11.11: Piper Diagram for Selected Nested Q1 and Q2 Aquifer Monitoring Wells (2018) ... 105

Appendices Figures

Tables

Appendix A WaterConnect Database Records

Appendix B Historical Aerial Photographs

Appendix C EPBC Protected Matters Search Results

Appendix D Figure Showing Historic AFFF Use Areas Still to be Investigated (Broadspectrum, 2016)

Appendix E Timeline for Analysis and Management Actions Regarding PFOS and PFOA within AFFF products at RAAF Edinburgh

Appendix F Response to AFFF Storage, Use and Disposal Questionnaire

Appendix G Fieldwork Methodology

Appendix H Non-PFAS COPC Analytical Results Summary Tables

Appendix I Data Quality Assessment

Appendix J Laboratory Analytical Reports and Sample Chain of Custody Documentation

Appendix K Surface Water Sampling Sheets

Appendix L Soil Bore Lithological Logs

Appendix M Field Investigation Photographs

Appendix N Monitoring Well Construction Logs

Appendix O Monitoring Well Development Sheets

Appendix P Well Construction Permits

Appendix Q Groundwater Sampling Sheets

Appendix R Results of Gamma Logging Survey

Appendix S Equipment Calibration Records

Appendix T Hydraulic Conductivity Test Analysis

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Abbreviations

Term Definition 6:2 FTS 6:2 Fluorotelomer Sulfonate, or 6:2 Fluorotelomer Sulfonic Acid ACM Asbestos Containing Material AFFF Aqueous Film Forming Foam AHD Australian Height Datum ALS Australian Laboratory Services ASC NEPM National Environment Protection (Assessment of Site Contamination) Measure 1999, as amended in

2013 ASLP Australian Standard Leaching Procedure ASR Aquifer Storage and Recovery Base RAAF Base Edinburgh bgs Below Ground Surface BOM Bureau of Meteorology CASG Capability Acquisition and Sustainment Group CAS No. Chemical Abstracts Service Number COC Chain of Custody COPC Contaminants of Potential Concern CRC CARE Cooperative Research Centre for Contamination Assessment and Remediation of the Environment CSM Conceptual Site Model CT Certificate of Title DEW Department for Environment and Water DEWNR Department of Environment, Water and Natural Resources DfW Department for Water DO Dissolved Oxygen DQI Data Quality Indicator DQO Data Quality Objective DSI Detailed Site Investigation DSRG Defence Support and Reform Group DSTG Defence Science and Technology Group DWLBC Department of Water, Land and Biodiversity Conservation EC Electrical Conductivity EDP Edinburgh Defence Precinct EILs Ecological Investigation Levels EMOS Estate Maintenance and Operations Services EPA Environment Protection Authority ERUP Engine Run Up Eurofins Eurofins | mgt GDA Geocentric Datum of Australia GPS Global Positioning System Ha Hectare HHERA Human Health and Ecological Risk Assessment HILs Health Investigation Levels JBS&G JBS&G Australia Pty Ltd KPW Kaurna Park Wetland LCS Laboratory Control Sample LIA Living-in accommodation LOR Limit of Reporting NATA National Association of Testing Authorities NEMP National Environmental Management Plan (PFAS) PARCCS Precision, Accuracy, Representativeness, Comparability, Completeness and Sensitivity PFAS Per and Polyfluoroalkyl Substances PFHxS Perfluorohexane Sulfonate, or Perfluorohexane Sulfonic Acid PFOA Perflourooctanoic Acid PFOS Perfluorooctane Sulfonate, or Perfluorooctane Sulfonic Acid pH A figure expressing the acidity or alkalinity of a solution on a logarithmic scale on which 7 is

neutral, lower values are more acid and higher values more alkaline Q1 First Quaternary Aquifer

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Q2 Second Quaternary Aquifer Q3 Third Quaternary Aquifer Q4 Fourth Quaternary Aquifer QA/QC Quality Assurance / Quality Control RAAF Royal Australian Air Force Redox Reduction/oxidation potential RL Relative Level RPD Relative Percent Difference RTU Recruit Training Unit SWL Standing Water Level SA South Australia SAQP Sampling, Analysis and Quality Plan SDB Southern Detention Basin STP Sewage treatment plant T1 First Tertiary Aquifer T2 Second Tertiary Aquifer T3 Third Tertiary Aquifer T4 Fourth Tertiary Aquifer WQEPP South Australia Environment Protection (Water Quality) Policy 2015 WWTP Waste Water Treatment Plant

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Executive Summary

Introduction

JBS&G Australia Pty Ltd (JBS&G) was engaged by the Department of Defence (Defence) to undertake a detailed environmental investigation of per- and poly-fluoroalkyl substances (PFAS) contamination at the Royal Australian Air Force (RAAF) Base Edinburgh (the Site) and surrounding areas collectively identified as the Investigation Area. The Site is located in the Northern Adelaide Plains, approximately 25 km north of the Adelaide central business district. The Site and Investigation Area are shown on Figure ES.1.

Figure ES.1: Site and Investigation Area Location

Background

RAAF Base Edinburgh has been subject to previous investigations that have identified contamination as a result of the historical use of legacy Aqueous Film Forming Foam (AFFF) that contained PFAS. AFFF has primarily been used at the Site in firefighting training exercises and for use in emergency response events to extinguish liquid fuel-based fires. The key PFAS of interest based on the legacy AFFF formulations used at the Site include perfluorooctane sulfonate (PFOS), perflourooctanoic acid (PFOA), and perfluorohexane sulfonate (PFHxS). These substances are now known to be highly persistent in the environment and in humans and have the potential to bioaccumulate.

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This report presents the findings of the investigations undertaken to determine the nature and extent of Site-derived PFAS contamination, and Tier 1 (screening level) risk assessment of potential risks posed to human health and ecological receptors at the Site and in the broader Investigation Area. The investigation took place over an approximate 21-month period from December 2016 to September 2018. The investigations were undertaken in accordance with the general guidelines for the assessment of site contamination as outlined in the National Environment Protection (Assessment of Site Contamination) Measure 1999, as amended in 2013 [the ASC NEPM (NEPC, 1999)]. Analytical data collected during the investigation program were compared to the nationally recognised human health based and ecological guidance values (screening criteria) presented in the PFAS National Environmental Management Plan (NEMP) (HEPA, 2018).

In order to guide the investigations at the Site, initial works comprised a preliminary sampling program and comprehensive review of the storage, use, distribution, and disposal of legacy firefighting foams known to contain high concentrations of PFAS, otherwise known as Aqueous Film Forming Foam (AFFF). In addition, a review of previous environmental assessments relevant to potential PFAS contamination, establishment of the geo-environmental setting of the Site, surrounding land use, and identification of licensed groundwater supply bores within the Investigation Area was completed to enable development of a preliminary conceptual site model (CSM). The preliminary CSM described the potential linkages between sources of PFAS contamination, the potential pathways of exposure, and the human and ecological (environmental) receptors at potential risk of exposure. The preliminary CSM was then used to guide the development of a detailed sampling, analysis and quality plan (SAQP) to define the scope of work and data quality objectives (DQOs) for the Detailed Site Investigation (DSI).

Objectives

The primary objectives of the project were to determine the nature and extent of Site-derived PFAS contamination at the Site and surrounding areas, and to collect sufficient data to inform the undertaking of a Human Health and Ecological Risk Assessment (HHERA), if required.

Scope of Works

The following scope of work was undertaken to achieve the project objectives: • Completion of a targeted preliminary sampling program and development of a preliminary

CSM, including interviews with site personnel and targeted site inspections; • Review of the registered bores within the Investigation Area, including a detailed search of

groundwater extraction licences that may be associated with water supply bores; • Direct distribution of over 70 Water Use Survey (WUS) to licensed water supply bore owners

and members of the community to gather information relating to the nature of groundwater use in the Investigation Area, with a further 5,000+ residents and businesses invited to participate in the WUS as part of invitations to attend community information sessions (delivered via letterbox drops);

• Targeted sampling of soil, surface water, sediment, pore water, and groundwater across the Site and the broader Investigation Area in accordance with an approved SAQP, to determine the nature and extent of PFAS contamination in the various environmental media;

• Targeted sampling of concrete in selected primary source areas to understand the potential for these areas to act as a secondary source of contamination;

• Laboratory analysis of over 1,450 environmental samples for PFAS, comprising:

o 691 soil samples collected from 244 locations;

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o 549 groundwater samples collected from 241 locations;

o 120 surface water samples collected from 60 locations;

o 90 sediment samples collected from 73 locations;

o 4 sediment pore water samples from 4 locations; and

o 30 concrete samples collected from 30 locations; • Collection of 71 private property samples for analysis of PFAS, comprising:

o 21 water samples collected from private water supply bores, rainwater tanks, and dams where water was sourced for domestic and/or commercial use (e.g. irrigation);

o 28 soil samples collected from areas subject to historical inundation of stormwater originating from the Site and/or were irrigated with groundwater sourced from within the Investigation Area;

o 20 biota (wheat) samples collected from 10 locations within 1 property; and

o 2 water samples collected from former Defence groundwater monitoring wells now located on private property;

• Ongoing engagement with relevant project stakeholders, including the local community and businesses, local government (i.e. Councils), and state government agencies; and

• Preparation of this DSI report presenting the findings of the investigations, refinement of the preliminary CSM, and identification of potential risks to human health and ecological receptors associated with exposure to Site-derived PFAS contamination.

Environmental Setting

The Site and Investigation Area are located in the Northern Adelaide Plains area which comprises Quaternary and Tertiary aged sediments generated by the erosion of the Mount Lofty Ranges, located approximately 15km to the east. The sedimentary sequence in the Investigation Area comprises approximately 500m of Tertiary aged material overlain by approximately 100m of Quaternary aged sediments.

The main lithology within the Quaternary aged formations (the Pooraka Formation and the Hindmarsh Clay) typically comprises silty and sandy clays with isolated lenses of sand and gravel. These coarser units form a number of thin sub-aquifers separated by silt and clay aquitards. The shallowest of the Quaternary Aquifer units is the Q1 Aquifer, which may be semi-continuous and range from unconfined to semi-confined in nature. The Q1 Aquifer has generally been intersected at depths between 5 and 12m below ground level in the Investigation Area. The regional groundwater flow direction in the Q1 is in a general west to south-westerly direction.

Below the Q1 Aquifer are the Q2, Q3 and Q4 Aquifers which are typically intersected at depths ranging from 16 to 30m, 31 to 45m and 46 to 60m respectively. The Q2, Q3 and Q4 aquifers are also semi-continuous aquifers separated by clay and silt confining beds (i.e. aquitards). The Q4 Aquifer is also known regionally as the Carisbrooke Sand Aquifer. The regional groundwater flow direction within these aquifers is also expected to be in a general west to south-westerly direction, which has been observed for the Q2 Aquifer during the investigation.

The degree of vertical interconnection of the Quaternary aquifers is dependent upon the permeability and continuity of the intervening clayey aquitard materials. Where the aquitard material is absent or has lower resistance to vertical flow, interconnection of the successive aquifers can occur. The complexity of the Quaternary sequence and interconnection of individual lenses and layers of sands, clays, and silts means that groundwater is likely to move via preferential pathways

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through more permeable materials and has the potential to migrate vertically where interconnection between aquifers occurs.

Groundwater extraction from the Quaternary Aquifers within the Investigation Area is typically associated with lower volume domestic irrigation and stock water supply. There was no evidence gathered as part of the DSI to suggest this groundwater is currently being used as a potable water supply by anyone in the Investigation Area, noting the vast majority of residents and business are connected to mains (i.e. SA Water) supply. The information gathered from licensed water supply bore owners who completed a WUS indicated that the domestic use was typically associated with outdoor domestic use (e.g. irrigation of lawns and home-grown produce), with one respondent noting the use of bore water (groundwater) for flushing toilets.

The Tertiary sediments which underlie the Quaternary sediments comprise four confined aquifers designated T1 – T4, each of which may comprise various subaquifers. The majority of abstracted groundwater in the Adelaide metropolitan area, including the Northern Adelaide Plains, is obtained from the T1 Tertiary Aquifer. Within the Investigation Area, the T1 Aquifer is the primary aquifer used by market gardeners and commercial irrigators (i.e. high-volume irrigators). The T2 Aquifer, which is separated from the T1 Aquifer by a clay aquitard which has an approximate maximum thickness of 12m, is used in the Investigation Area by the City of Salisbury for Aquifer Storage and Recovery (ASR) operations. Once again, there was no evidence gathered as part of the DSI to suggest Tertiary Aquifer groundwater is being used as a potable water supply by anyone in the Investigation Area.

The topography of the Site and broader Investigation Area is relatively flat. Stormwater generated on Site is typically directed to the Helps Road Drain where it exits the Site across the southern boundary. There is a second stormwater discharge point across the southern boundary to the northwest of the Helps Road Drain (known as the Western Swale), however this typically receives much lower volumes of stormwater given the unsealed nature of the small sub-catchment in this area. Some of the stormwater in the Helps Road Drain on-Site is directed into the Southern Detention Basin (SDB) where it has historically been harvested for use in the Salisbury Council’s Edinburgh Park South ASR operations. Excess stormwater from the SDB that is not harvested by ASR operations is ultimately directed back to the Helps Road Drain.

Stormwater within the Helps Road Drain off-Site is directed to the Kaurna Park Wetland located approximately 2km south to southwest of the Site, entering the wetland at the north-eastern extent. Stormwater traverses through a meandering series of channels within the wetland prior to reaching a harvest point for the Salisbury Council’s Kaurna Park ASR operations. Stormwater that is not harvested as part of the ASR operations ultimately overflows from the wetland to the Helps Road Drain at the downstream discharge point, where it then continues downstream for some 7km before ultimately discharging to the Barker Inlet.

A graphical depiction of the aquifer units in the Investigation Area and major stormwater features and flow direction is depicted on Figure ES.2.

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Figure ES.2: Graphical Depiction of the Aquifers within the Investigation Area

Sources of PFAS Contamination

A total of 27 potential PFAS source areas were identified at the Site and were assessed during the DSI process. The results of the DSI confirmed 12 of these areas as representing a significant source of PFAS contamination, where environmental sample results exceeded the adopted human health and/or ecological guidance values (i.e. screening criteria relevant to the protection of human health or the environment). The confirmed source areas generally correlated with areas of current and former storage of AFFF concentrate and AFFF waste water, current and former firefighting training areas with a history of prolonged use of AFFF, and waste disposal areas. The source areas at the Site comprised the following:

1. The AFFF waste water retention tank (Building 521) and AFFF waste water evaporation pond, including soils in the vicinity of this infrastructure (Source Area P1).

2. The Site’s bulk fuel storage facility, including automated AFFF deluge system (Source Area P2).

3. The AFFF waste water retention infrastructure, identified as the Chesterfield Sumps, located at the eastern and western end of the Hangars (Source Area P3A and P3B). These sumps receive AFFF waste water generated during testing of automated AFFF suppression systems in the Aircraft Hangars.

4. The former fire training area and sub-surface waste dump in the central northern portion of the airside operations area (Source Area P4).

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5. The sub-surface waste dump located along the central portion of the western Site boundary (Source Area P8).

6. The current fire training area, including smokeroom training building (Building 618), located in the southern portion of the airside operations area near the Ordnance Unloading Area (Source Area P9).

7. Former sewage treatment plant (STP) and fire training area located in the most southern point of the airside operations area, adjacent to the Helps Road Drain discharge point across the southwestern Site boundary, and Southern Detention Basin (Source Area P10).

8. Current fire station and former AFFF concentrate storage area located near the new Air Traffic Control Tower (Source Area P11).

9. Former fire training area in the Ordnance Unloading Area, located in the southern portion of the airside operations area (Source Area P15).

10. Former fire training area around the Engine Run Up (ERUP) Facility, located to the northwest of the main apron (Source Area P16).

11. The approximate location of a historical train and semi-trailer crash, at the corner of the western and southwestern Site boundaries (Source Area P23), including the area up hydraulic gradient where historical discharge of AFFF may have occurred in the vicinity of the air craft wash down facility.

12. Suspected former fire training area adjacent to a parking area for aircraft refuelling tanker trucks, located to the west of the bulk fuel storage facility (Source Area P27).

In addition, significant groundwater contamination was identified in a groundwater monitoring well (GW2178) installed in the south-western portion of the airside operations area (up hydraulic gradient of source area P23), in relatively close proximity to the aircraft wash down facility known as the “Birdbath area”. This area was initially identified by Base firefighting personnel as a potential source area where historical testing of mobile firefighting equipment may have occurred but then was subsequently retracted during the 2017 on-Site interviews conducted by JBS&G. However, the groundwater results for GW2178 indicate that some historical discharge of AFFF may have occurred in this area and therefore may represent an additional source area.

In each of the source areas at the Site, the primary PFAS of concern comprised PFHxS and PFOS. The sum of these two PFAS compounds typically comprised the highest reported PFAS concentrations detected in the 28-analyte suite.

In addition to the primary source areas, surface water contamination exceeding the adopted human health and/or ecological screening criteria was identified in some areas of the stormwater drainage network throughout the Site, and the Helps Road Drain (on-Site). With the exception of a small number of isolated areas, significant sediment contamination was not identified throughout the on-Site drainage network. The location of the source areas at the Site and the extent of the major stormwater drainage features is depicted on Figure ES.3.

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Figure ES.3: Source Areas and Major Stormwater Drainage Features

Extent of PFAS Contamination in Soil

The soil investigations at the Site identified five source areas containing PFAS contamination present at levels above the adopted human health screening criteria applicable to commercial/industrial land use (i.e. >20 mg/kg for the sum of PFHxS and PFOS). The identified areas and associated maximum reported concentrations for the sum of PFHxS and PFOS are summarised below:

• Source Area P4 (Former Fire Training Area and Sub-surface Waste Dump) had concentrations ranging up to 161.8 mg/kg;

• Source Area P10 (Former STP and Fire Training Area) had concentrations ranging up to 45.6 mg/kg;

• Source Area P11 (Current Fire Station, including former AFFF Storage Area) had concentrations ranging up to 160.2 mg/kg;

• Source Area P15 (Former Fire Training Area in Ordnance Unloading Area) had concentrations ranging up to 34.71 mg/kg; and

• P16 (Former Fire Training Area around the ERUP Facility) had concentrations ranging up to 37.5 mg/kg.

Whilst soil investigations within source area P1 did not identify PFAS contamination in excess of the adopted human health screening criterion, sediment samples recovered from the base of the AFFF waste water evaporation pond in this area reported concentrations of the sum of PFHxS and PFOS

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up to 1,264 mg/kg. In addition, whilst soil investigations within source area P1 did not identify PFAS contamination in excess of the adopted human health screening criterion, the soil leachate results indicated soils in this area may represent a significant ongoing source of contamination to the nearby stormwater swales and underlying groundwater system. In addition, the targeted concrete sampling program identified the fire training building in this area as a potential ongoing source of PFAS contamination to surrounding areas.

Extent of PFAS Contamination in Groundwater

Widespread PFAS contamination has been identified in groundwater beneath and down hydraulic gradient of the Site that exceeds health based guidance values for drinking water, developed by the Australian Government, Department of Health (i.e. 0.07 µg/L for the sum of PFHxS and PFOS). To date, PFAS contamination has been confirmed in three of the four shallow Quaternary aquifers (i.e. Q1, Q2 and Q3) considered to be present in the Investigation Area. The highest reported concentration in the Q1 Aquifer on-Site was 23,100 µg/L for the sum of PFHxS and PFOS, measured in groundwater sampled from a monitoring well in Source Area P11, located adjacent to the former AFFF concentrate storage area (adjacent to the new air traffic control tower). The highest reported concentration for the sum of PFHxS and PFOS in groundwater sampled from the Q2 Aquifer on-Site was 1,540 µg/L, recovered from a monitoring well in Source Area P9 (Current Fire Training Area). The highest reported concentration in the Q3 Aquifer on-Site was 2.9µg/L in Source Area P9 (Current Fire Training Area).

The highest reported concentration for the sum of PFHxS and PFOS in the Q1 Aquifer off-Site was 24.6 µg/L, with concentrations of the sum of PFHxS and PFOS in the Q2 Aquifer and Q3 Aquifer reported up to 44 µg/L and 4.3 µg/L respectively.

The inferred groundwater flow direction in both the Q1 and Q2 Aquifers at the regional scale (i.e. Investigation Area level) is in a general west to south-westerly direction. In addition to the migration of PFAS contamination in the direction of groundwater flow, there is also evidence of significant groundwater contamination in the vicinity of the Southern Detention Basin, Helps Road Drain and Kaurna Park Wetland. There is an apparent radial spread of PFAS contamination away from these unlined surface water (stormwater) features which suggests that, at least historically, surface water discharging from the Site has provided a significant secondary source of contamination to the underlying groundwater system. The more recent surface water sampling program (i.e. DSI) results do not tend to correlate with the degree of contamination observed in the shallow Quaternary aquifers within the vicinity of these features, which supports a conclusion that historically the concentrations of PFAS in surface water discharging from the Site would have been significantly higher. The inferred lateral extent of PFAS contamination in the Q1 and Q2 Aquifers off Site extends approximately 6km to the southwest of the Site and approximately 1km to the west of the Site.

To date, no PFAS contamination has been identified in the deeper T1 Tertiary Aquifer, the primary aquifer used by market gardeners and commercial irrigators throughout the Investigation Area. This is based on results from private T1 Aquifer water supply bores where consent for sampling was given, and T1 Aquifer Council bores targeted for sampling within or in relatively close proximity to the Investigation Area.

It is noted that PFAS contaminated groundwater may exist in the T2 Tertiary Aquifer as a result of the injection of PFAS contaminated surface water during the operation of the Salisbury ASR scheme. The extent of any such contamination is considered to be restricted to the Edinburgh Park South bores that inject water sourced from the SDB, and the Kaurna Park ASR bores that inject water sourced from the Kaurna Park Wetland. Following the discovery of minor PFOS impacts in water sourced from these bores in July 2016 (above the current Health Based Guidance Values for Drinking Water), the bores were isolated from the ASR distribution network and water supply from these

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bores does not currently occur. It is understood that all other bores in the City of Salisbury ASR network did not detect PFAS above the laboratory limit of reporting (LOR) and/or the current Health Based Guidance Values for Drinking Water (DoH, 2017). It was beyond the scope of this DSI to assess impacts associated with the operation of the City of Salisbury ASR scheme within the Investigation Area.

Extent of PFAS Contamination in Surface Water and Sediment

Surface water contamination that exceeded the adopted human health screening criteria relevant to recreational water (i.e. 0.7 µg/L) was limited to on-Site areas. The potential risks associated with exposure to PFAS contaminated surface water at the Site will be addressed as part of the HHERA.

Surface water samples collected in all off-Site areas investigated did not identify PFAS contamination above the recreational screening criteria. However, PFAS contamination exceeding the adopted ecological screening criteria for freshwater (i.e. 0.13 µg/L for PFOS) was identified in samples collected from throughout the Kaurna Park Wetland, and a sample location upstream of the wetland in the Helps Road Drain.

The DSI also identified concentrations of PFAS in surface water exceeding the ecological screening criteria for freshwater in samples collected at the downstream extent of the Helps Road Drain, near the discharge point into the Barker Inlet. It is possible that these impacts may have been contributed to by an unidentified off-Site source or existing PFAS contamination in the Barker Inlet. An investigation undertaken by the South Australian Environment Protection Authority in 2017 assessing PFAS in the marine environment (SA EPA, 2017) indicated that the Barker Inlet represents a surface water body impacted by multiple sources of PFAS contamination. Although the Site appears to represent a contributing source of PFAS contamination to Barker Inlet, it is considered impractical to determine the relative contribution from the Site versus other sources.

The results of the sediment sampling program within the stormwater drainage network across the Site and the broader Investigation Area, including throughout the Kaurna Park Wetland, did not identify PFAS concentrations exceeding the adopted Tier 1 human health screening criteria (i.e. >20 mg/kg for the sum of PFHxS and PFOS). The highest reported sediment concentration was 3.28 mg/kg for the sum of PFHxS and PFOS, reported in a sample collected from a swale drain near the front of the on-Site fire station (within Source Area P11).

Contaminant Transport Mechanisms and Migration Pathways

Leachate analysis conducted on soil and concrete samples recovered throughout the DSI showed that the key analytes of interest, namely PFOS and PFHxS, were readily leached from the samples under neutral leaching conditions (i.e. simulating rainfall). These results indicate that the source areas at the Site will present an ongoing source of contamination to nearby stormwater drainage features (including the Helps Road Drain), and the underlying shallow groundwater system.

Due to the persistence of PFAS in the environment, when PFAS contamination enters surface water and groundwater it can migrate long distances in the direction of flow. Evidence of off-Site migration of PFAS in both surface water and groundwater discharging from the Site was confirmed by the DSI sampling program. Given the presence of numerous significant soil and concrete source areas across the Site, some of which are in relatively close proximity to stormwater drainage features and/or the Site boundary, and existence of significant contamination in groundwater beneath the Site, it is reasonable to expect that PFAS contamination will continue to migrate from the Site in the absence of suitable remediation measures.

In addition to the lateral migration of PFAS contamination in groundwater, the DSI sampling program identified vertical migration of PFAS contamination through the shallow Quaternary aquifers

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beneath and down hydraulic gradient of the Site. To date, PFAS contamination has been confirmed to extend to the Q3 Aquifer in some areas. Field observations, groundwater analytical results, and assessments of water chemistry have indicated a varying degree of hydraulic connectivity between the Q1 and Q2 Aquifers. Given the identification of PFAS contamination in the Q3 Aquifer, both on and off-Site, it is considered there is also a degree of hydraulic connectivity between the Q2 and Q3 Aquifers, although this is likely to vary throughout the Investigation Area. It is not yet known if there is interconnectivity between the Q3 and Q4 Aquifers, however additional groundwater investigations being conducted at the time of this report will seek to determine if PFAS contamination has extended to the underlying Q4 Aquifer. The results of these investigations will be reported in an addendum to the DSI Report.

The major stormwater drainage features throughout the Site and the broader Investigation Area (in areas that receive stormwater from the Site), are unlined stormwater drains and detention basins. These features are likely to have a high degree of leakage (i.e. seepage) given their unlined nature, providing a migration pathway for contaminated surface water to enter the underlying shallow groundwater system. Whilst the leakage rates are not known, it is suspected that they would be relatively high given the lateral extent of the features. Evidence of significant groundwater contamination in the vicinity of the Southern Detention Basin, Helps Road Drain (on and off-Site) and Kaurna Park Wetland, with an apparent radial spread of PFAS contamination away from these features (as noted above), supports this conclusion.

Potential Risks to Human Health and Ecological Receptors

Based on the results of the DSI, the following receptors that may be exposed to PFAS contamination are considered to exist at the Site:

• Defence personnel and contractors working at the Base; • Intrusive maintenance workers and construction workers, including workers performing

maintenance in the stormwater network; and • Visitors to the Site (including children).

The following receptors that may potentially be exposed to Site-derived PFAS contamination are considered to exist in the broader Investigation Area:

• Members of the public (limited to the potential exposure pathways identified below); • People who may be catching and consuming edible biota (e.g. yabbies, fish) from the Kaurna

Park Wetland; • Off-Site users and consumers of groundwater; • Terrestrial and aquatic fauna (e.g. birds).

The ways in which the receptors identified above may be exposed to Site-derived PFAS contamination (i.e. the exposure pathways) are considered to be limited to the following:

On-Site • Direct contact or incidental exposure to PFAS contaminated soil and surface water.

Off-Site • Direct contact or incidental exposure during irrigation or use of PFAS contaminated

groundwater for domestic activities, recreational activities, or commercial activities (including potential for inhalation of spray mist) – not yet confirmed to have occurred;

• Direct contact or incidental exposure to soils irrigated with PFAS contaminated groundwater (i.e. sourced from the Quaternary Aquifers) – not yet confirmed to have occurred;

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• Consumption of crops, market garden and home-grown produce irrigated with PFAS contaminated groundwater (i.e. sourced from the Quaternary Aquifers) – not yet confirmed to have occurred;

• Consumption of livestock (e.g. cattle, sheep, chickens), milk, and eggs where PFAS contaminated groundwater has been used as water supply for livestock (i.e. sourced from the Quaternary Aquifers) – not yet confirmed to have occurred;

• Consumption of edible aquatic biota caught from the Kaurna Park Wetland; and • Consumption of honey produced in bee hives located within, or in reasonable proximity to,

the Investigation Area.

Ecological • Direct contact with surface water contamination in the Kaurna Park Wetland exceeding the

adopted ecological screening criteria; • Ingestion of surface water contaminated by Site-derived PFAS contamination; and • Ingestion of flora and fauna affected by Site-derived PFAS contamination (bioaccumulation).

The potential for Site-derived PFAS contamination to present unacceptable risks to the identified receptors as a result of these potential exposure pathways will be considered as part of HHERA. At the time of this report, works were progressing in relation to the HHERA process with the findings to be reported in a standalone HHERA Report.

For full details regarding the assessment of source, pathway, receptor linkages assessed during the DSI program, including those assessed as being incomplete, please refer to the DSI Report body.

Next Steps

The recommended next steps to address the issues associated with Site-derived PFAS contamination comprise the following:

• Complete the remaining groundwater investigations to determine the vertical extent of PFAS contamination in groundwater beneath and down hydraulic gradient of the Site;

• Preparation of a DSI Addendum Report to include additional data gathered as part of the ongoing groundwater investigations undertaken to address the data gap of whether vertical migration of PFAS contamination to the Q4 Aquifer has occurred beneath the Site or in the broader Investigation Area;

• Complete the HHERA process, including execution of the HHERA-specific sampling program; • Prepare a PFAS Management Area Plan (PMAP) which identifies appropriate management

actions to address potential risks associated with human health and/or ecological receptor exposure to Site-derived PFAS contamination, and that seeks to mitigate off-Site migration of PFAS;

• Prepare and implement an ongoing monitoring program (OMP) to assess the ongoing migration of PFAS contamination in groundwater and surface water, and measure the success of implemented mitigation actions (to be included in the PMAP).

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1. Introduction

JBS&G Australia Pty Ltd (JBS&G) was engaged by the Department of Defence (Defence) to undertake a detailed environmental investigation of per- and poly-fluoroalkyl substances (PFAS) contamination at the Royal Australian Air Force (RAAF) Base Edinburgh (the Site) and surrounding areas, collectively identified as the Investigation Area. The Site is located in the northern metropolitan area of Adelaide, South Australia. A site location plan is provided as Figure 1 (attached).

An independent Site Contamination Auditor accredited by the South Australian Environment Protection Authority (SA EPA) has been engaged by Defence to complete a review of the environmental investigations completed by JBS&G.

1.1 Background

RAAF Base Edinburgh has been subject to previous investigations that have identified contamination as a result of the historical use of legacy Aqueous Film Forming Foam (AFFF) that contained PFAS. AFFF has primarily been used at the Site in firefighting training exercises and for use in emergency response events to extinguish liquid fuel-based fires. The key PFAS of interest based on the legacy AFFF formulations used at the Site include perfluorooctane sulfonate (PFOS), perflourooctanoic acid (PFOA), and perfluorohexane sulfonate (PFHxS). These substances are now known to be highly persistent in the environment and in humans and have the potential to bioaccumulate.

Based on results from previous investigations at the Site, there was strong evidence to suggest that PFAS compounds may have migrated off Site, particularly in surface waters, resulting in a potential exposure pathway to water users and ecological receptors. As a result, Defence commissioned a detailed investigation to understand the nature and extent of PFAS contamination at the Site and in the surrounding Investigation Area. The ultimate objective of this investigation was to understand whether Site-derived PFAS contamination has the potential to pose an elevated risk to human and/or ecological receptors.

1.1.1 Legacy AFFF

The main legacy AFFF product used at the Site was 3M Light WaterTM, which is known to contain high concentrations of PFAS, particularly those with a C8 carbon chain length (i.e. PFOS). The use of this legacy AFFF product commenced at the Site in 1978 (Defence, 2016a). In 2003, Defence became aware of environmental concerns associated with the use of 3M Light WaterTM, as documented in a report prepared by the former Defence Environmental Stewardship, Environment, Heritage and Risk Branch titled Environmental Issues Associated with Defence Use of Aqueous Film Forming Foam (AFFF) (Colville and McCarron, 2003). This report identifies that the 3M Light WaterTM product contained non-biodegradable fluorosurfactants (now referred to as PFAS) that are environmentally persistent, bioaccumulative, and toxic.

PFAS are an emerging contaminant of concern around the world and may potentially cause adverse impacts to human health and / or the environment when exposure occurs. On 26 August 2010, an amendment to Annex B of the Stockholm Convention on Persistent Organic Pollutants (POPs) to include PFOS, its salts and perfluorooctane sulfonyl fluoride (PFOSF) as POPs came into effect. This amendment to the Convention noted that the production and use of these chemicals should be restricted.

In 2005, Defence commenced the phase out of legacy AFFF at the Site, transitioning to the use of Ansulite (Defence, 2016a). Ansulite is an AFFF which is understood not to contain PFOS or PFOA as active ingredients. The transition began with the replacement of legacy AFFF in mobile fire vehicle units, followed by the replacement of legacy AFFF throughout the automated fire suppression systems located in a number of aircraft hangars at the Site between 2007 and 2009. The final bulk


volume of legacy AFFF concentrate stored at the Site (in the deluge system installed at the Bulk Fuel Store) was decanted and replaced with Ansulite in December 2013 (Defence, 2016a).

1.2 Project Objectives

The primary objectives of the project are to:

13. Conduct detailed environmental investigations to determine the nature and extent of Site-derived PFAS contamination at the Site and surrounding areas;

14. Collect sufficient data to inform the undertaking of a Human Health and Ecological Risk Assessment (HHERA); and

15. Identify appropriate response management actions to address potential risks associated with human health and/or ecological receptor exposure to Site-derived PFAS contamination.

This report focuses on the first two project objectives. The third project objective will be addressed in a separate document identified as the PFAS Management Area Plan (PMAP) to be produced following completion of the preliminary HHERA process.

1.3 Assessment Process

This detailed site investigation (DSI) report presents the findings of comprehensive environmental investigations undertaken to determine the nature and extent of Site-derived PFAS contamination, and Tier 1 (screening level) risk assessment of potential risks posed to human health and ecological receptors. These investigations have been undertaken in accordance with the general guidelines for the assessment of site contamination as outlined in the National Environment Protection (Assessment of Site Contamination) Measure 1999, as amended in 2013 [the ASC NEPM (NEPC, 1999)].

In response to the project objectives and in consideration of defined project priorities, the following staged approach to the detailed environmental investigation was undertaken:

Preliminary Assessment: The first stage of the detailed environmental investigation comprised a targeted assessment of surface water and sediment in major stormwater drainage channels within and downstream of the Site, completed between December 2016 and February 2017. These works were undertaken to assess whether there were any elevated risks to Defence personnel and/or the wider community associated with exposure to PFAS contamination at the Site, and migrating from the Site, that required immediate management. Targeted groundwater sampling of registered groundwater supply bores within the initial Investigation Area was also proposed at up to 10 of the highest priority locations, being those associated with a licence to extract water for domestic use. The ability to sample the targeted priority bores was subject to consent being given by a landowner to collect a sample, which was not available at the time the preliminary assessment program was completed. This work was subsequently incorporated into the DSI program at a later date.

Preliminary Conceptual Site Model: A preliminary conceptual site model (CSM) report (JBS&G, 2017a) was prepared which included a comprehensive review of the storage, use, distribution and disposal of legacy AFFF on-Site, previous environmental assessments relevant to PFAS, a summary of potential source-pathway-receptor (S-P-R) linkages and an assessment of data gaps relating to understanding the nature and extent of PFAS contamination on and off-Site. The preliminary CSM also contained a summary of information relating to site characteristics and geo-environmental setting, surrounding land use, and registered groundwater supply bores within the Investigation Area.

Sampling, Analysis and Quality Plan: A detailed sampling, analysis and quality plan (SAQP) was prepared to define the scope of work and data quality objectives (DQOs) related to the DSI works (JBS&G, 2017b). The SAQP also outlined additional information gathered following the development of the preliminary CSM report relating to potential PFAS source areas across the Site. This


information was collected through interviews with Base firefighting personnel, and subsequent targeted site inspections. An addendum to the SAQP was prepared in February 2018 to define additional scope performed as part of the Stage 2B DSI program (JBS&G, 2018a).

Detailed Site Investigation: The DSI has been completed as a staged approach and has been implemented in accordance with the SAQP (including Addendum 1). The initial DSI program was completed between April and October 2017, referred to as Stage 2A. Additional DSI works were undertaken between January and September 2018 to address data gaps and incomplete DQOs that remained following completion of the Stage 2A program. This next stage of works is referred to as Stage 2B. It should be noted that at the time of this report groundwater investigations are ongoing to better define the vertical and lateral extent of PFAS contamination. Private property sampling works continued between execution of the Stage 2A and Stage 2B sampling programs.

Human Health and Ecological Risk Assessment (HHERA): At the time of this report, works are progressing in relation to a detailed HHERA. The methodology for the HHERA and the associated HHERA-specific sampling program have been detailed in separate stand-alone documents (JBS&G, 2018b and JBS&G, 2018c)

Stakeholder and Community Engagement: Ongoing stakeholder and community engagement activities have occurred through the comprehensive environmental investigation program and will continue beyond the DSI phase. These activities have included community walk in sessions to provide project progress updates at approximate 6-monthly intervals, engagement with registered water supply bore owners, and periodic updates to local and state government agencies.

1.4 Scope of Work

The scope of work undertaken prior to and throughout the DSI program included the following:

• Completion of a targeted preliminary sampling program;

• Development of a preliminary CSM, including review of available historical information relevant to the historical use, storage and disposal of AFFF at the Site, and interviews with site personnel and targeted site inspections;

• Review of the South Australian Department for Environment and Water (DEW) WaterConnect Database to identify registered bores within the Investigation Area, including a detailed search for groundwater extraction licences that may be associated with water supply bores;

• Distribution of a Water Use Survey (WUS) to licensed water supply bore owners to gather information relating to the nature of groundwater use in the Investigation Area and validate the desktop review of licensed water supply bores;

• Private property sampling works, principally targeting water supply bores within the Investigation Area, areas potentially irrigated with PFAS contaminated groundwater, and areas potentially affected by the historical discharge of PFAS contaminated surface water across the Site boundary;

• Development of a detailed SAQP to guide the DSI program, including a subsequent addendum to define additional works required to meet the established project DQOs;

• Execution of the DSI sampling program in accordance with the SAQP, including Addendum 1;

• Targeted sampling of concrete in selected primary source areas;

• Submission of recovered environmental samples for analysis of PFAS, and selected samples for analysis of non-PFAS contaminants of potential concern (COPC) and physical properties;


• Ongoing engagement with relevant project stakeholders, including the local community and businesses, local government (i.e. Councils), and state government agencies;

• Preparation of this DSI report, including update and refinement of the preliminary CSM.

1.5 Legislation, Legislative Instruments and Relevant Contaminated Sites Guidance Documents

The DSI was undertaken in accordance with, or with consideration of, the following legislation, legislative instruments, guidance documents, and information sheets, as relevant:

• South Australia Environment Protection Act 1993 (the EP Act);

• South Australia Environment Protection Regulations 2009;

• National Environment Protection (Assessment of Site Contamination) Measure 1999 (as amended 2013), National Environment Protection Council (NEPC), 1999 (NEPC, 1999);

• PFAS National Environmental Management Plan (NEMP), Heads of EPAs Australia and New Zealand (HEPA), January 2018 (HEPA, 2018);

• South Australia Environment Protection (Water Quality) Policy 2015, amended January 2018 (WQEPP 2015);

• SA EPA Site Contamination – Guidelines for the assessment and remediation of groundwater contamination (SA EPA, 2009)1;

• SA EPA Guidelines for the assessment and remediation of site contamination (SA EPA, 2018);

• SA EPA Regulatory Monitoring and Testing: Groundwater Sampling (SA EPA, 2007);

• SA EPA Site Contamination – Assessment of background concentrations, updated July 2018 (SA EPA, 2018);

• Defence Contamination Directive (DCD) #8 (Version 2) – Screening Guidelines, Defence Project Guidance for Per- and Poly-Fluoroalkyl Substances (PFAS), Department of Defence, 13 March 2018 (Defence, 2018a)

• Health Based Guidance Values for PFAS, Australian Government, Department of Health (DoH), April 2017 (DoH, 2017);

• Contaminated Sites Guideline: Interim Guideline on the Assessment and Management of Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS), Government of Western Australia Department of Environment Regulation (WA DER), January 2017 (WA DER, 2017);

• Draft Commonwealth Environmental Management Guidance on Perfluorooctane Sulfonic Acid (PFOS) and Perfluorooctanoic Acid (PFOA), Australian Government, Department of Environment and Energy (DoEE), October 2016 (DoEE, 2016);

• Draft PFAS Screening Criteria (May 2017), NSW Office of Environment & Heritage (OEH), May 2017 (OEH, 2017);

• Environmental Health Risk Assessment: Guidelines for assessing human health risks from environmental hazards (enHealth, 2012);

• Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC and ARMCANZ, 2000);

• Australian Drinking Water Guidelines (NHMRC and NRMMC, 2011);

1 It should be noted that this guideline has been superseded by the Guidelines for the assessment and remediation of site

contamination (SA EPA, 2018)


• Guidelines for Managing Risks in Recreational Water (NHMRC, 2008); and

• Australian/New Zealand Standard, Water Quality – Sampling Guidance on Sampling of Rivers and Streams (AS/NZS 5667.6:1998).


2. The Site and Investigation Area

2.1 Site Identification and Land Use

RAAF Base Edinburgh (the Site) is located in Edinburgh, South Australia, approximately 25 km north of the Adelaide central business district (CBD). The location of the Site is shown on Figure 1 (attached).

The Defence Estate Base Plan, Base Overview produced for the Edinburgh Defence Precinct (EDP) (Jacobs, 2016a) identifies RAAF Base Edinburgh as occupying an area of 1,077 hectares (ha) and containing the following major features:

• An airfield;

• Airfield navigational aids;

• Explosive ordnance (EO) areas;

• Fuel farm;

• Maintenance buildings;

• Hangars and aprons;

• Recreational, minor retail and training facilities;

• Working accommodation (e.g. temporary), living-in accommodation (LIA), and messing facilities;

• North East Defence Community Centre; and

• Open space used as an airfield buffer.

The approximate locations of the major Site features identified above are depicted on Figure 2 (attached).

The North East Defence Community Centre located on Site provides playgroup services for children up to the age of 5 and hosts family days, however does not provide permanent childcare services. The current LIA and temporary accommodation at the Site does not provide facilities for family members to reside on Base (i.e. spouses and children do not reside on Site).

RAAF Base Edinburgh also accommodates a large Army contingent located centrally on the Base, with associated features comprising office, vehicle and hangar buildings, two small arms firing ranges and large areas of hardstand. There is a close training area that contains an urban training facility, driver training track, obstacle course, open areas for dismounted training, and an engineer training area (Jacobs, 2016).

The EDP Zone and Precinct Plan developed in 2007 and summarised in the Defence Estate Base Plan, Base Overview, categorises Defence functions and activities in the EDP into six overarching zones, comprising:

• Operational – functions that are the key function of the EDP, i.e. runways and taxiways, air traffic control tower, air movements, hangar and flight line facilities for RAAF operations, and deployable front-line Army units;

• Operational Support – functions that provide support to the key operations of the EDP or operational units, such as flight support operations, workshops, force element working accommodation, Capability Acquisition and Sustainment Group (CASG) elements, and research and development;


• Base Support – functions required to support the general operations of the Base, including base command units, medical, contractors, administration, office functions, shop fronts, mail centre, common user facilities (e.g. messing, physical fitness, and commercial), Defence support, and training;

• Domestic – functions required by living-in personnel such as LIA, messing, and physical fitness facilities;

• Future Development – can be rezoned to any of the above functional zones in the future;

• Open – functions that require land relatively clear of structures, such as close training areas, passive security, and ranges or conservation.

The approximate extent of the relevant zones across the Site are also depicted on Figure 2. It should be noted that the majority of the Site is considered to represent general commercial/industrial land use (as per the ASC NEPM land use classifications), with the exceptions being the domestic areas which represent residential land use (equivalent to ASC NEPM residential land use with minimal opportunities for soil access) and the recreational areas (equivalent to ASC NEPM public open space such as parks, playgrounds, playing fields etc.). Further discussion regarding the land use at the Site that has been considered in the adoption of appropriate screening criteria for assessment of PFAS analytical results is discussed in Section 10.

A summary of the Site location, owner and occupier details, local government area and council zoning is provided in Table 2.1.

Table 2.1: Site Details Category Details Defence Property ID 0939 Street Address West Avenue, Edinburgh, South Australia Certificates of Title (CTs) CT Volume 6114 Folio 320, CT Volume 5870 Folio 504,

CT Volume 6052 Folio 298, CT Volume 5942 Folio 911, CT Volume 5847 Folio 156, CT Volume 5420 Folio 865, CT Volume 5133 Folio 7

Site Owner Commonwealth of Australia Site Occupier Department of Defence Area of Site Approximately 1,080 hectares, including recently acquired

land to accommodate the northern runway extension for the AIR 7000 Project

Local Government Area City of Salisbury and City of Playford Zoning The Site is excluded from Council zoning

2.2 Investigation Area

The current (refined) Investigation Area includes the Site and an off-Site investigation area as shown on Figure 3 (attached). The Investigation Area was developed in accordance with the Defence guidelines for Investigation Area establishment (Defence, 2017a), which exclude the consideration of background locations from the establishment of the Investigation Area.

The Investigation Area was targeted to areas that may have been affected by Site-derived PFAS contamination that has the potential to present an unacceptable risk to human and/or environmental receptors, and which can be distinguished from other off-Site sources of PFAS contamination. As such, the off-Site lateral extent of the Investigation Area was focussed on the following:

• Areas considered to be located hydraulically downgradient from the Site based on groundwater flow direction in the shallow Quaternary aquifers (inferred to be west to south-west from the western portion of the Site and south to southwest from the southern portion of the Site);


• Areas downstream of the major stormwater drainage channel passing through the Site (identified as the Helps Road Drain); and

• The Kaurna Park Wetland (which receives water from the Helps Road Drain) and areas further downstream to the stormwater discharge point at the Barker Inlet of the Gulf St Vincent, including an offset area to account for the potential of surface water acting as a secondary source of impact to shallow groundwater.

The Investigation Area was refined in April 2018, following the completion of the Stage 2A program and during execution of the Stage 2B program, on the basis of off-Site surface water and groundwater sampling results that identified Site-derived PFAS contamination beyond the extent of the initial Investigation Area. The extent of the original Investigation Area is also shown on Figure 3. It is possible that the off-Site portion of the Investigation Area may be further refined in the future as a result of ongoing groundwater investigations, some of which are occurring beyond the extent of the Investigation Area.

The off-Site portion of the Investigation Area comprises parts of the suburbs of Penfield, Direk, Burton, Salisbury North, Paralowie, Waterloo Corner, St Kilda and Bolivar. The suburb boundaries relative to the Investigation Area are shown on Figure 3 (attached).

As noted above, investigations undertaken to assess background surface water and groundwater quality have been completed outside the extent of the Investigation Area. These investigations targeted areas outside of the Investigation Area in locations considered to be unaffected by Site-derived PFAS contamination (i.e. areas considered upstream and up hydraulic gradient of the Site).

Details regarding the vertical extent of the investigation are provided in Section 8.1.3.

2.3 Surrounding Land Use and Zoning

A figure showing the Council land use zoning within the Investigation Area, based on information sourced from the relevant Council Development Plans2, is provided as Figure 4 (attached). A general summary of the current land uses adjacent to the Site is provided below:

• North: A child care facility is located within 200 m of the Site boundary (on Argent Road). Industrial, agricultural, and recreational land uses are located to the north of the Site, with low-density residential land to the northeast.

• East: Industrial, residential and commercial properties are located to the east of the Site, including the Defence Science and Technology Group (DSTG) site located immediately southeast.

• South: Agricultural (Primary Production), industrial, commercial and residential properties are located to the south of the Site, with some areas designated open space (e.g. the Kaurna Park Wetland).

• West: Agricultural (Primary Production) and industrial (Urban Employment) land uses are located to the west of the Site, with some low-density residential land use.

Broadly, the Primary Production areas off-Site include broad acre cultivation of edible produce (e.g. wheat, vegetables) interspersed with more intensive market garden and hydroponic farming of fruits and vegetables, and smaller scale hobby farms used primarily for domestic scale production of edible produce. In addition, there are several properties that are used for domestic and commercial horse training activities to the north and west of the Site, one property known to be used as a dog breeding facility to the west of the Site, and two properties suspected to be keeping bees for domestic scale honey production located to the north of the Site (one confirmed through results of a

2 Downloaded via the South Australian Government Data Directory, URL: https://data.sa.gov.au/

https://data.sa.gov.au/


WUS). Groundwater is known to be used within the Primary Production areas for both domestic and commercial use (e.g. irrigation), which is discussed further in Section 3.2.5.2.

The public open space areas located within the Investigation Area, to the south-southwest of the Base, comprise the Kaurna Park Wetland and constructed water and wetland features of the Springbank Waters residential estate (refer Figure 4, attached). Whilst information gathered throughout the DSI has indicated that the wetlands are not used by members of the public for swimming, anecdotal information provided by several sources (including members of the public and Council staff) has indicated that recreational fishing and catching of yabbies from the Kaurna Park Wetland for possible consumption may be occurring.


3. Environmental Setting

3.1 Geology

3.1.1 Regional Setting

The Site and Investigation Area are located in the Northern Adelaide Plains area which comprises sediments generated by the erosion of the Mount Lofty Ranges, located approximately 15km to the east. The Mount Lofty Ranges comprise Proterozoic aged sedimentary rocks, which were metamorphosed, folded and faulted during Palaeozoic times. The sedimentary sequence in the region varies substantially between the eastern and western side of the Para Fault and this fault defines the boundary between the upper and lower Alluvial Plains. West of the fault (the Investigation Area) the sedimentary sequence is approximately 600m thick, while east of the fault the sequence is relatively thin (Bowman & Sheard, 1996). This sedimentary sequence typically comprises approximately 500m of Tertiary aged material overlain by approximately 100m of Quaternary aged sediments.

3.1.2 Quaternary Units

The two main Quaternary aged units in the region are the Pooraka Formation and Hindmarsh Clay. Generally, the Pooraka Formation (where present) overlies the Hindmarsh Clay in this region. These units are further underlain by the Carisbrooke Sand.

The Quaternary aged sediments comprise a mixture of alluvial fan and streambed deposits with mottled clay and silt predominating, but with interbedded sand and gravel layers which form aquifers (DfW, 2010). The Quaternary aquifers are complex due to the interconnection of individual lenses and layers of gravels, sands, clays, and silts. This presents a complex 3-dimensional groundwater flow regime where the mechanisms of contaminant transport are likely to be defined by preferential flow paths through more permeable materials and retardation of contaminant migration through less permeable materials. These complexities complicate the interpretation of contaminant migration within, and between, the Quaternary aquifers.

The Late Pleistocene aged (~35 000 years old) Pooraka Formation is highly variable and consists of sandy clay and clayey to sandy silt, with interbeds and layers of clay, sand, gravel, pebbles, cobbles and boulders. The thickness of the Pooraka Formation is highly variable given its deposition over pre-existing topography and subsequent erosion, but typically ranges from 6 to 8m depth west of the Para Fault (Bowman & Sheard, 1996).

The Hindmarsh Clay is a stiff, highly plastic, pale grey or brown clay, which underlies the Pooraka Formation and extends to a maximum depth of approximately 100m. The Hindmarsh Clay also contains sandy, silty, micaceous or gravelly materials, forming lenses where fluvial influences have been pronounced (Bowman & Sheard, 1996).

The Carisbrooke Sand typically comprises the deepest of the Quaternary aged sediments in the region. The Carisbrooke Sand is a quartz sand, of medium to coarse grain size, with a minor silt and clay component illuviated from the overlying Hindmarsh Clay (Bowman & Sheard, 1996).

3.1.3 Tertiary Units

The deposition of Tertiary aged sediments occurred regionally during the Middle Eocene, commencing with river-deposited sands identified as the North Maslin Sand (Bowman & Sheard, 1996). The North Maslin Sand is overlain by carbonaceous and silty clays of the Clinton Formation which is further overlain by the South Maslin Sand formation comprising glauconitic marine sands.

Overlying the South Maslin Sand is the Chinaman Gully Formation, comprising lignitic silt and clays, with sandy layers (DfW, 2010), and the Blanche Point Formation comprising fossiliferous and glauconitic marls, siltstone and limestone.


The most recent Tertiary sediments, and the most significant from a regional groundwater use perspective, comprises the Hallett Cove Sandstone and Dry Creek Sand, and the underlying Port Willunga Formation. The Hallett Cove Sandstone and Dry Creek Sand units comprise limestone, calcareous sandstone and sands of marine deposition (DfW, 2010). The underlying Port Willunga Formation is separated into two units – the upper and lower formations – by Munno Para Clay. The Port Willunga Formation comprises fossiliferous limestone with sands and sandstones, grading to a dense siliceous unit towards the base of the lower formation. The Munno Para Clay is an aquitard unit within the Port Willunga Formation and comprises sandy, shelly clay (DfW, 2010).

3.2 Hydrogeology

3.2.1 Regional Setting

The Site and Investigation Area are located within the Northern Adelaide Plains Prescribed Wells Area. Groundwater of varying natural quality (e.g. conductivity) occurs within several aquifer systems present across the Northern Adelaide Plains. The properties of the regional aquifers are discussed below. The water bearing zones of the Quaternary sediments are likely to be contained within the more permeable sediments, which may be discontinuous and with variable connectivity spatially. As mentioned previously, the mechanisms of contaminant transport are likely to be defined by preferential flow paths through the more permeable materials, with retardation of contaminant migration through less permeable materials.

A conceptual understanding of the hydrogeology in the vicinity of the Site and the Investigation Area has been developed based on previous investigations at the Site (e.g. GHD, 2014a and GHD, 2016) and the Department of Water, Land and Biodiversity Conservation (DWLBC) Report Overview of the hydrogeology of the Adelaide metropolitan area (Gerges, 2006), and the Department for Water (DfW) Report Northern Adelaide Plains PWA, Groundwater Level and Salinity Status Report 2009–2010 (DfW, 2010). The regional stratigraphy and hydrostratigraphy (adopted from DfW, 2010 and with consideration of Gerges, 2006 and Bowman & Sheard, 1996) is summarised in Table 3.1.


Table 3.1: Regional Stratigraphy and Hydrostratigraphy of the Northern Adelaide Plains

Age Epoch Stratigraphy Hydrostratigraphy

Unit Lithology Unit Description Quaternary Late to Early

Pleistocene Pooraka Formation

Sandy clay and clayey to sandy silt, with interbeds and layers of clay, sand, gravel, pebbles, cobbles and boulders.

Q1 Aquifer Q2 Aquifer Q3 Aquifer

Up to three semi-confined aquifers. Relatively saline groundwater, except near streams, and low yields. Domestic and stock use.

Hindmarsh Clay Fluviatile and alluvial clays and silts, with interbedded sands and gravels in outwash areas.

Pliocene/ Pleistocene

Carisbrooke Sand

Fluviatile, alluvial, multicoloured fine sands and silts with some clay and thin gravel beds in outwash areas.

Q4 Aquifer Confined aquifer; not widely developed because of low yields. Possible hydraulic connection with T1 Aquifer in some areas (near Little Para River).

Tertiary Late Pliocene Hallett Cove Sandstone, Dry Creek Sand and Croydon Facies

Limestone, calcareous sandstone and sands of marine deposition. Usually abundantly fossiliferous.

T1 Aquifer T1a Confined aquifer; developed for irrigation stock and domestic purposes.

Middle Miocene Port Willunga Formation (upper)

Fossiliferous sandy limestone, fine grained. T1b Confined aquifer; developed mainly for irrigation. Salinity ranges between 500–3000 mg/L.

Munno Para Clay

Blue-grey, sandy, shelly clay, missing in some coastal areas

Aquitard Confining bed for the T2 Aquifer.

Early Miocene to Late Eocene

Port Willunga Formation (lower)

Fossiliferous limestone with sands and sandstones, grading to a dense siliceous unit towards the base

T2 Aquifer Confined aquifer, salinity ranges between 500–2000 mg/L in the Gawler River area to >3000 mg/L to the north and south. Developed mainly for irrigation.

Late Eocene Chinaman Gully Formation

Dark-brown to black lignitic silt and clays, with sandy layers

Aquitard T3 Aquifer

Lignitic clays. Chinaman Gully Sands.

Blanche Point Formation

Marls, siltstone, limestone, fossiliferous and glauconitic. Aquitard Generally confining bed, but may be a low-grade aquifer in some areas

Middle Eocene South Maslin Sand

Marginal marine sands, glauconitic and poorly fossiliferous.

T4 Aquifer Confined aquifer, highly saline.

Clinton Formation

Grey to blue clay, carbonaceous and silty Aquitard Confining bed where present.

North Maslin Sand

Pebbly quartz-sand, slightly clayey, pyritic, carbonaceous; fluviatile and estuarine deposition. Contains thin impure lignite in places.

T4 Aquifer Confined aquifer, highly saline.

Proterozoic Undifferentiated Adelaidean

Slates, quartzite, dolomites, tillites, shales and limestone.

Fractured Rock Aquifer


3.2.2 Quaternary Aged Sediments

The main lithology within the Quaternary aged formations (the Pooraka Formation and the Hindmarsh Clay) typically comprises silty and sandy clays with isolated lenses of sand and gravel. These coarser units form a number of thin sub-aquifers separated by silt and clay aquitards. The coarser grained sediments may be discontinuous over relatively short distances due to abrupt facies changes within these formations resulting from the fluviatile depositional environment (Gerges, 2006). These units are underlain by the Carisbrooke Sand, which forms the Q4 Aquifer in the area of interest.

As noted previously, it is likely that the water bearing zones within the Investigation Area are contained within the more permeable sediments, which are discontinuous with variable connectivity spatially. To remain consistent with regional descriptions, these water bearing zones have been labelled according to the local convention within the Quaternary units.

The Quaternary aquifers are summarised below:

• Q1 Aquifer: The Q1 Aquifer consists of a number of semi-continuous aquifers that may range from unconfined to semi-confined, and is likely to be intersected at depths between 3 and 15m below ground level. The aquifer yield and natural salinity of water is variable in this aquifer being dependent on local recharge sources and the extent and nature of the coarser sediments (Gerges, 2006). Recent groundwater investigations undertaken by GHD (2014a, and 2016) indicated the depth to groundwater in the Q1 Aquifer beneath the Site and the surrounding area ranged from approximately 3m below the top of casing (bTOC) to 15m bTOC. GHD (2016) indicates the field measured salinity [as total dissolved solids (TDS)] in the Q1 Aquifer beneath the Site and the broader EDP ranges from 326 mg/L to 16,900 mg/L, with the majority of TDS results being greater than 1,200 mg/L (considered to be the upper acceptable limit for potable water, refer WQEPP 2015).

• Q2 to Q4 Aquifers: In the area, aquifers Q2, Q3 and Q4 are intersected at approximate depths ranging from 16 to 30m, 31 to 45m and 46 to 60m respectively. The Q2, Q3 and Q4 aquifers are semi-continuous aquifers and semi-confined to confined, with aquifers separated by clay and silt confining beds (Gerges, 2006). Previous groundwater investigations undertaken by GHD (2014a, and 2016) across the EDP indicated the depth to groundwater in the Q2 Aquifer beneath the Site and the surrounding area ranged from approximately 6m bTOC to 26m bTOC (although GHD note that the Q2 Aquifer is under slight pressure and the measured static groundwater level does not reflect the actual depth to the intersection of groundwater in the Q2 Aquifer).

• Q5 and Q6 Aquifers: Regionally, approximately 45 to 50m of clay aquitard separates the Q4 Aquifer from the top of the Tertiary aquifers. The Q5 and Q6 aquifers are present in some locations as gravelly and sandy layers within this aquitard sequence. It is noted that the Q5 and Q6 aquifers are not present in all areas (Gerges, 2006), and based on DfW (2010), it is considered unlikely that they are present in the Investigation Area.

The degree of vertical interconnection of the various aquifers will be dependent upon the permeability and continuity of the intervening clayey aquitard (confining bed) materials. Where the aquitard material is absent or has lower resistance to vertical flow, interconnection of the successive aquifers may occur. The vertical connection of the various aquifers is critical to the development of vertical head gradients and the vertical transport of contaminants between the aquifers.

The result of the above complexity of the Quaternary sequence and interconnection of individual lenses and layers of sands, clays, and silts is that groundwater is likely to move via preferential pathways through more permeable materials, and has the potential to migrate vertically where interconnection between aquifers occurs. This heterogeneity may result in uncertainties in interpreting the migration of contaminated groundwater beneath the Site.


Given the above, all Quaternary aquifers have the potential to be impacted by contamination occurring initially within the Q1 Aquifer, with the vertical extent dependant on the physical connection between the aquifers and the vertical head differentials.

3.2.3 Tertiary Aged Sediments

The Tertiary aged Hallett Cove Sandstone/Dry Creek Sand formations underlie the Hindmarsh Clay and Carisbrook Sand sequences at approximately 60 to 100m below ground level close to the Investigation Area (refer DfW, 2010). The majority of abstracted groundwater in the Adelaide metropolitan area is obtained from the Tertiary sediments, in particular the first (T1) Tertiary Aquifer (Gerges, 2006). The Tertiary sediments comprise four confined aquifers designated T1 – T4, each of which may comprise various subaquifers.

The T2 Aquifer consists of well cemented limestone of the Lower Port Willunga Formation. It is separated from aquifer T1 by Munno Para Clay, which has an approximate maximum thickness of 12m (Gerges, 2006).

The distribution of the T3 Aquifer in the area is not well known because of its depth and poor quality, but it is thought to occur in most of the Northern Adelaide Plains area as a thin sandy layer with an average thickness of 5m. Aquifer T4 consists mainly of South Maslin Sand and occasionally North Maslin Sand which directly overlies the fractured rock aquifer which consists of Adelaidean basement rocks (DfW, 2010).

3.2.4 Groundwater Flow Direction

The regional groundwater flow direction is expected to be in a general south-westerly direction (Gerges, 2006). However, previous groundwater monitoring undertaken at the Site (GHD, 2014a, and GHD, 2016) indicates that significant variability occurs in localised groundwater flow direction beneath the Site. Locally, groundwater is anticipated to be flowing in a general westerly to southerly direction, and is likely to be influenced by unlined surface water features (such as stormwater drains and swales).

3.2.5 Use of Groundwater within the Investigation Area

3.2.5.1 On Site

Based on information supplied by Defence, and supported by the DEW WaterConnect groundwater database records (pertaining to water supply licences), it is understood that there is no extraction or use of groundwater that occurs on Site.

A site inspection completed on 22 February 2018 targeting potential legacy Tertiary Aquifer bores at the Site identified the presence of a T2 Aquifer observation bore within the airside operations area of the Site (bore 6628-3043, refer Appendix A). The WaterConnect database identified this bore as an old observation bore. There was no evidence to suggest the bore was historically used for water supply. Groundwater samples for analysis of PFAS were subsequently recovered from this bore with results presented in Section 11.8.2.3.

With the exception of an operational T2 Aquifer monitoring bore (6628-21321) located in the area of the Southern Detention Basin (associated with the Salisbury Aquifer Storage and Recovery operations at Edinburgh Park South, refer Section 3.2.5.3), no other Tertiary Aquifer bores were identified at the Site.

3.2.5.2 Off Site

A search of the WaterConnect groundwater database indicates there are 394 registered bores located within the current Investigation Area, of which 50 are currently licensed to extract groundwater for private water supply purposes (with a further 6 located in the former Investigation Area). A further six wells are licensed to the City of Salisbury for Aquifer Storage and Recovery operations and/or irrigation (within the current or former Investigation Area). An extract of the


WaterConnect database records for all registered bores in the Investigation Area is provided in Appendix A. A refined list of licensed water supply bores, and a figure showing their location relative to the Site is included in Appendix A.

A summary of the aquifers in which the water supply bores are installed, and the licensed groundwater use recorded on the water supply licences is provided below in Table 3.2. Further information regarding the individual use of groundwater by private licensed water supply bores (gathered where individuals completed a WUS) is discussed in Section 11.8. A figure showing the licensed use of groundwater for each of the licensed water supply bores is also provided in Appendix A.

Table 3.2: Summary of Licensed Water Supply Bores in Current Investigation Area Aquifer No. of Licensed Bores Licensed Use of Groundwater Q2 6 4 x Stock and Domestic

1 x Stock, Domestic and Irrigation 1 x Stock

Q3 1 1 x Irrigation Q4 1 1 x Irrigation T1 39 34 x Irrigation

2 x Stock and Domestic 1 x Domestic 1 x Irrigation, Stock and Domestic 1 x Industrial and Irrigation

T2 3 3 x Irrigation

Historical salinity records for the Quaternary aquifers within the Investigation Area indicate a TDS range between 434 mg/L (6628-3769, recorded in 1948) and 9,929 mg/L (6628-13350, recorded in 1985), with the majority of more recent records (i.e. post-1980) indicating a TDS concentration greater than 1,200 mg/L (considered to be the upper acceptable limit for potable water, refer WQEPP 2015).

Salinity records available for the Tertiary Aquifers indicate a TDS range between 129 mg/L (6628-18545, recorded in 2001) and 4,597 mg/L (6628-3042, recorded in 1946), with the majority of records less than 1,200 mg/L.

3.2.5.3 City of Salisbury Aquifer Storage and Recovery (ASR) Scheme

The City of Salisbury ASR scheme includes two areas comprising injection/extraction bores within the Investigation Area. One area is located immediately southeast of the Site and comprises three operational injection/extraction bores and two associated monitoring bores (identified as the Edinburgh Park South ASR), and the other is located within the Kaurna Park Wetland area approximately 2km south to southwest of the Site and comprises two injection/extraction bores (identified as the Kaurna Park ASR).

The ASR scheme operates through the injection of surface water into the Tertiary Aquifers (T1 and T2) during times of high rainfall (e.g. winter) where it is “stored” for subsequent “recovery” during drier times of the year (e.g. summer). The ASR scheme is operated by Salisbury Water and distributes water to a range of clients for use as irrigation water, industrial process water, pond water, and may be plumbed to toilets3.

The Edinburgh Park South ASR injects water sourced from the Southern Detention Basin (SDB) located on the Site, and the Kaurna Park ASR injects water sourced from the Kaurna Park Wetland. Following the discovery of minor PFOS impacts in groundwater sourced from the Edinburgh Park

3 Information sourced from City of Salisbury website

<http://www.salisbury.sa.gov.au/Live/Salisbury_Water/What_is_Salisbury_Water>


South and Kaurna Park ASR bores in July 2016 (above the current Health Based Guidance Values for Drinking Water), the bores were isolated from the ASR distribution network and water supply from these bores does not currently occur. It is understood that all other bores in the City of Salisbury ASR network did not detect PFAS above the laboratory limit of reporting (LOR) and/or the current Health Based Guidance Values for Drinking Water (DoH, 2017). It was beyond the scope of this DSI to assess impacts associated with the operation of the City of Salisbury ASR scheme within the Investigation Area.

The location of the Edinburgh Park South and Kaurna Park bores in relation to the Site and the Investigation Area is shown on Figure 5 (attached).

3.2.6 Environmental Values of Groundwater

Based on the available salinity records for the shallow Quaternary Aquifers within the Investigation Area (recorded as TDS in mg/L), an assessment of the likely protected environmental values of groundwater has been undertaken. This assessment comprised the comparison of the most conservative (i.e. lowest) TDS records to the TDS ranges provided in the table contained in clause 3 of Schedule 1 of the WQEPP 2015. The adoption of the most conservative TDS value for determining the protected environmental values of groundwater is consistent with the process outlined in the SA EPA Guidelines for the assessment and remediation of site contamination (SA EPA, 2018). The results of the assessment are summarised below in Table 3.3.

Table 3.3: Assessment of Protected Environmental Values of Groundwater Environmental Values of Underground Water (Groundwater)

Background TDS Level Indicates Suitability of Underground Water for Selected Environmental Value?

Drinking Water for Human Consumption Yes Primary Industries—Irrigation and General Water Uses Yes Primary industries—Livestock Drinking Water Yes Primary industries—Aquaculture and Human Consumption of Aquatic Foods

Yes

3.3 Topography and Hydrology

The topography of the Site is generally flat with reported ground surface elevations across the Site ranging from 11.7m relative to the Australian Height Datum (AHD) to 29m AHD (GHD, 2016). Within the Site there are a number of lined and unlined stormwater drainage channels that are fed by various catchment zones, as depicted on Figure 6 (attached). This figure also shows the direction of surface water flow within the main stormwater drainage channels and also shows the approximate location of the Salisbury ASR harvest point for the Edinburgh Park South ASR bores.

The main stormwater drainage channels present within the Site are the Helps Road Drain and Taranaki Drain, both of which are open and unlined in their construction (i.e. earthen drains). Stormwater captured on Site east of the runway is typically directed via a series of shallow unlined stormwater swales into the Helps Road Drain at various points along the on-Site portion of the drain. Stormwater generated on Site to the east of Helps Road Drain (i.e. generally comprising the non-airside areas) is directed toward the Helps Road Drain and/or the Taranaki Drain, which ultimately feeds back into the Helps Road Drain upstream of the SDB. The on-Site portion of the Helps Road Drain is understood to have a maximum drainage capacity of approximately 30m3 per second, however typical winter flow volumes would be expected to be significantly less than this.

It is understood that the SDB was constructed on Site in 2003 to facilitate stormwater harvesting as part of the Salisbury ASR Scheme, for the Edinburgh Park South operations. The construction of the SDB is evident on the 2003 aerial photograph included in Appendix B. Stormwater in the Helps Road Drain is directed into the SDB during low flow regimes with the aid of a small concrete diversion weir. The weir directs stormwater into the northern portion of the SDB via a low flow channel to the Edinburgh Park South ASR harvest point (refer Figure 6). Excess stormwater from the SDB that is not harvested by ASR operations is ultimately directed back to the Helps Road Drain where it exits the


Site across the southern boundary. In addition, the catchment zones depicted on Figure 6 show an external catchment area (shaded yellow) that directs stormwater generated off-Site into the southern portion of the SDB (i.e. on Site) via the Kaufmann Canal and the Port Augusta Railway Drain. This stormwater is once again directed to the Helps Road Drain where it discharges from Site across the southern boundary and is conveyed to the Kaurna Park Wetland located further downstream. Prior to 2003, stormwater generated on Site and directed to the Helps Road Drain (i.e. all areas east of the main runway) is understood to have discharged across the southern Site boundary without any on-Site detention.

West of the runway there is a point of surface water/stormwater discharge across the southern boundary, to the northwest of the Helps Road Drain. This western drainage catchment area comprises an unlined swale drain (identified as the Western Swale, refer Figure 6) that conveys surface water from north to south and discharges to a swale adjacent to the Adelaide-Port Augusta railway line (identified as the Port Augusta Railway Drain). Anecdotal evidence provided by an off-site landowner indicated that historical inundation of a portion of the commercial/industrial land to the southwest of the Western Swale discharge point occurred occasionally prior to construction of a swale drain adjacent to Heaslip Road. This unlined swale drain is understood to have been constructed some time in the late 1990s or early 2000s and now directs stormwater from the Port Augusta Railway Drain to the south (refer Figure 6). It is noted that no flow of stormwater away from the Western Swale discharge point was observed during the DSI, with only minor surface ponding observed within the Port Augusta Railway Drain in this area.

The stormwater network on-Site acts as an ephemeral system with no permanent surface water bodies present on-Site. The stormwater drainage channels and SDB are depicted on Figure 5 (attached), with surface water flow direction in the individual stormwater drains depicted on Figure 6.

Stormwater within the Helps Road Drain off-Site is directed to the Kaurna Park Wetland located approximately 2km south to southwest of the Site, entering the wetland at the north-eastern extent. Stormwater traverses through a meandering series of channels within the wetland in a general northeast to southwest direction. Stormwater within the Kaurna Park Wetland that is not harvested as part of the Salisbury ASR Scheme (refer Section 3.2.5.3) ultimately overflows back to the Helps Road Drain at the downstream discharge point, where it then continues downstream for some 7km before ultimately discharging to the Barker Inlet. The off-Site extent of the Helps Road Drain between the Site and the Kaurna Park Wetland, and between the Kaurna Park Wetland and the Barker Inlet, has also been constructed as an open unlined drainage channel.

The Kaurna Park Wetland was originally constructed in the mid-1990s as a floodwater detention basin and was intended to undergo alternating wetting and drying cycles throughout the year (Kurylowicz, 2009). As such, the Kaurna Park Wetland is also expected to represent an ephemeral surface water system. The location of the Kaurna Park Wetland is also depicted on Figure 5, with the direction of stormwater flow within the Helps Road Drain off Site depicted on Figure 6 (attached).

During construction of the Kaurna Park Wetland, the off-Site portion of the Helps Road Drain between the Site and the wetland was realigned to direct stormwater flows into the wetland. In addition, the commencement of residential development within the Springbank Waters residential estate in approximately 2003 resulted in realignment of the Helps Road Drain downstream of the Kaurna Park Wetland (upstream of Port Wakefield Road). Prior to this time, the Helps Road Drain followed the alignment of what is now Helps Road and the eastern edge of the Springbank Waters residential estate. Review of a 1989 aerial photograph showing the off-Site route of the Helps Road Drain prior to realignment (refer Appendix B) indicates that the historic drain also comprised an unlined open drain. The historical route of the Helps Road Drain is depicted on Figure 5 (attached).


3.4 Climate

The closest Bureau of Meteorology (BOM) meteorological monitoring station is Edinburgh RAAF (Station Reference: 023083) located on Site in the central airside operations area, approximately 200m west of the new Air Traffic Control Tower. A summary of the mean climatic data recorded by this weather station since records commenced in 1972 is provided in Table 3.4.

Highest temperatures are experienced during the months of January and February, both with a mean daily maximum temperature of 30oC. Lowest temperatures typically occur in July with a mean maximum temperature of 15.3oC.

Table 3.4: Summary of Mean Climate Data for RAAF Base Edinburgh (BOM, 2018) Mean Annual Minimum Temperature Range

Mean Annual Maximum Temperature Range

Mean Annual Rainfall

Mean Monthly Rainfall

Mean Evaporation Rates

6.1oC in July – 16.6oC in February

15.3oC in July – 30.1oC in January and February

434.6 mm 18 mm in February – 53.8 mm in July

1.8 mm in June – 10.2 mm in January

3.4.1 Rainfall

Due to the PFAS of concern being highly soluble and leachable, rainfall is considered to be the most significant meteorological factor that will influence PFAS migration. The highest rainfall rates across the Investigation Area typically occur during the month of July with a mean monthly rainfall of 53.8 mm, whilst the lowest mean rainfall occurs in the month of February (18mm). A summary of monthly rainfall data recorded since 1972 is provided in Table 3.5.

Table 3.5: Summary of Monthly Rainfall Data (BOM, 2018)

Month Average Monthly Rainfall (mm)

Lowest Monthly Rainfall (mm)

Highest Monthly Rainfall (mm)

January 21.7 0.2 (2009) 92.2 (1996) February 18.0 0.0 (2015) 104.0 (2014) March 24.9 0.0 (1994) 139.6 (1983) April 30.2 1.8 (1997) 101.8 (2007) May 44.8 2.4 (2005) 87.8 (1988) June 52.7 8.6 (1975) 115.6 (2005) July 53.8 13.8 (1997) 109.4 (1995) August 50.1 9.2 (2006) 103.2 (1979) September 48.3 14.8 (1980) 117 (1992) October 37.2 0.0 (2006) 91.2 (1980) November 23.7 1.2 (1982) 89.4 (1992) December 25.7 0.0 (2001) 127.0 (2010)

3.4.2 Wind Conditions

Whilst rainfall is considered to be the most significant climatic condition that will influence PFAS migration, wind speed and direction may also influence PFAS migration under certain conditions. For example, prevailing winds may have influenced foam spray movement during training and emergency response activities, and aeolian transport may have influenced migration of PFAS impacted surface soils in unsealed areas. The average prevailing wind direction across the Investigation Area since 1972 has been from the northeast in the morning (9am readings) and southwest in the afternoon (3pm readings), as depicted in the wind rose presented as Figure 3.1 and Figure 3.2.


Figure 3.1: 9am Prevailing Wind Direction – All Data 1972 to Present (BOM, 2018)


Figure 3.2: 3pm Prevailing Wind Direction – All Data 1972 to Present (BOM, 2018)

3.5 Heritage

A draft Heritage Management Plan (GML Heritage, 2016) has been prepared for the EDP to address Indigenous and historic Commonwealth Heritage Values. Heritage values in the EDP include a range of buildings, structures, roads and plantings demonstrating the history and importance of the Salisbury Explosive Factory and the site’s broader role in the Anglo-Australian Joint Project. Indigenous values include components of the Kaurna people’s cultural, spiritual and social landscape which includes recorded stone artefact and mound sites and two known burial locations.

3.6 Flora and Fauna

The nearest off-Site ecological receptor that receives surface water (stormwater) originating from the Site (via the Helps Road Drain) is the Kaurna Park Wetland. The Kaurna Park Wetland is a constructed wetland system that lies within the Helps Road Stormwater Catchment. It was constructed in the mid-1990s to contain stormwater and provide a floodwater detention function within the catchment. With consideration of the ecosystem classification guidance provided in the Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC and ARMCANZ, 2000), and the three ecosystem conditions recognised in the guidelines, the Kaurna Park Wetland is considered to be categorised as a Highly Disturbed System, which in the guidelines includes urban streams receiving road and stormwater runoff.


A desktop review of available ecological data for the Kaurna Park Wetland (including a report provided by the City of Salisbury Council – Kurylowicz, 2009) has not identified any factors that would cause the Kaurna Park Wetlands to be elevated to a higher ecosystem condition category. A review of available reports, as well as online databases, indicated that:

• There are no records of native fish in the local area and the removal of the introduced pest fish Gambusia holbrooki (Plague Minnow) from the Kaurna Park Wetlands would be required prior to the introduction of any native fish species (Kurylowicz, 2009).

• A number of rare and vulnerable bird species have been sighted in the area, however, none of these species are considered to be breeding in the wetlands. Two bird species of national significance have been observed on a very small number of occasions (DEWNR, 2016 and Kurylowicz, 2009) however were not considered to be resident or reliant on the wetlands due to the ephemeral nature of the wetland.

• Historically, the site of the Kaurna Park Wetlands was a Eucalyptus porosa (Mallee Box) Woodland however, the interior of the wetlands was landscaped to mimic a typical River Murray floodplain. The planted vegetation in the wetland consists of local and non-local native eucalypts, wattles and other shrubs – many originating from the River Murray (Kurylowicz, 2009).

The Edinburgh Defence Precinct (EDP) Estate Base Plan, Base Specific Investigations report (Jacobs, 2016) identifies threatened flora and fauna species that are known to occur throughout the EDP and surrounding areas based on a search of the Commonwealth Environment Protection and Biodiversity Conservation (EPBC) Protected Matters database and the Biological Database of South Australia. Within the Site itself, there are no threatened flora species identified, and only one threatened fauna species identified – the Bush Stone-curlew (a species of ground-dwelling bird). The report further indicates that flora, fauna and threatened species are not identified as a significant constraint or issue for Base planning.

To support the information presented above, JBS&G conducted a search of the relevant ecological databases with reference to the Kaurna Park Wetlands area in April 2017. The species identified in these searches were consistent with those identified in the Estate Base Plan Base Specific Investigations report (Jacobs, 2016). The results for the EPBC Protected Matters Search are provided in Appendix B.

A search of the BOM Groundwater Dependent Ecosystems (GDEs) Atlas4 did not identify any known or potential GDEs within the Investigation Area based on regional studies. It is noted that a national assessment identified a high potential for aquatic GDEs to exist within the eastern extent of the Investigation Area, however the areas identified comprise the Bolivar Waste Water Treatment Plant stabilisation lagoons and therefore this information is considered unreliable.

4 Accessed via: http://www.bom.gov.au/water/groundwater/gde/map.shtml

http://www.bom.gov.au/water/groundwater/gde/map.shtml


4. Site History

RAAF Base Edinburgh (the Site) forms part of the broader EDP which comprises land that was compulsorily acquired by the Commonwealth Government in 1940 to build a munitions factory (RAAF Association, 2018). Prior to this time the area was primarily used for agricultural purposes, with farming activities dating back to the mid-19th century. A munitions plant, historically identified as the Salisbury Explosives Factory (Jacobs, 2016a), was established across the EDP in 1942 and produced a wide variety of explosives for ammunition until the end of World War II.

The construction of the RAAF Base commenced in 1953 to sustain operational support to joint Australian and British weapons testing and a long-range experimental firing range at Woomera, formerly serviced by RAAF Mallala. The base was officially opened in March 1954 and supported a large number of British and Australian personnel as well as Royal Air Force (RAF) and RAAF aircraft of diverse types involved in the weapons trials (RAAF Association, 2018). In the late 1970s the base underwent major development following a decision by Defence to make RAAF Base Edinburgh the primary base for the RAAF’s maritime capability. New facilities were built from across the base between 1978 and 1981.

In 2010, Army elements began relocating to the RAAF Base, beginning with the reformation of 7th Battalion, Royal Australian Regiment (7RAR). This was followed by the development of the Hardened Network Army (HNA) precinct at the base (refer Figure 2), and subsequent relocation of 1 Armoured Regiment from Darwin (Jacobs, 2016a).

4.1 Historical Aerial Photographs

A review of historical aerial photographs for the Site, available on the DEW Map Finder database, indicated that prior to 2000 the aerials had been redacted to remove visibility of the base. An example of this is evident on the 1989 aerial photograph provided in Appendix B. As such, only more recent aerial images showing the Site and immediate surrounds were available for review and have been provided in Appendix B. A summary of the review of the aerial images with respect to site features and development is provided in the following sections, with a particular focus on known or suspected AFFF storage, use and disposal areas (e.g. fire training grounds, concentrate storage area) as described in later sections of this report.

4.1.1 May 2003

The 2003 aerial photograph shows that the RAAF Base was well established in 2003 with the main runway and grass runway evident within the airside operations area of the Site. The main apron and Hangar area is also visible and well developed. The development within the non-airside area of the Site is largely present in the northern and southern sections. The central portion of the non-airside area, where the HNA is now located, is largely vacant/undeveloped with the exception of the historic ordnance storage pyramids (legacy infrastructure associated with the former munitions plant).

The former Base golf course is visible to the south of the Bulk Fuel Store, and there is evidence of earthworks associated with the construction of the SDB in the southern portion of the Site. The Helps Road Drain is visible on and off-Site and is consistent with the current alignment. The Taranaki Drain has not yet been constructed at the Site, although there is evidence of what appears to be a stormwater swale in a similar location and alignment to the current alignment of the Taranaki Drain in the south-eastern portion of the Site.

The current fire station is visible in the area to the west of the Hangars, as is the original air traffic control tower and associated buildings immediately to the south of the fire station. The area of the new air traffic control tower is undeveloped and appears to have vehicles parked within the current footprint of the tower. The former AFFF concentrate loading pad is visible adjacent to the northern extent of this area, although it is not discernible if the AFFF concentrate tank and stand is still present in the area at this time.


The area of the bulk fuel store is visible and appears to have been largely developed into its current layout by this time. The deluge system building is evident within the bulk fuel store area in the south-western portion of the zoomed aerial graphic. The AFFF waste water evaporation pond and associated fire tender test pad have not yet been constructed in the area to east of the bulk fuel store, with what appear to be soil stockpiles present in this area.

The smokeroom training building (a concrete walled and rooved building) within the current fire training area is evident in the 2003 aerial photograph, with a small number of other indistinguishable features present immediately northeast of this structure. The former fire training area in the north-eastern portion of the airfield does not appear dissimilar to the most recent 2018 aerial photograph, with evidence of remnant fire training props and small stockpiles likely associated with the former landfilling activities in this area evident in the aerial photograph.

With the exception of the DSTG site to the east, the surrounding land use appears to predominantly comprise open agricultural and market garden properties. There is also evidence of some horse training properties to the west and north of the Site as indicated by the oval trotting track patterns.

4.1.2 October 2009

The most significant development of the Site evident in the 2009 aerial photograph comprises new buildings and earthworks in the central portion of the non-airside area, largely associated with the development of the HNA facilities at the Site. The construction of the SDB in the southern portion of the Site is now complete, and the Taranaki Drain is now evident to the south of the HNA area and former golf course. A new explosive ordnance loading area has been constructed in the central southern portion of the airfield, to the east of the main runway.

The AFFF evaporation pond and associated fire tender test pad and current AFFF concentrate storage area are now evident at the Site having been constructed in 2004 (refer Section 5.7), with a new building also constructed to the east-southeast of these site features. The AFFF evaporation pond appears to be full of water at this time. There are four new buildings present to the east and southeast of the fire station with the area of the new air traffic control tower remaining vacant. The current fire training area has undergone minor development with a new building present to the east-southeast of the smokeroom training building (an open shed). There is also evidence of what appear to be old vehicles and other materials, presumably used for training exercises. The former fire training area in the north-eastern portion of the airfield appears largely unchanged from the 2003 aerial photograph.

Notable changes to the surrounding land use comprise the development of the Coles Distribution Warehouse to the south of the Site, the commencement of the commercial/industrial development to the southwest of the airfield, and minor development of the surrounding agricultural properties. The construction of the Northern Expressway is also evident in the north-western corner of the aerial photograph.

4.1.3 February 2013

The 2013 aerial photograph indicates development of the HNA area at the Site has been completed. The temporary accommodation and LIA areas have been developed at the Site, as have the current recreational and retail facilities and the North East Defence Community Centre in the central portion of the non-airside area of the Site. Two new explosive ordnance loading areas have been constructed in the central portion of the airfield, between the grass runway and main runway, and the new air traffic control tower has now been constructed to the southwest of the old tower.

The AFFF waste water evaporation pond appears to be dry in the 2013 aerial photograph, however there is evidence of what appears to be recent foam discharge present within the eastern section of the pond. There also appears to be water runoff from the adjacent fire tender test pad and current


AFFF concentrate storage area suggesting there had been testing occurring shortly prior to the photograph being captured.

The current fire training area appears largely unchanged from the 2009 aerial photograph with the exception of some additional materials present to the east of the smokeroom training building. The former fire training area in the north-eastern portion of the airfield appears unchanged.

The notable change to the land use surrounding the Site comprises further development of the commercial/industrial area to the southwest of the airfield.

4.1.4 February 2018

The most significant developments at the Site that are evident in the February 2018 aerial photograph are associated with the AIR 7000 Maritime Patrol Aircraft Replacement Project. The northern and southern runway extension works are evident in airside operations area, and the construction of new Hangar Maintenance and Operational Facilities is evident in the area comprising the northern portion of the main apron and the area to the immediate north. The AIR 7000 project stockpile storage facility is also visible to the south of the former golf course, northeast of the SDB.

Two new sheds have been constructed to the west of the new air traffic control tower and a new building constructed to the northwest of the aviation fuel tanks in the northern portion of the bulk fuel store. The AFFF evaporation pond is dry in the aerial photograph, although shipping containers with a 75kL capacity brought onto Site to decant liquid waste from the evaporation pond are now evident in the area surrounding the fire tender test pad.

A notable change to the current fire training area is the addition of two old shipping containers on the northern side of the smokeroom training building that have been used for testing exercises. The former fire training area in the north-eastern portion of the airfield appears unchanged.

The notable change to the land use surrounding the Site comprises further development of the commercial/industrial area to the southwest of the airfield.


5. Summary of Previous Investigations Relevant to PFAS

A total of 56 documents relating to the environmental investigation of potentially contaminated sites at RAAF Base Edinburgh are listed on the CSR database as provided to JBS&G on 17 November 2016 (Defence, 2016b). Of these reports, only seven were identified to include information relevant to the historical use, storage, disposal, assessment and / or management of legacy AFFF (i.e. AFFF containing high levels of PFAS). A further 18 documents not registered on the CSR database have been identified as containing, or potentially containing, information relevant to potential PFAS impacts at RAAF Base Edinburgh that were provided to, and / or requested by, JBS&G.

Table 5.1 provides a list of the relevant documents and identifies those that have been provided to JBS&G for review and consideration to develop a preliminary CSM.

Table 5.1: List of Relevant Documents Provided and/or Requested to Inform Preliminary CSM Development

Author Year Title / Reference Received by JBS&G

Defence 2016b RAAF Base Edinburgh Contaminated Sites Register (CSR), updated 23 September 2016

Yes

Documents registered on the CSR database GHD 2008 Stage 2 Environmental Investigations Edinburgh Defence Precinct – SA2232,

Part 1, prepared for Spotless Services Australia, April 2008 (CSR Ref. AF13126745)

Yes

URS 2011 SA 2684 - AFFF Soil and Surface Water Assessment Edinburgh, RAAF Base, Salisbury SA, prepared for Spotless Services Australia, 42657324, 5 April 2011 (CSR Ref. AF13312263)

Yes

AEC 2012 SA 3139 Asbestos and Contaminated Soil Remediation Option Report, RAAF Edinburgh Site SA019 (DRAFT), prepared for Transfield Services Australia Pty Ltd, January 2012 (CSR Ref. AF13122232)

Yes

URS 2012 AFFF Infrastructure Assessment (SA2662), Final Report, prepared for Spotless Australia, 42657490-RPE-0001, 20 June 2012 (CSR Ref. AF21007759)

Yes

GHD 2014a Edinburgh Defence Precinct Groundwater Monitoring, Groundwater Monitoring Event March 2014, 33/17471, prepared for Transfield Services, September 2014 (CSR Ref. AF26692559)

Yes

GHD 2014b SA3787 Edinburgh Defence Precinct Groundwater Well Installation, 33/17529, prepared for APP Corporation Pty Ltd, September 2014 (CSR Ref. AF26692597)

Yes

Defence 2015 SA Environmental comments - Defence Estate Legacy PFC Review July 2015, email from Nicole McCarron dated 4 August 2015 (CSR Ref. AF22730800)

Yes

AIR 7000 Project Documents AECOM 2016a Segregation of Soils proposed for Excavation from Areas 1, 2 and 3, AIR 7000

Project Area, RAAF Base Edinburgh, letter report to Lendlease Building Contractors Pty Ltd (Vik Kumar), 5 September 2016

Yes

AECOM 2016b AIR7000 Project, RAAF Base Edinburgh – In-situ Waste Soil Characterisation of Areas 1-3, Job No 60287313, dated 10 August 2016

No

AECOM 2016c In-Situ Waste Soil Characterisation for Northern Runway Extension, AIR7000 Project, RAAF Base Edinburgh, 60487178, prepared for Lend Lease Building Contractors Pty Ltd, 11 November 2016

Yes

Lendlease 2016 Email correspondence: Air7000 Sites - Boundary Confirmation, email providing plan of project site areas and laboratory results of sediment, surface water and pore water sampling for the AIR 7000 project, from Mr Vik Kumar (Senior Project Engineer) dated 12 December 2016

Yes

Base Estate Plans Jacobs 2016b Edinburgh Defence Precinct Base Specific Investigations, Estate Base Plans,

prepared for the Department of Defence, 27 June 2016 Yes

Other CRC CARE 2007 Report: Environmental impacts of AFFF at long term contaminated sites

(referenced in the Timeline for Analysis and Management Actions Regarding PFOS and PFOA within AFFF products at RAAF Edinburgh as at 25 July 2016)

No


Author Year Title / Reference Received by JBS&G

CRC CARE 2009 Report: Soil and surface water assessment following AFFF waste water discharge (Objective reference D1881074) (referenced in the Timeline for Analysis and Management Actions Regarding PFOS and PFOA within AFFF products at RAAF Edinburgh as at 25 July 2016)

No

Aurecon 2012 Stormwater – Base Water Quality Assessment, Edinburgh Defence Precinct – Base Engineering Assessment Program (BEAP), Reference: 8T7T227737-002 (DRAFT), prepared for the Department of Defence, 28 August 2012.

Yes

Aurecon 2012 Base Engineering Assessment Program Phase 3 Report. Referenced in Stormwater – Base Water Quality Assessment, Edinburgh Defence Precinct – Base Engineering Assessment Program (BEAP) (Aurecon, 2012) as providing data pertaining to AFFF analysis.

No

AEC 2013 Environmental Assessment: Sediment Classification – unlined drain RAAF Edinburgh (referenced in the Timeline for Analysis and Management Actions Regarding PFOS and PFOA within AFFF products at RAAF Edinburgh as at 25 July 2016)

No

GHD 2014c EDP Groundwater Management, Sampling Analysis Plan, prepared for Transfield Services, Reference 3317375/55167

No

CH2M 2015 Defence Estate Legacy PFC Review - DEHP-ID-022, Reference: 656801, prepared for the Department of Defence, July 2015

Yes

Defence 2016b RAAF Base Edinburgh Environmental Investigation, Timeline for Analysis and Management Actions Regarding PFOS and PFOA within AFFF products at RAAF Edinburgh as at 25 July 2016 (update to 9 Nov 2015 timeline), Department of Defence, 25 July 2016

Yes

GHD 2016 SA Environmental Groundwater Monitoring, Edinburgh Defence Precinct (DRAFT), 3134412, prepared for Broadspectrum (Australia) Pty Ltd, November 2016

Yes

Broadspectrum 2016 Figure showing historic AFFF use areas still to be investigated, provided to JBS&G at Site Inspection 29-11-16 (provided as Appendix D)

Yes

Unknown 2016 EDP Stockpile Assessment Report which reportedly identified PFAS impacts within 25 stockpiles at the EDP, referenced in email correspondence from Nicole McCarron to PFAS Investigation and Management Branch dated 22 November 2016

No

JBS&G is satisfied that the content and data provided in the historical documents are of sufficient integrity for the purposes of supporting the identification of potential source areas for consideration in the Preliminary CSM. Laboratory analytical data presented in the documents was considered for information only, with notable limitations pertaining to data quality identified in the relevant report reviews provided in the following sections. Data within these reports has not been relied upon in determining the nature and extent of PFAS contamination at the Site and in surrounding areas.

5.1 RAAF Base Edinburgh Contaminated Sites Register (CSR)

A copy of the RAAF Base Edinburgh CSR was provided to JBS&G in November 2016. The CSR is a database managed by Defence and provides a list of sites located within RAAF Base Edinburgh that are known, or highly suspected, to be associated with current and historical site contamination issues. A review of the CSR identified 49 sites at RAAF Base Edinburgh, of which eight were identified to have AFFF (PFAS) listed as a contaminant of concern, as summarised in Table 5.2.


Table 5.2: Relevant Extracts from the RAAF Base Edinburgh CSR Legacy CSR Number

Current CSR Number

CSR Classification CSR Name Location Description Spatial Nature

of Source Area CSR Description

SA0068 CSR_SA_000301 Sewage Treatment Plants

Site 17 - Abandoned Sewage Treatment Plant

Zone 6A Single Point Source

Abandoned Sewage Treatment Plant

SA0072 CSR_SA_000292 Fuel Storage – Bulk

Bulk Fuel Store - Tank Farm

Zone 6B - located in the western half of the EDP, south east of the Airfield area, east of the main runway.

Multiple Point Source

The site comprises two separate bunded areas, each with 2 x 1.5 ML tanks, totalling 6 ML of F34 jet fuel storage. An older 30 kL tank is separately located and also stores jet fuel. RAAF Edinburgh also has several fuel transport vehicles used for refuelling aircraft; these run fuel to and from the Bulk Fuel Store. Fuel vehicles include 5 x 30,000 L DAFs and 2 x 7,500 L Isuzu vehicles for servicing aircraft. The site was constructed between the 1960s and 1970s and was extensively upgraded in 1999. HLA (2005) indicated the 4 ASTs were installed in approx. 1990, and contain Avgas each with a 1.5 ML capacity.

SA0075 CSR_SA_000293 Landfill Site 125 - Airfield Taxiway Dump

Zone 6C - located on the north-east corner of the intersection of Taxiway E with Taxiway F, approximately 100 metres north of Taxiway E.

Single Point Source

Site 125 has historically been used as a dumping area for building and construction waste resulting from site activities, as identified in a Weapons Research Establishment document detailing the 1960/61 Works Program. RUST PPK (1994) discussed the removal of buildings on the site that were constructed to house labourers during construction of the airfield. No other structure or features at Site 125 have been documented.

SA0076 CSR_SA_000282 Fire Training Area

Site 19 - Fire Fighting Area & Waste Dump

Zone 6D - located in the western half of the EDP, to the west of the second airfield runway. The site is approximately 1 hectare in size.

Localised Diffuse Source

Site 19 was previously used as a firefighting training area including six former burning off areas. Previous investigations conducted by RUST PPK (1994) indicate that there were two large loam pits at Site 19, “into which the Long Range Weapons Establishment (LRWE) and Weapons Research Establishment (WRE) personnel dumped a great variety of wastes (including toxic chemicals and asbestos)”. RUST PPK (1994) concluded that the likelihood of the existence of such dumps at Site 19 was reduced, following inconclusive geophysical results.


Legacy CSR Number

Current CSR Number

CSR Classification CSR Name Location Description Spatial Nature

of Source Area CSR Description

SA0077 CSR_SA_000287 Landfill Site 49 - Isolated Aircraft Parking

Zone 6D - located within the RAAF base compound. The site is accessed via an unsealed back road. The area borders the grass runway to the north-west, the joint logistics unit to the east and the explosive ordinance area to the south-west.


Site 49 was reportedly identified from aerial photographs showing a large plane positioned at the site in question. This plane was blackened as was the grass around the base. There were potentially one or more waste dumps in the area and that wastes, toxic or otherwise, may have been acceptably disposed of to the ‘dumps’ as was the practice of the time. The dump was noted to be kidney shaped with an approximate surface area of 2900 square metres. Fill material was observed to extend to between 0.5 metres in depth at the periphery of the dump to 3.2 metres at the centre. The fill was composed of assorted refuse including large concrete blocks (footings from original overhead service lines), bottles and crockery, scrap metal, bricks, glass, ash, bitumen and asbestos sheeting.

SA0079 CSR_SA_000291 Landfill Site 63 - Burning Off Area

Zone 6D - located west of Smithfield Road in the 3-hectare paddock immediately south of the DSTO static rocket-firing site, GP1. The Missile Testing Facilities Buildings border the north of the site area, whilst security fencing marks the eastern and southern boundaries of the site.

Single Point Source

The site has historically been used as a burning off compound and subsurface waste dump. Burning off at the site was conducted via incineration, as a method of eradicating redundant waste materials. The burning off compound incorporated a store building, coal bunker, incinerator and blower, shelter shed, oil drum stand and a kerbed burn off area. A concrete drain ran from the burn off area into a sump, northwest of the site. Previous investigations at the site have identified buried waste material in the area including metallic and glass material, ash and cinder.

SA0080 CSR_SA_000276 Firing Range Sites 155 & 156 - Static Rocket Firing Sites

Zone 6A Single Point Source

Static rocket firing site

SA1029 CSR_SA_000278 Waste Management - Solid

AFFF Waste Water Evaporation Pond

Located east of the Bulk Fuel Store, CSR listing includes the evaporation pond and sounding areas impacted to AFFF. The area impacted are to low lying areas especially within the vicinity of Building 521.


In 2005 a pond was built to retain PFOS/PFOA contaminated water from the AFFF closed system to stop the discharge of untreated water to the sewerage system and/or stormwater. The vicinity of the site also displays AFFF impacted soils predominantly in the low-lying areas. This has occurred via onsite activities/processes i.e. disposal of AFFF from fire trucks to ponds, etc. Spray and foam drift during fire training has been identified as one source of soil impact near the evaporation pond. The site previously had a pump and treat system in place funded under the National AFFF remediation program. This system was maintained by CRC CARE under a contract arrangement and was intended to assist with the treatment of contaminated water during poor evaporation conditions/high rainfall seasons.


Landfill areas identified within the CSR that had the potential to have been associated with the historical disposal of AFFF concentrate or AFFF waste products have been considered in the DSI as potential source areas. Other landfill areas identified for specific landfilling activities (e.g. the Mineral Jelly Dump, Asbestos Dumps) were not targeted as part of the DSI, however are being (or have been) investigated by Defence as part of targeted works in relation to the COPC that may be associated with these activities. Similarly, underground storage tanks (USTs) and/or above-ground storage tanks (ASTs) that may have historically contained AFFF concentrate and/or AFFF waste water were considered as part of the DSI. Other USTs and/or ASTs that were not associated with the historical storage of AFFF products were not targeted as part of the assessment (e.g. diesel fuel tanks, aviation fuel tanks) unless there was evidence to suggest the presence of an AFFF deluge system associated with this infrastructure, or there had been a historical fire associated with the infrastructure (noting there was no evidence of this identified as part of the DSI).

5.2 CSR Document Reviews

5.2.1 Stage 2 Environmental Investigations Edinburgh Defence Precinct - SA2232, Part 1 (GHD, 2008)

GHD was engaged to undertake a series of Stage 2 (detailed) environmental investigations within the EDP to assess site contamination risks at seven priority sites of potential concern. Each of the seven sites was located within the RAAF Base Edinburgh site boundary. The seven sites were identified as the following:

• SA0070 (CSR_SA_000220) – Site 98: Bird Bath (an operating wash down area for aircraft);

• SA0072 (CSR_SA_000292) – Bulk Fuel Store;

• SA0073 (CSR_SA_000286) – Site 16: Subsurface Waste Dump;

• SA0076 (CSR_SA_000282) – Site 19: Subsurface Waste Dump / Firefighting Area;

• SA0078 (CSR_SA_000290) – Site 58: Gas Gun in Quarry Waste Dump;

• SA0079 (CSR_SA_000291) – Site 63: Burning off Area; and

• SA0075 (CSR_SA_000293) – Site 125: Airfield Taxiway Dump Site.

Of the above sites, two sites (SA0076 – Site 19 and SA0079 – Site 63) were assessed for the potential presence of PFAS (PFOS and PFOA). Each location had two surface soil samples [0-0.1m below ground surface (bgs)] reportedly analysed for PFOS, PFOA, and Ansulite. In addition, groundwater samples recovered from two monitoring wells at Site 19 (GW8 and GW322) were also analysed for PFOS, PFOA, and Ansulite. Laboratory analytical works for PFAS were performed by CRC CARE at its University of South Australia (UniSA) laboratory. The report notes that CRC CARE was not accredited by the National Association of Testing Authorities (NATA) for the analytical works performed, however they were the only known laboratory at the time of the investigation with the capability to test for selected PFAS.

The results reported detectable concentrations of PFOS in surface samples TP13-0.1 and TP4-0.1 (Site 19) at concentrations of 0.486 mg/kg and 0.143 mg/kg respectively, and in surface sample TP23-SS (Site 63) at a concentration 0.053 mg/kg (although the associated duplicate sample reported PFOS below the laboratory LOR). The remaining surface sample TP22-SS (Site 63) reported PFOS below the laboratory LOR. All soil analytical results for PFOA and Ansulite were reported below the laboratory LOR.

A detectable concentration of PFOS was reported in groundwater sampled from monitoring well GW8 at a concentration of 0.313 mg/L, with the remaining groundwater sample recovered from monitoring well GW322 (identified as down-hydraulic gradient of GW8) reporting all results below the laboratory LOR.


The report makes reference to an earlier investigation by CRC CARE (2007)5 as having reported PFOS concentrations ranging from 64 mg/kg to 1760 mg/kg in surface soils and from 12 mg/kg to 190 mg/kg in subsurface soils, at a former firefighting training area at RAAF Edinburgh. It was noted that the CRC CARE investigation did not specify sampling locations or a specific site within RAAF Base Edinburgh and that the data was used for comparison only. A copy of the 2007 CRC CARE investigation has not been sighted.

The report describes Site 19 as an open paddock with six former burning off areas (three of which are bunded by earthen walls), a surface stockpile area and general surface debris consisting of scrap material, ash and construction rubble. Site 19 was identified to have historically been subject to landfilling and firefighting training activities.

The report describes Site 63 as flat vacant land located within the Missile Testing Facilities Compound. Site 63 was identified to have historically been used as a burning off compound and subsurface waste dump, with a concrete drain reported to run from the former burn-off area to a sump located northwest of the site (with anecdotal evidence suggesting historical overflows from the sump). The location of the drain and associated sump are not shown in the report.

The locations of Site 19 and Site 63 are depicted on Figure 7 (attached).

5.2.2 AFFF Soil and Surface Water Assessment Edinburgh (URS, 2011)

URS was engaged to undertake an assessment of the nature and extent of soil and surface water impacted by the historical use and management of legacy AFFF in the vicinity of Building 521 (identified as the pre-disposal retention tank) and the associated waste-water disposal pond (evaporation pond), and down gradient surface water bodies on site at RAAF Base Edinburgh. The assessment also sought to identify the source of AFFF impact and determine whether remediation was required.

The assessment was commissioned following the discovery by Defence and the Estate Maintenance and Operations Services (EMOS) contractor (Spotless) that foaming and odorous water had discharged through site stormwater drainage channels and into the SDB, from which the City of Salisbury draws water for its ASR system (Edinburgh Park South). The investigation commenced in 2009 and comprised the following:

• Drilling of soil bores across the investigation area on a 15m to 30m grid to a maximum depth of 4m bgs;

• Collection of surface soil samples from the sides of the evaporation pond and along the length of the earthen stormwater drain that flows past the evaporation pond and Building 521 (and ultimately connects to the Helps Road Drain, otherwise identified as the RAAF Drain in the report); and

• Collection of surface water samples from the SDB and ponded water within the investigation area (following heavy rainfall).

All samples submitted for laboratory analysis were reportedly analysed for PFOS, PFOA, Ansulite and 3M Light WaterTM. Laboratory analytical works were performed by CRC CARE at its UniSA laboratory.

The URS investigation found detectable concentrations of PFOS in all surface soil samples analysed. The maximum reported PFOS concentration was 58.2 mg/kg reported in a duplicate sample, with the corresponding primary sample (BH13_0-0.1 m, located near the water tanks to the south of Building 521) reporting a concentration of 53.22 mg/kg. Concentrations of PFOS were reported to typically decrease with depth, with a few exceptions.

5 CRC CARE, 2007. Environmental Impacts of AFFF at Long term Contaminated Sites. Megharaj & Naidu. University of South Australia.


Detectable concentrations of PFOS were also reported in soil samples collected from the open stormwater drain adjacent to Building 521 and the RAAF Drain (i.e. Helps Road Drain). Concentrations were less than 1 mg/kg upstream of Building 521 and increased downstream of the evaporation pond and Building 521. The PFOS concentrations in soil recovered from the confluence of the RAAF drain and open stormwater channel that passes Building 521 and the evaporation pond was less than 1 mg/kg, however the PFOS concentration in a sample recovered approximately 100m further downstream in the RAAF Drain was 2.45 mg/kg (SS14).

Two investigation locations were targeted in the Bulk Fuel Area to the west of Building 521 and the evaporation pond (BH48 and BH49). The soil results for samples recovered from these locations also reported detectable concentrations of PFOS in surface samples up to a maximum concentration of 0.19 mg/kg, with PFOS detected to the maximum depth extent of the borehole at location BH48 (0.75m bgs).

Surface water samples collected from ponded water in the area between Building 521 and the evaporation pond reported concentrations of PFOS in all samples ranging from 190 µg/L (SW03) to 6,450 µg/L (duplicate sample associated with SW01, located immediately northeast of the evaporation pond). A surface water sample collected from water within Building 521 (foam retention tank) reported a PFOS concentration of 2,770 µg/L. PFOS concentrations in surface water collected from the SDB ranged from below the laboratory LOR (WS01) to 60 µg/L (WS02).

The report also presents a summary of potential on-site sources of PFOS and associated pathways for contamination. A summary of these sources and associated pathways is provided below in Table 5.3.

Table 5.3: Summary of Primary PFOS Sources Identified in URS, 2011 Primary Source Contamination Pathways Evaporation Pond • Liner leakage

• Pipe work leakage • Pond topping over • Foam drift from surface of pond

Fire training/testing from concrete pad spray point into evaporation pond

• Foam drift during testing • Spray drift during training • Foam concentrate handling adjacent to the pond

Building 521, foam retention tank • Leakage through the base and sides of the concrete-lined tank

• Pipe work leakage Historical disposal, training, and spraying within the investigation area

• Direct discharge to surface • Accidental spillage/incidents

Historical disposal, training, and spraying outside the investigation area

• Direct discharge to surface • Accidental spillage/incidents

Of the above listed contamination pathways, spray drift from fire training activities and from foam blowing out of the evaporation pond were witnessed by URS personnel during the site investigation and were therefore considered likely to be at least one of the sources of the soil impacts identified during the investigation.

The report included a qualitative risk assessment completed to assess potential risks to on-site employees, on-site fire fighters, and Salisbury ASR scheme users. The report concluded that, whilst there was significant potential for dilution of PFOS during operation of the ASR scheme (e.g. mixing with non-impacted groundwater), the use of water from the SDB in the ASR scheme was not recommended without some form of remediation to reduce PFOS concentrations. The remaining human health receptor groups were not considered to be at an elevated risk based on the likely exposure scenarios.

The approximate extent of the investigations in the vicinity of Building 521 and the evaporation pond, and throughout the SDB, are depicted on Figure 7 (attached).


5.2.3 SA 3139 Asbestos and Contaminated Soil Remediation Option Report, RAAF Edinburgh Site SA019 (AEC, 2012)

AEC was engaged to undertake an investigation to verify if asbestos containing material (ACM) and/or other soil contamination was present at a former dumping site at RAAF Base Edinburgh, identified as site SA019 (referenced as SA0076 in the Edinburgh CSR). The investigation considered the potential presence of selected PFAS as a result of the historical use of legacy AFFF at the Base. A total of three primary soil samples were analysed for PFOS, PFOA, and 6:2 Fluorotelomer Sulfonate (6:2 FTS). Laboratory analytical works for PFAS were performed by ALS Laboratory Group.

Detectable concentrations of PFOS and PFOA were reported in all three soil samples with concentrations ranging from 1.13 mg/kg to 53.3 mg/kg for PFOS, and from 0.0096 mg/kg to 0.29 mg/kg for PFOA. A single sample reported a detectable concentration of 6:2 FTS (0.013 mg/kg).

The report indicates that the source of the identified PFAS impacts is anecdotally from the historical incineration of waste materials at the investigation site for firefighting training exercises, that would have been extinguished using AFFF.

The extent of the investigation area referenced in the report is depicted on Figure 7 (attached).

5.2.4 AFFF Infrastructure Assessment (URS, 2012)

URS was engaged to undertake an AFFF infrastructure assessment at RAAF Base Edinburgh including assessment of the integrity, design, functionality, suitability, and capacity of the waste water system infrastructure and equipment from hangar catchment drains through to the evaporation pond. The scope of the assessment also included mapping of the existing AFFF waste water system infrastructure and determination of any required rectification works. The relevant findings and recommendations from the report are summarised below:

• The evaporation pond did not meet the requirements of the Environmental Guidelines for Management of Fire Fighting Aqueous Film Forming Foam (AFFF) Products (DEIM, 2007) due to the absence of a sufficient liner (i.e. there were cracks in the existing clay liner) that could result in the leaching of waste water from the pond;

• The evaporation pond had insufficient containment volume for AFFF hangar and fire tender testing;

• The installation of a second evaporation pond was recommended to provide sufficient containment volume for the AFFF waste water;

• Large quantities of AFFF concentrate (estimated at 16,000L) were noted to have historically been disposed directly into the evaporation pond during maintenance activities (such as changing the foam concentrate storage tank bladders);

• The report stated that the evaporation pond should never be used to ‘dump’ AFFF concentrate as occurred at the time of the report; and

• The report recommended an improved design of the fire tender test pad adjacent to the evaporation pond (asset T0769) to reduce contamination of surrounding areas from wind-blown foam during fire tender testing, including the potential use of de-foaming agents.

The report indicated that an automated AFFF fire suppression system had been installed in Hangars T0564, T0592, T0593, T0594, and T0595 located to the north and northeast of Building 521 and the evaporation pond. Under testing of these systems (understood to be on a 5-yearly basis), AFFF waste water was directed to a series of stormwater grates on the adjacent tarmac area where water was directed (gravity fed) via underground pipe work either directly to:

1. The foam retention tank in Building 521; and/or

2. The adjacent evaporation pond; and/or


3. Two open holding tanks located to the northwest (Holding Tank HT-2) and southeast of the Hangars (Holding Tank HT-1) where it was mechanically transferred via a submersible pump setup (adjacent to each holding tank in a pump pit station) to the foam retention tank in Building 521 and/or the adjacent evaporation pond.

The report noted the presence of actuated diverter valves to retain water in the two holding tanks during testing of the AFFF system. Under normal operation (i.e. when the AFFF system is not being tested), the valves remain open to allow stormwater to flow out of the holding tanks to the adjacent open stormwater drainage channels.

The report also indicated the presence of a 1,000L AFFF concentrate storage tank in the area of the fire tender test pad, located immediately adjacent to the evaporation pond (asset T0769). The locations of Hangars T0564, T0532, T0593, T0594, and T0595, holding tanks HT-1 and HT-2, Building 521, the AFFF evaporation pond, and the fire tender test pad are shown on Figure 7 (attached).

Prior to construction of the AFFF evaporation pond in 2004, AFFF waste water was reportedly being discharged to the sewer. The report does not indicate whether discharge to the former sewage treatment plant (STP) at RAAF Base Edinburgh ever occurred, however the indication that the historical practice for AFFF waste water disposal was to discharge to sewer would suggest that this may have occurred during operation of the on-Site STP.

5.2.5 Edinburgh Defence Precinct Groundwater Monitoring, Groundwater Monitoring Event March 2014 (GHD, 2014a)

GHD was engaged to complete a groundwater monitoring event (GME) of 188 monitoring wells across the EDP. Of the 188 monitoring wells targeted for sampling, a total of 32 were analysed for PFAS (PFOS, PFOA, and 6:2 FTS) comprising all airside wells, and wells associated with the Bulk Fuel Store and Building 521 (foam retention tank).

PFAS were detected across the Site in varying concentrations with PFOS detected in 20 wells, PFOA detected in 14 wells, and 6:2 FTS detected in a single well. PFOS reported the highest concentrations in each well where PFAS were detected and typically comprised greater than 80% of the total PFAS concentrations. The highest PFOS concentrations were detected in monitoring wells GW0428 (1,140 µg/L) located close to the static rocket firing range and current firefighting training area (Building 155/156), GW0310 (239 µg/L) located close to the Bulk Fuel Store, and GW0008 (224 µg/L) located close to the former firefighting training area and waste dump (Site 19, CSR number SA0076).

The report notes that five of the wells sampled for PFAS (GW0435 to GW0439) were sampled using a Teflon-lined dedicated bailer. Due to the potential for Teflon to reportedly ‘adsorb’ PFAS (refer Concawe, 2016), the results from these wells should be treated with a degree of caution and may have underrepresented the actual PFAS contamination present at the time of sampling.

The location of the 32 wells targeted for PFAS sampling and the corresponding PFOS concentrations reported in the 2014 GME are shown on Figure 7 (attached).

5.2.6 SA3787 Edinburgh Defence Precinct Groundwater Well Installation (GHD, 2014b)

GHD was engaged to undertake the installation of 22 groundwater monitoring wells across the EDP to further define the extent of known groundwater contamination beneath the site. Of these, seven monitoring wells were installed within RAAF Base Edinburgh to assess PFAS as the key contaminants of concern. The wells are identified as follows:

• EDMW04 (installed near Building 521, foam retention tank; CSR Ref. SA1029);

• GW0196 (installed at Site 19; CSR Ref. SA0076);




• GW0428 (installed near Site 155/156; CSR Ref. 0080);

• GW0430 (installed adjacent to southern boundary, west of Site 17; CSR Ref. SA0068); and

• GW0431 (installed adjacent to southern boundary, west of Site 17; CSR Ref. SA0068).

During installation of these monitoring wells, soil samples were also recovered for laboratory analysis. A total of 17 soil samples were analysed for PFOS, PFOA, and 6:2 FTS. A summary of the results reported above the laboratory LOR is provided in Table 5.4.

Table 5.4: Detectable Concentrations of PFAS in Soil Samples (from GHD, 2014b) Well ID Depth (m) Analyte Concentration (mg/kg) GW0196 0.5 PFOS 0.007 GW0196 7.0 PFOS 0.0009 GW0197 0.5 PFOS 0.253 GW0197 0.5 PFOA 0.019 GW0197 7.0 PFOS 0.001 GW0198 0.5 PFOS 0.0005 EDMW03 (sampled from EDMW04) 4.0 PFOS 0.002 EDMW03 (sampled from EDMW04) 6.0 PFOS 0.006 GW0428 0.5 PFOS 0.745 GW0428 0.5 PFOA 0.002 GW0428 6.0 PFOS 0.074 GW0428 6.0 PFOA 0.002

The report notes that soil samples were collected in glass jars with Teflon lined lids. Due to the potential for glass and Teflon to reportedly ‘adsorb’ PFAS (refer WA DER, 2017 and Concawe, 2016), the soil sample results should be treated with a degree of caution and may have underrepresented the actual PFAS contamination present at the time of sampling.

The monitoring wells were subsequently sampled as part of the 2014 GME undertaken by GHD, discussed in Section 5.2.5 The location of the seven monitoring wells targeting PFAS are shown on Figure 7 (attached).

5.2.7 SA Environmental comments - Defence Estate Legacy PFC Review July 2015 (Defence, 2015)

This document is an email from the (at the time) Acting Assistant Director Environment and Sustainability, Estate and Facility Services, Defence Support – Central and West (SA), Ms Nicole McCarron, providing an apparent review response to a document referenced as “Defence Estate PFC Review July 2015”. The email provides the following information relevant to the historical use and/or distribution of AFFF at RAAF Base Edinburgh:

• AFFF was historically sprayed on multiple airside grassed areas as part of vehicle training/testing activities;

• PFAS impacts were considered to be more confined to soils, sediments and groundwater than surface water, and notes that there are no water bodies on RAAF Base Edinburgh other than the AFFF evaporation pond;

• Site AFFF use also included vehicle testing;

• Foam “fly-off” from the evaporation pond has historically occurred as a result of discharging vehicle testing waste water under conditions of high waste water levels in the pond (foam results on the water surface) and windy conditions (foam subsequently blown off to surrounding areas);

• The foam retention tank has historically overflowed to the surrounding area and adjacent open stormwater channel;


• Impacted surface water has been discharged direct to the open stormwater channel as a result of a historic pipe connection (now closed) and from general surface runoff from impacted soil in the area surrounding the evaporation pond;

• Faulty AFFF waste water infrastructure (diversion valves) may have resulted in the historic discharge of impacted waste water from hangar testing events being discharged direct to stormwater;

• Impacted waste water has historically been discharged from the fire tender test pad to the surrounding area during vehicle testing activities;

• The design of the fire station would result in any AFFF leaks from vehicles apparently being directed to an adjacent stormwater drain rather than contained; and

• The major site risks relating to historical impact from AFFF is identified as sedimentation in the stormwater/swale network, impacted surface soils that continue to leach into surface runoff during rainfall events, the unknown extent of groundwater impacts, off-Site groundwater impacts, unknown source zones, site infrastructure that does not currently contain AFFF waste water (i.e. the fire station), possible breaches in the evaporation pond liner, and impact to the downstream Salisbury ASR network.

5.3 AIR 7000 Project Documents

5.3.1 Segregation of Soils proposed for Excavation from Areas 1, 2 and 3, AIR 7000 Project Area, RAAF Base Edinburgh (AECOM, 2016a)

AECOM was engaged to undertake in-situ characterisation of waste soils within nominated Areas 1 to 3 of the AIR 7000 construction project at RAAF Base Edinburgh. The purpose of the investigation was to assess the nature and extent of potential contaminants within waste soils expected to be generated during the AIR 7000 project, including PFAS.

Intrusive investigations were undertaken in June 2016 and targeted shallow soils within and adjacent the location of proposed AIR 7000 infrastructure. Concentrations of PFAS were reported above the laboratory LOR across the majority of investigation locations, reportedly indicating the widespread presence of PFAS across the Site. The highest PFAS concentrations were reported to exceed the former DCD #8 interim screening criteria for Clean Fill. The report also noted that PFAS concentrations appear to typically decrease with increasing depth through the natural clay soils, although concentrations exceeding the laboratory LOR were observed at depths up to 2.2m bgs.

Leachate testing was conducted on a range of samples and reportedly indicated that the PFAS compounds were readily mobilised. The report concluded that soils containing PFAS impacts, even at concentrations below adopted investigation levels, should be considered to potentially pose a risk of impact to surface water and groundwater.

It is noted that the tabulated analytical results and the laboratory analytical reports were not included in this letter report. The report is identified as a “summary letter” and references a detailed report which is likely to contain the laboratory results, identified as:

Draft Report: AIR7000 Project, RAAF Base Edinburgh – In-situ Waste Soil Characterisation of Areas 1-3, Job No 60287313 dated 10 August 2016.

To date a copy of this detailed report has not been received by JBS&G. The approximate extent of the soil investigations in Areas 1 to 3 are depicted on Figure 7 (attached). JBS&G understands that the surplus soils generated by the project were initially stored in the southern stockpile storage facility, a dedicated on-Site stockpile storage facility constructed for the management of PFAS impacted soils generated by the AIR7000 project. It is further understood that the soils have since been managed in accordance with the Defence PFAS Framework for Construction and Maintenance Projects (Defence, 2018b).


5.3.2 In-Situ Waste Soil Characterisation for Northern Runway Extension, AIR 7000 Project, RAAF Base Edinburgh (AECOM, 2016b)

AECOM was engaged to undertake in-situ characterisation of waste soils within the northern runway extension of the AIR 7000 construction project at RAAF Base Edinburgh. The purpose of the investigation was to assess the nature and extent of potential contaminants within waste soils expected to be generated during construction of the northern runway extension for the AIR 7000 project, including PFAS.

Concentrations of selected PFAS compounds (in particular PFOS, PFHxS and PFOA) were reported above the laboratory LOR within the shallow soil profile across the majority of investigation locations (40 of 69 investigation locations). The highest concentrations of PFOS, PFHxS and PFOA were reported at the northern end of the current northern runway, and to the east of the northern portion of the current northern runway. The highest reported concentrations for PFOS, PFOA, and PFHxS were 0.159 mg/kg, 0.251 mg/kg, and 0.0086 mg/kg respectively.

The approximate extent of the soil investigations for the northern runway extension area are depicted on Figure 7 (attached).

5.3.3 Email correspondence: Air7000 Sites - Boundary Confirmation (Lendlease, 2016)

Following an email request to Lendlease (Mr Vik Kumar, Senior Project Engineer) for information regarding the extent of the AIR 7000 site boundary, JBS&G was provided a set of laboratory analytical results for sediment, surface water, and pore water testing that was undertaken for the AIR 7000 project construction work scheduled for the area to the north of the main apron. The sampling works were undertaken throughout the Helps Road Drain (RAAF Drain) passing through RAAF Base Edinburgh, and from within stormwater swales to the east of the Helps Road Drain (that ultimately discharge to the drain). A total of 10 sediment, and eight surface water and pore water samples were collected and analysed for PFAS (in addition to other analytes).

Detectable concentrations of PFOS were reported in all sediment samples, ranging from 0.009 mg/kg to 0.072 mg/kg. Detectable concentrations of PFOS were also reported in all surface water and pore water samples, with the highest reported concentration for the sum of PFHxS and PFOS being 7.09 µg/L (collected from a stormwater swale approximately 400m north of the main apron).

Subsequent correspondence received from Mr Michael Hood (Associate, Advisory, Aurecon) provided analytical results for additional surface water samples collected at three locations for the AIR 7000 project, comprising the following:

• One location within the Helps Road Drain to the north of the AIR 7000 project area;

• One location from within a temporary detention basin constructed for the AIR 7000 project (to the north of the main apron); and

• One location within the Helps Road Drain to the south of the AIR 7000 project area.

Detectable concentrations of PFOS and PFOA were reported in all samples, PFHxS was reported in two of the samples, and 6:2 FTS was reported in a single sample. The highest reported concentration for the sum of PFHxS and PFOS was 1.09 µg/L in the sample collected from within the temporary detention basin. The additional surface water samples referenced by Aurecon are shown on Figure 7 (attached).

5.4 Base Estate Plans

5.4.1 Edinburgh Defence Precinct Base Specific Investigations (Jacobs, 2016a and Jacobs, 2016b)

Jacobs was engaged to prepare the EDP Estate Base Plan. This document consolidates information regarding existing land use, environmental, facilities and infrastructure planning for the EDP into a single Estate Base Plan that will ultimately guide future development and re-investment for the EDP.


Part of the Estate Base Plan development process was the preparation of a Base Specific Investigations report that collates the findings and mapping from EDP specific investigations. This included a high-level assessment of historical environmental assessment and remediation work that has been undertaken across the EDP, including specific discussions regarding RAAF Base Edinburgh.

A site contamination map for the EDP presented in the report (refer Figure 2.38, p 68) identified the location of sites recorded on the CSR. In addition, two sites were identified within RAAF Base Edinburgh as being AFFF Waste Storage Areas; one covering the general area of the Hangars, Bulk Fuel Store, Building 521, and the AFFF evaporation pond; and the other covering the area of the SDB and a portion of land immediately south of the Site boundary. The approximate location and extent of the AFFF Waste Storage Areas are shown on Figure 7 (attached). No other information regarding the source of the areas shown as AFFF Waste Storage is presented in the report.

5.5 Stormwater – Base Water Quality Assessment, Edinburgh Defence Precinct – Base Engineering Assessment Program (Aurecon, 2012)

Aurecon was engaged to undertake a baseline stormwater quality assessment for the EDP assessing the quality of stormwater entering and leaving the EDP. The works were undertaken as part of the Base Engineering Assessment Program (BEAP), Phase 2. The report notes that AFFF (PFAS) analysis was undertaken as part of the stormwater quality assessment, however “due to project timelines and availability of laboratory results” the PFAS results were not presented in the report. Instead the report indicated that the PFAS results would be reported in BEAP Phase 3. A copy of the BEAP Phase 3 report has been requested but has not been provided at the time of this report.

A total of four surface water samples were collected for the investigation, of which three were collected at RAAF Base Edinburgh (two within the Taranaki Drain and one in the Helps Road drain upstream of the confluence with the Taranaki Drain) and the other collected at the DSTG site. The approximate location of the surface water samples collected at RAAF Base Edinburgh are shown on Figure 7 (attached).

5.6 Defence Estate Legacy PFC Review - DEHP-ID-022 (CH2M, 2015)

CH2M was engaged to conduct a desktop review of perfluorinated compounds (now referred to as PFAS) across the National Defence estate. The objectives of the project were to capture information relating to historical AFFF usage at nominated facilities, evaluate the potential risks to human health and/or ecological receptors, and to categorise facilities by priority for action. As part of these works, an assessment of the historical use of AFFF at RAAF Base Edinburgh was undertaken.

The report identified ten ‘sites’ as known or potential sources of AFFF or AFFF impacted sites. A summary of these 10 sites is provided in Table 5.5 below.

Table 5.5: Summary of Known or Potential AFFF Impacted Sites from CH2M, 2015 CSR Reference Number “Site” Name SA1029 (CSR_SA_000278) AFFF waste water evaporation pond SA0076 (CSR_SA_000282) Former Fire Training Area and Subsurface

dump (Site 19) SA0072 (CSR_SA_000292) AVTUR Tank Farm (i.e. the Bulk Fuel Store) SA0071 (CSR_SA_000034) Hangar 594 plus three other hangars SA0079 (CSR_SA_000291) Burning Off Area (Site 63) SA0068 (CSR_SA_000301) Former Sewage Treatment Plant N/A Southern Stormwater Detention Basin

and RAAF Drain N/A Smokeroom Training Area SA0077 (CSR_SA_000287) Site 49 - Isolated Aircraft Parking N/A Current Fire Station

The report comments that the general use of AFFF at RAAF Base Edinburgh is related to operations (hangars and the Bulk Fuel Store) and fire training activities. Building 521 and the AFFF evaporation


pond were identified as the main AFFF waste water management system infrastructure in place to process AFFF waste from these activities. The waste water infrastructure is reported to receive waste water from three principal sources - weekly foam testing of Aerodrome Rescue and Fire Fighting (ARFF) vehicles, automated hangar fire suppression systems, and a chemical storage shed which includes any incidental spills and vehicle washing. In addition, the report identified static and full foam testing of fire trucks was sprayed directly into the evaporation pond.

Anecdotal evidence identified the disposal of 3M Light WaterTM concentrate directly into the evaporation pond on one occasion, although JBS&G note that information reported by URS (2012) indicates large quantities of AFFF concentrate (estimated at 16,000L) may have been historically disposed directly into the evaporation pond during maintenance activities.

The evaporation pond was reported to have historically experienced containment breaches where foam was blown off the surface of the pond, and where waste water overflowed to surrounding unsealed ground during heavy rain events. The report also quotes that “in 2009 waste water from the pond was discharged to stormwater and into the southern detention basin”. Prior to the construction of the evaporation pond, AFFF waste water may have been directed to the former STP (CSR Ref. SA0068) which included associated lagoons.

The SDB was identified as a site impacted by AFFF. The report goes on to comment that surface water from the SDB has reported concentrations of PFOS above the nominated guidelines. Water sourced from the SDB is used by the City of Salisbury Council in their ASR scheme, whereby water is injected into the Tertiary Aquifer and recovered for future reuse. The report indicates that water recovered from the ASR scheme is distributed for irrigation (including to market gardens) and “it is therefore possible that PFASs are impacting a significant Council resource and potentially creating diffuse sources of PFASs off-facility via irrigation. This also creates the potential for PFASs impacted dust from surface irrigation”.

Other potential pathways and receptors of concern were considered to include several wetlands (from off-Site migration of PFAS impacted groundwater and/or off-Site migration of PFAS impacted sediment and surface water), and potential human health receptors including potential consumers of PFAS impacted groundwater being used as a drinking water supply, and “consumption of market garden vegetables irrigated with PFAS impacted groundwater”.

5.7 Timeline for Analysis and Management Actions Regarding PFOS and PFOA within AFFF products at RAAF Edinburgh

A table outlining the timeline for analysis and management actions regarding PFOS and PFOA within AFFF products at RAAF Base Edinburgh current up to 25 July 2016 was provided by Defence and is included as Appendix E. A summary of the key information provided in the timeline is provided below:

• The use of AFFF product 3M Light WaterTM commenced at the Site in 1978;

• Vehicle training and testing with AFFF (3M Light WaterTM) was undertaken on-Site from 1978 onwards with approximate locations identified on a hand-marked map (also included in Appendix E);

• Automated AFFF fire suppression systems were fitted to Hangars T0592, T0593, T0594 and T0595 in 1995 with each system containing 8,000L of AFFF concentrate;

• Hangar T0564 was constructed in 1996 and was also fitted with a system containing 8,000L of AFFF foam concentrate (comprising 8 x 1,000L foam concentrate tanks);

• A 2,800L AFFF deluge system was installed at the Bulk Fuel Store (Building 766) in 1998;

• In 2002, Airfield AFFF vehicle testing and training was restricted to one airside location within the fire training facility (identified as Building 618);


• In 2004, the fire tender test pad and AFFF waste water evaporation pond were constructed for containment of all vehicle wet testing and Hangar AFFF waste water. At this time all airside vehicle testing and training ceased;

• All hangars were modified in 2004 by installing a drain at the front of the hangars to recover AFFF discharged through either foam suppression system testing or actuation, with AFFF waste water directed to the AFFF waste water evaporation pond;

• In 2005, all mobile fire vehicle units transitioned from 3M Light WaterTM to Ansulite, however legacy 3M Light WaterTM product was retained by the Defence Support and Reform Group (DSRG) for use in the Hangar fixed foam suppression systems until sufficient stocks of Ansulite could be sourced;

• The first investigation identifying PFOS impacted surface and sub-surface soil at a former fire training ground on-Site was undertaken in 2007;

• Between 2007 and 2009, the Hangars transitioned from the use of 3M Light WaterTM to Ansulite (on a staggered basis to maintain operations) with the legacy 3M Light WaterTM concentrate from three hangars reportedly disposed direct to the AFFF evaporation pond;

• In 2008, PFOS was detected in groundwater (monitoring well GW8 located at Site 19, CSR Ref. SA0076), and soil impacts were identified at a new site (Site 63, CSR Ref. SA0079);

• In 2009, AFFF Waste Water was reportedly discharged from Hangar 595 direct to a stormwater drain (inferred to be the Helps Road Drain) as a result of a pump malfunction during the 5 yearly systems check;

• In 2013, AFFF waste water overflowed from Building 521 (foam retention tank) and discharged to stormwater due to an incorrectly installed and operated new AFFF waste water diversion valve which allowed stormwater into Building 521 during a high rainfall event;

• In 2013, a second AFFF concentrate discharge occurred as a result of vehicle damage to site AFFF infrastructure within the Bulk Fuel Store resulting in discharge to surrounding soil, internal swale drain and stormwater drain (which ultimately feed into the Helps Road Drain);

• The 2,800L of 3M Light WaterTM concentrate stored in the deluge system installed at the Bulk Fuel Store (Building 766) was decanted and replaced with Ansulite in December 2013;

• In 2014, a report prepared by GHD (Sampling Analysis Plan; GHD, 2014c) identified 15 sites with potential AFFF impacted groundwater including the Bulk Fuel Store, Building 521/AFFF waste water evaporation pond, Site 16 (CSR Ref. SA0073), Site 49 (SA0077), Site 125 (SA0075), Site 155/156 (SA0080), Site 19 (SA0076), Site 17 (SA0068), Site 63 (SA0079), missile test facility, engine run up facility, Runway 0422, fire station, Site 128/131 – Blue Steel Loading Facility (SA0215), and the SDB;

• Groundwater monitoring in 2014 identified 11 new sites impacted by AFFF;

• In 2014, the AFFF waste water retention tank in Building 521 was cleaned, inspected and resealed, and indicated to be free of historic PFOS contamination; and

• The remaining 2,800L of known 3M Light WaterTM concentrate was disposed off-Site in February 2015.


5.8 SA Environmental Groundwater Monitoring, Edinburgh Defence Precinct (DRAFT) (GHD, 2016)

GHD was engaged to complete a GME of 157 monitoring wells across the EDP. Of the 157 monitoring wells targeted for sampling, a total of 42 were analysed for PFAS comprising all airside wells, and wells associated with the Bulk Fuel Store and Building 521 (foam retention tank).

PFAS were detected across the Site in varying concentrations with detectable concentrations recorded in groundwater sampled from 29 wells. PFOS and PFHxS reported the highest concentrations in each well where PFAS were detected and typically comprised greater than 80% of the total PFAS concentrations. The three highest PFOS and PFHxS concentrations were detected in the following monitoring wells:

• GW0428 (1,220 µg/L), located close to the static rocket firing range and current firefighting training area (Building 155/156);

• GW0310 (192 µg/L) located close to the Bulk Fuel Store; and

• GW0008 (437 µg/L) located close to the former firefighting training area and waste dump.

These results were considered consistent with the results of the 2014 GME. Several wells on the boundary of the Site also reported detectable concentrations of PFAS.

Concentrations of PFAS were reported to exceed the enHealth (2016) interim Drinking Water Quality Guideline values (i.e. 0.5 µg/L for PFOS and 5 µg/l for PFOA) in 24 monitoring wells across the Site. The location of the 40 wells targeted for PFAS sampling and the corresponding PFOS concentrations reported in the 2016 GME are shown on Figure 7 (attached).

5.9 Figure Showing Historic AFFF Use Areas Still to be Investigated (Broadspectrum, 2016)

A figure showing historic legacy AFFF use areas identified as “still to be investigated” was provided to JBS&G at a site inspection undertaken on 29 November 2016. A copy of the figure is provided as Appendix D. The figure identifies six areas in the airside operations area of RAAF Base Edinburgh. These areas have been considered as potential AFFF source areas and are discussed further in Section 7.


6. Interviews with Site Personnel

To assist with the identification of potential legacy AFFF source areas, JBS&G undertook interviews with current and ex-serving firefighting personnel. To commence this process and identify relevant personnel with whom interviews may be relevant, a questionnaire relating to the historical storage, use and disposal of AFFF at the Site was distributed to relevant personnel via email in February 2017 (distributed by the EMOS contractor, Broadspectrum, responsible for the current provision of firefighting services at the Site). The questionnaire included the following questions:

• Do you know of any former storage areas of AFFF products on-Base?

• Have any major incidents within or around the Base required a significant discharge of AFFF?

• Have you witnessed, or know of any discharges of Aqueous Film Forming Foams (AFFF) outside of the designated fire training area and foam discharge pit (evaporation pond)?

• Do you know of any AFFF discharges that may have occurred as part of training drills, equipment/plant/systems malfunction or real-life incidents requiring AFFF application?

• Do you know of any areas where AFFF, or materials containing AFFF, may have been disposed (e.g. landfills, stockpile storage areas)?

In addition, a template table to capture information relating to approximate dates/years, location, incident/activity description, and estimated volume of AFFF stored/discharged/disposed was included. A collective response to the questionnaire was received and is provided as Appendix F.

Following receipt of the response from firefighting personnel, subsequent on-site interviews and targeted site inspections (to confirm the locations of the areas identified in the written response) were completed on 30 March and 3 April 2017. During the on-site interview process, additional areas where fire training exercises were reported to have taken place were identified. Details relating to these and other potential PFAS source areas are discussed further in Section 7.

During the interview process, the Base firefighting personnel indicated that the “Birdbath area” identified in the initial written response (Appendix F) was not a historical training/testing area. This area is an automated aircraft wash down facility located within the south-western portion of the airside operations area that is effectively off limits to other vehicles to avoid inadvertent operation of the facility (i.e. triggering of the automated aircraft sensors). However, the groundwater results for a monitoring well installed to the west-southwest of this infrastructure (GW2178) indicate that some historical discharge of AFFF may have occurred in this area (refer Section 11.4.5).

The fire training and testing exercises were typically described by firefighting personnel as a simulated response to an emergency event where mobile firefighting equipment was used in the response, including the discharge of AFFF. The simulations involved the use of firefighting cannons, mounted on the fire trucks, directing a mixture of water and AFFF concentrate into a target area, typically at the end of a hardstand area (e.g. at the edge of a taxiway). In some instances site features, such as the revetment (blast) walls within the ordnance unloading area in the southern portion of the airfield, were used as a target for application of AFFF during training exercises. Details relating to the frequency of use and likely volumes of AFFF concentrate discharged in the respective areas during training/testing exercises were not recorded and were not able to be provided (recalled) by the Base firefighting personnel during the interview process.


7. Preliminary Conceptual Site Model

As described in the ASC NEPM (NEPC, 1999), a CSM is a representation of site-related information regarding potential contamination sources, receptors that may be exposed to such contamination, and the exposure pathways between those sources and receptors. The development of a CSM is a critical part of any contaminated site investigation process. It provides the foundation for development of a DSI program that will efficiently and effectively investigate the contamination status of a site and the potential risks posed to the identified receptors.

The development of a CSM is a dynamic and iterative process. As such, the preliminary CSM presented in this section has subsequently been refined throughout the investigation program as new information and data has been gathered. The refined CSM following completion of the DSI program discussed in this report is provided in Section 12.

The preliminary CSM discussed below was used in the development of the DSI SAQP (JBS&G, 2017b), including DQOs.

7.1 Contaminant Profile

The primary COPC targeted for this investigation are PFAS. PFAS are a group of manufactured chemicals that have been used globally for more than 50 years in a wide range of products (HEPA, 2018). The unique properties of certain PFAS chemicals give them the ability to make products non-stick, water repellent, and fire resistant, and stain resistant. As such, PFAS have been used in the manufacturing of consumer products such as carpets, clothes and paper, and have been used as a key ingredient in firefighting foams (i.e. AFFF).

The unique properties of PFAS that make them suitable for use in water repellent and fire resistant products, also result in these chemicals being very stable and having the ability to resist physical, chemical and biological degradation. It is the persistence of PFAS in the environment and their widespread global use in various applications that has resulted in many types of PFAS being considered ubiquitous global contaminants (enHealth, 2017).

In addition to being used to make certain products water repellent, certain PFAS are also highly soluble in water. Molecules of PFAS are made up of a chain of carbon atoms flanked by fluorine atoms, with a hydrophilic group at their head that assists with solubility in water (HEPA, 2018). The high solubility of PFAS means they will readily leach from soil to nearby surface water and the underlying groundwater system where they can migrate long distances from the original source area.

As discussed in Section 1.1, the key PFAS of interest based on the legacy AFFF formulations used at the Site include PFOS, PFOA, and PFHxS. A summary of the chemical and physical properties of these PFAS, adopted from US EPA (2017), Food Standards Australia New Zealand (FSANZ, 2017), and the European Chemical Agency (ECHA, 2017) is provided in Table 7.1.

Table 7.1: Chemical and Physical Properties of PFOS, PFOA, and PFHxS Property PFOS PFOA PFHxS Chemical Abstracts Service (CAS) number

1763-23-1 335-67-1 355-46-4

Chemical Structure C8HF17O3S

C8HF15O2

C6HF13O3S

Physical State at Room Temperature and Atmospheric Pressure

White powder (potassium salt) White powder/ waxy white solid

White crystalline powder

Molecular Weight (g/mol) 500 414 400.11


Property PFOS PFOA PFHxS Water solubility at 25oC (mg/L)

680 9.5 x 103 2.3 x 103

Melting point (oC) > 400 54.3 272-274 Boiling point (oC) 258–260 192.4 114.7 Vapor pressure at 25oC (mm Hg)

0.002 0.525 0.0046

Organic carbon partition coefficient (Koc)

2.57 2.06 5.17

Henry’s law constant (atm-m3/mol)

Not measurable Not measurable Not measurable

Abbreviations: g/mol – grams per mole; mg/L – milligrams per litre; oC – degree Celsius; mm Hg – millimetres of mercury; atm-m3/mol – atmosphere-cubic meters per mole

7.2 Sources of Contamination

7.2.1 Primary Sources

Based on the relevant historical information gathered in relation to the Site, including interviews with site personnel, a review of the known and potential primary sources of PFAS contamination was undertaken and is summarised in Table 7.2 (below). The approximate location and extent of the known and potential primary source areas is shown on Figure 8.


Table 7.2: Summary of Known and Potential Primary Sources of PFAS Contamination Primary Source ID

Site Description CSR Reference Description Likelihood of Significant PFAS Contamination Based on Historical Information

P1 AFFF Waste Water Retention Tank (Building 521) and AFFF Waste Water Evaporation Pond

CSR_SA_000278 Building 521 (foam retention tank) and the AFFF evaporation pond are the primary infrastructure that receive AFFF waste water, as documented in the Defence CSR and AFFF Infrastructure Assessment completed by URS in 2012 (URS, 2012).

High, based on previous soil, surface water, and groundwater monitoring results.

P2 Bulk Fuel Store, including 2,800L AFFF deluge system

CSR_SA_000292 Located to the west of Building 521 and the AFFF evaporation pond and comprises two separate bunded areas, each with 2 x 1.5 ML aboveground storage tanks storing F34 Jet Fuel (totalling 6 ML of F34 jet fuel). The Bulk Fuel Store also comprises a 2,800L AFFF deluge system, as documented in the Defence AFFF Timeline (refer Appendix E). During the 2017 interviews conducted by JBS&G, firefighting personnel indicated there had historically been a significant accidental release (i.e. entire contents) of concentrate from the deluge system.

High, based on previous groundwater monitoring results.

P3 Hangars T0564, T0592, T0593, T0594, and T0595, including Chesterfield Sumps

CSR_SA_000034 These Hangars have automated fire suppression systems that previously contained 3M Light WaterTM in a series of foam concentrate tanks, as noted in in the Defence AFFF Timeline (refer Appendix E). The waste water generated during testing of the fire systems drains to the Chesterfield Sumps where it is retained before being pumped to the AFFF Evaporation pond, as documented by URS (2012).

High, based on legacy AFFF storage and previous groundwater monitoring results.

P4 Former Fire Training Area and Sub-surface Waste Dump (Site 19)

CSR_SA_000282 Located in the northern portion of the airside operations and was previously used as a firefighting training area, which included six former burning off areas as documented in the CSR.

High, based on previous soil and groundwater monitoring results.

P5 Isolated Aircraft Parking Area CSR_SA_000287 Located to the south of SA0076. According to the CSR, this site was reportedly identified from historical aerial photographs showing a large plane that was blackened, along with the grass around the base of the plane.

Low, based on previous groundwater monitoring results, however warrants confirmation during the DSI.

P6 Former Burning Off Area (Site 63) CSR_SA_000291 The site was historically used as a burning off compound and subsurface waste dump, as documented in the CSR.

High, based on previous soil and groundwater monitoring results

P7 Airfield Taxiway Dump (Site 125) CSR_SA_000293 According to the CSR, the site was historically used as a dumping area for building and construction waste resulting from site activities. The CSR identifies AFFF (PFAS) as a contaminant of potential concern for the Site.


P8 Sub-surface Waste Dump (Site 16) CSR_SA_000286 The site is located on the central portion of the western boundary of the airfield and according to the CSR was reportedly used as a dumping area sometime after 1960.

Moderate, based on previous groundwater monitoring results.


Primary Source ID


P9 Static Rocket Firing Sites and Current Fire Training Area (Sites 155 & 156; Building 618), including Smokeroom Training Area

CSR_SA_000276 The CSR indicates that the buildings around Sites 155/156 have been identified by RAAF firefighters as an area of training with legacy AFFF. Based on the 2017 interviews with site personnel conducted by JBS&G, there is no use of AFFF in current fire training activities in this area.

High, based on previous groundwater monitoring results.

P10 Former Sewage Treatment Plant (STP) and Fire Training Area (including old 1 Recruit Training Unit (RTU) Training Area)

CSR_SA_000301 Location of the former STP that may have received AFFF waste water prior to construction of the AFFF evaporation pond in 2004, as noted by URS (2012) and CH2M (2015). The potential source area includes the surrounding area of former fire training by 1RTU, identified by Base firefighting personnel during the 2017 interviews conducted by JBS&G.

Moderate to High, based on previous groundwater monitoring results.

P11 Current Fire Station, including former AFFF Storage Area and foam test areas

N/A[1] Potential source area identified in the Defence Estate Legacy PFC Review (CH2M, 2015), and based on information provided by current firefighting personnel during the 2017 interviews conducted by JBS&G, is an area where legacy AFFF concentrate was historically stored and tested.

Unknown

P12 Taxiway AFFF N/A[1] Comprises two potential source areas of AFFF (PFAS) contamination identified in the 2016 GME Report (GHD, 2016) and shown on the Broadspectrum (2016) figure showing historic AFFF use areas still to be investigated (refer Appendix D).

Unknown

P13 AFFF Use Area 1 N/A[1] Identified on the Broadspectrum (2016) figure showing historic AFFF use areas still to be investigated (refer Appendix D). The potential source area was extended to the northern side of the access track in this area following information provided by Base firefighting personnel during the 2017 interviews conducted by JBS&G.


P14 Former Fire Training Area N/A[1] Area of historic fire training activities identified by Base firefighting personnel in the 2017 interviews conducted by JBS&G. Anecdotally firefighting personnel would advance to the intersection of the taxiways in this area and discharge water and AFFF from the fire truck cannons when stationary at the edge of the taxiway.

Unknown

P15 Former Fire Training Area in Ordnance Unloading Area

N/A[1] Area of historic fire training activities identified by Base firefighting personnel in the 2017 interviews conducted by JBS&G. The firefighting personnel indicated that the revetment walls within the ordnance unloading area were used as a target for discharge of AFFF during training exercises in this area.

Unknown


Primary Source ID


P16 Former Fire Training Area around Engine Run Up (ERUP) Facility

N/A[1] Identified in the 2014 Sampling Analysis Plan prepared by GHD (2014c), referenced in the Defence PFAS Timeline (refer Appendix E), as two areas of potential impact immediately northeast and northwest of the Engine Run Up Facility respectively. Information gathered during the 2017 interviews with Base firefighting personnel conducted by JBS&G indicated the training area encompasses the entire area around the ERUP Facility.

Unknown

P17 Former Fire Training Area in old Aerodynamics Area

N/A[1] Area of historic fire training activities identified by Base firefighting personnel in the 2017 interviews conducted by JBS&G. Personnel had recalled some historical exercises where AFFF may have been discharged during training in the vicinity of the old aerodynamics testing area.

Unknown

P18 Former Fire Training Area (eastern Pyramid)

N/A[1] Area of historic fire training activities identified by Base firefighting personnel in the 2017 interviews conducted by JBS&G. Personnel had recalled some historical exercises where AFFF may have been discharged during training in the unsealed areas surrounding the historic ordnance storage pyramids.

Unknown

P19 Former Fire Training Area (western Pyramid)

N/A[1] Area of historic fire training activities identified by Base firefighting personnel in the 2017 interviews conducted by JBS&G. Personnel had recalled some historical exercises where AFFF may have been discharged during training in the unsealed areas surrounding the historic ordnance storage pyramids.

Unknown

P20 Former Fire Training Area northeast of Site 19 (P4)

N/A[1] Area of historic fire training activities identified by Base firefighting personnel in the 2017 interviews conducted by JBS&G. Reportedly firefighting personnel would discharge water and AFFF from the fire truck cannons to the north of the vehicle access track in the area to the northwest of the northern extent of the grass runway.

Unknown

P21 Former Fire Training Area along Taxiway Bravo

N/A[1] Area of historic fire training activities identified by Base firefighting personnel in the 2017 interviews conducted by JBS&G, approximately 50m either side of the Taxiway. Firefighting personnel indicated they would discharge water and AFFF from the fire truck cannons when travelling along Taxiway Bravo (to both the eastern and western sides).

Unknown

P22 Site of several car fires (off-Site) N/A[1] Area where several car fires were extinguished by Base personnel with AFFF, as identified during the 2017 interviews conducted by JBS&G. The site is located at a cul-de-sac area immediately south of the Port Augusta Railway Line, near Crash Gate 1.

Unknown


Primary Source ID


P23 Site of train and semi-trailer crash N/A[1] Area where a train and semi-trailer collided in the late 1980s resulting in a vehicle fire being extinguished by Base personnel (as first respondents) with AFFF. Identified by Base firefighting personnel in the 2017 interviews conducted by JBS&G.

Unknown

P24 Fire truck rollover at southern end of main runway

N/A[1] Area where a fire truck rolled over and lost its load of AFFF concentrate (approximately 400L) sometime in the early 1990s. Identified by Base firefighting personnel in the 2017 interviews conducted by JBS&G.

Unknown

P25 Former 1RTU Fire Training Area N/A[1] Area of historic fire training activities identified by Base firefighting personnel in the 2017 interviews conducted by JBS&G. Firefighting personnel indicated they would discharge train with the use of water and AFFF in this area prior to it being redeveloped as a sporting ground and car park.

Unknown

P26 Historical AFFF Concentrate Spill N/A[1] Area of historic AFFF concentrate spill resulting from accidental leakage from fire truck foam tank, as identified by Base firefighting personnel during the 2017 interviews conducted by JBS&G.

Unknown

(1) N/A - new potential source areas identified as part of the PFAS Preliminary CSM development, not detailed in the Contaminated Sites Register


7.2.2 Secondary

In addition to the known and potential primary sources of PFAS identified above, there were a number of potential secondary sources of PFAS contamination considered to exist at the Site. In relation to PFAS compounds, secondary sources are typically described as locations where soil and/or sediment contamination has been present and has leached to the surrounding environment (i.e. surface water and/or groundwater) when water (e.g. rainfall) is introduced. In addition, PFAS contaminated surface water may present a secondary source of contamination to groundwater in unlined streams and stormwater drainage channels (in a losing stream environment). A summary of the potential secondary sources of PFAS contamination at the Site is provided below in Table 7.3. The approximate location and extent of the known and potential secondary source areas is also shown on Figure 8.

Table 7.3: Summary of Known and Potential Secondary Sources of PFAS Contamination Secondary Source ID Description Likelihood of Significant PFAS Contamination Based on

Historical Information S1 Contaminated soils surrounding Building

521, the AFFF evaporation pond, and adjacent Bulk Fuel Store.

High, based on evidence of historic AFFF waste water overflows from the evaporation pond and Building 521 (foam retention tank), and evidence of foam fly-off from the evaporation pond. This area has also been considered as a primary source area and has been assessed through primary source area investigations, thus is not depicted separately as a secondary source area on Figure 8.

S2 Contaminated surface water and/or soils/sediments within the unlined stormwater swale that passes the northern side of Building 521 and the AFFF evaporation pond.

High, based on evidence of historic AFFF waste water overflows from the evaporation pond and Building 521 (foam retention tank).

S3 Contaminated surface water and/or soils/sediments within the Helps Road Drain traversing through the Site.

High, based on evidence of historic contamination from waste water overflows from the evaporation pond and Building 521 (foam retention tank), and direct AFFF discharge from Hangar T0594 during a fire suppression system testing event.

S4 Contaminated surface water and/or soils/sediments within the SDB.

Moderate to high. The SDB receives stormwater from the upstream portion of the Helps Road Drain prior to stormwater overflowing to the downstream portion of the Helps Road Drain and ultimately flowing off-Site across the southern boundary. Historical investigations have identified PFAS contaminated surface water and sediment within the SDB.

S5 Contaminated surface water and/or soils/sediments within unlined stormwater swales in the airside operations area.

Unknown

In addition to the above, previous environmental investigations completed at the Site indicated the widespread presence of PFAS impacts in soils across the airside operations area of the Site.

7.3 Off-Site

7.3.1 Primary

During development of the preliminary CSM, a consideration of the potential for significant off-Site source of PFAS contamination was also undertaken. This included engagement with the SA EPA regarding work being undertaken to assess the likely sources of PFAS in South Australia to enhance its understanding of the current and historical use and distribution of PFAS containing chemicals, as identified in an EPA media release dated 11 June 2016 (EPA, 2016). JBS&G contacted the EPA to determine if any significant sources of PFAS had been identified in the vicinity of the Edinburgh area. The EPA response indicated that the work undertaken by the EPA to date had not identified any additional PFAS sources in the vicinity of Edinburgh.

Notwithstanding the above, the former General Motors Holden (GMH) site, located approximately 3km southeast of the Site, the industrial areas to the northeast of the Site (i.e. the upstream area),


and the DSTG site to the east were considered as potential off-Site sources of PFAS contamination. As such, consideration was given to the potential for PFAS contamination in surface water (i.e. stormwater) originating from these areas to be migrating toward the RAAF Base Edinburgh site as part of background surface water quality assessments conducted during the DSI. The catchment zones depicted on Figure 6 (attached) show an external catchment area adjacent to the GMH site that directs stormwater to the SDB via the Kaufmann Canal and the Port Augusta Railway Drain, before the stormwater ultimately discharges back into the Helps Road Drain downstream of the Site. This figure also shows stormwater generated within the DSTG catchment is directed onto Site via Taranaki Drain and/or Kaufmann Canal, and stormwater from the upstream industrial area to the northeast is directed onto Site via the Helps Road Drain and/or a drain that runs parallel to Stebonheath Road.

7.3.2 Secondary

The following potential off-Site secondary sources of PFAS contamination are considered to exist:

• Contaminated surface water and/or soils/sediments within the Helps Road Drain downstream of the Site (refer S3 on Figure 8);

• Contaminated surface water and/or soils/sediments with the Port Augusta Railway Drain downstream of the Site (located within source area P23 shown on Figure 8);

• Contaminated surface water and/or soils/sediments within the Kaurna Park Wetland which receives stormwater from the Helps Road Drain, located approximately 1.5km south-southeast of the Site (refer S5 of Figure 8);

• Areas irrigated with PFAS contaminated groundwater sourced from private irrigation bores located within the Investigation Area;

• Contaminated groundwater in the T2 Tertiary Aquifer as a result of the injection of PFAS contaminated surface water during the operation of the Salisbury ASR scheme (considered to be restricted to the Edinburgh Park South and Kaurna Park ASR bores); and

• Areas irrigated with potential PFAS contaminated groundwater formerly sourced from the Salisbury ASR scheme (in particular the Edinburgh Park South and Kaurna Park ASR bores)6.

Due to the widespread global use of PFAS in various applications, and persistence in the environment, many types of PFAS are considered to be ubiquitous global contaminants (refer enHealth, 2017). As such, it is not unreasonable to expect that low levels of some PFAS may be identified in some background groundwater and surface water samples, even in the absence of a specific identified off-Site source.

7.4 Potentially Affected Media

A summary of the media considered to have been impacted, or potentially impacted, by PFAS contamination resulting from the historic use of legacy AFFF at the Site is provided in Table 7.4.

Table 7.4: Summary of Known and Potentially Affected Media Based on Historical Information Media Comments Regarding PFAS Contamination Soil (and dust) Likely to be highest in the areas adjacent to Building 521 and the AFFF evaporation pond, and historic

fire training areas where AFFF may have been discharged direct to the soil surface. Soil impacts may also exist off-Site in areas irrigated with potential PFAS contaminated groundwater.

Surface Water Given legacy AFFF are no longer used on Site, and measures have been put in place to better manage the use of Ansulite AFFF, the potential for ongoing contamination of surface water is considered most likely to result from the leaching of PFAS from contaminated soils and/or sediments in primary source areas (i.e. representing secondary source contamination)

6 It is noted that the City of Salisbury isolated the injection/extraction bores at these sites from the broader ASR network in mid-2016

following the discovery of PFAS contamination in the extraction water


Media Comments Regarding PFAS Contamination Sediments Likely to be highest within the Helps Road Drain immediately downstream of the AFFF retention tank

(Building 521) and the AFFF evaporation pond, Bulk Fuel Store, former fire training areas, and within the SDB. The potential exists for sediments within the Helps Road Drain downstream of the Site, and within the Kaurna Park Wetland to be contaminated with PFAS. In addition, PFAS contamination in sediment pore water is likely to exist.

Groundwater PFAS contamination is known to exist in shallow groundwater (i.e. the Q1 Aquifer) beneath the Site. It is unknown if PFAS contamination extends to the underlying Quaternary Aquifers (i.e. Q2-Q4), however given the potential for a degree of vertical interconnection between these Aquifer units it is considered possible. Contaminated groundwater beneath the Site has the potential to migrate off-Site to surrounding areas. No historical off-Site investigations have been undertaken to assess the potential for PFAS contamination in the Q1 Aquifer to have migrated off-Site. In addition, there are known PFAS impacts in the T2 Tertiary Aquifer as a result of the injection of PFAS contaminated surface water during the operation of the Salisbury ASR scheme.

Concrete Likely to be highest in areas where current and historical AFFF concentrate storage pads are located and where potential spillage may have occurred, infrastructure that has been used for the storage of AFFF waste water, and in areas that have been subject to prolonged fire training exercises involving the discharge of AFFF.

Biota Terrestrial and aquatic biota (including vegetation and lower order species, such as invertebrates) may have been impacted by exposure to PFAS contaminated soil, surface water, sediment and/or groundwater.

7.5 Preliminary Exposure Pathways and Receptors at Risk

Based on the primary and secondary source areas identified above, and the known and potentially contaminated media, a preliminary assessment of the potential human and ecological receptors that may be exposed to Site-derived PFAS contamination was undertaken. In addition, a review of the exposure pathways and exposure routes via which the receptors may be exposed to PFAS contamination was undertaken. A summary of the potential receptors and exposure pathways is provided in Table 7.5 (Human Health) and Table 7.6 (Ecological).

For a potentially unacceptable risk of exposure to site contamination to exist there must be a complete linkage between a source (e.g. contaminated soil, groundwater), a pathway of exposure of a receptor to the source (e.g. direct contact, ingestion), and a receptor that may be exposed to the source (e.g. a person, a species of significance). This is otherwise known as a Source-Pathway-Receptor (S-P-R) linkage. Where one or more of the source, pathway or receptor elements does not exist at a site, then an S-P-R linkage is considered incomplete and an unacceptable risk is not considered to exist.


Table 7.5: Preliminary Summary of Potential Receptors and Exposure Pathways – Human Health Potentially Contaminated Media (Source)

Potential Human Receptors Potential Exposure Pathways Potential Exposure Route

Ingestion Dermal Contact Inhalation Others/remarks

Soil On-Site Defence personnel and contractors working on Base

• Direct contact or incidental exposure • Dust emissions

Inhalation relates to incidental inhalation of dust

Defence personnel residing on Base (in temporary or living-in accommodation)

Intrusive maintenance and construction workers

Recreational users of on-Site sporting grounds

Visitors to Site, including families attending the Community Centre

Soil Off-Site Members of the public • Off-Site migration of dust from impacted surface soils

• Direct contact or incidental exposure to soils irrigated with PFAS impacted water


Surface Water On-Site

Defence Personnel and contractors working on Base

• Direct contact or incidental exposure -


- - - It is considered unlikely that Defence personnel residing on Base would be entering surface water bodies (e.g. stormwater channels). Where this activity occurs as part of their working duties, the exposure scenario is captured against Defence personnel working on Base.

Intrusive maintenance and construction workers, including workers performing maintenance in the stormwater network

-


- - - It is considered unlikely that visitors to the Site would be entering surface water bodies (e.g. stormwater channels)

Surface Water Off-Site

Recreational users of the Kaurna Park Wetland

• Direct contact or incidental exposure - Includes potential for ingestion of biota

Maintenance Workers and contractors (e.g. City of Salisbury workers)



Potentially Contaminated Media (Source)

Potential Human Receptors Potential Exposure Pathways Potential Exposure Route

Ingestion Dermal Contact Inhalation Others/remarks

Sediment On-Site




- - - It is considered unlikely that Defence personnel residing on Base would be exposed to sediment (e.g. stormwater channels). Where this activity occurs as part of their working duties, the exposure scenario is captured against Defence personnel working on Base.

Intrusive maintenance and construction workers, including workers performing maintenance in the stormwater network

-


- - - It is considered unlikely that visitors to the Site would be exposed to sediment (e.g. entering stormwater channels)

Sediment Off-Site



Maintenance Workers and contractors (e.g. Council workers)


Groundwater On-Site

On-Site users and consumers of groundwater

• None - - - Information provided by Defence indicates that there is no extraction of groundwater occurring on Site and therefore no human exposure pathway

Groundwater Off-Site

Off-Site users and consumers of groundwater

• Extraction of groundwater • Irrigation or use of groundwater for

domestic activities (e.g. showering), recreational activities (e.g. in swimming pools), or commercial activities (e.g. process water)

• Consumption of crops, market garden produce, and home-grown produce.

• Consumption of livestock (e.g. cattle, sheep, chickens), milk, and eggs

Potential for inhalation of spray mist during irrigation may be an exposure route. Potential for PFAS contaminated water to have been used for commercial irrigation of plants or as water supply for livestock

Members of the public • Consumption of crops and market garden produce


- - Potential for PFAS contaminated water to have been used for commercial irrigation of plants or as water supply for livestock


Table 7.6: Preliminary Summary of Potential Receptors and Exposure Pathways – Ecological Potentially Contaminated Media (Source) Potential Ecological Receptors Potential Exposure Pathways Soil On-Site • Terrestrial fauna (e.g. birds) • Direct contact

• Ingestion of flora and fauna affected by PFAS • Terrestrial flora • Uptake of PFAS from soil

Soil Off-Site • Terrestrial fauna (e.g. birds) • Direct contact • Ingestion of flora and fauna affected by PFAS

• Terrestrial flora • Uptake of PFAS from soil Surface Water On-Site • Terrestrial and aquatic fauna • Direct contact

• Ingestion • Consumption of flora and fauna affected by PFAS

• Aquatic flora • Uptake of PFAS from surface water Surface water Off-Site • Terrestrial and aquatic fauna • Direct contact

• Ingestion • Consumption of flora and fauna affected by PFAS

• Aquatic flora • Uptake of PFAS from surface water Sediment On-Site • Terrestrial and aquatic fauna • Direct contact

• Incidental ingestion • Consumption of flora and fauna affected by PFAS

• Aquatic flora • Uptake of PFAS from sediment Sediment Off-Site • Terrestrial and aquatic fauna • Direct contact

• Incidental ingestion • Consumption of flora and fauna affected by PFAS

• Aquatic flora • Uptake of PFAS from sediment Groundwater On-Site • Terrestrial flora • Uptake of PFAS from groundwater

• Groundwater dependent ecosystems • No groundwater dependent ecosystems have been identified at the Site Groundwater Off-Site • Terrestrial flora • Uptake of PFAS from groundwater

• Groundwater dependent ecosystems • No groundwater dependent ecosystems have been identified within the Investigation Area


7.6 Initial Uncertainties and Data Gaps

Following a review of available historical information, a number of uncertainties and data gaps associated with understanding the nature and extent of PFAS contamination at the Site were identified that warranted consideration as part of the DSI works. These included:

• Previous investigations indicated uncertainties regarding groundwater flow direction beneath the Site in the shallow Quaternary Aquifer, and show significant variability in the localised flow direction beneath discrete areas of the Site;

• There were limited PFAS sampling data (e.g. soil, surface water, sediment) for stormwater swales and drains throughout the Site;

• There were limited PFAS data for groundwater sampled across the Site based on the distribution of the groundwater monitoring well network relative to potential primary and secondary PFAS source areas;

• The lateral and vertical extent of PFAS contamination in groundwater beneath and down hydraulic gradient of the Site had not been defined;

• The groundwater monitoring network at the Site was not installed to monitor PFAS as the primary contaminant of concern;

• The degree of interconnectivity or otherwise between the Quaternary Aquifers beneath the Site was not well understood;

• With the exception of a limited data set relating to groundwater sampled from selected ASR wells, there was no off-Site data relating to Site-derived PFAS contamination;

• It was not known if PFAS contaminated groundwater had migrated off-Site and was being extracted by off-Site users of groundwater (e.g. commercial, domestic users);

• Data collected prior to 2016 predated much of the current PFAS guidance and may not have adopted appropriate sampling protocols as required for sampling PFAS (i.e. measures to avoid known or commonly-suspected sources of environmental sample contamination during PFAS investigations);

• Early sampling data (e.g. pre-2016) relating to PFAS was typically limited to PFOS, PFOA, and 6:2 FTS only, and in some circumstances analysis was undertaken by a laboratory that was not NATA accredited for analysis of PFAS;

• It was not known if impacted sediments were present within the Helps Road Drain and/or Kaurna Park Wetland, which may have represented a secondary source of contamination;

• The relationship between PFAS concentrations detected in soils at the Site and the subsequent risk presented to surface water and/or groundwater (via dissolved PFAS in leachate) was not well understood.

The conduct of the DSI at the Site and the surrounding areas sought to address these data gaps and refine the preliminary CSM to give a more detailed understanding of the nature and extent of PFAS contamination originating from the Site.


8. Data Quality Objectives

Data quality objectives (DQOs) are statements that define the confidence required in conclusions drawn from data produced for a project, and which must be set to realistically define and measure the quality of data needed. The development of appropriate DQOs is recommended by the ASC NEPM when site contamination data is being relied on for risk-based decision following the conduct of a DSI.

The DQO process outlined in the ASC NEPM (adapted from US EPA, 2006) comprises a seven-step iterative planning approach to define the type, quantity and quality of data to be collected during a DSI. The seven steps in the DQO process are:

• Step 1: State the problem

• Step 2: Identify the decision/goal of the study

• Step 3: Identify the information inputs

• Step 4: Define the boundaries of the study

• Step 5: Develop the analytical approach

• Step 6: Specify performance or acceptance criteria

• Step 7: Develop the plan for obtaining data

The DQOs developed for the preliminary assessment and subsequent DSI are discussed in the following sections.

8.1 State the Problem

Surface releases of AFFF containing PFAS has occurred at the Site, associated with fire suppression requirements (storage, training, testing, waste disposal), and all potentially impacted locations have not been assessed nor the level of potential risk posed by these impacts understood.

Soil, sediment, surface waters and shallow groundwater are known to be impacted with PFAS at various locations on-Site. It is likely that off-Site migration of these chemicals has occurred via surface water and groundwater. There is the potential that edible biota (e.g. fish, yabbies) are being caught and consumed from areas where PFAS contaminated surface water has migrated from the Site (i.e. Kaurna Park Wetland).

Significant use of groundwater occurs off-Site, including irrigation for market gardening, and general domestic, agricultural and industrial purposes. However, it is not understood whether groundwater potentially contaminated with PFAS is extracted for these purposes. In addition, surface water/stormwater originating from the Site has historically been “harvested” for irrigation purposes through the City of Salisbury ASR program7.

Incidental ingestion of PFAS may occur when in contact with surface water and associated soils in drainage lines (e.g. maintenance), or during irrigation using PFAS impacted groundwater.

The release of PFAS into the environment is an emerging concern because these chemicals are highly persistent and have been shown to accumulate in the bodies of fish, animals and people who come into contact with them. However, information published by the Australian Government Department

7 It is beyond the current scope of this investigation to assess potential impacts associated with the operation of the ASR. Therefore,

any impacts associated with potential distribution of PFAS impacted water as part of the historical operation of the Edinburgh Park South and Kaurna Park ASR remains an ongoing data gap.


of Health (DoH, 2018) and enHealth (2016) indicates there is currently no consistent evidence that exposure to PFAS causes adverse human health effects.

8.1.1 Identify the Decision/Goal of the Study

8.1.1.1 Preliminary Assessment

The key objectives of the PA were as follows:

• Early assessment of whether there is potential ingestion of PFAS impacted waters in the wider community by collection of groundwater samples from off-Site bores, as well as surface waters and soils in stormwater drainage lines; and

• Preliminary assessment of whether there is an unacceptable risk associated with any complete human health pathways associated with PFAS contamination in surface waters and associated soils in stormwater drainage lines on-Site.

It should be noted that the collection of groundwater samples was not undertaken during the PA due to delays with sampling and access agreement approvals and was therefore amalgamated into the DSI program of works.

8.1.1.2 Detailed Site Investigation

The key questions for the DSI program to resolve are as follows:

• Is PFAS contamination present at the Site, or has PFAS contamination potentially migrated off-Site at concentrations that may present a risk to human health or the environment?

• Is there sufficient information to inform a HHERA if required?

8.1.2 Identify Inputs to the Decision

Inputs to the decisions include:

• Available data relevant to the Investigation Area, including historical information, site observations, laboratory results (bore, surface and ASR water) and previous investigation findings;

• Identification of potential receptors and accessibility of water supply for drinking or incidental consumption in areas potentially contaminated by Site-derived PFAS, via completed Water Use Surveys;

• Identification of representative sampling locations;

• Assessment of registered bores within the Investigation Area associated with a licence to extract water;

• Results of the environmental data collected by sampling and analysis and site observations made during the investigations;

• Adopted assessment criteria as presented in Section 10; and

• Confirmation that data generated by sampling and analysis are of an acceptable quality to allow reliable comparison to assessment criteria as undertaken by assessment of quality assurance/quality control (QA/QC) against the data quality indicators (DQIs) defined in Section 8.1.5.

Data collected during the investigation was compared against the adopted Tier 1 screening criteria (preliminary criteria for screening purposes) presented in Section 10. The assessment of data against these Tier 1 screening criteria has been used to inform the requirement for completing a detailed HHERA in subsequent stages of the study.


8.1.3 Define the Study Boundaries

8.1.3.1 Lateral

The lateral study boundary comprises the extent of the current Investigation Area, as depicted on Figure 3. In addition, the lateral study boundaries include the following:

• Areas considered upstream and up hydraulic gradient (hydrological and hydrogeological) for the consideration of background concentrations; and

• Areas down hydraulic gradient (hydrogeological) to assess PFAS contamination to the extent necessary to understand the subsequent risks to receptors (noting additional groundwater investigations continue at the time of this report).

The Investigation Area was developed in accordance with the Defence guidelines for Investigation Area establishment (Defence, 2017a), which exclude the consideration of background locations from the establishment of the initial Investigation Area.

8.1.3.2 Vertical

The vertical boundaries of the study were initially focussed on the shallow Q1 and Q2 Aquifers. As investigations have progressed, the need for assessment of the deeper Quaternary aquifers (i.e. Q3 and Q4) has been evaluated.

Assessment of the deeper Tertiary aquifers has been limited to the sampling of licensed water supply bores within the Investigation Area to account for the potential that these bores may have poor integrity (i.e. may be hydraulically connected with the overlying Quaternary sequences as a result of poorly constructed or degraded casing, otherwise known as a “leaky well”).

8.1.3.3 Temporal

The temporal boundaries of the study comprise the extent of the field investigations. This report includes an assessment of all data collected from field investigations completed up to 14 September 2018. As discussed earlier, some additional groundwater investigations continue at the time of this report and will be reported in an addendum.

8.1.4 Develop a Decision Rule

Laboratory analytical data will be assessed against the Tier 1 screening criteria identified in Section 10.

The decision rules adopted to answer the decisions identified in Section 8.1.1 are summarised in Table 8.1.

Table 8.1: Summary of Decision Rules Decision Required to be Made Decision Rule 1. Is data of acceptable quality for interpretive purposes?

The QA/QC program for samples recovered throughout the investigation program will be reviewed against the precision, accuracy, representativeness, comparability, completeness and sensitivity (PARCCS) parameters and associated DQIs detailed in Section 8.1.5. If the criteria are satisfied, the decision is Yes. If the criteria are not satisfied, the decision may be No and further assessment of the quality and reliability of the data may be required.

2. Is there an appropriate level of understanding of background concentrations to inform the investigation outcomes?

If there is sufficient data collected from representative background locations to characterise background concentrations sufficiently to address SA EPA and ASC NEPM requirements, the decision is Yes. Otherwise, the decision is No.


Decision Required to be Made Decision Rule 3. Has sufficient environmental data been collected to address the study objectives?

The presence or otherwise of PFAS will be understood vertically and laterally in surface water, groundwater, soil and/or sediments, and the PFAS concentrations screened against the appropriate and adopted screening criteria. If the above is satisfied then the decision is Yes. Otherwise the decision is No and additional data will need to be collected as part of this program of works.

4. Are there potentially unacceptable risks to human health and/or ecological receptors on-Site or off-Site as a result of exposure to PFAS contaminated media?

Are contaminants present in surface water, groundwater, soil and/or sediments at concentrations exceeding the appropriate and adopted screening criteria? If yes, the decision is Yes. Otherwise, the decision is No.

5. Has the nature and extent of Site-derived PFAS contamination been determined to the extent necessary to inform the undertaking of a HHERA?

If sufficient environmental data has been collected to allow the completion of a detailed HHERA relating to exposure of sensitive receptors to PFAS impacted media then the answer is Yes. Otherwise the decision is No.

8.1.5 Specify Limits of Decision Error

This step is to establish the decision maker’s tolerable limits on decision errors, which are used to establish performance goals for limiting uncertainty in the data. Data generated during this project must be appropriate to allow decisions to be made with confidence.

A decision error may lead to either underestimation or overestimation of the risk level associated with a sample location. Decision errors may include:

• Not adequately detecting the variability of a contaminant over time. Completing an investigation within a 12 to 24-month timeframe may mean this cannot be readily avoided.

• Limitations in ability to acquire representative information from the data collected where access to locations is restricted (e.g. land owner denies access or gauging/sampling bores is prevented by the presence of pumps).

• In sampling for PFAS to obtain low detection limits, errors can occur during sample collection, handling, preparation and analysis.

Acceptance limits on field and laboratory data collected for this investigation will be in accordance with the ASC NEPM and the WA DER Interim Guideline on the Assessment and Management of Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) (WA DER, 2017).

The potential for significant decision errors will be minimised by completing a QA/QC program, including adoption of appropriate Data Quality Indicators (DQIs) used to assess QA/QC performance, and implementing JBS&G procedures for field sampling and handling designed specifically for PFAS investigations (as outlined in the DSI SAQP – JBS&G, 2017b).

The pre-determined DQIs established for the project are discussed below in relation to precision, accuracy, representativeness, comparability, completeness and sensitivity (PARCCS parameters), and are shown in Table 8.2. The DQIs are based on the ASC NEPM and the requirements of the NATA accreditation for the nominated laboratories.

• Precision - measures the reproducibility of measurements under a given set of conditions. The precision of the laboratory data and sampling techniques is assessed by calculating the Relative Percent Difference (RPD) of duplicate samples.

• Accuracy - measures the bias in a measurement system. The accuracy of the laboratory data that are generated during this study is a measure of the closeness of the analytical results obtained by a method to the ‘true’ value. Accuracy is assessed by reference to the analytical results of laboratory control samples, laboratory spikes and analyses against reference standards.


• Representativeness –expresses the degree which sample data accurately and precisely represent a characteristic of a population or an environmental condition. Representativeness is achieved by collecting samples on a representative basis across a site, and by using an adequate number of sample locations to characterise a site to the required accuracy.

• Comparability - expresses the confidence with which one data set can be compared with another. This is achieved through maintaining a level of consistency in techniques used to collect samples; ensuring analysing laboratories use consistent analysis techniques and reporting methods.

• Completeness – is defined as the percentage of measurements made which are judged to be valid measurements. The completeness goal is set at there being sufficient valid data generated during the study.

• Sensitivity – expresses the appropriateness of the chosen laboratory methods, including the limits of reporting, in producing reliable data in relation to the adopted criteria.

If any of the DQIs are not met, further assessment will be necessary to determine whether the non-conformance will significantly affect the usefulness of the data. Corrective actions may include requesting further information from samplers and/or analytical laboratories, downgrading of the quality of the data or alternatively, re-collection of the data.

Table 8.2: Summary of Quality Assurance / Quality Control Program Data Quality Objectives Frequency Data Quality Indicator

Precision Blind duplicates (intra laboratory) 1 / 20 samples <30% RPD1 Blind duplicates (inter laboratory) 1 / 20 samples <30% RPD1 Laboratory duplicates3 1 / 20 samples <30% RPD1

Accuracy Surrogate spikes All organic samples 70-130% or as

nominated in the laboratory’s QC report Laboratory control samples 1 per lab batch 70-130% or as

nominated in the laboratory’s QC report Matrix spikes 1 per lab batch 70-130% or as

nominated in the laboratory’s QC report Representativeness

Sampling appropriate for media and analytes - -2

Samples extracted and analysed within holding times.

- PFAS – two weeks primary laboratory, 6 months secondary laboratory

Storage blank 1 per day (total) <LOR Rinsate blank 1 per day per field crew,

where reusable equipment is used

<LOR

Field Blank 1 per day (total) <LOR Laboratory blanks 1 per lab batch <LOR

Comparability Standard operating procedures for sample collection & handling

All Samples All samples2

Standard analytical methods used for all analyses


Consistent field conditions, sampling staff and laboratory analysis


Limits of reporting appropriate and consistent All Samples All samples2 Completeness

Sample description and COCs completed and appropriate


Appropriate documentation All Samples All samples2 Satisfactory frequency and result for QC samples All QA/QC samples -2 Data from critical samples is considered valid - Critical samples valid3


Data Quality Objectives Frequency Data Quality Indicator Sensitivity

Analytical methods and limits of recovery appropriate for media and adopted site assessment criteria

All Samples All samples

1 If the RPD between duplicates is greater than the pre-determined data quality indicator, a judgment will be made as to whether the exceedance is critical in relation to the validation of the data set or unacceptable sampling error is occurring in the field. 2 A qualitative assessment of compliance with standard procedures and appropriate sample collection methods will be completed during the DQI compliance assessment. 3 Duplicate sample analysis performed by the laboratory as part of their internal QA/QC program for the data.

8.1.6 Optimise the Design for Obtaining Data

The sampling programs detailed in the DSI SAQP (JBS&G, 2017b), including Addendum 1 (JBS&G, 2018a), were designed to obtain the data necessary to achieve the objectives outlined in Section 8.1.1. In addition, the DSI SAQP included a process for modifications to the DSI program where data collected and assessed during the conduct of the DSI indicated that the investigations would be insufficient to appropriately characterise individual source areas and/or would not meet the project DQOs.


9. Field Investigation Approach and Methodology

9.1 Overview

All sampling was completed in accordance with guidance provided in the ASC NEPM (NEPC, 1999) with additional amendments made in accordance with WA DER (2017) guidance which addresses the specific issues associated with PFAS sampling that are not covered in ASC NEPM.

In addition, sampling was completed in accordance with the JBS&G field sampling guide which has been developed specifically for sampling for PFAS (refer JBS&G, 2017b). The field sampling guide includes a detailed field checklist to mitigate potential sample contamination during field investigations. All sampling equipment and consumables used throughout the investigation program were Teflon free to minimise potential for false negative results. In addition, glass sample jars and bottles were not used for any sample collected for analysis of PFAS.

As discussed in Section 1.3, the early assessment works comprised a preliminary sampling program followed by completion of the DSI in two stages – referred to as Stage 2A and Stage 2B. A summary of the works completed during each stage of the assessment process is provided in the following sections.

In addition, private property sampling works have been completed throughout the investigation program and are also discussed below.

9.2 Preliminary Assessment

The preliminary assessment program comprised targeted sampling of surface water and surface soil/sediment from open unlined stormwater drainage channels (on-Site) and the Helps Road Drain (on and off-Site). The on-Site sampling program was undertaken at the site on 19 December 2016. The off-Site sampling program was undertaken on 16 February 2017.

The preliminary sampling works included the following:

• Collection of seven surface soil/sediment samples (SS001-SS007) from selected locations throughout on-Site stormwater drainage channels, including the Helps Road Drain;

• Collection of four off-Site surface soil/sediment samples (SS008-SS011) from the Helps Road Drain and the inlet and outlet area of the Kaurna Park Wetland;

• Collection of nine surface water samples (SW003-SW011) from the Helps Road Drain on and off-Site, co-located with the surface soil/sediment samples; and

• Submission of the collected samples for laboratory analysis of selected PFAS (PFOS, PFHxS, PFOA and 6:2 FTS).

The preliminary assessment sample locations are shown on Figure 9 (attached).

9.3 Stage 2A Investigation Program

The Stage 2A DSI program was undertaken between 16 May and 10 October 2017. The scope of work was undertaken in accordance with that proposed in the DSI SAQP (JBS&G, 2017b) and included the following:

• Drilling and sampling of 190 soil bores throughout 26 potential primary source areas;

• Installation of 57 new groundwater monitoring wells comprising:

o 36 x Q1 Aquifer monitoring wells on-Site;

o 16 x Q1 Aquifer monitoring wells off-Site (including 3 up hydraulic gradient background wells);



• Co-located sampling of surface water and sediment at 66 targeted locations within stormwater drainage channels comprising:

o 40 locations on-Site;

o 6 upstream background locations;

o 20 locations downstream of the Site;

• Sampling of pore water at four targeted locations;

• Groundwater sampling of all newly installed monitoring wells, and 54 targeted existing on-Site monitoring wells; and

• Completion of aquifer hydraulic conductivity testing (“slug tests”) on 10 x Q1 Aquifer and 2 x Q2 Aquifer monitoring wells.

A summary of the field program dates for Stage 2A DSI is provided in Table 9.1.

Table 9.1: Summary of Stage 2A Field Program Activity Date Completed Initial Inductions and Site Reconnaissance 16 May 2017 Soil Investigation 24 May 2017 to 5 July 2017 Groundwater Monitoring Well Construction and Development, including Pre-GME Sampling

17 May 2017 to 6 July 2017

Groundwater Gauging and Sampling – Boundary & Off-Site Wells Only

19 to 20 June 2017

Full GME – Gauging 13 to 14 July 2017 Full GME – Sampling 17 to 28 July 2017 and 3 August 2017 Sediment Sampling 20 to 21 July 2017, and 10 August 2017 (downstream of

Springbank Waters estate) Pore Water Sampling 20 July 2017 Surface Water Sampling Event 1: 20 to 21 July 2017, and 10 August 2017

(downstream of Springbank Waters estate) Event 2: 6 to 7 September 2017

Aquifer Hydraulic Conductivity Testing 4 to 10 October 2017

9.4 Stage 2B Investigation Program

The Stage 2B DSI program summarised in this report was undertaken between 8 January and 6 September 2018 (noting some additional groundwater investigations continue at the time of this report and will be reported in an addendum). The scope of work was undertaken in accordance with that proposed in the DSI SAQP Addendum 1 (JBS&G, 2018a), and additional work agreed with the Site Contamination Auditor and/or Defence, and included the following:

• Drilling and sampling of 49 soil delineation and investigation bores across 8 primary source areas, including a previously unidentified potential source area (P27);

• Installation of 121 groundwater monitoring wells comprising:


o 35 x Q1 Aquifer monitoring wells off-Site;


o 16 x Q2 Aquifer monitoring wells off-Site (including 1 upgradient background well);


o 2 x Q3 Aquifer monitoring wells off-Site;


• Sampling of surface water at 9 targeted locations within stormwater drainage channels and the Kaurna Park Wetland, downstream of the Site;

• Sediment sampling at two locations within the Helps Road Drain on Site, and five locations within the AFFF waste water evaporation pond;

• Groundwater sampling of all newly installed monitoring wells, all monitoring wells installed during Stage 2A, and 62 targeted existing on-Site monitoring wells; and

• Completion of aquifer hydraulic conductivity testing (“slug tests”) on 10 x Q1 Aquifer 13 x Q2 Aquifer, and 1 x Q3 Aquifer monitoring wells.

In addition to the above, a concrete sampling program was undertaken across targeted primary source areas. Concrete sampling was completed to understand the potential for this infrastructure to act as a secondary source of PFAS contamination to groundwater and nearby surface water (via leaching) in source areas exposed to persistent use of AFFF. The targeted areas and number of samples collected from each area, including justification, are summarised below:

• Former AFFF Concentrate Storage Area (within source area P11): One sample location targeting the concrete base where the AFFF Concentrate tank was historically mounted and three locations in a herringbone pattern in the concentrate loading pad for spatial coverage.

• Current Fire Station (within source area P11): Four sample locations for spatial coverage across parking pad at front of fire station where former fire trucks were serviced and anecdotally had foam concentrate dumped to ground during servicing activities.

• Building 618 within the Current Fire Training Area (source area P9): Four locations from areas throughout the structure to assess variability of PFAS concentrations within the structure, nominally targeting the four corners of the building.

• Engine Run Up Facility (source area P16): Four sample locations at approximate 30m spacing in line with highest recorded soil and groundwater concentrations in the P16 area.

• Ordnance Unloading Area (source area P15): One sample from the smaller revetment wall and two from the larger revetment wall, and two samples from the ordnance unloading pad.

• Fire Tender Test Pad (within source area P1, adjacent to the AFFF waste water evaporation pond): Two sample locations within the pad and one location beneath the current AFFF concentrate storage tank.

• Chesterfield Sumps, located west and east of the Technical Area and Hangars (within source area P3): Three sample locations within each sump comprising two from the base and one from the wall.

Concrete samples were recovered using a concrete coring machine with samples recovered to an approximate depth of 0.05m within the targeted concrete structures.

A summary of the field program dates for the Stage 2B program is provided in Table 9.2.

Table 9.2: Summary of Stage 2A Field Program Activity Date Completed Soil Investigations 15 January 2018 to 4 September 2018 Groundwater Monitoring Well Construction and Development, including Pre-GME Sampling

8 January 2018 to 29 August 2018

Concrete core sampling 20 April 2018 Full GME on-Site – Gauging 4 July 2018 Full GME on-Site – Sampling 25 June 2018 to 4 July 2018 Full GME off-Site – Sampling 30 July 2018 to 1 August 2018 Full GME off-Site – Gauging 7 August 2018


Activity Date Completed Sediment Sampling 31 January 2018 – AFFF waste water evaporation pond

20 April 2018 – Helps Road Drain

Surface Water Sampling 31 January 2018: AFFF waste water retention tank (Building 521) 1 May 2018: Inlet and outlet of Kaurna Park Wetland 13 and 29 August 2018: Helps Road Drain downstream of Kaurna Park Wetland and Springbank Waters estate through Bolivar Waste Water Treatment Plant (WWTP) to the Barker Inlet

Aquifer Hydraulic Conductivity Testing 25 July 2018 to 6 September 2018

9.5 Private Property Sampling Program

To date the private property sampling program has comprised targeted sampling activities at nine individual properties. A summary of the works completed is provided in Table 9.3.

Table 9.3: Summary of Private Property Sampling Works Property ID Sampling Program Date of Sampling Property 1 2 bore water (i.e. groundwater) samples collected from a water supply bore,

comprising first flush and full purge 3 water samples collected from rainwater tanks

3 April 2017

Property 2 2 groundwater samples collected from a water supply bore, comprising first flush with full purge sample collected during a subsequent (confirmatory) sampling event 4 water samples collected from on-site rainwater tanks 1 additional water sample collected post tank cleaning

3 April 2017 19 May 2017 6 July 2017

Property 3 4 soil bores with 2 samples per bore (surface and shallow sub-surface) recovered for analysis

5 April 2017

Property 4 2 groundwater samples collected from a water supply bore, comprising first flush and full purge

12 August 2017

Property 5 2 groundwater samples collected from a water supply bore, comprising first flush and full purge

24 August 2017

Property 6 10 soil bores with 2 samples per bore (surface and shallow sub-surface) recovered for analysis 20 biota samples collected from wheat plants, comprising 10 samples of the flower and 10 samples of the stem 3 groundwater samples collected from two water supply bores, comprising one first flush sample and two full purge samples (noting one bore was operating at the time of sampling) 2 surface water samples collected from on-site dams filled with groundwater from the water supply bores

17 October 2017

Property 7 Sampling of disused water supply bore attempted, however no samples recovered due to collapse of the bore

9 November 2017

Property 8 2 bore water (i.e. groundwater) samples collected from a water supply bore, comprising first flush and full purge

16 December 2017

Property 9 2 legacy monitoring wells sampled (i.e. not water supply bores) 16 May 2018

In addition to the above, three irrigation bores owned and operated by the City of Salisbury Council were also targeted for sampling (completed 7 August 2017).

9.6 Fieldwork Methodology

A detailed summary of the fieldwork methodology adopted for each of the field activities is provided in Appendix G.


9.7 Laboratory Analysis

Eurofins MGT (Eurofins) was contracted as the primary laboratory for analytical works, with Australian Laboratory Services Pty Ltd (ALS) contracted as the secondary laboratory. Both laboratories are NATA registered for the analytical works performed.

9.7.1 PFAS Analysis

In accordance with Defence Directive PFAS Detailed Environmental Investigation Program: Guidelines for Laboratory Analytical Suite, Defence Records and Investigation Area Establishment (Defence, 2017a), the minimum PFAS analytical suite adopted for the DSI comprised the analytes listed in Table 9.4.

Table 9.4: Standard Minimum PFAS Analytical Suite Chemical Compound CAS No. Perflurobutanoic acid (PFBA) 375-22-4 Perfluoro pentanoic aicd (PFPA or PFPeA) 2706-90-3 Perfluoro-n-hexanoic acid (PFHxA) 307-24-4 Perfluoro-n-heptanoic acid (PFHpA) 375-85-9 Perfluoro-n-octanoic acid (PFOA) 335-67-1 Perfluoro-n-nonanoic acid (PFNA) 375-95-1 Perfluoro-n-decanoic acid (PFDA) 335-76-2 Perfluoro-n-undecanoic acid (PFUnDA) 2058-94-8 Perfluoro-n-dodecanoic acid (PFDoDA) 307-55-1 Perfluoro-n-tridecanoic acid (PFTriDA) 72629-94-8 Perfluoro-n-tetradecanoic acid (PFTeDA) 376-06-7 Perfluorobutane sulfonic acid (PFBS) 375-73-5 Perfluoro-n-hexane sulfonic acid (PFHxS) 355-46-4 Perfluoro-n-heptane sulfonic acid (PFHpS) 375-92-8 Perfluoro-n-octane sulfonic acid (PFOS) 1763-23-1 Perfluorooctane sulfonamide (PFOSA) 754-91-6 N-Methylperfluoro-1-octane sulphonamide (N-MeFOSA) 31506-32-8 N-Ethylperfluoro-1-octane sulphonamide (N-EtFOSA) 4151-50-2 2-(N-Methylperfluoro-1-octane sulphonamide)-ethanol (N-MeFOSE) 24448-09-7 2-(N-Ethylperfluoro-1-octane sulphonamide)-ethanol (N-EtFOSE) 1691-99-2 1H,1H,2H,2H-Perfluorooctanesulfonic Acid (6:2 FTS) 27619-97-2 1H,1H,2H,2H-Perfluorodecanesulfonic Acid (8:2 FTS) 39108-34-4

In addition to the analytes listed in Table 9.4, the standard PFAS analytical suite adopted for the DSI program included the following:

• 1H,1H,2H,2H-perfluorohexanesulfonic acid (4:2 FTS);

• 1H,1H,2H,2H-dodecanesulfonic acid (10:2 FTS);

• Perfluorodecanesulfonic acid (PFDS);

• Perfluropentanesulfonic acid (PFPeS);

• N-ethyl-perfluorooctanesulfonamidoacetic acid (NEtFOSAA); and

• N-methyl-perfluorooctanesulfonamidoacetic acid (NMEFOSAA).

9.7.2 Laboratory Analytical Methods

The analytical methods used by the primary and secondary laboratories for analysis of PFAS in both water and soil matrices are detailed below.

Primary Laboratory (Eurofins)

Analysis of water samples: USEPA Method 537 Determination of Selected Perfluorinated Alkyl Acids in Drinking Water by Solid Phase Extraction and Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS), Version 1.1 September 2009.


Analysis of soil samples: USEPA Method EPA-821-R-11-007 Draft Procedure for Analysis of Perfluorinated Carboxylic Acids and Sulfonic Acids in Sewage Sludge and Biosolids by HPLC/MS/MS, December 2011.

Secondary Laboratory (ALS)

Analysis of water samples: ISO 25101:2009, Water quality — Determination of perfluorooctanesulfonate (PFOS) and perfluorooctanate (PFOA) — Method for unfiltered samples using solid phase extraction and liquid chromatography/mass spectrometry.

Analysis of soil samples: Ontario Ministry of the Environment – Laboratory Services Branch Analytical Methods E4357 and Fluoro-E3457A – The Determination of Perfluorinated Alkyl Compounds (PFASs) in Environmental Matrices by LC/MS-MS.

9.7.3 Leachable PFAS

Leachate analysis was undertaken on all soil and sediment samples analysed throughout the Stage 2A DSI program, and concrete core samples recovered during the Stage 2B DSI program, for the full PFAS analytical suite. Leachate analysis was undertaken to enable an assessment of the leachable portion of PFAS within the soil, sediment and concrete that may present a risk of contamination to nearby surface water and the underlying groundwater system.

Leachate testing was undertaken using the Australian Standard Leaching Procedure (ASLP) (Australian Standard 4439.3) and adopted the use of a neutral leaching solution to replicate rainfall infiltration.

9.7.4 Physical and Physicochemical Properties

In order to inform potential future groundwater modelling for the project, as may be required to inform the HHERA and/or subsequent response management measures, a selection of physical and physicochemical properties within targeted environmental samples were analysed. This analysis included the following:

• Particle size distribution (PSD);

• Percentage clay content (% clay);

• Total organic carbon (TOC);

• Total iron;

• Conductivity and pH; and

• Cations and cation exchange capacity.

9.7.5 Non-PFAS Contaminants of Potential Concern

In accordance with the Defence guideline PFAS Detailed Environmental Investigation Program: Guidelines for Laboratory Analytical Suite, Defence Records and Investigation Area Establishment (Defence, 2017a), a selection of non-PFAS COPC were analysed from selected environmental media collected during the conduct of the DSI. A summary of the minimum scope for the analytical suite and frequency of non-PFAS COPC is detailed in Appendix F of the DSI SAQP (JBS&G, 2017b).

The non-PFAS COPC analytical suite was adopted for the Stage 2A program only and included analysis of non-PFAS COPC in 100% of groundwater samples collected on-Site. In addition, selected soil, sediment, and surface water samples were analysed for non-PFAS COPC. A summary of the non-PFAS sampling program is provided below:

• Soil – a total of 388 samples were analysed for heavy metals (comprising all surface and shallow subsurface samples in all soil bores), and 96 samples were analysed for the remaining non-PFAS COPC;


• Sediment – a total of 8 samples were analysed from throughout the on-Site stormwater drainage network; and

• Surface water – a total of 8 samples, corresponding with the targeted sediment sample locations, were analysed from throughout the on-Site stormwater drainage network.

The locations targeted for analysis of non-PFAS COPC, excluding groundwater which consisted of all groundwater sampling locations during Stage 2A, are shown on Figure 10 (attached). The analytical results summary tables for non-PFAS COPC are included in G1.1.

In addition to the above, a sample of potential asbestos containing material (ACM) was recovered from soil bore location BH151 (in source area P18) and submitted for analysis of asbestos (presence/absence).

9.8 Deviations from the SAQP

As noted earlier, the DSI SAQP (JBS&G, 2017b) included a process for modifications to the sampling program where data collected and assessed during the conduct of the DSI indicated that the extent of investigations would be insufficient to appropriately characterise individual source areas and/or would not meet the project DQOs. As such, any deviations to the sampling program and/or methodologies outlined in the SAQP were agreed with Defence and the Site Contamination Auditor prior to being implemented. Generally, deviations from the sampling program comprised an increase in the number of sample locations (including monitoring well installations) and/or samples selected for analysis to better define the nature and extent of PFAS contamination in the various environmental matrices.

A brief summary of notable amendments to the sampling program and methodologies is provided below:

• One targeted on-Site Q2 Aquifer monitoring well (GW2145) was unable to be installed during the Stage 2A program due to collapsing sand geology resulting in the inability to install a pre-collar of appropriate integrity at this location. In addition, one targeted off-Site Q1 Aquifer monitoring well (GW2123) was unable to be installed due to site access restrictions. The installation of these monitoring wells was subsequently completed during the Stage 2B program.

• To date, a total of two additional Q1 monitoring wells have been installed beyond the combined Stage 2A and Stage 2B program allowances to further delineate the extent of PFAS contamination in the Q1 Aquifer off-Site;

• To date, a total of two Q2 Aquifer (contingency) monitoring wells from the Stage 2B program are yet to be installed, however these installations will be completed as part of the ongoing groundwater investigation program;

• To date a total of five Q3 Aquifer monitoring wells from the Stage 2B program are yet to be installed, however these installations will be completed as part of the ongoing groundwater investigation program;

• In February 2018 a change in drilling technique from solid auger drilling to Sonic drilling for the installation of monitoring wells crossing multiple aquifers (i.e. Q2 and Q3 Aquifer monitoring wells) was made. The change was initiated as a result of collapsing sand geology being encountered in some areas near the base of the Q1 Aquifer, ultimately affecting the driller’s ability to install pre-collars using the solid auger drilling technique.

• Seven additional soil delineation bores were completed across four primary source areas;

• Targeted soil sampling was completed immediately adjacent to remnant firefighting training props within primary source area P4;


• Two surface soil samples were collected from an earthen bund that abutted the concrete building within the current fire training ground (source area P9);

• A targeted soil bore within source area P26 (BH194) was not able to be drilled due to the presence of significant underground services;

• Collection of sediment samples from the base of the AFFF waste water evaporation pond (when the pond was dry) and a surface water sample from the foam retention tank (Building 521);

• Sampling of a legacy T2 Aquifer observation bore identified at the Site in the airside operations area during the Stage 2B DSI program;

• Additional off-Site surface water samples were collected from Kaurna Park Wetland (inlet and outlet areas) toward the end of the 2017-18 dry period, prior to the commencement of winter rains (i.e. early May 2018); and

• Soil investigations were completed across an additional potential primary source area (identified as source area P27) that was identified following the Stage 2B on-Site GME8 (discussed further in Section 11.3).

In addition to the above, an attempt was made to collect samples of any residual sediment that may have been present within remnant STP infrastructure within source area P10, considered most likely to be old stone media Trickling Filters. However, the stone media (cobble-sized rock) was observed to extend beyond 1m in depth and no recovery of sediment (or confirmation of its presence) was able to be achieved.

9.9 Quality Assurance and Quality Control (QA/QC)

A QA/QC program in accordance with the requirements of the DSI SAQP and that summarised in Section 8 was undertaken throughout the investigation programs. The QA/QC program was implemented to allow an assessment of the quality and reliability of the data produced for the investigation. A detailed assessment of the data quality has been completed with reference to the relevant DQIs and is provided in Appendix I. The laboratory analytical reports, including associated laboratory QA/QC results, are provided in Appendix J.

It is noted that there were a number of non-conformances identified as part of the QA/QC assessment. A summary of the identified non-conformances, investigation and outcome is provided below in Table 9.5. Further details are provided in Appendix I.

Table 9.5: Summary of QA/QC Non-Conformances and Investigation Outcome Description/Nature Response/Investigation Outcome RPD Exceedances (soil/water/leachate)

Investigation into the nature and extent of RPD exceedances, evaluation of causal factors, trends, quantity of inter and intra laboratory exceedances and potential for bias in laboratory reporting and potential for impact on data quality or reliability.

In the majority of cases, the exceedances can be attributed to two factors: • the heterogeneity of sediment/soil making it difficult to

isolate distinct identical samples in nature and therefore potential contaminant concentration; and

• reported concentrations were close to the respective laboratory LORs (where precision and accuracy can be compromised) with the absolute differences between concentrations considered minor, however the RPD variances were exaggerated due to the low absolute concentrations.

In all cases the most conservative (i.e. highest) concentration was adopted to address any potential bias in laboratory reporting. This was not considered to impact on data quality or reliability.

8 The potential source area was identified following significant groundwater contamination identified in an existing monitoring well

(GW0416) in the area of potential concern. It is suspected that this may be former fire training area given it is located adjacent to a parking area for aircraft refuelling tanker trucks.


Description/Nature Response/Investigation Outcome Missing Rinsate/Field/Trip Blank samples

One storage blank, three rinsate blanks and two field blanks were lost on transit to the laboratory. Investigation undertaken into the field activities for the corresponding dates and potential for impact on data quality or reliability.

Field records for the QA/QC program confirmed the samples were collected and dispatched to the laboratory on the corresponding dates. In the cases where individual QC samples were lost in transit (two rinsate and one field blank) the other QC samples submitted for these dates and overall QA/QC trends supported the quality of the field data for those dates. All QAQC samples collected for 24/05/2017 were lost in transit. The data for the soil sampling activity on that day was reviewed and confirmed that all samples that exceeded criteria for that day, did so by a significant margin and any potential residual contamination is unlikely to have impacted on the interpretation of results for that source area.

Reportable concentrations in Rinsate/Field/Trip Blank samples

Reportable concentrations of PFAS identified in 3 storage blanks (3%), 7 rinsate blanks (2%) and 3 field blanks (3%). Investigation undertaken into the field activities for the corresponding dates and potential for impact on data quality or reliability.

On review of a worst-case scenario where potential reported contamination in QA/QC blanks was reported in analysed samples, at the same concentration (all media), no material impact on the interpretation of site conditions would have occurred. All locations either report below LOR or at concentrations well above the relevant screening criteria.

Incorrect deployment of HydraSleeve sampler

Identified ten instances of incorrect deployment of the HydraSleeve sampler (not positioned appropriately within the screen interval). All 10 wells were resampled correctly.

Wells were resampled correctly. No impact on data quality.

Laboratory quality control exceedances

Some exceedances identified in primary and secondary laboratory QA/QC metrics including laboratory control spikes and matrix spikes outside the applicable range.

Internal laboratory investigations into the reported exceedances have confirmed other metrics including method blanks, duplicates and surrogates reported within criteria and therefore reported concentrations meet the internal laboratory QAQC criteria. No impact on data quality or reliability.

Samples analysed outside of holding times

11 samples from four batches sent to the secondary laboratory for specific analysis were incorrectly analysed for other non-PFAS COPC not requested on COC (i.e. in error).

The data for analytes extracted out of holding time has been removed from the project assessment data and therefore there is no impact on data quality or reliability.

Based on the results of the data quality assessment and evaluation of the QA/QC data collected, it is considered that:

• The field and laboratory quality assurance measures implemented provide an acceptable level of confidence that the data collected and reported is appropriately complete, comparable and representative; and

• The field and laboratory quality control measures implemented provide an acceptable level of confidence that the data collected and reported is appropriately accurate and precise.

Therefore, it is concluded that the data collected is sufficiently reliable and suitable for the purpose of the assessment.


10. Assessment Criteria

10.1 Overview

As described in the ASC NEPM, the objective of a site assessment is to determine the human health and ecological risks associated with the presence of site contamination, and to assess whether subsequent remediation and/or management is required to mitigate such risks. The recommended general process for assessment of site contamination comprises a tiered risk assessment approach which can be summarised as follows:

• Tier 1 (or screening level) focuses upon the comparison of available analytical results to published guidance levels. A Tier 2 assessment is warranted where one or more contaminants are detected above adopted Tier 1 criteria or where there are significant uncertainties in the Tier 1 assessment;

• Tier 2 represents a site-specific process and typically includes the development of site-specific risk-based criteria. A Tier 3 process may be required where the Tier 2 process identifies potentially elevated risks to human health and/or the environment, noting that remediation and/or management measures may also be implemented on the basis of a Tier 2 assessment; and

• Tier 3 represents a more detailed site-specific process focused towards the risk driving contaminant/s and exposure assessment/s considered in the Tier 2 process. The Tier 3 process can include statistical analysis and modelling of exposures.

Tier 1 screening criteria are considered to represent the concentrations of a contaminant above which further appropriate investigation and evaluation will be required (i.e. Tier 2 or Tier 3 assessment). The development of Tier 1 screening criteria is necessarily a highly detailed and scientifically robust process that considers available scientific literature and studies related to the toxicity of the particular COPC for which they are being developed and makes assumptions regarding exposure scenarios considered to be representative of the applicable land use scenarios. Tier 1 screening criteria are intentionally conservative to ensure they are sufficiently protective of human health and the environment and are based on a reasonable worst-case scenario. The selection of appropriate screening criteria for any site assessment needs to be made using professional judgement and with reference to the CSM (e.g. understanding the relevant land use scenarios and associated receptors).

It is noted that the ASC NEPM does not provide Tier 1 screening criteria relating to PFAS. As such, an assessment of relevant state-based and national guidance documents was undertaken throughout the DSI process to determine the most appropriate Tier 1 criteria for PFAS for use in this investigation. The PFAS NEMP (HEPA, 2018) provides a summary of nationally recognised human health based and ecological guidance values (screening criteria) for use in site investigations in Australia, which have been adopted for the Tier 1 screening risk assessment of potential impacts to human health and the environment.

The screening criteria in the PFAS NEMP applicable to human health and ecological protection are provided for a range of land use and exposure scenarios. The selection of appropriate screening criteria based on the applicable on-Site and off-Site land use and exposure scenarios is detailed below in Section 10.2. It is noted that some of the adopted screening criteria differ to those identified in the DSI SAQP which has been necessitated by the evolving scientific knowledge regarding PFAS impacts to human health and the environment in the Australian context. The guidance values listed in the PFAS NEMP were considered as the most appropriate Tier 1 screening criteria for application at the time of this DSI.


10.2 PFAS

A summary of the adopted human health and ecological screening criteria selected for the preliminary assessment of risk to these receptors as a result of exposure to PFAS contaminated media within the Investigation Area is provided in Table 10.1. This table also identifies the applicable source areas for the different soil screening criteria that have been adopted based on the various land use categories defined in the PFAS NEMP (HEPA, 2018).

In addition to the criteria summarised in Table 10.1, leachate analytical data for soil samples have been screened against a value that is based on the application of a dilution factor of 10 to the relevant surface water and groundwater screening criteria (consistent with the methodology adopted in EnRisks, 2016). This forms the basis for consideration of whether a soil source area may represent an ongoing source of impact to nearby surface water and/or the underlying groundwater system as a result of the leaching of PFAS from the soil profile following water infiltration, such as rainfall (i.e. secondary source contamination).


Table 10.1: Summary of Adopted Tier 1 PFAS Screening Criteria

Exposure Scenario Compound Primary Laboratory LOR

Criteria Commentary / Rationale

Human Health Drinking Water (groundwater)

PFOS/PFHxS 0.01 µg/L 0.07 µg/L Based on the environmental values of groundwater (refer Section 3.2.6 and Section 11.4.4.1), and the presence of licensed water supply bores registered for domestic use within the Investigation Area, the health based guidance values applicable to drinking water have been adopted. The values are sourced from the Australian Government, Department of Health, Health Based Guidance Values for PFAS (Department of Health, 2017). The Department of Health used the final tolerable daily intakes for PFOS and PFOA as determined by FSANZ published in the Hazard Assessment Report—PFOS, PFOA and PFHxS (FSANZ, 2017) and the methodology described in Chapter 6.3.3 of the National Health and Medical Research Council’s Australian Drinking Water Guidelines (NHMRC and NRMMC, 2011) to determine the guidance values.

PFOA 0.01 µg/L 0.56 µg/L

Recreational Water (surface water)

PFOS/PFHxS 0.01 µg/L 0.7 µg/L The health based guidance values for recreational water have been adopted for the initial screening assessment of impacts associated with exposure to PFAS contaminated surface water on and off-Site. It is noted however there has been no evidence gathered during the conduct of the DSI to suggest that surface water at the Site or within the broader Investigation Area is being used for swimming, which is the key exposure scenario considered in the development of these criteria.

PFOA 0.01 µg/L 5.6 µg/L

Soil On-Site (Commercial/industrial)

PFOS/PFHxS 0.005 mg/kg 20 mg/kg The screening criteria are based on 20% of the FSANZ tolerable daily intakes for PFOS and PFOA (i.e. up to 80% of exposure is assumed to come from other pathways) and apply the ASC NEPM HIL D assumptions for commercial/industrial land use including 8 hrs spent indoors and 1 hr spent outdoors at a site such as a shop, office, factory or industrial site. The criteria have been applied across the Site with the exception of the domestic land use zone and recreational areas (i.e. sporting ovals) at the Site (refer Figure 2). Applicable Source Areas: P1 – P24, P26, and P27 It is noted that the Tier 1 screening criteria for commercial/industrial land use are not directly applicable to firefighting personnel and intrusive maintenance and construction workers as the ASC NEPM HIL D exposure assumptions used in the derivation of the screening criteria may differ from the exposure scenarios for these workers. As such the screening criteria have not been applied to these potential receptors. The potential risk to these on-Site workers associated with exposure to PFAS contaminated soil will be assessed as part of the HHERA, which was in progress at the time of this report.

PFOA 0.005 mg/kg 50 mg/kg

Soil On-Site (Residential)

PFOS/PFHxS 0.005 mg/kg 2 mg/kg The screening criteria are based on 20% of the FSANZ tolerable daily intakes for PFOS and PFOA (i.e. up to 80% of exposure is assumed to come from other pathways) and apply the ASC NEPM HIL B assumptions for residential land use with minimal opportunities for soil access, with no use for home-grown produce and poultry. The adopted scenario is considered appropriate for the domestic land use zone within the Site (refer Figure 2) where consumption of home-grown produce is not a foreseeable activity at that Site. Applicable Source Areas: No source areas identified or assessed within the domestic land use zone





Soil On-Site (Public open space)

PFOS/PFHxS 0.005 mg/kg 1 mg/kg The screening criteria are based on 20% of the FSANZ tolerable daily intakes for PFOS and PFOA (i.e. up to 80% of exposure is assumed to come from other pathways) and apply the ASC NEPM HIL C assumptions for public open space such as parks, playgrounds, playing fields (e.g. ovals), secondary schools (except where soil used for agriculture studies) and footpaths. The adopted scenario is considered appropriate for the recreational areas of the Site (e.g. playing fields). Applicable Source Areas: P25


Soil Off-Site (Residential)

PFOS/PFHxS 0.005 mg/kg 0.009 mg/kg

The screening criteria are based on 20% of the FSANZ tolerable daily intakes for PFOS and PFOA (i.e. up to 80% of exposure is assumed to come from other pathways) and apply the ASC NEPM HIL A assumptions with home-grown produce providing up to 10% of fruit and vegetable intake (no poultry), also includes children’s day care centres, preschools and primary schools. These criteria will also be applied in the initial screening assessment of soils within the North East Defence Community Centre playground that will be targeted for assessment as part of the HHERA. It is noted that these values are not protective of other food-based exposures such as consumption of eggs or home-slaughtered livestock.

PFOA 0.005 mg/kg 0.1 mg/kg

Sediment PFOS/PFHxS 0.005 mg/kg 20 mg/kg For the purposes of the initial screening assessment of the risk to human health through exposure to potential PFAS impacted sediments (e.g. by maintenance personnel), the adopted soil screening criteria for the on-site commercial/industrial land use scenario have been applied. However, as noted above the Tier 1 screening criteria for commercial/industrial land use are not directly applicable to intrusive maintenance and construction workers as the ASC NEPM HIL D exposure assumptions used in the derivation of the screening criteria may differ from the exposure scenarios for these workers. As such the screening criteria have not been applied to these potential receptors. The potential risk to these workers associated with exposure to PFAS contaminated sediment will be assessed as part of the HHERA, which was in progress at the time of this report.


Ecological

Surface Water (including pore water)

PFOS 0.01 µg/L 0.13 µg/L The screening criteria are based on the Australian and New Zealand Guidelines for Fresh and Marine Water Quality – technical draft default guideline values applicable to slightly to moderately disturbed freshwater ecosystems (95% species protection), as documented in the PFAS NEMP (HEPA, 2018). As described in DSI SAQP (JBS&G, 2017b), and discussed in Section 3.6, the nearest sensitive surface water receptor is considered to be the Kaurna Park Wetland. This is a constructed stormwater detention system that is classified as a highly disturbed ecosystem according to guidance provided in the Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC/ARMCANZ, 2000). Therefore, more appropriate screening criteria may be the draft 90% species protection values applicable to highly disturbed ecosystems. However, in the interest of applying a conservative approach in the initial screening assessment of potential impact to ecological receptors, and with consideration of the fact that the guidelines do not account for effects which result from the biomagnification of toxicants in air-breathing animals or in animals which prey on aquatic organisms, the 95% species protection values have been adopted.

PFOA 0.01 µg/L 220 µg/L




Soil PFOS 0.005 mg/kg 1 mg/kg The values adopted are interim soil screening criteria for ecological direct exposure in public open space land use scenarios, and are applicable to organisms that live within, or are closely associated with, the soil, such as earthworms and plants. The direct exposure values have been adopted in lieu of the indirect exposure criteria as the ecological impacts from exposure to PFAS contaminated surface water have been directly assessed as part of the DSI.


Sediment PFOS 0.005 mg/kg N/A It is noted that there are no current Australian screening criteria that consider impacts to ecological health based on exposure to PFAS contaminated sediments. The potential impact on ecological health in surface water features at the Site and in the broader Investigation Area has been assessed through application of the adopted ecological soil and surface water screening criteria outlined above.


10.3 Non-PFAS COPC

As per the Defence guidance regarding non-PFAS COPC (Defence, 2017a), the analytical results for non-PFAS COPC have be screened against the established screening or investigation levels as defined in Schedule B1 of the ASC NEPM (refer analytical tables attached). Comparison has been made against the generic screening criteria only. The development of Site-specific ecological investigation levels based on the physical or physiochemical properties of the soil, or consideration of ambient background concentrations has not been undertaken. Furthermore, in accordance with the Defence guidance, no assessment or interpretation of results or recommendations regarding future investigations has been undertaken.


11. Investigation Results

11.1 Preliminary Assessment Results

11.1.1 Field Observations

The on-Site sampling program for the Preliminary Assessment was undertaken over the course of a single day (19 December 2016) with no rainfall observed during sampling. The off-Site sampling program was also completed over the course of a single day (16 February 2017) with no rainfall observed during sampling. The preliminary assessment sample locations are shown on Figure 9 (attached).

The daily rainfall and maximum recorded temperatures at the RAAF Edinburgh weather station9 sourced from the Bureau of Meteorology (BOM, 2018) for the 14 days leading up to and including the day of sampling are shown on Figure 11.1 (on-Site sampling) and Figure 11.2 (off-Site sampling).

The preliminary sampling program comprised opportunistic sampling events that were executed shortly following site access coordination and sample permitting (i.e. Council permits for off-Site sampling). The sampling events sought to provide preliminary information on the nature of PFAS contamination in surface water and soil/sediment within the major drainage features at the Site, and a targeted area downstream of the Site (as discussed in Section 1.3). The sampling was not specifically targeted to be completed following a rain event given the time of year in which it the works were undertaken (i.e. summer). However, given the ephemeral nature of the stormwater drainage network, the results are considered to be reasonably representative of the conditions that would typically be encountered at the Site during the drier months of the year.

Minor flow within the Helps Road Drain was observed during sampling, however no flow rate measurements were taken to provide a quantitative measure of stream flow. The depth of surface water at the on-Site sampling locations was estimated to range from 0.2m (SW004) to 0.7m (SW006). The depth of surface water at the off-Site sampling locations was estimated to range from 0.3m (SW010) to 0.8m (SS011) at the outlet of the Kaurna Park Wetland. The Western Swale in the airside operations area (in the western portion of the Site) was observed to be dry at the time of sampling.

9 BOM weather station reference 23083


Figure 11.1: Summary of Climatic Conditions During Preliminary On-Site Sampling Program

Figure 11.2: Summary of Climatic Conditions During Preliminary Off-Site Sampling Program

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11.1.2 Physicochemical Field Parameters

The physicochemical field parameters recorded during the preliminary surface water sampling program are presented in Table 1 (attached). The surface water sampling sheets are provided in Appendix K. The following surface water conditions were noted:

• Dissolved oxygen (DO) ranged from 1.62 parts per million (ppm) to 6.92 ppm indicating a moderate to highly oxygenated environment;

• Electrical conductivity (EC) values ranged from 150 µS/cm (SW010) to 617 µS/cm (SW003), which equates to approximate TDS concentrations10 between 96 mg/L and 395 mg/L;

• The pH values ranged from 6.92 (SW008) to 8.77 pH units (SW006), indicating that the surface water has a near neutral to alkaline pH;

• Reduction/oxidation potential (Redox) ranged from 25 mV (SW009) to 128 mV (SW003) indicating oxidising conditions in the surface water; and

• Observed surface water was typically clear to light brown in colour with low to medium turbidity.

11.1.3 Sediment Observations and Materials Encountered

No visual or olfactory evidence of contamination was observed at any of the sediment investigation locations. The sediments encountered generally consisted of a natural or re-worked natural material with the exception of location SS007 which consisted of fill material. The natural and re-worked natural material typically comprised sandy silty clay material that was usually dark brown to black in colour with significant organic inclusions. Samples SS001 and SS002 (within the Western Swale) were dry whilst the remaining samples were saturated. Sample SS007 consisted of a clayey sand material and was dark brown in colour.

11.1.4 Analytical Results

The tabulated analytical results with comparison against the relevant screening criteria for surface water and sediment are provided in the attached Table 2 (Surface Water) and Table 3 (Sediment). The certified laboratory analytical reports are included in Appendix J.

A summary of the analytical results is presented below:

• All surface water and sediment samples reported concentrations of targeted PFAS analytes below the adopted human health screening criteria and/or below the laboratory LOR;

• Two on-Site surface water samples (SW005 and SW006) and one off-Site surface water sample (SW011) reported concentrations of targeted PFAS analytes above the adopted ecological screening criteria;

• PFAS were detected in all surface water samples, summarised as follows:

o PFOS was reported in all samples ranging from 0.01 µg/L in SW007 to 0.3 µg/L in SW005;

o PFHxS was reported in five samples ranging from 0.01 µg/L in SW010 to 0.04 µg/L in SW005;

o PFOA was reported in three samples ranging from 0.01 µg/L in SW011 to 0.02 µg/L in SW005 and SW006;

o 6:2 FTS was reported below the laboratory LOR in all samples;

10 TDS values have been calculated by multiplying EC (µS/cm) by a factor of 0.64; this factor is put forward as a “rough guide” for

calculating TDS in the Australian Drinking Water Guidelines Paper 6 National Water Quality Management Strategy (NHMRC, NRMMC, 2011)


• PFOS was detected in four of the 11 sediment samples analysed ranging from 0.006 mg/kg in SS011 to 0.011 mg/kg in SS002 and SS005, with all other analytes reported below the laboratory LOR.

11.2 Climatic Conditions

A summary of rainfall and wind observations recorded by the RAAF Edinburgh weather station (BOM, 2018) throughout the Stage 2A and Stage 2B DSI sampling programs is provided in the following sections.

11.2.1 Rainfall

The average monthly rainfall recorded throughout the DSI field program, compared to the long-term average monthly rainfall (since records commenced at the Site in 1972) is shown in Figure 11.3. The records indicate a higher than average rainfall during the months of July and August 2017, corresponding with the Stage 2A GME and surface water sampling Event 1, and lower than average rainfall during the majority of the Stage 2B field program.

As described in the DSI SAQP (JBS&G, 2017b), the Stage 2A surface water sampling events were proposed to commence within 48 hours following a significant rainfall event (where significant rainfall was defined as rainfall greater than 10mm within a 48-hour period). A summary of the recorded rainfall in the seven days leading up to the two surface water sampling events, and that recorded during the sampling events, is shown on Figure 11.4 (Event 1) and Figure 11.5 (Event 2).

Figure 11.3: DSI Rainfall Versus Long-term Average (sourced from BOM, 2018)

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Figure 11.4: Rainfall Conditions – Surface Water Sampling Event 1

Figure 11.5: Rainfall Conditions – Surface Water Sampling Event 2

11.2.2 Wind Conditions

The prevailing winds recorded during the DSI field program were generally from the west to southwest, as depicted on the wind roses in Figure 11.6 (Stage 2A) and Figure 11.7 (Stage 2B).

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Figure 11.6: Prevailing Wind Direction – Stage 2A Sampling Program

Figure 11.7: Prevailing Wind Direction – Stage 2B Sampling Program


11.3 Soil Investigation

The soil investigation program completed throughout the DSI comprised the drilling and sampling of soil bores throughout each of the identified potential primary source areas. The sampling density was designed with consideration given to the size of the potential source areas and the nature and origin of potential PFAS contamination. The targeted soil bore drilling locations were located on Site using a hand-held GPS during the pre-drilling service clearance process, with locations pegged to allow for easy identification during the subsequent drilling program. The GPS coordinate data is presented on the soil bore lithological logs provided in Appendix L.

Drilling was initially progressed using a hand auger from surface to 1.2m bgs followed by mechanical push tube with HDPE liner from 1.2m to the base of each bore. Representative samples were collected from ground surface, shallow sub surface and at minimum 0.5m intervals (or change of lithology) to the base of each bore.

Soil samples selected for laboratory analysis typically targeted the surface and shallow subsurface samples in the first instance, as per the DSI SAQP (JBS&G, 2017b). Following review of the initial soil analytical results, deeper samples in selected bores were analysed to enable vertical profiling of PFAS concentrations throughout the soil profile, which typically comprised analysis of samples collected at approximate 0.5m intervals to the base of the bore. Vertical profiling results are discussed in Section 11.3.3.

Following the soil program completed during the Stage 2A DSI program, selected source areas were subject to an additional soil investigation program (Stage 2B) targeting lateral delineation of PFAS contamination exceeding the adopted Tier 1 human health screening criteria.

A summary of the geology encountered across the Site, including relevant field observations relating to indicators of general site contamination (e.g. suspicious fill, staining or odours), and soil analytical results for PFAS are summarised in the following sections. Where relevant and appropriate, reference has been made to the geology encountered during the monitoring well installation program. The soil bore lithological logs are provided as Appendix L.


Based on observations made throughout the DSI program, soils beneath the Site and within the Investigation Area typically comprise clay, silt and sands representative of the Pooraka Formation and Hindmarsh Clays.

Fill material comprising silty sand and sandy clay with varying gravel inclusions was encountered across many areas of the Site at depths between 0.2m and 0.7m bgs. Significant quantities of reworked natural sediments were encountered as backfill at depths up to 2m bgs, principally in areas comprising historical waste dumps, including source areas P4, P6, P7, P8 and P13. Localised building and industrial waste (e.g. concrete, bricks) was identified in soil bores drilled throughout source areas P1, P5, P7, P8, P9, P10, P15, P22 and P26. Soil bores within P8 encountered potential ACM, concrete, metal, glass, ash and cinder. In addition, a soil bore drilled in source area P18 encountered ACM (confirmed through laboratory analysis).

The natural clays encountered typically comprised silty and sandy clays of low to high plasticity with varying silt, sand and gravel inclusions. Several gravelly horizons up to 0.8m thick were encountered within source area P10. The nature and extent of lithological horizons varied significantly across individual source areas as well as across the Site and broader Investigation Area.

Significant shallow sand sequences were encountered in source area P4 (located at the northern end of the grass runway), P8 (located along the western boundary of the Site), P16 (adjacent to the ERUP Facility), in monitoring wells GW2166 (adjacent to the northern Site boundary), GW2182 (adjacent to the southern Site boundary) and GW2206 (to the west of source area P6), and adjacent to the Helps Road Drain to the east of source area P10.


Photographs of representative examples of the geology encountered across the Site are included in Appendix M. In addition, general photographs of site sampling activities and site features are included in Appendix M.

11.3.2 Soil Analytical Results

The soil laboratory analytical reports and sample chain of custody documentation are provided in Appendix J. The soil analytical results for PFAS have been tabulated and are provided in the attached Table 4A (Commercial/industrial land use areas) and Table 4B (Recreational land use areas), including a comparison of results against the adopted Tier 1 screening criteria for the relevant land uses. A summary of the range of PFAS concentrations for the key analytes of interest reported for each individual primary source area is provided in Table 11.1 (below). In addition, a graphical representation of all soil sample locations, including identification of those exceeding the adopted Tier 1 human health screening criteria and the corresponding highest reported result for the sum of PFHxS and PFOS, is depicted on Figures 11A to 11L (attached).

The soil investigations at the Site have identified 5 source areas that have PFAS contamination present at levels that exceed the adopted human health screening criteria applicable to commercial/industrial land use (i.e. >20 mg/kg for the sum of PFHxS and PFOS). The identified areas comprise the following:

• P4 – Former Fire Training Area and Sub-surface Waste Dump;

• P10 – Former STP and Fire Training Area;

• P11 – Current Fire Station, including former AFFF Storage Area and foam test areas;

• P15 – Former Fire Training Area in Ordnance Unloading Area; and

• P16 – Former Fire Training Area around the ERUP Facility.

Whilst soil investigations within source area P1 did not identify PFAS in excess of the adopted human health screening criterion, sediment samples recovered from the base of the AFFF waste water evaporation pond in this area reported concentrations of the sum of PFHxS and PFOS up to two orders of magnitude above the screening criterion (refer Section 11.6.1).

Concentrations of PFOA, where detected, were typically significantly lower than PFOS and PFHxS concentrations. All PFOA results were reported below the adopted Tier 1 human health screening criteria.


Table 11.1: Summary of Soil Analytical Results Source Area ID

Site Description No. of Sample Locations

No. of Primary Samples Analysed

No. of Detectable Concentrations

Detectable Concentration Range (mg/kg) No. of Samples Exceeding Adopted Screening Criteria PFOA PFOS Sum of PFHxS and

PFOS P1 AFFF Waste Water Retention Tank (Building

521) and AFFF Waste Water Evaporation Pond

16 47 45 0.006 – 0.11 0.0064 – 3.9 0.014 – 3.981 Human Health: 0 Ecological: 11


15 43 36 0.0054 – 0.086 0.0067 – 1.4 0.0076 – 1.67 Human Health: 0 Ecological: 3

P4 Former Fire Training Area and Sub-surface Waste Dump

18 48 47 0.0056 – 0.92 0.0066 – 160 0.0176 – 161.8 Human Health: 2 Ecological: 16

P5 Isolated Aircraft Parking Area 5 13 6 - 0.0051 – 0.74 0.0135 – 0.804 None P6 Former Burning Off Area 5 14 0 - - - None P7 Airfield Taxiway Dump 5 14 0 - - - None P8 Sub-surface Waste Dump 10 35 17 - 0.0082 – 0.078 0.0107 – 0.0805 None P9 Static Rocket Firing Sites and Current Fire

Training Area, including Smokeroom Training Area


P10 Former STP and Fire Training Area (including old 1 RTU Training Area)



19 55 55 0.0053 – 0.92 0.01 – 160[1] 0.01 – 160.2[1] Human Health: 10 Ecological: 26

P12 Taxiway AFFF 10 28 8 - 0.0051 – 0.054 0.0076 – 0.1125 None P13 AFFF Use Area 1 10 28 10 0.017[2] 0.0071 – 1.47[2] 0.0096 – 1.5[2] Ecological: 1 P14 Former Fire Training Area 3 10 2 - 0.011 – 0.0153[2] 0.0135 – 0.0153[2] None P15 Former Fire Training Area in Ordnance

Unloading Area 10 34 34 0.0065 – 0.46 0.03 – 34 0.03 – 34.71 Human Health: 2

Ecological: 18 P16 Former Fire Training Area around the ERUP

Facility 17 46 46 0.0057 – 0.62 0.0059 – 36 0.0072 – 37.5 Human Health: 2

Ecological: 20 P17 Former Fire Training Area in old

Aerodynamics Area 5 12 0 - - - None

P18 Former Fire Training Area (eastern Pyramid)

5 14 8 - 0.0051 – 0.036 0.0076 – 0.0385 None

P19 Former Fire Training Area (western Pyramid)

5 14 0 - - - None


5 13 4 0.021 – 0.023 0.0058 – 0.0076 0.0083 – 0.0101 None


10 30 27 0.0059 – 0.016 0.0059 – 1 0.0104 – 1.008 None


Source Area ID

Site Description No. of Sample Locations

No. of Primary Samples Analysed



PFOS P22 Site of several car fires (off-Site) 5 14 9 - 0.0056 – 0.0336[2] 0.0078 – 0.046[2] None P23 Site of train and semi-trailer crash 5 14 11 - 0.0051 – 0.057 0.0075 – 0.0595 None P24 Fire truck rollover at southern end of main

runway 3 10 9 - 0.0079 – 0.16 0.0104 – 0.1625 None

P25 Former 1RTU Fire Training Area 5 14 4 - 0.0055 – 0.049 0.008 – 0.108 None P26 Historical AFFF Concentrate Spill 4 11 2 - 0.01 – 0.017 0.0125 – 0.0195 None P27 Suspected former fire training area

adjacent to parking area for aircraft refuelling tanker trucks

6 19 19 <LOR – 0.06 <LOR – 4.3 0.051 – 4.34 Human Health: 0 Ecological: 8

(1) Highest sample result was recorded in an intra-laboratory duplicate sample (2) Highest sample result was recorded in an inter-laboratory duplicate sample


11.3.3 Vertical Profiling Results

As per the sampling program outlined in the DSI SAQP (JBS&G, 2017b), targeted soil bores within each potential primary source area were selected for vertical profiling of PFAS contamination beyond the surface and shallow sub-surface samples submitted for initial laboratory analysis. The vertical profiling assessment typically comprised analysis of sub-surface soil samples at approximate half metre intervals to the base of the soil bore. The laboratory analytical results for the sub-surface soil samples are included in Table 4 (attached). A summary of results for soil bores in source areas that had results exceeding the adopted Tier 1 human health screening criteria applicable to commercial/industrial land use (i.e. >20 mg/kg for the sum of PFHxS and PFOS) is provided in Table 11.2.

In addition to the observations made in Table 11.2, the following observations were made in relation to vertical migration of PFAS through the soil profile:

• Analytical results for PFHxS had a tendency to increase with depth through the soil profile to the base of the soil bores, generally between 1m and 2m bgs. Notable bores include BH044, BH078, BH083, BH097, BH101, BH131, BH132, and BH135 where PFHxS was reported at a higher concentration than PFOS toward the base of the bores.

• Analytical results for PFOA also had a tendency to increase throughout the soil profile. Notable bores include BH044, BH078, BH083, BH097, BH101, BH131, BH132, and BH135. The highest concentrations of PFOA in these bores was typically reported at a depth between 1m and 2m bgs.

• The highest reported concentrations of PFOS were typically reported in the upper 1m of the soil profile, generally in shallow sub-surface soils between 0.2m and 1.0m bgs.

A review of the soil lithology encountered at each of the aforementioned soil bore locations (refer Appendix L) has not identified anything unique about the geology compared to the balance of the soil bores drilled across the site. As such, the observations are considered most likely to be associated with the mobility of PFHxS and PFOA in the environment rather than the influence of location specific geology.


Table 11.2: Summary of Soil Vertical Profiling Results

Source Area No. of Bores Selected for Vertical Profiling

Highest Reported Concentration for Sum of PFHxS and PFOS in Vertical Profiling Samples (mg/kg)

Comments/Observations

P4 4 6.7 (BH044, 0.9-1.1m bgs) PFAS contamination was not detected above the adopted human health screening criteria for commercial/industrial land use in any of the vertical profiling samples. BH039, BH042 and BH044 all reported an initial increase in concentrations from surface to 0.9m, 0.8m, and 0.55m bgs respectively, then a decrease in concentrations to 2.0m bgs.

P10 4 45.6 (BH083, 0.7-0.9m bgs) PFAS contamination above the adopted human health screening criteria was detected in a single sample collected from BH083 at a depth of 0.7-0.9m bgs. The highest reported PFOA concentration was also detected at the base of this bore. This bore was subsequently redrilled (BH083A) to assess PFAS contamination beyond 2m bgs. BH083 reported an increase in concentrations from surface to 0.9m bgs then a steady decline in concentrations to the base of the bore. BH083A did not report contamination above the adopted human health screening criteria beyond 2m bgs.

P11 3 93.5 (BH101, 0.4-0.65m bgs) A soil bore was drilled at the location of Q2 Aquifer monitoring well GW2204 with samples collected at various depths from surface to 5.9m bgs, corresponding with the intersection of the Q1 Aquifer at this location. An additional soil sample was collected from this location during drilling of the monitoring well at a depth of 23.4-23.5m bgs, corresponding with the intersection of the Q2 Aquifer. The soil bore reported a general decrease in concentrations from surface to 3.6m bgs and then an increase in concentrations to 5.9m bgs. BH097 and BH101 reported an increase in concentrations from surface to 0.5m and 0.65m bgs respectively, then a decrease in concentrations to the base of the bores (2.0m bgs).

P15 3 34.71 (BH131A, 0.9-1.0m bgs) PFAS contamination above the adopted human health screening criteria for commercial/industrial land use was detected in vertical profiling samples collected from BH131 at a depth of 0.8-1.0m bgs. BH131 was subsequently redrilled (BH131A) to vertically delineate PFAS contamination beyond 2m bgs. BH131 reported an increase in concentrations from surface to 1.0m bgs then relatively steady concentrations from 1.0m bgs to the base of the bore. BH131A did not report contamination above the adopted human health screening criteria beyond 2.0m bgs. BH132 reported relatively steady concentrations throughout the full extent of the bore from surface to 2.0m bgs.


Source Area No. of Bores Selected for Vertical Profiling

Highest Reported Concentration for Sum of PFHxS and PFOS in Vertical Profiling Samples (mg/kg)

Comments/Observations

P16 4 37.5 (BH236, 0.9-1.0m bgs) PFAS contamination above the adopted human health screening criteria for commercial/industrial land use was detected at the base of BH135. This bore was subsequently redrilled (BH135A) to vertically delineate contamination beyond 2m bgs. BH135 reported relatively steady concentrations throughout the full extent of the bore from surface to 2.0m bgs. BH135A did not report contamination above the adopted human health screening criteria beyond 2.5m bgs. Lateral delineation bore BH236 reported an increase in concentrations from surface to 1m bgs with the highest reported concentration at the base of this bore.


11.3.4 Leachate Results

A total of 562 soil samples collected during Stage 2A of the DSI program were submitted for laboratory analysis of leachable PFAS. The laboratory analytical reports including leachate results are provided in Appendix J. The soil leachate analytical results have been tabulated and are provided in Table 5 (attached).

A comparison of the dry weight analytical results against the corresponding leachate analytical results for the key PFAS analytes of interest is shown below in Figure 11.8 (PFOS), Figure 11.9 (PFHxS), and Figure 11.10 (PFOA). These figures also show the fitted linear regression and calculated coefficient of determination (R2 value). Generally, the figures demonstrate a moderate positive correlation between increasing dry weight soil results and increasing leachate results. The average leachate concentration for PFOS (which demonstrated the strongest correlation) appears to be in the order of 5-6% of the dry weight results.

It should be noted that where a detectable leachate concentration was reported against a corresponding dry weight result that was below the laboratory LOR, for graphical representation purposes the corresponding laboratory LOR has been adopted as the dry weight soil result.

In addition to the comparison with dry weight soil results, leachate analytical data for soil samples have been screened against a value that is based on the application of a dilution factor of 10 to the relevant surface water and groundwater screening criteria (consistent with the methodology adopted in EnRisks, 2016). This forms the basis for consideration of whether soil contamination may present a secondary source and an ongoing risk to nearby surface water receptors and the underlying shallow (i.e. Q1 Aquifer) groundwater system (i.e. secondary source contamination). The screening results are shown in Table 5 (attached) and indicate that several source areas, in particular P1, P2, P4, P9, P10, P11, P15, and P16 may present an ongoing source of PFAS contamination to nearby surface water (i.e. stormwater drainage channels and the Helps Road Drain) and/or groundwater during rainfall events (and in the event these areas are subject to irrigation).

Figure 11.8: Comparison of Dry Weight Versus Soil Leachate Results - PFOS

R² = 0.7757

0

10

20

30

40

50

60

70

80

90

100

0 1000 2000 3000 4000 5000 6000

Dry

Wei

ght R

esul

t (m

g/kg

)

Leachate Result (µg/L)

PFOS


Figure 11.9: Comparison of Dry Weight Versus Soil Leachate Results - PFHxS

Figure 11.10: Comparison of Dry Weight Versus Soil Leachate Results - PFOA

R² = 0.6754

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6

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16

0 100 200 300 400 500 600 700 800

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ght R

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PFHxS

R² = 0.6493

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0.8

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1.4

0 5 10 15 20 25 30 35 40 45

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11.3.5 Physical Properties

A total of 37 soil samples collected throughout the DSI program were submitted for analysis of a range of physical and physicochemical properties. The sampling program typically targeted soils within the saturated portion of the soil profile, at depths coinciding with the Q1 and Q2 Aquifers. A tabulated summary of the results is provided as Table 6 (attached). A summary of relevant properties is provided below in Table 11.3.

Table 11.3: Summary of Aquifer Physical Properties Soil Property Q1 Aquifer Sequence Range Q2 Aquifer Sequence Range pH 7.2 – 8.5 6.4 – 8.9 Total Organic Carbon (%) <LOR – 0.2 <LOR Clay Content (%) 6.3 - 24 5 – 14 Total Iron (mg/kg) 8,600 – 38,000 4,400 – 63,000 Conductivity (µS/cm) 130 – 600 76 – 2,500 Cation Exchange Capacity (meq/100g) 8.8 – 33 0.1 – 15

11.4 Groundwater Investigation

The groundwater investigation program completed on Site and in the broader Investigation Area comprised the installation and sampling of new monitoring wells on and off-Site, and the targeted sampling of existing on-Site monitoring wells. New monitoring wells were installed in locations where there was an absence of existing monitoring wells to adequately characterise PFAS contamination beneath, and down hydraulic gradient, of the targeted primary and secondary source areas, along the down hydraulic gradient Site boundary, and in areas considered to represent data gaps in the Site-wide groundwater monitoring well network. The monitoring well installation program to date has comprised the following:

• Installation of 66 x Q1 Aquifer monitoring wells on-Site;

• Installation of 51 x Q1 Aquifer monitoring wells off-Site (including 3 up hydraulic gradient background wells);

• Installation of 37 x Q2 Aquifer monitoring wells on-Site;

• Installation of 16 x Q2 Aquifer monitoring wells off-Site (including 1 upgradient background well);

• Installation of 6 x Q3 Aquifer monitoring wells on-Site; and

• Installation of 2 x Q3 Aquifer monitoring wells off-Site.

Monitoring well installations were completed in accordance with the procedures outlined in the DSI SAQP (JBS&G, 2017b) and summarised in Appendix G, including development of all newly installed wells. The monitoring well construction logs are provided in Appendix N, the monitoring well development record sheets are provided in Appendix O, and the monitoring well construction permits are provided in Appendix P. The location of monitoring wells installed by JBS&G to date are shown on Figure 12 (attached). A summary of the aquifer geology encountered during well installations and the approximate depth to groundwater intersection is described in Section 11.4.1.

The groundwater sampling program completed throughout the DSI comprised sampling of all newly installed monitoring wells and targeted existing monitoring wells, including pre-GME sampling of newly installed wells. Two complete GMEs of on-Site and off-Site monitoring wells were undertaken as part of the Stage 2A and Stage 2B DSI programs, including full groundwater level gauging events. The groundwater sampling sheets are included in Appendix Q. A summary of the relevant field program dates is provided in Section 9.



Groundwater representative of the Q1 Aquifer was intersected in a variety of sedimentary lithologies (with variances in sand and gravel inclusions throughout) that can be broadly grouped into four main types, listed below in order of frequency:

• Sandy CLAY: orange to pale orange brown, occasional grey clay mottling, medium plasticity, fine to coarse grained sand, varying fine to coarse gravel inclusions grading to a gravelly clay;

• Silty CLAY: brown to orange brown, occasional grey clay mottling, low to medium plasticity, traces of fine to medium grained sand, varying fine gravel inclusions;

• Clayey and Silty SAND: light brown to orange brown, and brown, fine to medium grained, with low plasticity clay, varying fine to coarse gravel inclusions; and

• Gravelly CLAY: pale brown to red orange brown, low plasticity, with fine to coarse gravel, varying silt and sand inclusions grading to sandy gravelly clay.

The Q1 Aquifer was generally encountered at depths ranging between 5m and 8m bgs during the drilling and installation of Q1 groundwater monitoring wells, with some localised shallow and deeper variations (e.g. 11.5m in GW2280). The intersection of groundwater in the majority of the Q1 Aquifer monitoring wells installed across the Site and the broader Investigation Area was typically deeper than the subsequent static groundwater level measured during sampling. This supports the understanding that the Q1 Aquifer is semi-confined beneath the Investigation Area.

An apparent perched aquifer sequence was encountered during the drilling and installation of monitoring well GW2120 at a depth of 3.5m bgs. The subsequent drilling of the nested Q2 Aquifer well at this location (GW2200) encountered the Q1 Aquifer at an approximate depth of 9m bgs.

The thickness of the Q1 Aquifer was typically observed to be less than 2m. However, thicker sandy Q1 Aquifer sequences were identified in some areas during the Stage 2B drilling program which involved the use of a Sonic drilling rig that returned complete soil cores during monitoring well installations. This allowed for better observations to be made of the soil profile. In addition, some locations identified permeable sand sequences (lenses) between the typical Q1 and Q2 Aquifer depths (i.e. within the confining aquitard layer). These observations were made during the drilling of Q2 Aquifer groundwater wells at several locations across the investigation area, and through the conduct of a targeted gamma logging program (refer Appendix R). Examples include thicker sandy aquifer sequences intersected between 6.2m and 10.0m bgs during the drilling of the pre-collar for GW2176 (located in the south west corner of the Site), between 9m and 12.3m bgs in GW2209 (in source area P1), between 8 and 13.6m in GW2168 (located in the north western corner of the site), between 11.4m and 12.8 in GW2211 (located in the south western corner of source area P2) and between 10.4m and 14m in GW2215 (located in the southern portion of the former golf course, opposite source area P15). The sands encountered were variable in grain sizing, sorting and rounding and had variable quantities of inclusions including clay, silt and gravels. Several thin, moist to wet permeable gravel lenses (0.01-0.03m in thickness) were also intersected within the aquitard materials between the Q1 and Q2 Aquifers. Examples were identified at 9.8m and 10.8m bgs in GW2204, at 18.2m and 19.4m bgs in GW2207, and at 18.2m in GW2192.

Similarly, a thicker sandy Q1 Aquifer sequence was intersected during the drilling of Q3 monitoring well GW2270 (located in the source area P16) between 8.5m and 10.0m, and GW2276 (located off-Site on Edinburgh Road, south of the Southern Detention Basin) between 6.9m and 13.3m bgs.

Groundwater representative of the Q2 Aquifer was also intersected in a variety of sedimentary lithologies (with variances in sand and gravel inclusions throughout) that can be broadly grouped into three main types, listed below in order of frequency:


• SAND: orange brown, fine to coarse grained, varying fine to medium gravel inclusions and silt fines;

• Clayey SAND: orange brown with grey mottling, fine to medium grained, low to medium plasticity clay, varying fine to medium gravel inclusions and silt fines; and

• Sandy CLAY: orange to pale orange brown, low plasticity, fine to coarse grained sand, varying fine to coarse gravel inclusions.

The Q2 Aquifer was generally intersected at depths between 17m and 22m bgs, with some localised shallow variations (e.g. 14.2m in GW2158 and 15m in GW2205) and deeper variations (e.g. 27.5m in GW2238). The thickness of the Q2 Aquifer was typically observed to be in the order of 3-5m. However, thicker sandy Q2 Aquifer sequences were observed during the drilling of two of the Q3 Aquifer monitoring wells. A thicker Q2 Aquifer sequence was observed between 17.7m and 30.6m bgs in GW2270 (located in source area P16) and between 18.3m and 33.4m bgs in GW2276 (located off-Site on Edinburgh Road, south of the Southern Detention Basin).

Groundwater representative of the Q3 Aquifer was intersected in a variety of sedimentary lithologies (with variances in sand and gravel inclusions throughout) that can be broadly grouped into three main types, listed below in order of frequency:

• SAND: grey to orange brown with occasional grey sand, fine to coarse grained, varying fine to medium gravel inclusions and silt fines;

• Clayey SAND: orange brown to red brown with grey mottling, fine to medium grained, low to medium plasticity fines; and

• Sandy CLAY: red brown with occasional grey mottling, medium plasticity with fine grained sand.

The Q3 aquifer was generally intersected at depths between 35m and 42m, with the deepest intersection at 44.8m in GW2275. Some higher permeability sand and gravel lenses were intersected within the aquitard separating the Q2 and Q3 Aquifers in GW2270 and GW2274.

The presence of higher permeability lenses at varying depths within the aquitard materials between the Q1 and Q2 Aquifers, and to a lesser extent between the Q2 and Q3 Aquifers, support the potential for interconnectivity between the shallow Quaternary Aquifer systems.

Sandy aquifer sequences were the dominant lithology encountered in the Q2 Aquifer across the Site and the broader Investigation Area, with the exception being an area along the south-western corner of the site between groundwater wells GW2179 and GW2173 (near source area P23). Similarly, sandy aquifer sequences were the dominant lithology encountered in the Q3 Aquifers across the Site, with the exception being GW2275 located close to the south-western corner of the site. The presence of more permeable sandy Q1 Aquifer sequences was more variable across the Site with significant variability observed laterally making interpretation of the lateral extent of these sequences difficult. These findings are generally consistent with the descriptions of the discontinuous nature of the quaternary aquifer systems as noted in Gerges (2006) and described in Section 3.2.2. The large range of hydraulic conductivities for the Q1 Aquifer measured in a variety of monitoring wells installed across the Site and the broader Investigation Area (refer Section 11.4.8) support the field observations regarding the high degree of variability observed in the Q1 Aquifer geology.

Photographs of representative examples of the geology encountered in the various aquifer units across the Site and broader Investigation Area are included in Appendix M. A summary of results from the gamma logging program considered in the above summary, and completed to assist with understanding the depth and thickness of the Q1 and Q2 Aquifers and the potential presence of


more permeable geological sequences within the confining layers between the aquifers (i.e. that may act as preferential pathways for contaminant migration), is provided in Appendix R.

11.4.2 Groundwater Levels and Flow Direction

Groundwater level gauging data collected throughout the DSI program is provided in Table 7 (attached). The depths to groundwater measured as metres bTOC have been reduced relative to AHD to allow relative groundwater elevations to be compared across the Investigation Area. The inferred groundwater elevation contours for the Q1 and Q2 Aquifers across the 2017 and 2018 sampling programs, including the inferred groundwater flow direction, are depicted on Figures 13 to 18.

The assessment of groundwater flow direction within the Q1 and Q2 Aquifers beneath the Site and the broader Investigation Area identified the following:

• The inferred groundwater contours for the Q1 Aquifer indicated groundwater flow was typically to the west and southwest with apparent groundwater mounding and radial flows observed in the vicinity of the stormwater drainage features across the Site (i.e. areas where localised surface water recharge mechanisms are influencing groundwater levels). This is in general agreement with the conceptual understanding of flows within the Q1 Aquifer, based on the desktop review of regional hydrogeology. In the southern and south-eastern portions of the site, there appeared to be components of groundwater flow in a more southerly direction.

• The inferred groundwater contours for the Q2 Aquifer also indicated groundwater flow was typically to the west and southwest, and was similar to the overlying Q1 Aquifer with the exception of an absence of apparent impacts from surface water recharge (which was not unexpected for the deeper Q2 Aquifer).

Due to the potential for localised variability in groundwater flow direction, as discussed in Section 3.2, an assessment of inferred groundwater contours for the major PFAS source areas identified on-Site, including boundary source areas, has been undertaken and is depicted on Figures 19A to 19E. A summary of the groundwater flow direction for these areas is discussed below:

• The inferred groundwater contours in the vicinity of source area P1, P2, P3, P11 and P27 (Figure 19A) indicate an apparent groundwater mound in the vicinity of the western Chesterfield Sump (P3B) with radial flow to the southeast, south and west away from this feature. The general flow direction beneath source areas P1 and P2 appears to be in a more southerly direction, whilst the general flow beneath P11 and P27 is more west to south-westerly;

• Beneath source area P4, and in the vicinity of source area P8 (western Site boundary) and P23 (southwestern Site boundary), groundwater is inferred to be flowing in a general westerly direction (refer Figure 19B, Figure 19C and Figure 19E); and

• The inferred groundwater contours in the vicinity of source areas P9 and P15 indicate a general west to north-westerly flow direction beneath these source areas (Figure 19D).

It is noted that the horizontal hydraulic gradients in each of the areas is relatively flat. The hydraulic gradients beneath the Site and broader Investigation Area are discussed further below.

11.4.3 Groundwater Hydraulic Gradients

An assessment of the hydraulic gradients across the Site and broader Investigation Area, based on the 2018 reduced groundwater elevation data (refer Table 7, attached), was undertaken. A summary of the results is presented below in Table 11.4, including reference to the wells used to determine the gradient. Note, the assessment excluded wells considered to have an elevated groundwater level influenced by localised surface water recharge mechanisms. The results indicate the hydraulic


gradient beneath the Site and broader Investigation Area for both the Q1 and Q2 Aquifers are similar and are relatively flat.

Table 11.4: Summary of Hydraulic Gradients

Area Aquifer Wells Used Distance Between Wells (m)

Calculated Hydraulic Gradient (m/m)

Site Q1 GW2135 and GW2177 3,650 0.0009 Q2 GW2216 and GW2179 3,600 0.0010

Investigation Area Q1 GW2135 and GW2255 6,800 0.0011 Q2 GW2219 and GW2247 7,500 0.0013

In addition, an assessment of the vertical hydraulic gradient between the Q1 and Q2 Aquifers has been undertaken by dividing the difference in the relative groundwater elevation by the vertical distance between the relative elevation of the well screen midpoints. The assessment was completed for 48 nested well locations using standing water levels recorded during the most recent (i.e. July 2018) groundwater level gauging event. A summary of the results is provided in Table 8 (attached). The following observations are made in relation to the vertical hydraulic gradients between the aquifers:

• 26 nested well pairs exhibited a downward vertical hydraulic gradient ranging from -0.0002 to -0.425;

• 21 nested well pairs exhibited an upward vertical hydraulic gradient ranging from 0.001 to 0.014; and

• 1 nested well pair did not show a difference in hydraulic head.

The results indicate a relatively high degree of variability in vertical hydraulic gradients both spatially and in the relative magnitude of the observed gradients, particularly in the nested well locations exhibiting a downward vertical hydraulic gradient. The steepest downward vertical gradients were typically observed in nested well locations located in close proximity to stormwater drainage infrastructure, where there is apparent groundwater mounding in the Q1 Aquifer as a result of surface water recharge (e.g. GW2147 and GW2219, and GW2206 and GW2207).


The field measured physicochemical parameters for groundwater recorded during sampling events are detailed in Table 9 (attached). The groundwater sampling sheets are included in Appendix Q. Relevant calibration records for the water quality meters used to measure field parameters are included in Appendix S. A summary of the field parameters measured in groundwater beneath the Site and the broader Investigation Area during the most recent (2018) GME is provided below in Table 11.5.

It is noted that there is large range in the reported concentrations for DO and TDS parameters across the Site and the broader Investigation Area, in particular within the Q1 and Q2 Aquifers. The measured concentrations of dissolved oxygen ranged between 0.59 and 8.82 ppm for the Q1 Aquifer and between 0.74 and 6.52 ppm for the Q2 Aquifer. The range in values reflects both the large area of investigation (in the order of 3,000 hectares) and the varying and complex geo-environmental settings. In general, lower concentrations appear to be reflective of locations of lower recharge (e.g. isolated from unlined stormwater features that may provide enhanced aquifer recharge), and in lower permeability and potentially discontinuous aquifer formations. Higher concentrations appear to be reflective of locations of likely higher recharge (i.e. close to stormwater drainage features and unsealed areas), and areas of higher permeability lithologies. As noted in Section 3.2.2, Gerges (2006) identified that the salinity of the Quaternary aquifers in the Northern Adelaide Plains is variable depending on the local recharge sources and the nature and extent of the coarser sediments.


The large range in TDS values once again reflects both the large area of investigation, the varying and complex geo-environmental settings, and in many instances the large distances between sampling locations. Calculated concentrations of TDS (based on the measured EC) for the Q1 Aquifer ranged between 427 and 23,104 mg/L, and between 566 and 20,160 mg/L for the Q2 Aquifer. The locations corresponding with the lower TDS concentrations are typically representative of areas located close to unlined stormwater drainage features (where enhanced aquifer recharge of fresh water may occur), open unsealed areas and areas of higher permeability lithologies. The range of DO and TDS concentrations across the Site recorded during the 2018 GME are generally consistent with ranges recorded during the GMEs undertaken across the Edinburgh Defence estate by GHD in 2014 and 2016 (GHD, 2014a and GHD, 2016).


Table 11.5: Summary of Groundwater Field Parameters Sample Locations Aquifer DO (ppm) EC (µS/cm) TDS (mg/L)[1] pH (units) Redox (mV) Temperature

(oC) Comments

Background Wells

Q1 Aquifer 1.91 to 4.72 1,740 to 8,300 1,114 to 5,312 7.28 to 8.89 7.0 to 171 17.1 to 19.3 Results indicate neutral to alkaline pH conditions, fresh to brackish salinity, typically low dissolved oxygen content, and moderately oxidising conditions exist

Q2 Aquifer 1.60 6,450 4,128 7.68 100 17.6 Results indicate neutral to slightly alkaline pH, brackish salinity, low dissolved oxygen content, and moderately oxidising conditions exist

On-Site Wells Q1 Aquifer 0.59 to 6.41 714 to 36,100 457 to 23,104 6.30 to 9.08 -135 to 235 13.9 to 21.0 Results indicate slightly acidic to alkaline pH conditions, fresh to saline salinity, low to moderate dissolved oxygen content, and a range of reducing to oxidising conditions exist

Q2 Aquifer 0.81 to 6.52 968 to 31,500 620 to 20,160 6.91 to 9.06 -208.0 to 152 16.4 to 20.4 Results indicate slightly acidic to alkaline pH conditions, fresh to saline salinity, low to moderate dissolved oxygen content, and a range of reducing to oxidising conditions exist

Q3 Aquifer 0.70 to 1.87 2,156 to 7,375 1,380 to 4,720 7.10 to 9.72 -200.5 to 147.2 19.1 to 20.9 Results indicate neutral to alkaline pH conditions, fresh to brackish salinity, low dissolved oxygen content, and a range of reducing to oxidising conditions exist

Off-Site Wells Q1 Aquifer 0.90 to 8.82 667 to 29,100 427 to 18,624 7.04 to 8.32 -21.3 to 160.4 16.5 to 20.6 Results indicate neutral to alkaline pH conditions, fresh to saline salinity, a range of low to high dissolved oxygen content, and typically oxidising conditions exist

Q2 Aquifer 0.74 to 4.83 885 to 22,190 566 to 14,202 6.71 to 8.76 6.8 to 129 16.3 to 20.1 Results indicate slightly acidic to alkaline pH conditions, fresh to saline salinity, typically low dissolved oxygen content, and moderately oxidising conditions exist

Q3 Aquifer 1.07 to 2.40 1432 to 1,560 916 to 998 8.00 to 9.06 -210 to -182.9 19.7 to 19.9 Results indicate alkaline pH conditions, fresh salinity, typically low dissolved oxygen content, and reducing conditions exist

(1) Calculated by multiplying EC (µS/cm) by a factor of 0.64


11.4.4.1 Review of Protected Environmental Values of Groundwater

Based on conversion of the calculated TDS values for groundwater throughout the Investigations Area, an updated assessment of the likely protected environmental values of groundwater for each of the aquifers of interest has been undertaken. The assessment has once again comprised comparison of the most conservative (i.e. lowest) calculated TDS value to the TDS ranges provided in the table in clause 3 of Schedule 1 of the WQEPP 2015. The results of the assessment are summarised below in Table 11.6.

Table 11.6: Updated Assessment of Protected Environmental Values of Groundwater

Environmental Values of Underground Water (Groundwater)

Q1 Aquifer TDS Level Indicates Suitability for Selected Environmental Value?



Drinking Water for Human Consumption Yes Yes Yes Primary Industries—Irrigation and General Water Uses

Yes Yes Yes

Primary industries—Livestock Drinking Water

Yes Yes Yes

Primary industries—Aquaculture and Human Consumption of Aquatic Foods

Yes Yes Yes

11.4.5 Groundwater Analytical Results

The groundwater laboratory analytical reports and sample chain of custody documentation are provided in Appendix J. The groundwater analytical results for PFAS have been tabulated and are provided in Table 10 (attached), including a comparison of results against the adopted Tier 1 screening criteria for drinking water (i.e. 0.07 µg/L for the sum of PFHxS and PFOS). A summary of the range of PFAS concentrations reported in the Q1 Aquifer during the DSI program GMEs is summarised in Table 11.7 (below). This table summarises results relevant to each individual primary source area, other designated site areas (i.e. boundary wells and balance of Site), and off-Site areas. In addition, a summary of Q2 Aquifer and Q3 Aquifer results for the Site and off-Site areas is provided in Table 11.8 and Table 11.9.

A graphical representation of groundwater analytical results is provided on the following figures attached to this report:

• Figure 20 - All Q1 Aquifer groundwater monitoring well sampled during the DSI identifying those exceeding the adopted Tier 1 screening criteria and showing the corresponding 2017 and 2018 GME results for the sum of PFHxS and PFOS;

• Figures 21A to 21M – Q1 Aquifer results for the sum of PFHxS and PFOS for each of the primary source areas;

• Figure 22 – All Q2 Aquifer groundwater monitoring well sampled during the DSI identifying those exceeding the adopted Tier 1 screening criteria and showing the corresponding 2017 and 2018 GME results for the sum of PFHxS and PFOS;

• Figure 23 – All Q3 Aquifer groundwater monitoring well sampled during the DSI identifying those exceeding the adopted Tier 1 screening criteria and showing the 2018 sampling results for the sum of PFHxS and PFOS.

• Figure 24 – Nested Q1, Q2 and Q3 Aquifer monitoring well locations and 2018 sampling results for the sum of PFHxS and PFOS.


Table 11.7: Summary of Groundwater Analytical Results – Q1 Aquifer

Source Area ID Site Description Wells Considered

Detectable Concentration Range (µg/L) Results Exceed Tier 1 Screening Criteria?(1)

Reference Figure PFOA PFOS Sum of PFHxS

and PFOS P1 AFFF Waste Water Retention Tank (Building 521)

and AFFF Waste Water Evaporation Pond EDMW04, GW2114, GW2132 0.47 – 3.3 7.2 – 63 12.4 – 78 Yes Figure 21A


GW0434, GW0435, GW0436, GW0437, GW0438, GW0439, GW2151, GW2212

0.13 – 2.58 1.1 – 77 5.9 – 111 Yes Figure 21A


GW0335, GW2115, GW2130, and GW2131

<LOR – 43 0.12 – 910 0.34 – 1,160 Yes Figure 21B


GW0008, GW0191, GW0192, GW0193, GW0196, GW0197, GW0319, GW0321, and GW0322

<LOR – 15 <LOR – 300 <LOR – 660 Yes Figure 21C

P5 Isolated Aircraft Parking Area GW0301, GW0302, GW0303, and GW0304

<LOR – 0.02 <LOR – 0.94 <LOR – 0.23 Yes Figure 21C

P6 Former Burning Off Area GW0027 and GW2124 <LOR – 0.02 <LOR – 0.53 0.09 – 0.78 Yes Figure 21D P7 Airfield Taxiway Dump GW0329 and GW0330 <LOR – 0.02 0.01 – 0.15 0.06 – 1.2 Yes Figure 21E P8 Sub-surface Waste Dump GW0315, GW2121, GW2122, GW2129,

and GW2170 <LOR – 3.6 0.14 – 11 0.24 – 74 Yes Figure 21F

P9 Static Rocket Firing Sites and Current Fire Training Area, including Smokeroom Training Area

GW0428, GW2148 and GW2213 0.44 – 31 17 – 650 30.5 – 870 Yes Figure 21A


GW0026, GW2108, GW2109, GW2112, GW2137 and GW2138

0.13 – 0.87 <LOR – 35 2.03 – 46 Yes Figure 21G


GW2116, GW2197, and GW2203 5.1 – 500 100 – 14,000 200 – 23,100 Yes Figure 21H

P12 Taxiway AFFF GW2117 and GW2118 <LOR – 0.35 <LOR – 0.33 <LOR – 8.9 Yes Figure 21I P13 AFFF Use Area 1 GW0028, GW2125, and GW2153 <LOR – 0.02 0.03 – 0.27 0.07 – 0.43 Yes Figure 21D P14 Former Fire Training Area GW2154 <LOR 1.1 – 5.2 1.17 – 5.26 Yes Figure 21E P15 Former Fire Training Area in Ordnance Unloading

Area GW2149 8.7 – 14 120 – 180 204 – 320 Yes Figure 21A

P16 Former Fire Training Area around the ERUP Facility GW2119 and GW2120[2] 0.33 – 3.2 8.7 – 240 14.3 – 264 Yes Figure 21I P17 Former Fire Training Area in old Aerodynamics Area GW2135 <LOR <LOR <LOR No Figure 21J P18 Former Fire Training Area (eastern Pyramid) GW0075 and GW2134 <LOR – 0.01 0.03 – 0.07 0.03 – 0.1 Yes Figure 21K P19 Former Fire Training Area (western Pyramid) GW2133 <LOR 0.02 – 0.16 0.21 – 0.32 Yes Figure 21K P20 Former Fire Training Area northeast of Site 19 (P4) GW2140 <LOR <LOR – 0.03 <LOR – 0.035 No Figure 21C P21 Former Fire Training Area along Taxiway Bravo GW2152, GW2191, GW2193, and

GW2196 0.62 – 12 12 – 380 31 – 540 Yes Figure 21H

P22 Site of several car fires (off-Site) GW2136 0.03 – 0.05 0.65 – 0.91 2.41 – 2.42 Yes Figure 21G P23 Site of train and semi-trailer crash GW2110 and GW2180 0.23 – 12 6.1 – 94 11.5 – 214 Yes Figure 21L


Source Area ID Site Description Wells Considered

Detectable Concentration Range (µg/L) Results Exceed Tier 1 Screening Criteria?(1)

Reference Figure PFOA PFOS Sum of PFHxS

and PFOS P24 Fire truck rollover at southern end of main runway GW2150 0.14 – 0.17 17 – 21 20.7 – 25 Yes Figure 21M P25 Former 1RTU Fire Training Area GW2155 <LOR 0.02 0.11 – 0.16 Yes Figure 21K P26 Historical AFFF Concentrate Spill GW0359, GW0388, and GW2156 <LOR <LOR – 0.02 0.025 – 0.49 Yes Figure 21K P27 Suspected former fire training area adjacent to

parking area for aircraft refuelling tanker trucks GW0416, GW0418, GW0419 7.1 – 62 180 – 1,600 330 – 2,900 Yes Figure 21A

- Boundary Wells GW0015, GW0086, GW0357, GW0430, GW0431, GW2108, GW2110, GW2121, GW2122, GW2129, GW2137, GW2138, GW2139, GW2165, GW2166, GW2167, GW2169, GW2172, GW2174, GW2175, GW2177, GW2180, GW2181, GW2182, GW2184, GW2264,

<LOR – 12 <LOR – 94 <LOR – 214 Yes Figure 20

- Balance of Site All other wells <LOR – 26 <LOR – 740 <LOR – 796 Yes Figure 20 - Background Wells GW2127, GW2128, GW2147, GW0915

(DTSG) and GW0031 (DSTG) <LOR <LOR – 0.13 <LOR – 0.16 Yes Figure 20

- Off-Site All off-Site wells, excluding background <LOR – 0.29 <LOR – 19 <LOR – 24.6 Yes Figure 20 (1) Tier 1 human health screening criteria applicable to drinking water (i.e. 0.07 µg/L for the sum of PFHxS and PFOA, and 0.56 µg/L for PFOA) (2) Note, monitoring well GW2120 is considered to be installed in a perched groundwater lens


Site Description Wells Considered Detectable Concentration Range (mg/kg) No. of Wells with Results

Exceeding Adopted Screening Criteria(1) PFOA PFOS Sum of PFHxS and PFOS

On-Site All on-Site Q2 wells (39 wells) <LOR – 45 <LOR – 1,200 <LOR – 1,540 28 (72% of wells) Background Well GW2219 <LOR 0.31 0.43 1 Off-Site All off-Site Q2 wells, excluding

background wells (15 wells) <LOR – 0.5 <LOR – 33 <LOR – 44 8 (53% of wells)

(1) Tier 1 human health screening criteria applicable to drinking water (i.e. 0.07 µg/L for the sum of PFHxS and PFOA, and 0.56 µg/L for PFOA)


Site Description Wells Considered Detectable Concentration Range (mg/kg) No. of Wells Exceeding

Adopted Screening Criteria(1) PFOA PFOS Sum of PFHxS and PFOS

On-Site All on-Site Q3 wells (6 wells) <LOR – 0.15 <LOR – 1.4 <LOR – 2.9 3 (50% of wells) Off-Site All off-Site Q3 wells (2 wells) <LOR – 0.09 <LOR – 3.1 <LOR – 4.3 1 (50% of wells)

(1) Tier 1 human health screening criteria applicable to drinking water (i.e. 0.07 µg/L for the sum of PFHxS and PFOA, and 0.56 µg/L for PFOA)


11.4.5.1 On-Site Groundwater Results

Groundwater investigations to date have identified vertical migration of PFAS contamination beyond the shallow Q1 Aquifer to the underlying Q2 and Q3 Aquifers. In addition, the groundwater investigations have identified significant groundwater contamination that exceeds the adopted human health screening criteria11 for the sum of PFHxS and PFOS by two orders of magnitude or more within the Q1 and/or Q2 Aquifer beneath the following source areas:

• P1 - AFFF Waste Water Retention Tank (Building 521) and AFFF Waste Water Evaporation Pond;

• P2 – Bulk Fuel Store, including 2,800L AFFF deluge system;

• P3 – In proximity to the Chesterfield Sumps (that receive waste water from the Hangars);

• P4 – Former Fire Training Area and Sub-surface Waste Dump;

• P8 – Sub-surface Waste Dump (located on the western Site boundary);

• P9 – Static Rocket Firing Sites and Current Fire Training Area;

• P10 – Former STP and Fire Training Area;

• P11 – Current Fire Station, including former AFFF Storage Area and foam test areas;

• P15 – Former Fire Training Area in Ordnance Unloading Area;

• P16 – Former Fire Training Area around the ERUP Facility;

• P21 – Former Fire Training Area along Taxiway Bravo;

• P23 – Site of train and semi-trailer crash (south-western boundary of the Site); and

• P27 – Suspected former fire training area adjacent to parking area for aircraft refuelling tanker trucks.

The most significant of these, source areas P3, P4, P9, P11, and P27, had PFAS contamination in groundwater exceeding the adopted screening criteria by more than three orders of magnitude. These areas generally correlate with areas of current and former storage of AFFF concentrate and AFFF waste water, and current and former firefighting training areas with a history of prolonged use of AFFF.

PFAS concentrations in groundwater beneath the Site have typically been reported at the highest concentrations in the Q1 Aquifer, when considering results for nested Q1 and Q2 Aquifer wells. However, in a small number of locations PFAS have been detected at higher concentrations in the Q2 Aquifer than in the overlying Q1 Aquifer. Most notably, the Q2 Aquifer results have been greater than the corresponding Q1 Aquifer results in samples collected from the following Q2 Aquifer monitoring wells:

• GW2158 and GW2188, located within and down hydraulic gradient of source area P9;

• GW2208 adjacent to the Helps Road Drain between source areas P1 and P27;

• Southern boundary wells GW2137, GW2183, and GW2185; and

• GW2164 (where the corresponding Q1 Aquifer well reported all results below the laboratory LOR), located down hydraulic gradient of source area P4.

11 The DoH, 2017 Health Based Guidance Values for Drinking Water (i.e. 0.07 µg/L for the sum of PFHxS and PFOA, and 0.56 µg/L for

PFOA)


With the exception of a single location (GW2163/GW2164), where PFAS contamination has been detected in a Q2 Aquifer monitoring well, the corresponding (i.e. nested) Q1 Aquifer monitoring well has also detected PFAS contamination. The absence of PFAS contamination in Q1 Aquifer monitoring well GW2163, where PFAS was detected in the nested Q2 Aquifer monitoring well, suggests that the aquifers are not hydraulically connected in this area of the Site. It also suggests that the Q2 Aquifer contamination in this area is from an up hydraulic gradient source area (i.e. Source Area P4).

In addition, samples collected from several groundwater wells across the balance of the Site (i.e. not specifically targeting a potential source area) reported PFAS concentrations that significantly exceeded the adopted human health screening criteria. Most notably, results exceeded the screening criteria by three orders of magnitude or more in samples collected from the following monitoring wells:

• GW0310, located adjacent to Helps Road Drain between source areas P2 and P27, and to the south of source area P11;

• GW0417, located to the southeast of source area P27 and in close proximity to the Helps Road Drain;

• GW0440, GW0441 and GW0443, located to the south of the eastern Chesterfield Sump in source area P3; and

• GW2188, considered to be located down hydraulic gradient of source area P9 and P15.

In addition, GW2178 located in the south-western portion of the airside operations area (up hydraulic gradient of source area P23) reported PFAS concentrations that exceeded the adopted human health screening criteria and were higher than the majority of groundwater wells across the balance of the Site (i.e. not specifically targeting a potential source area). As noted in Section 6, this monitoring well is located in relatively close proximity to the aircraft wash down facility known as the “Birdbath area”. This area was initially identified by Base firefighting personnel as a potential source area where historical testing of mobile firefighting equipment may have occurred but then was subsequently retracted during the 2017 on-Site interviews conducted by JBS&G. However, the groundwater results for GW2178 indicate that some historical discharge of AFFF may have occurred in this area and therefore may represent an additional source area

Boundary monitoring wells installed along the down hydraulic gradient western and southern boundaries of the Site have also reported significant PFAS contamination in groundwater at the point where it would be discharging off-Site. The highest PFAS concentrations along the Site boundary have been recorded in samples collected from the following wells:

• GW2129, located immediately north of source area P8 along the approximate mid-point of the western Site boundary;

• GW2180, located at the southern end of source area P23 in the south-western corner of the Site; and

• GW2108 and GW2137, located at the southern end of source area P10, on the southern Site boundary near the point where the Helps Road Drain discharges across the Site boundary.

Targeted assessment of the Q3 Aquifer to date has identified PFAS contamination exceeding the adopted human health screening criteria in three of the six areas assessed. The highest PFAS concentrations on-Site have been detected in Q3 Aquifer monitoring well GW2271, installed in source area P9 (Static Rocket Firing Sites and Current Fire Training Area). In addition, PFAS contamination has been confirmed in the Q3 Aquifer monitoring well GW2275, installed on the southwestern Site boundary, at the southern end of source area P23.


11.4.5.2 Background Groundwater Results

Low levels of PFAS contamination (relative to on-Site results) were detected in one of the three up hydraulic gradient Q1 Aquifer background monitoring wells (GW2147) installed during the DSI program to assess ambient background groundwater quality in accordance with the SA EPA guideline Site Contamination – Assessment of background concentrations (SA EPA, 2018). The maximum recorded concentration for the sum of PFHxS and PFOS recorded at this location was 0.18 µg/L, recorded during the targeted boundary and off-Site monitoring well sampling event completed during the Stage 2A DSI program (June 2017). The dominant PFAS compound was PFOS, representing approximately 70% of the detectable concentrations of PFAS, with the remaining 30% comprising PFHxS. There were no other PFAS compounds detected in this groundwater sample.

The nested Q2 Aquifer monitoring well at this location (GW2219), installed to assess ambient background groundwater quality in the Q2 Aquifer, also detected relatively low levels of PFAS contamination (compared to on-Site concentrations). The highest reported PFAS concentration in this monitoring well was 0.49 µg/L. Once again, the dominant PFAS compound was PFOS, representing approximately 70% of the detectable concentrations of PFAS, with the remaining 30% comprising PFHxS. Minor concentrations of perfluorobutane sulfonate (PFBS) and perfluoropentane sulfonate (PFPeS) were also reported equivalent to the laboratory LOR (0.01 µg/L).

The source of PFAS contamination in this area is unknown, however as discussed in Section 7.3.2, many types of PFAS are considered to be ubiquitous global contaminants and therefore it is not unreasonable that low levels may be identified in some background locations, even in the absence of a specific identified off-Site source. It is also noted that the monitoring wells are installed in close proximity to the Edinburgh Park North detention basin (constructed by the Salisbury Council) which receives stormwater from a significant upstream catchment area. Therefore, it is possible that the origins of the identified PFAS contamination is from surface water contaminated in the upstream catchment historically recharging groundwater in the vicinity of the detention basin (i.e. ambient background resulting from general anthropogenic activities). An apparent groundwater mound in this area (identified through the significant difference in reduced standing water levels between the nested Q1 and Q2 monitoring wells, in the order of 6m, and to the nearest downgradient Q1 monitoring well, GW2135) supports the likelihood that groundwater is being recharged by ponded water within the detention basin and/or the adjacent stormwater swale.

A Q1 Aquifer groundwater monitoring well (GW0342) installed in relatively close proximity to the up hydraulic gradient boundary (i.e. down hydraulic gradient of the impacted background wells discussed above) reported minor concentrations of PFAS. The maximum reported concentration for the sum of PFHxS and PFOS was 0.055 µg/L, recorded during the Stage 2A GME. This may represent ambient background concentrations entering the Site. A second Q1 Aquifer groundwater monitoring well (GW2135) installed in relatively close proximity to the up hydraulic gradient boundary did not identify PFAS contamination (i.e. all results were less than the laboratory LOR).

Existing monitoring wells located within the DSTG site, to the east of the Site, also reported relatively low levels of PFAS contamination which suggest an off-Site source may be present in this area. However, the concentrations reported are significantly lower than the majority of source area concentrations reported on Site and therefore the DSTG site is not considered to represent a significant off-Site source of contamination in the areas tested.

11.4.5.3 Off-Site Groundwater Results (Down Hydraulic Gradient of Site)

The off-Site groundwater monitoring results have identified a diffuse spread of contamination throughout the Q1 and Q2 Aquifers within the Investigation Area. The highest degree of PFAS contamination has typically been observed in the vicinity of the Helps Road Drain and Kaurna Park Wetland, and areas considered to be down hydraulic gradient of the Southern Detention Basin. These results suggest that, at least historically, surface water discharging from the Site has provided


a significant secondary source of impact to the underlying groundwater system. The surface water results reported throughout the DSI program do not tend to correlate with the degree of contamination observed in the shallow Quaternary aquifers, and therefore it is considered likely that historically the concentrations of PFAS in surface water discharging from the Site would have been significantly higher than the concentrations observed more recently.

The observed groundwater contamination off-Site to the west and southwest is considered to be associated with the migration of PFAS contamination in groundwater away from the source areas identified in the western portion of the Site (i.e. P8 and P23). The off-Site migration of contamination in this area is generally consistent with the observations made in relation to the inferred groundwater flow direction (as discussed in Section 11.4.2).

Approximately 60% of off-Site Q1 Aquifer monitoring wells and 50% of off-Site Q2 Aquifer monitoring wells have reported PFAS concentrations that exceed the adopted Tier 1 human health screening criteria. The inferred extent of groundwater contamination exceeding the Tier 1 screening criteria is depicted on Figure 25 (Q1 Aquifer) and Figure 26 (Q2 Aquifer).

Targeted assessment of the Q3 Aquifer to date has identified PFAS contamination exceeding the adopted human health screening criteria in the monitoring well installed near the inlet of the Kaurna Park Wetland (GW2277). The second Q3 Aquifer monitoring well (GW2276), installed down hydraulic gradient of the Southern Detention Basin and nested with the Q2 Aquifer monitoring well that reported the highest PFAS results within the Q2 Aquifer off-Site, did not report detectable concentrations of PFAS.

11.4.6 Dominant PFAS in Groundwater

In 100% of sample results for the Q1 Aquifer (both on and off-Site), where positive results were reported for one or more PFAS compounds, the concentration of the sum of PFHxS and PFOS was the highest reported result. In approximately 70% of sample results PFOS was the dominant PFAS compound detected (i.e. highest reported result for a single PFAS compound). In the remaining 30% of samples, PFHxS was reported as the dominant PFAS compound.

A similar trend was observed in the Q2 and Q3 Aquifer monitoring wells both on and off-Site where the sum of PFHxS and PFOS was the highest reported result in each of the samples tested.

11.4.7 Water Chemistry

A selection of Q1 Aquifer and Q2 Aquifer monitoring wells installed across the Site were targeted for sampling and analysis of major ions (anions and cations). This analysis was undertaken to provide information on the water chemistry of the aquifer units and allow a comparison of the ionic composition as a line of evidence to assess the potential for hydraulic connectivity between the aquifers to exist. The analytical results for the major ion analysis are provided in Table 11 (attached). A graphical representation of the ionic composition of the targeted wells and aquifers sampled in 2018 is provided below in Figure 11.11.


Figure 11.11: Piper Diagram for Selected Nested Q1 and Q2 Aquifer Monitoring Wells (2018)

The piper diagram indicates that the groundwater beneath the Site is typically sodium and chloride dominant, with no discernible difference in water chemistry for many of the nested well pairs (i.e. between the Q1 and Q2 Aquifers). The similarity in water chemistry for nested wells indicates a degree of hydraulic connectivity between the between the Q1 and Q2 Aquifers across the majority of the Site and the broader Investigation Area, as supported by the extent of PFAS contamination observed in the Q2 Aquifer beneath and down hydraulic gradient of the Site.

A different water chemistry was observed in Q1 Aquifer monitoring wells EDMW04, GW2131, and GW2152, and to a lesser extent GW0321, GW2116, and GW2197, when compared to the nested Q2 Aquifer wells and the balance of the Q1 and Q2 Aquifer wells tested. It is noted that EDMW04 and GW2131 are located in immediate proximity of surface water drainage features and may have been influenced by infiltration of surface water, which typically has a water chemistry that is bicarbonate dominant and has a low chloride ratio similar to that observed in these wells.

Monitoring wells GW2216 and GW2197 are located adjacent to, and down hydraulic gradient of, the former AFFF concentrate storage area within source area P11. This area reported the highest degree of groundwater contamination within the Q1 Aquifer beneath the Site. The different water chemistry between the Q1 and Q2 Aquifers in this area suggests that there may be a lower degree of hydraulic connectivity in this area of the Site. This is supported by the relatively low concentrations


of PFAS detected in the Q2 Aquifer compared to the significant contamination observed in the Q1 Aquifer (in particular the significant difference in concentrations observed between GW2116 and GW2204).

Monitoring well GW0321 is located in the southern portion of source area P4 and had a greater relative proportion of sulfate compared to other anions in the water, which is different to the results for the nested Q2 Aquifer monitoring well (GW2161), and the balance of the monitoring wells where water chemistry was assessed. PFAS contamination was observed in GW0321, however the nested Q2 monitoring well did not report any detectable concentrations of PFAS. These results suggest the Q1 and Q2 Aquifers may not be hydraulically connected in this localised area of the Site.

11.4.8 Hydraulic Conductivity Testing Results

A selection of groundwater wells installed in each of the targeted aquifers across the Site and throughout the broader Investigation Area were subjected to falling head and/or rising head hydraulic conductivity testing (also known as a “slug test”). Slug tests were completed on a total of 19 x Q1 Aquifer, 15 x Q2 Aquifer and 1 x Q3 Aquifer wells. The results of the tests were analysed using AQTESOLV software with hydraulic conductivity (K values) calculated using the Bouwer-Rice (1976) and Hvorslev (1951) methods. The slug test analysis output curves are provided in Appendix T. The results of the analysis are summarised below in Table 11.10, including the average hydraulic conductivity calculated for each well.

Table 11.10: Summary of Hydraulic Conductivity Testing Results

Well Id Aquifer Hydraulic Conductivity (m/day)

Falling Head Rising Head Average

Bouwer-Rice Hvorslev Bouwer-Rice Hvorslev Q1 Aquifer Results

GW0008 Q1 0.060 0.071 0.31 0.36 0.2 GW0304 Q1 No Logger Data 2.4 2.8 2.6 GW0310 Q1 0.21 0.29 0.18 0.26 0.24 GW0416 Q1 0.30 0.48 0.20 0.30 0.32 GW2100 Q1 0.71 0.90 0.41 0.52 0.64 GW2108 Q1 0.62 0.76 0.54 0.67 0.65 GW2110 Q1 0.063 0.080 0.071 0.091 0.076 GW2118 Q1 2.0 2.4 2.1 2.5 2.25 GW2129 Q1 0.37 0.50 0.28 0.38 0.38 GW2116 Q1 0.06 0.09 0.06 0.09 0.08 GW2135 Q1 0.10 0.15 0.08 0.12 0.11 GW2137 Q1 0.92 1.45 0.46 0.73 0.89 GW2149 Q1 2.8 3.5 2.3 2.9 2.88 GW2152 Q1 0.13 0.15 0.15 0.18 0.15 GW2180 Q1 0.11 0.17 0.06 0.10 0.11 GW2220 Q1 1.00 1.52 0.80 1.1 1.11 GW2225 Q1 1.45 2.30 0.96 1.59 1.58 GW2255 Q1 1.05 1.52 0.63 1.0 1.05 GW2259 Q1 18.7 29.3 18.4 28.2 23.7

Q1 Aquifer Average 2.03 Q2 Aquifer Results

GW2144 Q2 0.15 0.17 0.15 0.17 0.16 GW2158 Q2 1.6 1.8 1.4 1.6 1.6 GW2173 Q2 0.06 0.08 0.005 0.007 0.038 GW2179 Q2 0.01 0.01 No Logger Data 0.01 GW2186 Q2 0.20 0.28 0.12 0.17 0.19 GW2189 Q2 1.26 1.74 1.39 1.91 1.58 GW2199 Q2 10.0 13.5 No Logger Data 11.8 GW2200 Q2 1.15 1.74 0.69 0.96 1.14 GW2204 Q2 No Logger Data 1.91 2.52 2.22 GW2208 Q2 0.13 0.18 0.001 0.002 0.078


Well Id Aquifer Hydraulic Conductivity (m/day)

Falling Head Rising Head Average

Bouwer-Rice Hvorslev Bouwer-Rice Hvorslev GW2210 Q2 0.15 0.17 0.08 0.09 0.12 GW2216 Q2 0.12 0.17 0.06 0.07 0.11 GW2226 Q2 0.05 0.07 0.04 0.05 0.053 GW2267 Q2 0.38 0.53 0.22 0.30 0.36 GW2268 Q2 0.14 0.19 0.08 0.12 0.13

Q2 Aquifer Average 0.93 Q3 Aquifer Results

GW2275 Q3 0.0007 0.0008 No Logger Data 0.0075

The calculated average hydraulic conductivity ranges for each aquifer of interest are summarised below:

• The Q1 Aquifer hydraulic conductivity ranged from 0.076 to 23.7 m/day, with an overall average of 2.03 m/day;

• The Q2 Aquifer hydraulic conductivity ranged from 0.01 to 11.8 m/day, with an overall average of 0.93 m/day; and

• The Q3 Aquifer hydraulic conductivity average was 0.0075 m/day.

Overall, the calculated values for the Q1 and Q2 Aquifers show a high degree of variability, with no discernible trend identifiable for either aquifer system across particular areas of the Site or the broader Investigation Area. This supports the conceptual understanding that there is likely to be a high degree of variability in the nature and extent of more permeable Quaternary sediments that will vary both horizontally and vertically throughout the aquifer units. In addition, the high degree of variability is not unexpected given the significant area of the Site and broader Investigation Area (i.e. covering some 3,000 hectares), and distance between some of the investigation locations.

11.5 Surface Water Investigation

To characterise PFAS concentrations in surface water at the Site, and in areas downstream of the Site, a surface water monitoring program was completed at targeted locations over two sampling events. The on-Site monitoring program comprised the sampling of surface water present throughout the major stormwater drainage channels and Southern Detention Basin. The off-Site monitoring program comprised the sampling of upstream (background) stormwater drainage channels, and the Helps Road Drain and Kaurna Park Wetland downstream of the Site. The surface water sampling locations are shown on Figure 27 and Figure 28 (attached).

All surface water locations were also targeted for collection of collocated sediment samples. Where surface water was not present at the time of sampling, only the corresponding sediment sample was collected. A summary of the sediment investigation program is provided in Section 11.6.

A summary of the field observations made during the surface sampling programs and the laboratory analytical results is provided in the following sections.


The on-Site stormwater drainage network typically comprises unlined drainage channels that vary in width and depth. The most significant of these is the Helps Road Drain which traverses through the approximate centre of the Site, and represents a nominal boundary separating the majority of the airside operational areas of the Site from the non-airside areas. The Helps Road Drain enters the Site at the north-eastern corner and exits adjacent to the Southern Detention Basin at the approximate mid-point of the southern boundary (refer Figure 5, attached). The on-Site portion of the Helps Road Drain is typically in the order of 25m in cross-sectional width and varies in depth up to approximately 1-1.5m below the surrounding land surface.


Whilst no measurements of surface water flow within the stormwater drainage network was undertaken during the DSI, observations made in relation to apparent surface flows were made and recorded on the surface water sampling sheets (Appendix K) and have been summarised in Table 1 (attached).

Throughout the late spring, summer and early autumn periods of the DSI program the stormwater drainage channels across the Site, including the Helps Road Drain, were typically observed to be dry. In addition, the Helps Road Drain downstream of the Site was typically observed to be dry. The only semi-permanent surface water body observed throughout the DSI program was the inlet pond of the Kaurna Park Wetland. This pond was observed to maintain a shallow volume of water at the end of the dry period, prior to the commencement of winter rainfall. In order to assess the potential that this water body may have been receiving groundwater at the time of the investigation, a targeted survey of the bathymetry of the pond was completed (refer Figure 29, attached). The survey data (recorded as m AHD) was compared to the relative depth of intersection of groundwater in the adjacent Q1 Aquifer monitoring well (GW2101), as well as the relative level of the highest recorded standing water level in this monitoring well. The bathymetric data suggests that the inlet pond was not receiving groundwater during the DSI program.


The field measured physicochemical parameters for surface water recorded throughout the DSI program are detailed in Table 1 (attached). The surface water sampling sheets are included in Appendix K. Relevant calibration records for the water quality meters used to measure field parameters are included in Appendix S. A summary of the field parameters measured during the two primary surface water sampling events is provided below in Table 11.11.

Table 11.11: Summary of Surface Water Field Parameters

Sample Locations Sampling Event Dissolved Oxygen (ppm) EC (µS/cm) pH (units) Redox (mV) Temperature

(oC) Upstream (background)

Event 1 – July 2017 3.43 to 6.16 -[1] -[1] 116 to 180 11.3 to 11.7

Event 2 – September 2017 6.32 to 9.04 82.3 to 179.5 7.49 to 8.19 90.1 to 233.0 11.2 to 20.4

On-Site Stormwater Swales

Event 1 – July 2017

2.15 to 7.86 70.4 to 754 6.83 to 8.57 53.1 to 147 7.7 to 14.8

Event 2 – September 2017 3.59 to 11.6 75.7 to 1,379 7.02 to 8.39 -22.3 to 237.0 11.5 to 17.8

Southern Detention Basin


5.37 to 7.29 117.5 to 163.1 7.33 to 7.87 103.7 to 135.6 8.9 to 14.3


Helps Road Drain Downstream of Site


4.26 to 7.14 -[1] -[1] 108 to 210 10.0 to 16.0


Kaurna Park Wetland


5.44 to 8.06 -[1] -[1] 107 to 173 10.8 to 13.4


Helps Road Drain Downstream of Springbank Waters (Additional)

Event 1 – August 2017 3.51 to 8.74 199.0 to 4,768 7.81 to 8.68 123 to 179.3 11.6 to 13.1

Event 2 – August 2018 6.14 to 10.47 433.9 to 8,014 7.55 to 8.6 -83.6 to 103.8 12.2 to 17.1

(1) Field measured parameters for pH and EC were considered erroneous, likely due to malfunctioning water quality meter probes, and have been excluded from the results.


11.5.3 Surface Water Analytical Results

The surface water laboratory analytical reports and sample chain of custody documentation are provided in Appendix J. The surface water analytical results for PFAS have been tabulated and are provided in Table 2 (attached), including a comparison of results against the adopted Tier 1 human health (recreational water) and ecological (freshwater ecosystems, 95% species protection) screening criteria. A summary of the range of PFAS concentrations reported for the key analytes of interest, based on discretised on-Site and off-Site areas, is provided in Table 11.12 (below). In addition, a graphical representation of all surface water sample locations including identification of those exceeding the adopted Tier 1 screening criteria is depicted on Figure 27 (Human Health) and Figure 28 (Ecological).

Detectable concentrations of PFAS (namely PFOS and/or PFHxS) were reported in samples collected from four of the six upstream background locations targeted to assess ambient background concentrations in accordance with the SA EPA guideline Site Contamination – Assessment of background concentrations (SA EPA, 2018). The results indicate that there is ambient PFAS contamination contributing impacts to the Site, however concentrations were minor with all results reported at least one order of magnitude below the adopted Tier 1 screening criteria for recreational water (i.e. 0.7 µg/L), and significantly lower than samples collected near primary source areas on Site. The dominant PFAS compounds detected in background surface water samples generally comprised PFHxS and/or PFOS, although two locations (SW033 and SW034) detected 8:2 FTS and one location (SW034) also detected 6:2 FTS.

The results of on-Site surface water sampling detected PFAS contamination above the adopted Tier 1 screening criteria at several locations, typically in close proximity to primary source areas and within the Southern Detention Basin. The highest reported concentration for the sum of PFHxS and PFOS was 148 µg/L (SW019) in the July 2017 sampling event, collected from surface water in a swale drain that passes between the Hangars and the AFFF waste water evaporation pond (i.e. between source areas P1 and P3). The corresponding location reported a concentration of 15 µg/L for the sum of PFHxS and PFOS in the September 2017 sampling event.

The off-Site surface water investigations downstream of the Site did not identify PFAS concentrations exceeding the adopted Tier 1 human health screening criteria for recreational water in any of the locations tested.

Concentrations of PFOS exceeding the adopted Tier 1 ecological screening criterion for freshwater ecosystems (i.e. >0.13 µg/L) were detected in all sample locations throughout the Kaurna Park Wetland and a sample location within the Helps Road Drain immediately upstream of the wetland. PFOS concentrations within the Helps Road Drain downstream of the Kaurna Park Wetland, to the point where the drain discharges to the Barker Inlet, were typically lower than those reported within the wetland and below the adopted Tier 1 ecological screening criterion. An exception was the two most downstream sample locations, SW066 and SW067 (refer Figure 28) located within 900m of the discharge point, which reported PFOS concentrations of 0.15 µg/L and 0.19 µg/L respectively in August 2018. These locations reported concentrations of PFOS exceeding the adopted Tier 1 ecological screening criterion. A review of the field measured salinity for these sample locations suggests there may have been some interaction with marine water from the Barker Inlet.

Concentrations of PFOA were only detected in a small number of surface water samples and were reported below the adopted Tier 1 screening criteria.

The highest concentrations of the sum of PFHxS and PFOS in surface water samples collected at locations that were able to be sampled during both DSI sampling events (i.e. where water was present each time at individual sample locations) were typically reported in the second event (i.e. September 2017). Of the 26 locations where a positive detection of PFAS was reported during both sampling events, 19 reported a higher concentration in the September 2017 sampling event


(representing 73% of sample results). It is noted however that the concentrations between the two sampling events were typically of the same order of magnitude and therefore only represented marginal changes to concentrations that may be associated with the temporal change. A notable exception was location SW019, discussed above, where the concentration was an order of magnitude higher during the first sampling event (i.e. July 2017). This may have been due to the presence of sediment within the sample owing to the relatively shallow depth of water and high turbidity in the sample noted on the field sampling sheet during the first sampling event (refer Appendix K).

Concentrations were also similar when comparing the DSI sampling results to the preliminary sampling program results at locations that were sampled during each event (i.e. SW03-SW011), noting that the preliminary sampling program was undertaken during the summer months. This suggests that there may not be a significant difference in the temporal variation of surface water concentrations between summer and winter periods (when water is present within the stormwater drainage network), although it is acknowledged that this is based on a relatively limited temporal data set.

In addition to the surface water sampling program within the stormwater network across the Site, a surface water sample (SW077) was collected from water present within the AFFF waste water retention tank (Building 521) in source area P1. The results for this sample reported a PFOS concentration of 13 µg/L with the sum of PFHxS and PFOS 18.5 µg/L, both of which exceed the adopted Tier 1 human health screening criteria. The laboratory analytical results are summarised in Table 2 (attached).


Table 11.12: Summary of Surface Water Analytical Results

Sample Locations No. of Primary Samples Analysed


Detectable Concentration Range (µg/L) No. of Samples Exceeding Adopted Screening Criteria PFOA PFOS Sum of PFHxS and

PFOS Upstream (background) 8 5 <LOR <LOR – 0.03 <LOR – 0.05 None On-Site Stormwater Swales 42 38 <LOR – 3.3 <LOR – 120 <LOR – 148 Human Health: 12

Ecological: 13 Southern Detention Basin 18 17 <LOR <LOR – 0.24 <LOR – 0.26 Human Health: 0

Ecological: 5 Outlet of Western Swale (Off-Site) 1 1 <LOR 0.12 0.14 None Helps Road Drain Downstream of Site 11 11 <LOR 0.01 – 0.14 0.01 – 0.16 Human Health: 0

Ecological: 1 Kaurna Park Wetland 18 18 <LOR – 0.08 0.1 – 0.26 0.1 – 0.4 Human Health: 0

Ecological: 15 Helps Road Drain Downstream of Springbank Waters (Additional)

12 12 <LOR – 0.1 0.04 – 0.19 0.05 – 0.24 Human Health: 0 Ecological: 3


11.6 Sediment Investigation

As discussed in Section 11.5, all targeted surface water sampling locations were also targeted for collection of collocated sediment samples. Where surface was not present at the time of sampling, only the corresponding sediment sample was collected. All sediment samples were analysed for both dry weight and leachable PFAS concentrations. In addition, a limited pore water sampling program was also completed at two on-Site and two off-Site sediment sampling locations.

A summary of the sediment laboratory analytical results and associated pore water and leachate results is provided in the following sections. The sediment and pore water sampling locations are shown on Figure 30 and Figure 31 (attached).

11.6.1 Sediment Analytical Results

The sediment laboratory analytical reports and sample chain of custody documentation are provided in Appendix J. The sediment analytical results for PFAS have been tabulated and are provided in Table 3 (attached), including a comparison of results against the adopted Tier 1 screening criteria applicable to commercial/industrial land use. A summary of the range of PFAS concentrations reported for the key analytes of interest, based on discretised on-Site and off-Site areas, is provided in Table 11.13 (below). In addition, a graphical representation of all sediment sample locations including concentrations for the sum of PFHxS and PFOS where PFAS were detected is depicted on Figure 30 (attached).

The results of the sediment sampling program within the stormwater drainage network and Kaurna Park Wetland did not identify PFAS concentrations exceeding the adopted Tier 1 human health screening criteria (i.e. >20 mg/kg for the sum of PFHxS and PFOS).

In addition to the sediment sampling program completed throughout the stormwater drainage network across the Site, sediment samples were collected from the base of the AFFF waste water evaporation pond in source area P1 (SD072 – SD076). Four of the five samples collected reported concentrations of PFAS exceeding the adopted Tier 1 human health screening criteria for commercial/industrial land use (i.e. >20 mg/kg for the sum of PFHxS and PFOS), with two samples reporting concentrations of the sum of PFOS and PFHxS greater than 100 mg/kg and a further two samples reporting concentrations greater than 1,000 mg/kg.


Table 11.13: Summary of Sediment Analytical Results

Sample Locations No. of Primary Samples Analysed



PFOS Upstream (background) 5 1 <LOR <LOR – 0.0057 <LOR – 0.0057 None On-Site Stormwater Swales 40 23 <LOR – 0.016 <LOR – 3.1 <LOR – 3.28 None Southern Detention Basin 9 0 <LOR <LOR <LOR None Outlet of Western Swale (Off-Site) 1 1 <LOR 0.01 0.01 None Helps Road Drain Downstream of Site 5 0 <LOR <LOR <LOR None Kaurna Park Wetland 8 5 <LOR <LOR – 0.023 <LOR – 0.023 None Helps Road Drain Downstream of Springbank Waters (Additional)

6 1 <LOR <LOR – 0.011 <LOR – 0.011 None

AFFF Waste Water Evaporation Pond 5 5 0.78 – 13 4.1 – 1,230 7.8 – 1,264 Human Health: 4


11.6.2 Vertical Profiling Results

As per the sampling program outlined in the DSI SAQP Addendum 1 (JBS&G, 2018a), two targeted bores (SD070 and SD071) were extended beyond the surficial sediments within the Helps Road Drain on-Site to understand the potential for vertical migration of PFAS contamination. Both bores detected minor concentrations of PFAS within one or more samples (refer Table 3, attached).

Sediment bore SD070 observed a minor increase in results for the sum of PFHxS and PFOS from surface to the full depth of the bore (i.e. 1m bgs), however all results were reported well below the adopted Tier 1 human health and ecological screening criteria. Sediment bore SD071 detected PFOS in the surface sample, however all underlying samples reported PFOS results below the laboratory LOR. On the basis of the results, it is considered unlikely that the observed sediment contamination exceeding the adopted ecological screening criteria in source area P11 and adjacent to source area P9 extends significantly beyond the surficial layer of sediments within the swale drains.

11.6.3 Leachate Results

A total of 65 sediment samples collected during Stage 2A of the DSI program were submitted for laboratory analysis of leachable PFAS. The laboratory analytical reports including leachate results are provided in Appendix J. The sediment leachate analytical results have been tabulated and are provided in Table 12 (attached), including screening against a value that is based on the application of a dilution factor of 10 to the relevant surface water and groundwater screening criteria (consistent with the methodology adopted in EnRisks, 2016). This forms the basis for consideration of whether sediment contamination is likely to present an ongoing source of impact to surface water and the underlying shallow (i.e. Q1 Aquifer) groundwater system when stormwater enters the Site drainage system.

The sediment leachate analysis reported results for PFOS greater than the other key analytes of interest (i.e. PFOA and PFHxS). Of the 65 samples analysed, 57 reported leachable PFOS concentrations above the laboratory LOR, ranging from 0.01µg/L to 48 µg/L. A total of four samples (SD019, SD039, SD041, and SD043) reported leachable PFOS at concentrations above the adopted surface water screening criteria (with 10x dilution factor applied), indicating the potential for ongoing contamination of stormwater entering the drainage channels in the vicinity of source areas P1/P3, P11, P10/P15, and P16.

11.6.4 Pore Water Results

The results of a limited pore water sampling program are included in Table 2 (attached). The results reported PFAS concentrations above the laboratory LOR at all locations, with three samples reporting PFOS concentrations above the adopted Tier 1 ecological screening criteria (refer Figure 31, attached). The highest reported pore water concentrations were for PFOS, ranging from 0.1 µg/L in the Helps Road Drain immediately downstream of the Site (PW012 – corresponding with surface water sample location SW012 and sediment sample location SD012) to 59 µg/L in the Helps Road Drain on-Site (PW018 – located at the confluence with the stormwater swale that passes between the Hangars and the AFFF waste water evaporation pond).

11.7 Concrete Investigation Analytical Results

The concrete sample laboratory analytical reports and sample chain of custody documentation are provided in Appendix J. The analytical results for PFAS in concrete have been tabulated and are provided in the attached Table 13 (dry weight) and Table 14 (leachate). A summary of the range of dry weight and leachable PFAS concentrations reported for the key analytes of interest for each of the targeted source areas is provided in Table 11.14 (below). The targeted concrete sample locations are shown on Figure 32 (attached).

The leachability results indicate that concrete may represent an ongoing secondary source of PFAS contamination to the surrounding environment, in particular the former AFFF concentrate storage


tank pad in source area P11, the concrete parking area at the front of the current fire station (within source area P11), and the concrete building within the current fire training area (source area P9). However, it is noted that the concrete core samples submitted for laboratory analysis were crushed by the laboratory prior to analysis of both the dry weight and leachable PFAS concentrations. The crushing of the concrete cores prior to analysis increases the contact area and is considered likely to overestimate the concentrations that would otherwise leach from the undisturbed in-situ concrete.


Table 11.14: Summary of Concrete Analytical Results

Targeted Source Area No. of Samples Analysed

Dry Weight Analytical Results Range (mg/kg) Leachate Analytical Results Range (µg/L)

PFOA PFOS Sum of PFHxS and PFOS PFOA PFOS Sum of PFHxS and

PFOS Former AFFF Concentrate Storage Area (within source area P11)

4 <LOR – 17 0.079 – 630 0.158 – 780 1.6 – 300 14 – 4,600 29 – 7,500

Current Fire Station (within source area P11)

4 0.017 – 0.38 0.22 – 17 1.62 – 24.5 2.2 – 36 13 – 560 163 – 1,170

Building 618 within the Current Fire Training Area (source area P9)

4 <LOR – 0.11 0.77 – 5.8 0.835 – 7.2 0.43 – 1.2 29 – 160 45 – 211

Engine Run Up Facility (source area P16)

4 <LOR – 0.012 <LOR – 0.17 <LOR – 0.31 <LOR – 0.54 0.02 – 4.9 0.02 – 11.3

Ordnance Unloading Area (source area P15)

5 <LOR – 0.0073 0.03 – 0.14 0.06 – 0.27 0.09 – 0.54 0.98 – 6.1 2.58 – 13.3

Fire Tender Test Pad (within source area P1)

3 0.013 – 0.15 0.0056 – 2 0.0121 – 2.56 0.49 – 4.1 0.2 – 31 0.45 – 40

Chesterfield Sumps, located west and east of the Technical Area and Hangars (within source area P3)

6 <LOR – 0.075 0.031 – 2.6 0.041 – 2.98 0.21 – 1.7 1 – 33 1.76 – 56


11.8 Private Property and Water Supply Bore Investigations

The DSI program included a review of all registered and licensed water supply bores within the Investigation Area (refer Section 3.2.5 for details). A subsequent attempt was made to contact each of the registered property owners (either through door-knocking or via mail) to issue a Water Use Survey and gather information in relation the status of the water supply bores and details relating to the nature and extent of bore water (i.e. groundwater) use at each of the respective properties. For those properties that returned a Water Use Survey, a subsequent approach was made to the property owners in order to seek consent to collect representative samples from the water supply bores, infrastructure that contained or had historically contained bore water, and areas that had been irrigated with bore water where PFAS was detected in the bore water samples.

In addition to the direct contact attempts with licensed bore owners, each of the residents and businesses located within the Investigation Area was invited to complete a Water Use Survey with details included on Community Walk-In-Session invitations issued via letterbox drop.

A summary of the Water Use Survey results and results of private property and water supply bore sampling completed throughout the DSI program are provided in the following sections.

11.8.1 Water Use Survey Results

A Water Use Survey was developed to collect information about water supply and use on properties within the Investigation Area, in particular to identify properties which may be accessing bore water (i.e. groundwater) for indoor and outdoor domestic use (including fruit and vegetable production), and commercial irrigation purposes. It is noted that the vast majority of the approximately 5,000 residents located within the Investigation Area source their water from the mains supply (SA Water).

At the time of this report, JBS&G had received 29 completed Water Use Surveys. Of the 29 surveys returned, seven were associated with properties outside the current or former (i.e. original) Investigation Area and nine were returned from properties with mains water supply and no operational bore. Of the remaining 13 surveys, the following observations were made:

• 11 were completed by property owners with a licensed water supply bore. These surveys indicated the current or historic use of bore water on these properties was generally for the purposes of outside domestic activities, fruit, vegetable and lawn watering, watering of livestock or poultry, and commercial irrigation. One survey noted historic use of bore water mixed with rainwater as part of the property drinking water supply. One survey noted use of bore water for flushing toilets;

• No surveys indicated the current use of bore water for drinking water supply;

• 4 surveys indicated the presence of surface water on the property (dams, surface drainage);

• 2 surveys were returned from properties within the Investigation Area which did not have water supply bores, but where the property owners were concerned about impacts from bore water use on adjoining properties;

• 6 property owners subsequently agreed to sampling; and

• 4 property owners with a licensed water supply bore declined the offer to have sampling undertaken, and one is yet to agree to or decline sampling.

A summary of the Water Use Survey responses for these 13 properties is provided below in Table 11.15.


Table 11.15: Summary of Water Use Survey Responses Survey ID

Direction from Site

Property Type Water Supply No. of Water

Tanks No. of Bores on Property

Bore Depth(s)/ Aquifer(s) Bore Water Use Comments

1 North Residential Hobby farm

Rain water Bore water

3 1 active 22 m (Q2) • Fruit/vegetable – occasionally • Lawn watering – weekly • Dust suppression - weekly

• Fruit and vegetables for family consumption.

• Tanks and bores sampled. Results below laboratory LOR.

2 North Childcare Mains water Bore water

1 1 inactive 10.5 m (Q1) Historic use: • Outdoor domestic – occasionally • Fruit/vegetable garden – weekly • Lawn watering – weekly • Livestock (not for consumption) –

daily • Poultry (not for consumption) –

daily

• Bore not used for 2 years following pump malfunction.

• Sampling unable to be undertaken due to collapsed bore.

• Property is located outside revised Investigation Area.

3 North Residential Hobby farm

Mains water Rain water Bore water

7+ 1 active 114 m (T2) • Fruit/vegetable garden – occasionally

• Lawn watering – occasionally • Livestock (piggery, goats) – daily • Honey harvested

• Surface drain on property • Fruit, vegetables, goats and milk

consumed by family and friends. • Property is outside revised

Investigation Area but will be targeted for sampling for HHERA (honey).

4 West Place of Worship Residential (previous)


4 1 active Unknown (Q2) • Historic use: • Indoor domestic – daily • Lawn watering – weekly • Livestock – weekly • Dust suppression – daily

• Tanks topped up with bore water by previous owner.

• No current bore water use. • Tanks and bores sampled. Results

below LOR. 5 West Hobby Farm Mains water

Bore water 1 1 active 78 m (T1) • Bore water not currently used • Bore sampling declined.

6 West Residential Hobby farm


6 1 active 93 m (T1) • Livestock (horses) – weekly • Bore sampled. Results below laboratory LOR.

7 West Residential Hobby Farm

Rain water Bore water Recycled water

8 1 active (unused for 10 years) 1 inactive

19.5 m (Q2) • Other indoor domestic – daily • Outdoor domestic – daily • Fruit/vegetable garden – daily • Livestock – daily • Poultry – daily

• Bore plumbed to house (for toilet flushing only)

• Fruit, vegetables, chickens and eggs consumed by family.

• Bore sampling declined. 8 South Residential Mains water

Rain water 1 0 N/A • N/A • Soil sampled following concerns about

spray drift from adjoining property bore water irrigation.

• All results below laboratory LOR.


Survey ID

Direction from Site

Property Type Water Supply No. of Water

Tanks No. of Bores on Property

Bore Depth(s)/ Aquifer(s) Bore Water Use Comments

9 South-west Agricultural Horticultural

Bore water 1 2 active 1 inactive

100 m (3 x T1) • Lawn watering – daily • Livestock – daily (historical) • Commercial crop irrigation - daily

• Commercial vegetable grower. • Dam on property • Bores, surface water, soils and biota

(crops) sampled. • All results below laboratory LOR for

PFOA, PFOS, and PFHxS. 10 South Residential

Agricultural Mains water Bore water

0 1 active 113 m (T1) • Fruit/vegetable garden – weekly • Lawn watering – occasionally

• Fruit and vegetable consumed by friends and family.

• Bore sampled. 11 South-west Commercial

Food Production

Mains water Bore water

3 1 active 2 inactive

107 m (2 x T1) 29 m (Q3)

• Outdoor domestic use – daily • Lawn watering – daily • Livestock – daily • Poultry - daily

• Surface drain on property • Commercial produce processing facility • Bore sampling declined.

12 South Residential Hobby farm Food Production

Mains water 0 0 N/A • Bore water from adjoining property previously used on the property

• Dam on property • Soil sampling offered due to concerns

about bore water but declined by owner.

13 South Residential Agricultural

Mains water Bore water

1 1 active 110 m (T1) • Fruit/vegetable garden – daily • Lawn watering – daily • Commercial crop irrigation - daily

• Commercial fruit grower • Bore not connected to the house • Tank water mixed with bore water

used for outdoor purposes • Sampling yet to be agreed/declined


11.8.2 Analytical Results

11.8.2.1 Private Property Sampling Program

At the time of this report, a total of nine property owners had consented to bore water, tank water, dam water, soil and/or biota (produce) sampling. Note, some property owners that consented to sampling have declined to complete the Water Use Survey. A summary of the results for each of the properties where consent was given to include results in the DSI report is provided in Table 11.16, including reference to the relevant aquifer from which the water supply bores are drawing groundwater. The complete set of tabulated analytical results is provided in the attached Table 15 (Water) and Table 16 (Soil and Biota). The location of the private water supply bores, where consent was given to include this information by the property owner, are shown on the attached Figure 33.

The samples collected from private water supply bores throughout the DSI program did not report detectable concentrations of PFAS in any of the samples considered representative of aquifer conditions in the locations tested. The only positive detection of PFAS was in a legacy monitoring well (located on former Defence property) that is not used as a water supply bore.

Table 11.16: Summary of Private Property Sampling Results

Property ID Samples Collected Production Aquifer Analytical Results

Property 1 2 bore water samples (first flush and purge) 3 rainwater tank samples

Q2 All results below the laboratory LOR

Property 2 2 bore water samples (first flush and purge) 5 rainwater tank samples

Q2 One bore water sample (first flush) reported a concentration of 0.01 µg/L for PFOS. A subsequent confirmatory (purged) bore water sample from the bore reported all results below the laboratory LOR. Therefore, the initial result was considered to be erroneous and not representative of aquifer conditions at the location tested. All rainwater tank sample results were below the laboratory LOR.

Property 3 4 soil bores with 2 samples analysed per bore (surface and shallow sub-surface)

N/A All results below the laboratory LOR

Property 4 2 bore water samples (first flush and purge) T1 All results below the laboratory LOR Property 5 2 bore water samples (first flush and purge) T1 All results below the laboratory LOR Property 6 10 soil bores with 2 samples analysed per

bore (surface and shallow sub-surface) 20 biota samples collected from wheat plants, comprising 10 flower and 10 stem samples 3 bore water samples recovered from two bores (1x first flush and 2 x purge) 2 dam water samples

T1 (x2) All soil, bore water and dam water sample results were below the laboratory LOR. 7 wheat stem samples and 4 wheat flower samples reported concentrations of PFBA[1] ranging from 0.0006 mg/kg to 0.0009 mg/kg. All other PFAS analysed were below the laboratory LOR, including the key analytes of interest (i.e. PFOA, PFOS and PFHxS)

Property 7 No bore water sample recovered due to collapse of the bore

T1 N/A

Property 9 2 samples recovered from former Defence Q1 Aquifer monitoring wells

N/A 1 monitoring well sample reported a result of 0.07ug/L for the sum of PFHxS and PFOS with all other results below the laboratory LOR. The other monitoring well sample reported all results below the laboratory LOR.

(1) PFBA - Perfluorobutanoic acid

11.8.2.2 Council Bore Sampling Program

In addition to the sampling of private water supply bores, a targeted sampling program of Council observation and production bores located within the Investigation Area was undertaken. The


sampling comprised recovery of representative groundwater samples from three bores installed in the T1 Tertiary Aquifer. The laboratory analytical results are included in Appendix J and are summarised in Table 15 (attached). The location of the Council bores subject to sampling is shown on Figure 33 (attached).

The sampling results for T1 Aquifer Council bores did not report any detectable concentrations of PFAS.

11.8.2.3 On-Site Former Tertiary Aquifer Observation Bore

As noted in Section 3.2.5, during the Stage 2B DSI program one legacy T2 Aquifer observation bore was identified in the airside operations area of the Site. A review of the DEW WaterConnect database identified the bore (Id: 6628-3043) as a T2 Aquifer bore installed in 1947, completed with steel casing to 85m bgs and open hole (i.e. no casing) from 85m to 120m bgs. The completion records indicated that the production zone of the bore may have actually comprised the T1 Aquifer (regionally expected to be intersected at depths ranging from 65 to 110m bgs). The bore was subsequently sampled with results summarised in Table 11.17. The measured bore depth compared to the listed completion depth suggests that the lower open hole section of the bore may have collapsed (or bridged). Groundwater samples were recovered from two depths – shallow (approximately 1.5m below the standing water level, 12m bTOC) and deep (80m bTOC). The location of the bore is shown on Figure 33 (attached).

Table 11.17: On-Site T2 Bore Water Level Gauging and Sampling Results Standing Water Level (m bTOC)

Well Depth (m bTOC) Sample Result – Shallow Sample Result - Deep

10.55 87.80 0.06 µg/L for 6:2 FTS, all other results below the laboratory LOR

All results below the laboratory LOR


12. Refined Conceptual Site Model

Based on the information gathered throughout the DSI program, including information gathered during the preliminary sampling and private property sampling programs, an update of the preliminary CSM has been undertaken and is detailed in the following sections. Particular focus has been given to an updated understanding of the following:

• The nature and extent of Site-derived PFAS contamination at the Site and throughout the broader Investigation Area, including the media affected by PFAS contamination;

• The mechanisms via which PFAS contamination has moved, and may continue to move (migrate), through the environment; and

• The receptors (both human health and ecological) that may be at risk of exposure to Site-derived PFAS contamination, including the ways in which the identified receptors may be exposed to such contamination.

A visual depiction of the refined CSM is provided on the attached Figure 34A (three-dimensional cross section), and Figure 34B (two-dimensional cross-section).

12.1 Nature and Extent of Site Contamination

12.1.1 Primary Source Areas

A total of 27 potential primary source areas were identified at the Site based on an assessment of historical information, interviews with site personnel, and information gathered throughout the DSI program. Based on the DSI results, a review of these potential source areas identifying those confirmed to represent a significant primary source of contamination has been undertaken and is summarised in Table 12.1. A significant source of PFAS contamination has been considered as an area that has reported PFAS concentrations in soil above the adopted Tier 1 human health screening criteria for commercial/industrial land use (i.e. 20 mg/kg for the sum of PFHxS and PFOS) and/or groundwater results that exceed the adopted Tier 1 human health screening criteria for drinking water (i.e. 0.07 µg/L) by two orders of magnitude or more, which are not considered to be associated with an adjacent or up hydraulic gradient source.

Based on the results of the primary source area review, the following significant PFAS source areas are considered to exist at the Site:

• Source Area P1 – AFFF waste water retention tank (Building 521) and AFFF waste water evaporation pond, including soils in the vicinity of this infrastructure;

• Source Area P2 – Bulk fuel storage facility, including an automated AFFF deluge system;

• Source Area P3 – Chesterfield Sumps (and surrounding areas), which receive AFFF waste water generated during testing of automated AFFF suppression systems in the Hangars;

• Source Area P4 – Former fire training area and sub-surface waste dump;

• Source Area P8 – Sub-surface waste dump on western Site boundary;

• Source Area P9 – Current fire training area, including smokeroom training building;

• Source Area P10 – Former STP and fire training area;

• Source Area P11 – Current fire station and former AFFF concentrate storage area;

• Source Area P15 – Former fire training area in Ordnance Unloading Area;

• Source Area P16 – Former fire training area around the ERUP Facility;


• Source Area P23 – Site of historical train and semi-trailer crash, including the area up hydraulic gradient where historical discharge of AFFF may have occurred in the vicinity of the air craft wash down facility; and

• Source Area P27 – Suspected former fire training area adjacent to parking area for aircraft refuelling tanker trucks.


Table 12.1: Summary of Primary Source Area Assessment

Source ID Site Description

Soil Results Exceed Human Health Screening Criteria?

Groundwater Results Exceed Screening Criteria?

Confirmed Significant Source Area?

Comments

P1 AFFF Waste Water Retention Tank (Building 521) and AFFF Waste Water Evaporation Pond

No Yes Yes The AFFF waste water evaporation pond is considered to represent one of the most significant source areas on Site based on the PFAS contamination observed in sediments in the base of the pond. However, the underlying shallow groundwater results (i.e. Q1 Aquifer) do not indicate significant vertical migration of PFAS has occurred from these sediments. Soils in the vicinity of the pond and nearby waste water retention tank reported relatively low dry weight concentrations of the sum of PFHxS and PFOS compared to other source areas (i.e. < 4 mg/kg), however the leachate results indicated these soils may represent an ongoing source of contamination to the nearby stormwater swale and the underlying groundwater system. The concrete AFFF waste water retention tank is also considered to be a likely source of PFAS contamination, although concrete samples from the base of this tank were not able to be recovered during the DSI.


No Yes Yes Whilst the soil investigations throughout this source area did not report PFAS concentrations exceeding the adopted human health screening criteria, the soil leachate results did indicated soils within the source area may represent an ongoing source of contamination to the nearby Helps Road Drain and the underlying groundwater system. The groundwater results have identified this area as a significant source of groundwater contamination beneath the Site.


N/A Yes Yes The groundwater results in the vicinity of the Chesterfield Sumps at the eastern and western end of the Hangars have identified these areas as a significant source of groundwater contamination beneath the Site. The concrete results for samples recovered from the sumps did not report significant levels of PFAS contamination (relative to other areas), however the soils underlying this infrastructure may represent a significant source of PFAS contamination. To differentiate the sumps from the Hangars, the source area has been discretised into three sub areas – P3A (eastern Chesterfield Sump), P3B (western Chesterfield Sump), and P3C (Hangars).


Yes Yes Yes The soil and groundwater results have identified this area as a significant source of PFAS contamination at the Site. In addition, the soil leachate results indicated these soils may represent an ongoing source of contamination to the underlying groundwater system.






Comments

P5 Isolated Aircraft Parking Area No Yes No Groundwater contamination beneath this area is considered to be associated with source area P4.

P6 Former Burning Off Area No Yes No Soil investigations in this area did not report any detectable concentrations of PFAS and groundwater analytical results were relatively low when compared to confirmed source areas.

P7 Airfield Taxiway Dump No Yes No Soil investigations in this area did not report any detectable concentrations of PFAS and groundwater analytical results were relatively low when compared to confirmed source areas.

P8 Sub-surface Waste Dump No Yes Yes Whilst soil investigations did not identify significant PFAS contamination, the groundwater results have identified this area as a significant source of groundwater contamination at the down hydraulic gradient Site boundary.

P9 Static Rocket Firing Sites and Current Fire Training Area, including Smokeroom Training Area

No Yes Yes The soil and groundwater results have identified this area as a significant source of PFAS contamination at the Site. The soil leachate results indicated soils in this area may represent an ongoing source of contamination to the nearby stormwater swales and underlying groundwater system. In addition, the concrete sampling program identified the fire training building as a potential ongoing source of PFAS contamination to surrounding areas. Groundwater contamination in this area has been confirmed to extend to the Q3 Aquifer.


Yes Yes Yes The soil and groundwater results have identified this area as a significant source of PFAS contamination at the Site. It is noted that significant soil contamination was only identified in the northern portion of this source area, however groundwater contamination appears to be more prevalent with significant contamination observed in the southern portion of the source area, including on the down hydraulic gradient southwestern Site boundary.


Yes Yes Yes This area has been identified as the most significant source area on Site in relation to soil and groundwater contamination. The highest concentrations of PFAS contamination have been recorded in the vicinity of the former AFFF concentrate storage tank (adjacent to the new Air Traffic Control Tower), and in the vicinity of the current fire station.

P12 Taxiway AFFF No Yes No Groundwater contamination beneath this area is considered to be associated with source area P16.






Comments

P13 AFFF Use Area 1 No Yes No Soil investigations in this area did not identify significant PFAS contamination and groundwater analytical results were relatively low when compared to confirmed source areas.

P14 Former Fire Training Area No Yes No Soil investigations in this area did not identify significant PFAS contamination and groundwater analytical results were relatively low when compared to confirmed source areas.

P15 Former Fire Training Area in Ordnance Unloading Area

Yes Yes Yes The soil and groundwater results have identified this area as a significant source of PFAS contamination at the Site. The soil leachate results indicated soils in this area may represent an ongoing source of contamination to the nearby stormwater swales and underlying groundwater system.

P16 Former Fire Training Area around the ERUP Facility

Yes Yes Yes The soil and groundwater results have identified this area as a significant source of PFAS contamination at the Site. The soil leachate results indicated soils in this area may represent an ongoing source of contamination to the nearby stormwater swales and underlying groundwater system.

P17 Former Fire Training Area in old Aerodynamics Area

No No No No PFAS contamination was identified in any soil or groundwater samples recovered from this area.

P18 Former Fire Training Area (eastern Pyramid) No Yes No Soil investigations in this area did not identify significant PFAS contamination and groundwater analytical results were relatively low when compared to confirmed source areas.

P19 Former Fire Training Area (western Pyramid) No Yes No Soil investigations in this area did not report any detectable concentrations of PFAS and groundwater analytical results were relatively low when compared to confirmed source areas.


No No No Soil investigations in this area did not identify significant PFAS contamination and groundwater analytical results did not exceed screening criteria.


No Yes No Groundwater contamination beneath this area is considered to be associated with source areas P11, P9 and P27.

P22 Site of several car fires (off-Site) No Yes No Groundwater contamination beneath this area is considered to be associated with up hydraulic gradient on-Site source areas (e.g. P10).

P23 Site of train and semi-trailer crash No Yes Yes Whilst soil investigations did not identify significant PFAS contamination, the groundwater results have identified this area as a significant source of groundwater contamination at the down hydraulic gradient southwestern Site boundary. In addition, groundwater contamination in this area has been confirmed to extend to the Q3 Aquifer.






Comments

P24 Fire truck rollover at southern end of main runway

No Yes No Groundwater contamination beneath this area is considered to be associated with up hydraulic gradient source areas (e.g. P9 and P15).

P25 Former 1RTU Fire Training Area No Yes No Soil investigations in this area did not report any detectable concentrations of PFAS and groundwater analytical results were relatively low when compared to confirmed source areas.

P26 Historical AFFF Concentrate Spill No Yes No Soil investigations in this area did not report any detectable concentrations of PFAS and groundwater analytical results were relatively low when compared to confirmed source areas.

P27 Suspected former fire training area adjacent to parking area for aircraft refuelling tanker trucks

No Yes Yes The groundwater results have identified this area as a significant source of PFAS contamination at the Site.


12.1.2 Secondary Source Areas

In addition to the review of potential primary source areas, a review of the potential secondary source areas across the Site has been undertaken. A summary of this review is provided below in Table 12.2.

Table 12.2: Summary of Secondary Source Area Assessment Source ID Description Confirmed Source

Area Comments

S2 Contaminated surface water and/or soils/sediments within the unlined stormwater swale that passes the northern side of Building 521 and the AFFF evaporation pond

Yes Significant surface water contamination was identified in this section of the stormwater drainage network. Significant sediment contamination was not identified in the areas tested.

S3 Contaminated surface water and/or soils/sediments within the Helps Road Drain traversing through the Site

No Surface water samples did not identify concentrations exceeding the human health or ecological screening criteria. Only low levels of PFAS were detected in sediment samples.

S4 Contaminated surface water and/or soils/sediments within the SDB

No All sediment results were reported below the laboratory LOR. Surface water results were below the adopted human health screening criteria.

S5 Contaminated surface water and/or soils/sediments within unlined stormwater swales in the airside operations area

Yes (limited) Leachate results for sediment samples collected from swales in the vicinity source areas P11, P10/P15, and P16 indicated a potential for ongoing contamination of stormwater.

12.1.3 Off-Site

The DSI results to date have indicated that the off-Site extent of Site-derived PFAS contamination that may present an elevated risk to human health and/or ecological receptors is limited to groundwater within the upper Quaternary aquifers12 and surface water within the Kaurna Park Wetland. It is noted that the surface water results for all samples recovered from the Kaurna Park Wetland were below the adopted human health screening criteria (relevant to use of the water for recreational purposes), however the potential for bioaccumulation of elevated levels of PFAS within edible aquatic biota (e.g. yabbies and fish) that may be captured and consumed by members of the public cannot be discounted at this stage. This issue will be further assessed during completion of the HHERA.

The elevated PFAS concentrations identified in two surface water sample locations near the Helps Road Drain discharge point into the Barker Inlet (SW066 and SW067, refer Figure 28) are higher than the upstream samples collected within the Helps Road Drain (downstream of the Kaurna Park Wetland). It is possible that there may be an off-Site source contributing to surface water contamination in this portion of the drain (e.g. the Bolivar WWTP) or may be associated with existing PFAS contamination in the Barker Inlet (as identified by the SA EPA during a preliminary investigation of PFAS in the marine environment – SA EPA, 2017). It is noted that there was some evidence of marine and fresh water mixing in these samples based on the salinity results (refer Section 11.5.3).

To date there has been no indications of PFAS contamination in the T1 Aquifer, although it is noted this conclusion is based on a relatively small number of private bore sampling results and is limited to the areas where consent was given to allow sampling.

12 It is noted that PFAS contamination is likely to be present in the T2 Tertiary Aquifer in the vicinity of the Edinburgh Park South and

Kaurna Park ASR injection/extraction wells, however it was beyond the scope of the DSI to consider impacts associated with the operation of the Salisbury ASR Scheme.


No PFAS contamination was identified in soils or sediments exceeding the adopted Tier 1 human health or ecological screening criteria in any of the off-Site areas investigated. However, there is the potential for soil contamination to exist in areas irrigated with PFAS contaminated groundwater, should this activity have occurred. The HHERA will seek to establish if this has, or is likely to have, occurred in the Investigation Area.

12.2 Contaminant Transport Mechanisms and Migration Pathways

Leachate analysis conducted on soil and concrete samples recovered throughout the DSI showed that the key analytes of interest, namely PFOS and PFHxS, were readily leached from the samples under neutral leaching conditions (i.e. simulating rainfall). These results indicate that the source areas at the Site will present an ongoing source of contamination to nearby stormwater drainage features (including the Helps Road Drain), and the underlying shallow groundwater system. In addition, overland transport of particulate matter from these source areas may occur during significant rainfall events (i.e. soil erosion contaminating nearby stormwater swales).

Due to the persistence of PFAS in the environment, when PFAS contamination enters surface water and groundwater it can migrate long distances in the direction of flow. Evidence of off-Site migration of PFAS in both surface water and groundwater discharging from the Site was confirmed by the DSI sampling program. Given the presence of numerous significant soil and concrete source areas across the Site, some of which are in relatively close proximity to stormwater drainage features and/or the Site boundary, and existence of significant contamination in groundwater beneath the Site, it is reasonable to expect that PFAS contamination will continue to migrate from the Site in the absence of suitable remediation measures.

In addition to the lateral migration of PFAS contamination in groundwater, the DSI sampling program identified vertical migration of PFAS contamination through the shallow Quaternary aquifers beneath and down hydraulic gradient of the Site. To date, PFAS contamination has been confirmed to extend to the Q3 Aquifer in some areas. Field observations, groundwater analytical results, and assessments of water chemistry (refer Section 11.4) have indicated a varying degree of hydraulic connectivity between the Q1 and Q2 Aquifers. The absence of PFAS contamination in the Q1 Aquifer in the central north-western portion of the airfield, between source area P4 and the northern runway extension, where PFAS contamination was detected in the Q2 Aquifer suggests that the aquifers are not hydraulically connected in this area of the Site. In addition, a different water chemistry observed between the Q1 and Q2 Aquifers in the area down hydraulic gradient of the former AFFF concentrate storage area (source area P11) suggests that there may also be a lower degree of hydraulic connectivity in this area of the Site. This is supported by the relatively low concentrations of PFAS detected in the Q2 Aquifer compared to the significant contamination observed in the Q1 Aquifer (in particular the significant difference in concentrations observed between GW2116 and GW2204). A similar observation was made for the nested Q1 and Q2 Aquifer monitoring wells in the southern portion of source area P4, where there was a difference in water chemistry and an absence of PFAS contamination in the Q2 Aquifer where it was observed in the Q1 Aquifer (refer Section 11.4.7).

Given the identification of PFAS contamination in the Q3 Aquifer, both on and off-Site, it is considered there is also a degree of hydraulic connectivity between the Q2 and Q3 Aquifers, although this is likely to vary throughout the Investigation Area. It is not yet known if there is interconnectivity between the Q3 and Q4 Aquifers, however additional groundwater investigations being conducted at the time of this report will seek to determine if PFAS contamination has extended to the underlying Q4 Aquifer.

Whilst the Tertiary aquifers in the Investigation Area are considered to be hydraulically isolated from the Quaternary aquifers by the presence of a continuous and substantial confining layer (aquitard), a potential for old unused and potentially “leaky” groundwater wells (leaky wells) to act as preferential pathways allowing migration of PFAS contaminated groundwater in shallow Quaternary


aquifers into the deeper Tertiary Aquifer systems may exist. Studies undertaken by the former DWLBC (now DEW) in 1998 confirmed downward leakage from the more saline Quaternary aquifers into the Tertiary aquifers in the Northern Adelaide Plains region due to the corrosion of old steel-cased, non-pressure cemented wells (DWLBC, 2002). The issue was exacerbated by the presence of a cone of depression in the T1 Aquifer around the Waterloo Corner irrigation area due to heavy extraction. Therefore, the potential for leaky Tertiary aquifer wells to exist within the Investigation Area should be considered as an issue that warrants further investigation and consideration in development of the PMAP.

The major surface water (i.e. stormwater) drainage features throughout the Site and the broader Investigation Area (in areas that receive stormwater from the Site), are unlined stormwater drains and detention basins. These features are likely to have a high degree of leakage (i.e. seepage) given their unlined nature, providing a migration pathway for contaminated surface water to enter the underlying shallow groundwater system. Whilst the leakage rates are not known, it is suspected that they would be relatively high given the lateral extent of the features. Evidence of significant groundwater contamination in the vicinity of the Southern Detention Basin, Helps Road Drain (on and off-Site) and Kaurna Park Wetland, with an apparent radial spread of PFAS contamination away from these ephemeral stormwater features (refer Figure 25 and Figure 26, attached), was identified during the DSI program. These results suggest that, at least historically, surface water discharging from the Site has migrated into the underlying groundwater system and supports the conclusion that significant leakage of surface water from the stormwater drainage network has occurred across the Site and the broader Investigation Area.

12.3 Exposure Pathways and Receptors at Risk

The results of the DSI program have been used to inform an update to the preliminary assessment of potential human and ecological receptors that may be exposed to Site-derived PFAS contamination, and the associated exposure pathways and exposure routes identified in the preliminary CSM (refer Section 7.5). The updated summaries are provided below in Table 12.3 (human health) and Table 12.4 (ecological). The tables also include an assessment of S-P-R linkages, relevant results from the DSI, and identify where potentially unacceptable risks may exist based on complete S-P-R linkages and the Tier 1 screening level risk assessment.

In addition to the S-P-R linkages assessed in the below tables, the consumption of honey produced in bee hives located within, or in reasonable proximity to, the Investigation Area is considered a potential exposure pathway that warrants consideration as part of the HHERA.


Table 12.3: Updated Summary of Potential Receptors and Exposure Pathways – Human Health Potentially Contaminated Media (Source)

Potential Human Receptors

Potential Exposure Pathways

Potential Exposure Route Considered S-P-R Linkage Comments

Potentially Unacceptable Risks Identified? Ingestion Dermal Inhalation Others/Remarks

Soil On-Site Defence personnel and contractors working on Base

• Direct contact or incidental exposure

• Dust emissions


Complete The DSI results identified PFAS contamination in soils exceeding the applicable Tier 1 human health screening criteria for commercial/industrial land use in source areas P4, P10, P11, P15, and P16.

As noted in Section 9, the Tier 1 screening criteria are not directly applicable to firefighting personnel and therefore the potential risk to these workers will be assessed as part of the HHERA, with consideration of site-specific exposure scenarios where this information is available.

Yes, complete and potentially complete S-P-R linkages to be considered in the HHERA

Defence personnel residing on Base

Incomplete There were no source areas assessed within the domestic area of the Site and therefore no exceedances of the residential screening criteria. Potential exposure of Defence personnel residing on Base to the areas of contaminated soil will be considered as part of the receptor Defence personnel working on Base.

Intrusive maintenance workers and construction workers

Complete The DSI results identified PFAS contamination in soils exceeding the Tier 1 human health screening criteria for commercial/industrial land use in source areas P4, P10, P11, P15, and P16. However, as noted in Section 9, the Tier 1 screening criteria are not directly applicable to these receptors and therefore the potential risk will be assessed as part of the HHERA.







Recreational users of on-Site sporting grounds

Incomplete There were no exceedances of the recreational screening criteria in the recreational land use areas of the Site.


Potentially Complete

During the conduct of the DSI, an observation was made that the North East Defence Community Centre located on Site provides playgroup services for children up to the age of 5 and hosts family days. This area of the Site has not been identified as a potential source area, however an assessment of soils within the outdoor play areas is considered warranted given the sensitive nature of the land use. This issue will be addressed as part of the HHERA.

Soil Off-Site Members of the public • Off-Site migration of dust from impacted surface soils

• Direct contact or incidental exposure to soils irrigated with PFAS impacted water

• Consumption of crops, market garden and home-grown produce


Incomplete To date no PFAS contamination above the adopted Tier 1 screening criteria for residential land use has been identified in soil samples collected off-Site. The potential for unacceptable risks to members of the public to exist associated with off-Site migration of dust from impacted surface soils will be addressed as part the HHERA. The potential for unacceptable risks to members of the public to exist associated with direct contact or incidental exposure to soils irrigated with PFAS contaminated groundwater, or consumption of produce grown in soils irrigated with PFAS contaminated groundwater, will also be addressed as part of the HHERA, including additional private property sampling works (where consent is given).

None to date










- Complete The DSI results identified PFAS contamination in surface water exceeding the applicable Tier 1 human health screening criteria for recreational use within some of the airside stormwater swales, the stormwater drain that passes between source areas P1 and P3, and the Helps Road Drain (on Site). Given there are no applicable surface water screening criteria for a commercial/industrial land use scenario, the potential risk to these receptors associated with exposure to PFAS contaminated surface water will be considered as part of the HHERA.

Yes, complete S-P-R linkages to be considered in the HHERA


- Complete The DSI results identified PFAS contamination in surface water exceeding the applicable Tier 1 human health screening criteria for recreational use within some of the airside stormwater swales, the stormwater drain that passes between source areas P1 and P3, and the Helps Road Drain (on Site). Given there are no applicable surface water screening criteria for intrusive maintenance and construction workers, the potential risk to these receptors associated with exposure to PFAS contaminated surface water will be considered as part of the HHERA.







Surface Water Off-Site



- Incomplete There were no off-Site surface water results reported above the adopted Tier 1 human health screening criteria for recreational use.

Yes, potentially complete S-P-R linkage to be considered in the HHERA • Consumption of

aquatic biota - - Potentially

complete Whilst there were no surface water results reported above the adopted Tier 1 human health screening criteria for recreational use, anecdotal information gathered throughout the DSI suggests people may be fishing and catching yabbies within the Kaurna Park Wetland for domestic consumption. This issue will be addressed as part of the HHERA.

Maintenance workers and contractors (e.g. Council)


- Incomplete There were no off-Site surface water results reported above the adopted Tier 1 human health screening criteria for recreational use, which are considered to be appropriately conservative for the initial screening assessment of potential risks to these workers.

Sediment On-Site



- Incomplete The DSI results did not identify any exceedances of the adopted Tier 1 screening criteria for commercial/industrial land use.

No


- Potentially complete

The DSI results did not identify any exceedances of the adopted Tier 1 screening criteria for commercial/industrial land use. However, as noted in Section 9, the Tier 1 screening criteria are not directly applicable to these receptors and therefore the potential risk will be assessed as part of the HHERA.







Sediment Off-Site



- Incomplete Only minor concentrations of PFAS were detected in sediments off-Site with all results below the adopted Tier 1 soil screening criteria for recreational land use.

No

Maintenance workers and contractors (e.g. Council)


- Incomplete Only minor concentrations of PFAS were detected in sediments off-Site with all results below the adopted Tier 1 soil screening criteria for commercial/industrial land use and recreational land use. Therefore, PFAS concentrations in sediments off-Site are not considered to present an elevated risk to off-Site maintenance workers who may be infrequently be exposed to such sediments.

Groundwater On-Site

None • None - - - Incomplete It is understood that there is no extraction of groundwater occurring on Site and therefore no human exposure pathway. The observed depths to groundwater beneath the Site (i.e. >2m bgs) mean that exposure during intrusive works is not a likely pathway for maintenance workers.

No








Off-Site users and consumers of groundwater

• Extraction of groundwater

• Irrigation or use of groundwater for domestic activities, recreational activities, or commercial activities

• Consumption of crops, market garden and home-grown produce


Potential for inhalation of spray mist during irrigation may be an exposure route

Potentially complete

The DSI results have identified widespread PFAS contamination within the shallow Q1 and Q2 Aquifers within the Investigation Area. In addition, a targeted assessment of the Q3 Aquifer (to date) has identified PFAS contamination in the vicinity of the Kaurna Park Wetland. To date, PFAS contamination has not been identified within the T1 Aquifer within the Investigation Area, although it is acknowledged that this conclusion is based on a relatively small number of results for private water supply bores where owners consented to sampling, and available Council bores.

Yes, potentially complete S-P-R linkages to be considered in the HHERA

Members of the public • Consumption of crops, market garden and home-grown produce


- - PFAS contaminated groundwater used for irrigation of plants or as water supply for livestock

Potentially complete

It is not yet known whether PFAS contaminated groundwater is being used for commercial irrigation of produce or as water supply for livestock.

Yes, potentially complete S-P-R linkages to be considered in the HHERA


Table 12.4: Updated Summary of Potential Receptors and Exposure Pathways – Ecological Potentially Contaminated Media (Source)

Potential Ecological Receptors Potential Exposure Pathways S-P-R Linkage Comments

Potentially Unacceptable Risks Identified?

Soil On-Site • Terrestrial fauna (e.g. birds)

• Direct contact • Ingestion of flora and fauna

affected by PFAS

Incomplete The DSI results identified PFAS contamination in soils exceeding the applicable Tier 1 ecological screening criteria in several source areas, however there were no significant ecological receptors of concern (e.g. areas of ecological significance) identified at the Site.

No

• Terrestrial flora • Uptake of PFAS from soil Incomplete

Soil Off-Site • Terrestrial fauna (e.g. birds)

• Direct contact • Ingestion of flora and fauna

affected by PFAS

Incomplete To date no PFAS contamination above the adopted Tier 1 ecological screening criteria has been identified in soil samples collected off-Site. The potential for unacceptable risks to ecological receptors of concern to exist associated with exposure to soils irrigated with PFAS contaminated groundwater will be addressed as part of the HHERA, including additional private property sampling works (where consent is given).

None to date

• Terrestrial flora • Uptake of PFAS from soil Incomplete


• Terrestrial and aquatic fauna

• Direct contact • Ingestion • Consumption of flora and

fauna affected by PFAS

Incomplete The DSI results identified PFAS contamination in surface water exceeding the adopted Tier 1 ecological screening criteria within some of the airside stormwater swales, the stormwater drain that passes between source areas P1 and P3, the Helps Road Drain (on Site), and the Southern Detention Basin. However, there were no significant ecological receptors of concern (e.g. areas of ecological significance) identified at the Site.

No

• Aquatic flora • Uptake of PFAS from surface water

Incomplete

Surface water Off-Site

• Terrestrial and aquatic fauna

• Direct contact • Ingestion • Consumption of flora and


Complete The DSI results identified PFAS contamination in surface water exceeding the adopted Tier 1 ecological screening criteria within the Kaurna Park Wetland and the Helps Road Drain. Available information regarding the ecology of the Kaurna Park Wetland suggests an absence of high ecological value species (i.e. ecological receptors of concern), with the exception of migratory birds which are understood to occasionally be using the wetland.

Yes, to be considered further in the HHERA

• Aquatic flora • Uptake of PFAS from surface water

Incomplete

Sediment On-Site • Terrestrial and aquatic fauna

• Direct contact • Incidental ingestion • Consumption of flora and


Incomplete The DSI identified elevated PFAS concentrations in sediments in source areas P10, P11, and P16, however there were no significant ecological receptors of concern (e.g. areas of ecological significance) identified at the Site.

No

• Aquatic flora • Uptake of PFAS from sediment

Incomplete



Potential Ecological Receptors Potential Exposure Pathways S-P-R Linkage Comments

Potentially Unacceptable Risks Identified?

Sediment Off-Site • Terrestrial and aquatic fauna

• Direct contact • Incidental ingestion • Consumption of flora and


Incomplete Only minor concentrations of PFAS were detected in sediments off Site. Notwithstanding, given the absence of an appropriate Tier 1 ecological screening criteria, the potential for unacceptable risks to exist for any ecological receptors of concern will be assessed as part of the HHERA with consideration given to areas where surface water samples reported PFAS concentrations exceeding the adopted Tier 1 ecological screening criteria (i.e. Kaurna Park Wetland).

No, however this will be considered further in the HHERA

• Aquatic flora • Uptake of PFAS from sediment

Incomplete

Groundwater On-Site

• Terrestrial flora • Uptake of PFAS from groundwater

Incomplete The DSI results identified significant PFAS contamination in the shallow Q1 Aquifer beneath the Site. However, the depth to groundwater in the Q1 Aquifer is typically greater than 2m bgs; the depth to which ecological investigation levels are principally applied as per the ASC NEPM (refer Schedule B1, Section 2.5.6). It is therefore considered that the uptake of PFAS contaminated groundwater by terrestrial flora present on the Site is not a significant pathway of concern. In addition, there were no significant ecological receptors of concern (e.g. areas of ecological significance) identified at the Site.

No


• Terrestrial flora • Uptake of PFAS from groundwater

Incomplete The DSI results identified significant PFAS contamination in the shallow Q1 Aquifer off Site. However, the depth to groundwater in the Q1 Aquifer is typically greater than 2m bgs. As noted above, it is considered that the uptake of PFAS contaminated groundwater by terrestrial flora is not a significant pathway of concern.

No


12.4 Remaining Uncertainties and Data Gaps

With consideration of the results of the DSI, a review of the uncertainties and data gaps associated with understanding the nature and extent of PFAS contamination at the Site and in the broader Investigation Area has been undertaken. The remaining uncertainties and data gaps are considered to exist:

• An understanding of the temporal variations in surface water and groundwater concentrations (to be addressed in the PMAP, i.e. ongoing monitoring program);

• Whether soils beneath the Chesterfield Sumps and AFFF waste water retention tank contain significant levels of PFAS contamination and present an ongoing source of contamination to stormwater and groundwater (to be considered as part of the PMAP and any response management activities);

• The vertical extent of PFAS contamination in sediments/soils beneath the AFFF waste water evaporation pond;

• Whether vertical migration of PFAS contamination to the Q4 Aquifer has occurred (being addressed as part of the ongoing groundwater investigation program that will be reported in a DSI Addendum Report);

• An understanding of the potential for leaky wells to exist, that may provide a preferential pathway for vertical migration of PFAS contamination from the Quaternary to Tertiary aquifers;

• The potential for PFAS contamination to exist in soil within the on-Site child-minding area (this will be assessed as part of the HHERA process);

• Whether identified exceedances of the Tier 1 screening criteria present an unacceptable risk to human health and/or the environment (this will be addressed by the HHERA);

• Whether edible biota present within the Kaurna Park Wetland contains elevated levels of PFAS that may present an unacceptable risk to consumers (this will be addressed by the HHERA);

• Whether PFAS contaminated groundwater within the Investigation Area is being extracted for irrigation or stock water supply, and whether such use has caused secondary source contamination (e.g. soils, produce) (this will be addressed by the HHERA);

• Whether honey being harvested within, or in reasonable proximity to, the Investigation Area (as identified by results of the WUS) is contaminated with PFAS (this will be addressed by the HHERA); and

• The nature and extent of any impacts associated with potential distribution of PFAS impacted water as part of the historical operation of the Edinburgh Park South and Kaurna Park ASR (noting it was beyond the scope of the DSI to assess this issue).

It should be noted that several of the data gaps identified above will be addressed as part of the HHERA with others to be considered during preparation of the PMAP. In addition, the additional groundwater investigations occurring at the time of this report will seek to assess whether groundwater contamination has migrated to the Q4 Aquifer.


13. Discussion and Conclusions

The primary objectives of the project were to determine the nature and extent of Site-derived PFAS contamination at the Site and surrounding areas that may present a risk to human health or the environment, and to collect sufficient information to inform the undertaking of a HHERA (if required). These objectives have been achieved through completion of detailed desktop and intrusive field investigations at the Site and in the broader Investigation Area. The investigations sought to understand the following:

• The PFAS source areas at the Site, including the degree and extent of contamination in relevant environmental media;

• The off-Site extent of Site-derived PFAS contamination;

• The receptors that may exist at the Site, and in the broader Investigation Area; and

• The ways in which the identified receptors may be exposed to Site-derived PFAS contamination.

A summary of the DSI findings in relation to the above is discussed below.

13.1 PFAS Contamination Source Areas

The results of the DSI program identified 12 primary source areas at the Site that are considered to represent a significant source of PFAS contamination. Each of these source areas identified PFAS contamination in one or more of the environmental media investigated exceeding the adopted Tier 1 screening criteria. A summary of each of these source areas is provided below:

1. The AFFF waste water retention tank (Building 521) and AFFF waste water evaporation pond, including soils in the vicinity of this infrastructure (Source Area P1). The most significant source within this area has been identified as the AFFF waste water evaporation pond where sediment samples recovered from the base of the pond reported concentrations for the sum of PFHxS and PFOS up to 1,264 mg/kg. Soil samples recovered from the surrounding area reported concentrations of the sum of PFHxS and PFOS below the adopted human health screening criteria for commercial/industrial land use (i.e. 20 mg/kg for the sum of PFHxS and PFOS, however the associated soil leachate results indicated these soils may present an ongoing source of contamination to the nearby stormwater swale and the underlying groundwater system. Groundwater concentrations were reported up to 78 µg/L for the sum of PFHxS and PFOS, with contamination confirmed to extend to the Q2 Aquifer.

2. The Site’s bulk fuel storage facility, which includes an automated AFFF deluge system (Source Area P2). The most significant contamination in this area was identified in groundwater with concentrations of the sum of PFHxS and PFOS ranging up to 111 µg/L in the Q1 Aquifer. Soil contamination was relatively low compared to other source areas, however the soil leachate results indicated that the soils in this area may present an ongoing source of contamination to the nearby Helps Road Drain and the underlying groundwater system.

3. The AFFF waste water retention infrastructure, identified as the Chesterfield Sumps, located at the eastern and western end of the Aircraft Hangars (Source Area P3A and P3B). These sumps receive AFFF waste water generated during testing of automated AFFF suppression systems in the Hangars. Groundwater results in the vicinity of the sumps reported concentrations of the sum of PFHxS and PFOS up to 1,160 µg/L, with contamination confirmed to extend to the Q2 Aquifer.

4. The former fire training area and sub-surface waste dump in the central northern portion of the airside operations area (Source Area P4). Significant PFAS contamination has been reported in soils and groundwater sampled from this area, with groundwater contamination confirmed to


extend to the Q2 Aquifer. The highest reported soil concentration was 161.8 mg/kg for the sum of PFHxS and PFOS, with concentrations in groundwater reported up to 660 µg/L.

5. The sub-surface waste dump located along the central portion of the western Site boundary (Source Area P8). The most significant contamination in this area was identified in groundwater with concentrations of the sum of PFHxS and PFOS ranging up to 74 µg/L in the Q1 Aquifer. This was the second highest concentration reported in a boundary monitoring well. Significant soil contamination was not identified in this area.

6. The current fire training area, including smokeroom training building (Building 618), located in the southern portion of the airside operations area near the Ordnance Unloading Area (Source Area P9). Significant PFAS contamination has been reported in soils (including soil leachate) and groundwater sampled from this area, with groundwater contamination confirmed to extend to the Q3 Aquifer. The highest reported soil concentration was 18 mg/kg for the sum of PFHxS and PFOS, with concentrations in groundwater reported up to 1,540 µg/L in the Q2 Aquifer. This was the highest reported Q2 Aquifer concentration at the Site, with the highest Q3 Aquifer concentration also reported in this area.

7. Former STP and fire training area located in the most southern point of the airside operations area, adjacent to the Helps Road Drain discharge point across the southwestern Site boundary, and Southern Detention Basin (Source Area P10). The soil results identified significant contamination in the northern portion of this area with concentrations of the sum of PFHxS and PFOS reported up to 45.6 mg/kg. The groundwater results indicate contamination is more widespread with concentrations reported up to 46 µg/L. Significant groundwater contamination was observed in the southern portion of the source area, including on the down hydraulic gradient southwestern Site boundary in both the Q1 and Q2 Aquifers.

8. Current fire station and former AFFF concentrate storage area located near the new Air Traffic Control Tower (Source Area P11). This area has been identified as the most significant source area on Site in relation to soil and groundwater contamination. The highest degree of contamination has been observed in the vicinity of the former AFFF concentrate storage tank with concentrations of the sum of PFHxS and PFOS reported up to 160 mg/kg in soil and up to 23,100 µg/L in groundwater. Groundwater samples recovered from the front of the fire station reported the second highest concentrations at the Site with results for the sum of PFHxS and PFOS up to 6,500 µg/L. Contamination has been confirmed to extend to the Q2 Aquifer, however at much lower concentrations than reported in the Q1 Aquifer. A Q3 Aquifer monitoring well installed down hydraulic gradient of this area did not identify PFAS contamination exceeding the adopted Tier 1 human health screening criteria for drinking water (i.e. 0.07 µg/L for the sum of PFHxS and PFOS). Testing of concrete in the area where the AFFF concentrate tank was historically located, and in the parking area at the front of the fire station, also identified significant concentrations of PFAS contamination.

9. Former fire training area in the Ordnance Unloading Area, located in the southern portion of the airside operations area (Source Area P15). Significant PFAS contamination has been reported in soils and groundwater sampled from this area, with groundwater contamination confirmed to extend to the Q2 Aquifer. The highest reported soil concentration was 34.7 mg/kg for the sum of PFHxS and PFOS, with concentrations in groundwater reported up to 320 µg/L.

10. Former fire training area around the ERUP Facility, located to the northwest of the main apron (Source Area P16). Significant PFAS contamination has been reported in soils and groundwater sampled from this area, with significant groundwater contamination confirmed in the Q2 Aquifer. The highest reported soil concentration was 37.5 mg/kg for the sum of PFHxS and PFOS, with concentrations in groundwater reported up to 480 µg/L in the Q2 Aquifer. Groundwater contamination has also been confirmed to extend to the Q3 Aquifer in this area.


11. The approximate location of a historical train and semi-trailer crash, at the corner of the western and southwestern Site boundaries (Source Area P23). The most significant contamination in this area was identified in groundwater with concentrations of the sum of PFHxS and PFOS ranging up to 214 µg/L in the Q1 Aquifer. This was the highest concentration reported in a boundary monitoring well. Groundwater contamination in this area has been confirmed to extend to the Q3 Aquifer. Significant soil contamination was not identified in this area.

12. Suspected former fire training area adjacent to a parking area for aircraft refuelling tanker trucks, located to the west of the bulk fuel storage facility (Source Area P27). The most significant contamination in this area was identified in groundwater with concentrations of the sum of PFHxS and PFOS ranging up to 2,900 µg/L in the Q1 Aquifer. Soil contamination was also identified in this area however all results were below the adopted Tier 1 human health screening criteria for commercial/industrial land use (i.e. 20 mg/kg for the sum of PFHxS and PFOS).

In addition, significant groundwater contamination was identified in a groundwater monitoring well (GW2178) installed in the south-western portion of the airside operations area (up hydraulic gradient of source area P23), in relatively close proximity to the aircraft wash down facility known as the “Birdbath area”. This area was initially identified by Base firefighting personnel as a potential source area where historical testing of mobile firefighting equipment may have occurred but then was subsequently retracted during the 2017 on-Site interviews conducted by JBS&G. However, the groundwater results for GW2178 indicate that some historical discharge of AFFF may have occurred in this area and therefore may represent an additional source area.

In each of the source areas at the Site, the primary PFAS of concern comprised PFHxS and PFOS. The sum of these two PFAS compounds typically comprised the highest reported PFAS concentrations detected in the 28-analyte suite.

In addition to the primary source areas, surface water contamination exceeding the adopted Tier 1 human health (recreational) and/or ecological screening criteria was identified in some areas of the stormwater drainage network throughout the Site, and the Helps Road Drain (on-Site). With the exception of a small number of isolated areas, significant sediment contamination was not identified throughout the on-Site drainage network.

13.2 Off-Site Extent of Contamination

Widespread PFAS contamination has been identified in groundwater down hydraulic gradient of the Site that exceeds the adopted Tier 1 human health screening criteria relevant to drinking water (i.e. 0.07 µg/L for the sum of PFHxS and PFOS). Contamination has been confirmed to extend to the Q3 Aquifer in one area investigated to date, indicating vertical migration of contamination has occurred through the Q1, Q2 and Q3 Aquifer sequences. The inferred groundwater flow direction in both the Q1 and Q2 Aquifers at the regional scale (i.e. Investigation Area level) is in a general west to south-westerly direction. The inferred lateral extent of PFAS contamination in the Q1 and Q2 Aquifers off Site (as depicted on Figure 25 and Figure 26), generally shows good correlation with the inferred groundwater flow direction away from the Site and the identified source areas.

There is also evidence of significant groundwater contamination in the vicinity of the Southern Detention Basin, Helps Road Drain and Kaurna Park Wetland, with an apparent radial spread of PFAS contamination away from these ephemeral surface water (stormwater) features. These results suggest that, at least historically, surface water discharging from the Site has provided a significant secondary source of impact to the underlying groundwater system. The more recent surface water sampling program (i.e. DSI) results do not tend to correlate with the degree of contamination observed in the shallow Quaternary aquifers, which supports the conclusion that historically the concentrations of PFAS in surface water discharging from the Site would have been significantly higher.


Whilst no groundwater investigations have been undertaken in proximity of the Helps Road Drain within the Bolivar WWTP site (at the southern-most extent of the drain), based on upgradient investigation results it is reasonable to expect that PFAS contamination would be present in shallow groundwater beneath, and in the vicinity of, the full extent of the drain to the discharge point into the Barker Inlet. This has been inferred on the attached groundwater contamination extent figures (refer Figure 25 and Figure 26).

To date, no PFAS contamination has been identified in the deeper T1 Tertiary Aquifer, which is the primary aquifer used by market gardeners and commercial irrigators throughout the Investigation Area.

Surface water samples collected off-Site did not identify PFAS contamination exceeding the adopted Tier 1 human health screening criteria relevant to recreational water (i.e. 0.7 µg/L) in any of the locations tested. However, PFAS contamination exceeding the adopted Tier 1 ecological screening criteria (0.13 µg/L) was identified in all samples collected from the Kaurna Park Wetland, and a sample location upstream of the wetland in the Helps Road Drain.

It is noted that there were minor exceedances of the Tier 1 ecological screening criteria observed in surface water samples collected at the downstream extent of the Helps Road Drain, near the discharge point into the Barker Inlet. As noted in Section 12.1.3, it is possible that these impacts may have been contributed to by an unidentified off-Site source or may be associated with existing PFAS contamination in the Barker Inlet. The SA EPA investigation into PFAS in the marine environment (SA EPA, 2017) indicated that the Barker Inlet represents a surface water body impacted by multiple sources of PFAS contamination. The SA EPA is in the process of auditing facilities where PFAS may have been historically used, with a focus on the greater Port Adelaide area. Although the Site appears to represent a contributing source of PFAS into Barker Inlet, it is considered impractical to determine the relative contribution from the Site versus other sources.

13.3 Human and Ecological Receptors

Based on the results of the DSI, the following receptors are considered to exist at the Site:

• Defence personnel and contractors (e.g. the EMOS Contractor) working at the Base;

• Intrusive maintenance workers and construction workers; and

• Visitors to the Site (including children).

It is noted that no ecological receptors have been identified in the above list. The Site is not considered to comprise any ecological receptors of concern (e.g. areas of ecological significance) that warrant targeted protection against exposure to the identified PFAS contamination beyond such measures that would be implemented to be protective of human health. It is noted that a threatened species of ground-dwelling bird may visit the Site, however the potential presence of this species is not likely to drive on-Site response management works (e.g. remediation). Notwithstanding, response management measures that focus on the protection of human health will inherently reduce potential risks to ecological receptors.

The following potential receptors are considered to exist in the broader Investigation Area:

• Members of the public (limited to the potential exposure pathways identified below);

• People who may be catching and consuming edible biota (e.g. yabbies, fish) from the Kaurna Park Wetland;

• Off-Site users and consumers of groundwater;

• Terrestrial and aquatic fauna (e.g. birds).


Once again, there are no areas of ecological significance considered to exist within the Investigation Area. The Kaurna Park Wetland is considered to represent the only potential off-Site ecological receptor within the Investigation Area, however the wetland is a constructed system that lies within the Helps Road Stormwater Catchment. The wetland was constructed in the mid-1990s as a stormwater detention basin to provide floodwater control within the catchment. As such, the wetland is not considered to represent a natural ecosystem of high importance. Notwithstanding, the potential for migratory species (i.e. birds) to frequent the wetland and be exposed to Site-derived PFAS contamination should be considered as part of the HHERA.

13.4 Potential PFAS Contamination Exposure Pathways

Based on the results of the DSI and understanding of the nature and extent of PFAS contamination, the following potential exposure pathways are considered to exist for the identified human and ecological receptors:

Human Health On-Site

• Direct contact or incidental exposure to soil and surface water contamination.

Human Health Off-Site

• Direct contact or incidental exposure during irrigation or use of PFAS contaminated groundwater for domestic activities, recreational activities, or commercial activities (including potential for inhalation of spray mist) – not yet confirmed to have occurred;

• Direct contact or incidental exposure to soils irrigated with PFAS contaminated groundwater (i.e. sourced from the Quaternary Aquifers) – not yet confirmed to have occurred;

• Consumption of crops, market garden and home-grown produce irrigated with PFAS contaminated groundwater (i.e. sourced from the Quaternary Aquifers) – not yet confirmed to have occurred;

• Consumption of livestock (e.g. cattle, sheep, chickens), milk, and eggs where PFAS contaminated groundwater has been used as water supply for livestock (i.e. sourced from the Quaternary Aquifers) – not yet confirmed to have occurred;

• Consumption of edible aquatic biota (e.g. yabbies, fish) caught from the Kaurna Park Wetland; and

• Consumption of honey produced in bee hives located within, or in reasonable proximity to, the Investigation Area.

Ecological

• Direct contact with surface water contamination in the Kaurna Park Wetland exceeding the adopted Tier 1 ecological screening criteria;

• Ingestion of surface water contaminated by Site-derived PFAS contamination; and

• Ingestion of flora and fauna affected by Site-derived PFAS contamination (bioaccumulation).

The potential for Site-derived PFAS contamination to present unacceptable risks to the identified receptors as a result of the potential exposure pathways will be considered as part of the HHERA.


14. Next Steps

The DSI has identified significant PFAS contamination is present at the Site which has migrated off-Site into the broader Investigation Area. The recommended next steps to address the issues associated with the identified PFAS contamination comprise the following:

• Complete the additional groundwater investigations to determine the vertical extent of PFAS contamination in groundwater beneath and down hydraulic gradient of the Site;

• Preparation of a DSI Addendum to include additional data gathered as part of the ongoing groundwater investigations undertaken to address the data gap of whether vertical migration of PFAS contamination to the Q4 Aquifer has occurred beneath the Site or in the broader Investigation Area;

• Progress completion of a Human Health and Ecological Risk Assessment (HHERA) to assess the potential risks posed to the identified receptors as a result of exposure to Site-derived PFAS contamination, including execution of a HHERA-specific sampling program;

• Prepare a PFAS Management Area Plan (PMAP) which Identifies appropriate response management actions to address potential risks associated with human health and/or ecological receptor exposure to Site-derived PFAS contamination, and that seeks to mitigate off-Site migration of PFAS; and

• Prepare an ongoing monitoring program (OMP) to assess the potential for ongoing migration of PFAS contamination from the Site, ongoing migration of existing off-Site groundwater contamination beyond the extent that has occurred to date, the temporal variation in PFAS concentrations in groundwater and surface water, and measure the success of implemented mitigations actions (to be included in the PMAP).


15. Limitations

This report has been prepared for use by the client who has commissioned the works in accordance with the project brief only, and has been based in part on information obtained from the client and other parties.

The advice herein relates only to this project and all results conclusions and recommendations made should be reviewed by a competent person with experience in environmental investigations, before being used for any other purpose.

JBS&G accepts no liability for use or interpretation by any person or body other than the client who commissioned the works. This report should not be reproduced without prior approval by the client, or amended in any way without prior approval by JBS&G, and should not be relied upon by other parties, who should make their own enquires.

Sampling and chemical analysis of environmental media is based on appropriate guidance documents made and approved by the relevant regulatory authorities. Conclusions arising from the review and assessment of environmental data are based on the sampling and analysis considered appropriate based on the regulatory requirements.

Targeted sampling and laboratory analyses were undertaken as part of the investigations undertaken, as described herein. Ground conditions between sampling locations and media may vary, and this should be considered when extrapolating between sampling points. Chemical analytes are based on the information detailed in the site history. Further chemicals or categories of chemicals may exist at the site, which were not identified in the site history and which may not be expected at the site.

Changes to the subsurface conditions may occur subsequent to the investigations described herein, through natural processes or through the intentional or accidental addition of contaminants. The conclusions and recommendations reached in this report are based on the information obtained at the time of the investigations.

This report does not provide a complete assessment of the environmental status of the site, and it is limited to the scope defined herein. Should information become available regarding conditions at the site including previously unknown sources of contamination, JBS&G reserves the right to review the report in the context of the additional information.


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This document is and shall remain the property of JBS&G. The document may only be used for the purposes for which it was commissioned and in accordance with the Terms of Engagement for the commission. Unauthorised use of this document in any form whatsoever is prohibited

Document Distribution

Rev No. Copies Recipient Date

A 1 x Electronic Defence: Andrea Barrett (Project Director) Site Auditor: Paul Fridell (ERM)

5 October 2018

B 1 x Electronic Defence: Andrea Barrett (Project Director) Site Auditor: Paul Fridell (ERM)

26 October 2018

C 1 x Electronic Defence: Andrea Barrett (Project Director) South Australian Environment Protection Authority

12 November 2018

D 1 x Electronic Defence: Andrea Barrett (Project Director) Site Auditor: Paul Fridell (ERM)

5 December 2018

0 (Final) 1 x Electronic Defence: Andrea Barrett (Project Director) 11 December 2018

Document Status

Rev No. Author Reviewer Approved for Issue

Name Name Signature Date

A Michael Cowin Will Ellis Steve Green [Draft for client review] 5 October 2018

B Michael Cowin Will Ellis Steve Green [Draft for client review] 26 October 2018

C Michael Cowin Will Ellis Steve Green [Draft for EPA review] 09 November 2018

D Michael Cowin Will Ellis Steve Green [Draft for final client review]

5 December 2018

0 (Final) Michael Cowin Will Ellis Steve Green

11 December 2018