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LONDON BOROUGH OF TOWER HAMLETS

ENVIRONMENTAL ASSESSMENT, GLAMIS ESTATE, TOWER HAMLETS, LONDON DRAFT December 2006

Prepared for London Borough of Tower Hamlets Mulberry Place (AH) PO BOX 55739 5 Clove Crescent London E14 1BY

Prepared by Parsons Brinckerhoff Ltd Queen Victoria House Redland Hill Bristol BS6 6US

Report Title : Environmental Assessment, Glamis Estate, Tower Hamlets, London.

Report Status :

FSE96608A

December 2006

Prepared by : ............................

Checked by : ........................................

.............................................. Approved by :

CONTENTS Page

EXECUTIVE SUMMARY 0

SECTION 1 0

PRELIMINARY RISK ASSESSMENT 0 1.1 Context and Objectives 1 1.2 Site Referencing Information 1 1.3 Site Setting and Surrounding Environment 1 1.4 Recorded Pollution Incidents 2 1.5 Historical Development & Potentially Contaminative Land Uses 2 1.6 Previously Prepared Reports 4 1.7 Geological and Hydrogeological Information 4 1.8 Hydrological and Drainage Information 5 1.9 Conceptual Site Model 6

SECTION 2 8

SITE INVESTIGATION 8 2.1 Rationale for Site Investigation and Specific Objectives 9 2.2 Methods of Site Investigation 9 2.3 General Ground Conditions 11 2.4 Groundwater Observations 12 2.5 Vapour Monitoring 12 2.6 Photo Ionisation Detector 13 2.7 Soil Gas Emissions (CH4, CO2 and O2) 13 2.8 Quality Assurance / Quality Control 13

SECTION 3 14

GENERIC QUANTITATIVE RISK ASSESSMENT 14 3.1 Context and Objectives 15 3.2 Numerical Assessment Criteria - Soils 15 3.3 Numerical Assessment Criteria - Groundwater 18 3.4 Identification of Unacceptable Risks 19 3.5 Identification of Pollutant Linkages not to be Considered Further 27 3.6 Remaining Pollutant Linkages 30 3.7 Foundation Assessment 31

SECTION 4 32

DETAILED QUANTITATIVE RISK ASSESSMENT 32 4.1 Context and Objectives 33 4.2 Aliphatic EC8-10 34

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4.3 Benzo(a)pyrene 35 4.4 Bioaccessability (PBET) Testing 37 4.5 Identification of Pollutant Linkages not to be Considered Further 43 4.6 Remaining Pollutant Linkages 44

REFERENCES 46


EXECUTIVE SUMMARY

The London Borough of Tower Hamlets (LBTH) has commissioned Parsons Brinckerhoff Ltd (PB) to undertake an environmental study of the Glamis Estate, London. The London Borough of Tower Hamlets order number for this work is 619714. The objectives of the study were to determine the nature and extent of contaminants potentially present at the site, and to establish the presence of significant pollutant linkages, in accordance with the procedures set out with the EA report R&D CLR 11.

Site History The site was historically occupied in part by a Ropery Works (1831–1869) and a Leather Tanning Works (1920-1952). Surrounding land uses included Paper Works, Iron Foundry, Sugar Refinery, Boat Building, Oil Works, Chemical Works and Gas Works.

Geology & Hydrogeology

A review of the LBTH GIS records and a British Geological Survey borehole record of the site has been undertaken. This indicates a sequence of Made Ground (1.6 m - 2.7 m thickness), over lying Taplow Gravels (2.0 m – 4.1 m thickness), overlying the London Clay (3.7 - 13.0 m thickness). The Taplow Gravels are classified by the EA as a Minor Aquifer.

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Hydrology The site lies within the catchment of the River Thames, which is located approximately 234 m to the southeast. In addition, the Shadwell Basin is located approximately 80 m to the south of the site.

Site Investigation A site investigation was undertaken between the 26th June 2006 and the 7th July 2006, under the full time supervision of a PB engineer (Gareth Wills). • A total of 264 No. soil samples were taken during the site works, and

submitted for laboratory analysis; • 5 No. boreholes were installed to monitor groundwater within the Taplow

Gravels. Samples were collected over 4 monitoring rounds; • A total of 15 No. gas wells were installed in private gardens across the

site, and both soil gas and vapour monitoring works were undertaken. All site works were undertaken in accordance with BS10175: 2001, and were completed without incident.

Risk Assessment and Recommendations

Following the completion of the site works, a two-tiered risk assessment was undertaken on the analytical data. Relevant pollutant linkages were identified, resulting from ‘hotspots’ of elevated benzo(a)pyrene (possibly relating to the presence of coke/coal and vesicular waste materials observed within the soils) and nickel within the Made Ground across the site. Following detailed quantitative risk assessment, incorporating bioaccessability testing data, relevant pollutant linkages have been identified for cadmium, copper and zinc at the Glamis Estate (for the consumption of edible plants pathway). A foundation assessment may be required to assess the potential risks to buildings and building foundations across the Estate, if the foundations were constructed of non-sulphate resisting concrete.


SECTION 1

PRELIMINARY RISK ASSESSMENT

SECTION 1 PRELIMINARY RISK ASSESSMENT

1 PRELIMINARY RISK ASSESSMENT

1.1 Context and Objectives

1.1.1 The London Borough of Tower Hamlets (LBTH) has commissioned Parsons Brinckerhoff Ltd (PB) to undertake an environmental study of the Glamis Estate, London. The London Borough of Tower Hamlets order number for this work is 619714.

1.1.2 The objectives of the study were to determine the nature and extent of contaminants potentially present at the site, and to establish the presence of significant pollutant linkages, in accordance with the procedures set out with the EA report R&D CLR 11.

1.1.3 All work has been undertaken in accordance with PB’s proposal to London Borough of Tower Hamlets dated 9th March 2006, the LBTH document ‘Technical Guidance for Site Investigation and Remediation’ and, to the extent possible, the Environment Agency document CLR11 ‘Model Procedures for the Management of Land Contamination’.

1.2 Site Referencing Information

1.2.1 Site referencing information is provided within Table 1.1, and the site location is shown on Figure 1.

Table 1.1: Site Referencing Information Name of Site Glamis Estate. Address of Site The site is bordered by Cable Street, Glamis Road, King

David Lane and The Highway, London E1. NGR 535271, 180849. Site Occupation The site is predominantly comprised of low-level,

residential terraced housing. Ground floor properties have private gardens, and a number of communal gardens are also present across the site.

Proposed Site Use Continuation of current use.

1.3 Site Setting and Surrounding Environment

1.3.1 The details provided within this preliminary risk assessment are based upon information provided by the London Borough of Tower Hamlets, and on observations made by PB whilst on site at the Glamis Estate.

Table 1.2: Site Setting and Surrounding Environment Site Access The site can be accessed from Redcastle Close, off

Glamis Road, with additional limited access via Juniper Street. There are also a number of unnamed footpaths providing entry to the site by foot.

Site Boundaries The site is bounded by Cable Street to the north (163 m), Glamis Road to the east (32 m), King David Lane to the west (91 m) and The Highway to the south (208 m).

Ground Cover Ground cover is a mixture of concrete, tarmacadam and soft standing.

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Table 1.2: Site Setting and Surrounding Environment Site Topography & Elevation

The site slopes gently from the north (11.2 m AOL) to the south (9.7 m AOL).

On-site plant & equipment

None identified.

Services Service plans provided by the statutory undertakers are provided as Appendix E.

Development to the North

The site is bordered to the north by Cable Street, beyond which lies residential housing. A community garden is located 20 m to the northeast of the site.

Development to the South

The site is bordered to the south by The Highway. Immediately to the south east of the site lies Gordon House, a residential tower block. The Shadwell Basin lies approximately 80 m to the south of the site, and the River Thames lies approximately 230 m to the southeast.

Development to the East

The site is bordered to the east by Glamis Road, beyond which is located a family centre and an adventure playground.

Development to the West

The site is bordered to the west by King David Lane, beyond which is a primary school. A public church garden is located 310 m to the west of the site.

Potentially contaminative land-uses in the vicinity of the site

Potentially contaminative land uses identified in the vicinity of the site comprise 2 No. petrol filling stations to the west of the site, located on The Highway. This is based upon a limited visual assessment of the site and surrounding area. A detailed desk study has not been undertaken.

Environmentally Sensitive Areas

The River Thames (234 m to the southeast of the study site) is deemed a Site of Metropolitan Importance. Shadwell Basin (80 m to the south) and St Georges in East Church Gardens (310 m to the west) are deemed Sites of Local Importance. The Cable Street Community Garden (approximately 20 m northeast) is deemed a Site of Borough Importance (Grade II).

1.4 Recorded Pollution Incidents

1.4.1 No information has been obtained on recorded pollution incidents at the site.

1.5 Historical Development & Potentially Contaminative Land Uses

1.5.1 The development of the site and surrounding area has been reviewed by reference to information provided by the London Borough of Tower Hamlets. Historical maps and archive information are provided in Appendix A.

1.5.2 The historic development of the site is summarised within Table 1.3.



Table 1.3: Historical Development Dates Relevant Historical Information 1745 The site (as part of a larger site extending to the east) is

labelled as Sun Tavern Fields, and there are a number of structures apparent within the site boundaries. The areas to the south, east and west are largely developed based on trade from the River Thames. The area to the north appears to be largely undeveloped.

1766 The site and surrounding area appear to be largely unchanged. The area continues to be dominated by trade from the River Thames, indicated by the persistence of the numerous local docking points and the location of Shadwell market, established approximately 30 m to the south of the site.

1801 and 1802 There appears to be limited development along the southern site boundary. The surrounding area remains unchanged.

1822 The site remains largely unchanged and is still referred to as Sun Tavern Fields. There has been extensive residential development to the north. Two large docking areas and the Wapping Tunnel across the River Thames have been established to the south east.

1831 The site (as part of the larger area extending to the east) is now used as a ropery, with ropewalks positioned east-west across the site.

1844 The site remains largely unchanged, still referred to as Sun Tavern Fields, and still used as a rope walk. The area to the north of the site is now completely developed, apparently with residential use. In addition, a railway track has been laid to the north, running in an east-west direction.

1853 The site and surrounding area remain largely unchanged. 1869 The site continues to be used as a ropery. Many small

units, possibly residential dwellings, occupy the majority of the site. A police station is located within the eastern site boundary.

1882 The site is no longer used as a ropery however the small units persist on site.

1896 The small (residential) units continue to persist on site and a larger unit has been constructed in the east of the site area. The use of the large unit is not indicated.

1920 The large unit is now labelled as St. Paul’s Leather Works. The police station and surrounding small (residential) units persist.

1952 St. Paul’s Leather Works is no longer labelled but the small (residential) dwellings persist. There have been several developments surrounding the site including a hospital to the east; King Edward’s Memorial Park, the Rotherhithe Tunnel and Shadwell Basin to the south; and a school, town hall and recreation ground to the west.



Table 1.3: Historical Development Dates Relevant Historical Information 2000 The site comprises the Glamis Estate, with numerous

schools, a health centre and day hospital developed to the north, a tobacco dock to the south west and a swimming pool to the west.

1.5.3 Table 1.4 lists all potentially contaminative historic land uses identified both on and

adjoining the study site, and highlights the contaminants (relevant to Part IIA) potentially present beneath the site as a result.

Table 1.4: Potentially Contaminative Historic Land Uses Process/ Land use Location Contaminants Potentially Present

On Site Rope Walks Leather Works

On-site

Paper Works Biscuit Factory Iron Foundry Sugar Refinery Boat Building Oil Works Chemical Works Gas Works

Surrounding area

Metals & Metalloids; Coal Dust; Coal Tar; Cyanides; Spent Oxide & Foul Lime; Ammoniacal Liquor; Fuel Oils; Polycyclic Aromatic Hydrocarbons; Sulphates; & Asbestos.

1.6 Previously Prepared Reports

LBTH Soil Sampling

1.6.2 A total of 3 No. soil samples (0 – 0.1 m BGL) were taken by LBTH on 15th December 2005, within communal, landscaped areas of the Glamis Estate. Samples were analysed by a UKAS and MCerts accredited laboratory (The Environmental Laboratory, East Sussex) for the presence of metals and metalloids, speciated PAH, TPH, phenols, sulphate, cyanide and pH.

1.6.3 Elevated concentrations of heavy metals, particularly lead (ranging from 1,727 to 2,462 mg/kg), were reported.

1.7 Geological and Hydrogeological Information

1.7.1 The geology and hydrogeology of the site has been reviewed with reference to the following sources:

• London Borough of Tower Hamlets GIS; and

• British Geological Survey borehole logs, Ref. TQ38SE/815, TQ38SE/816 and TQ38SE/818.



1.7.2 The geology and hydrogeology of the study area is summarised in Table 1.5, below.

Although the London Borough of Tower Hamlets GIS indicates no record of Made Ground on the site, British Geological Survey borehole logs constructed within the site boundaries suggest that Made Ground is present.

Table 1.5: Geology & Hydrogeology Formation Estimated thickness (m)

Description Aquifer Classification

Flow Mechanism (if applicable)

Made Ground 1.6 m – 2.7 m

Tarmacadam, hardcore and general fill materials.

- -

Taplow Gravels 2.0 m – 4.1 m

Coarse, dense sand and gravel Minor Aquifer -

London Clay 3.7 m - 13.0 m

Stiff to very stiff blue clay. Non-aquifer -

1.7.3 The geological succession identified on site during the ground investigation works

undertaken by PB is summarised within Section 2.

1.7.4 The site is located within the Catchment Abstraction Management Strategy (CAMS) Thames Corridor. It is not located within a Groundwater Source Protection Zone (SPZ).

1.8 Hydrological and Drainage Information

1.8.1 The site lies within the catchment of the River Thames, which is located approximately 234 m to the southeast of the site. In addition, the Shadwell Basin is located approximately 80 m to the south of the site.

1.8.2 Approximately 1.2 km to the east of the study site, Regent’s Canal and the Limehouse Cut flow into the Limehouse Basin, prior to entering the River Thames.

1.8.3 Drainage plans obtained from Thames Water indicate that water distribution mains run along each of the site boundaries, with an additional main cutting through the site along Redcastle Close and Tarbert Walk. Combined public sewers (carrying surface water and foul sewage) also run along each of the sites boundaries, with a storm relief sewer cutting across the site in a south easterly direction.

Licensed Abstractions

1.8.4 No information has been obtained relating to licensed abstractions at the site.

Discharge Consents

1.8.5 No information has been obtained relating to discharge consents at the site.



1.9 Conceptual Site Model

1.9.1 On the basis of the information summarised above, a conceptual site model (CSM) has been developed for the study site. The CSM is used to guide the investigation activities at the site, and identifies potential contaminants, receptors (both on and off-site) and exposure pathways that may be present. The identification of such potential “pollutant linkages” is a key aspect of the evaluation of potentially contaminated land.

1.9.2 Potential pollutant linkages identified at the site are detailed within Table 1.6, below.

Table 1.6: Potential Pollutant Linkages Contaminant(s) Pathway(s) Receptor(s)

Inge

blown du

stion, inhalation or dermal contact with contaminated soils, shallow groundwater and wind

st. Consumption of edible plants.

Residents of homes on Glamis Estate with private gardens.

Ingestion, inhalation or dermal contact with contaminated soil and wind blown dust.

Current site users (including non-residents) utilising communal areas.

Volatile Organic Compounds (VOCs) within Made Ground and shallow surface waters across the site.

Off-site migration of contaminants within shallow groundwater.

Off-site receptors; minor aquifer (Taplow Gravels) and surface water bodies (River Thames).

Ingestion, inhalation or dermal contact with contaminated soils, shallow

ndwater and wind st. Consumption of

edible plants.

groublown du




Non-halogenated hydrocarbons within Made Ground and shallow surface waters across the site.



Polycyclic aromatic hydrocarbons within Made Ground and shallow surface waters across the site.

Ingestion, inhalation or dermal contact with contaminated soils, shallow groundwater and wind blown dust. Consumption of edible plants.




Table 1.6: Potential Pollutant Linkages Contaminant(s) Pathway(s) Receptor(s)

In

blow

gestion, inhalation or dermal contact with contaminated soil and wind

n dust.





Ingestion, inhalation or al contact with

contaminated soils, shallow ndwater and wind

st. Consumption of edible plants.

derm

groublown du




Heavy metals and metalloids within Made Ground and shallow surface waters across the site.



Inge

contagrou

stion, inhalation or dermal contact with

minated soils, shallow ndwater and wind

blown dust. Consumption of edible plants.




Cyanides within Made Ground and shallow surface waters across the site.



Sulphate and sulphides present within shallow soils and shallow groundwater across the site.

Direct contact with building foundations.

Buildings and building foundations.

1.9.3 It should be noted that the identification of potential pollutant linkages does not

indicate that they are significant in any way or that the site is unsuitable for its current use. It does however act as a way of focusing data collection at the site, as explained in Section 2.


SECTION 2

SITE INVESTIGATION

SECTION 2 SITE INVESTIGATION

2 SITE INVESTIGATION

2.1 Rationale for Site Investigation and Specific Objectives

2.1.1 Site investigation works were undertaken to collect the information required for assessment of the potential pollutant linkages identified within Table 1.6.

2.2 Methods of Site Investigation

2.2.1 The site investigation was undertaken between the 26th June 2006 and 7th July 2006, under the full time supervision of a PB engineer. The scope of the works are detailed within Table 2.1, below;

Table 2.1: Scope of Site Investigation Works Rationale Excavation of up to 128 No. hand excavations (maximum depth 0.5 m BGL), within the private gardens of the properties of Glamis Estate. Soil samples to be collected at 0.1 m and 0.5 m BGL.

Due to the industrial processes known to have operated historically on and in the general vicinity of the site, it is possible that elevated concentrations of contaminants are present within the shallow soils beneath the sites. The excavation of shallow inspection pits within all private gardens across the site will enable PB to assess any risks to residents on the Glamis Estate, arising from potentially elevated concentrations of contaminants within the soil. Samples are to be taken at both 0.1 m and 0.5 m BGL in order to assess risks arising from all potential exposure scenarios in this environment.

Installation of up to 15 No. excavations for soil gas and soil vapour monitoring. A total of 2 No. rounds of gas monitoring and 1 round of vapour sampling.

The installation and subsequent sampling of shallow gas/vapour wells at the site will enable PB to assess any risks to residents on the Glamis Estate, arising from potentially elevated vapour and soil gas concentrations.

Excavation of up to 30 No. shallow excavations within communal areas. Soil samples to be collected at 0.1 m BGL.

The collection of shallow surface soil samples within the communal areas of the Glamis Estate will enable PB to assess any risks to current site users (including non-Estate residents) arising from potentially elevated contaminant concentrations within the topsoil.

Excavation of 5 No. boreholes, to be drilled to a maximum depth of 6 m BGL, and installed into the underlying Taplow Gravels (minor aquifer). A total of 4 rounds of groundwater monitoring & sampling to be undertaken.

Due to the industrial processes known to have operated historically on and in the general vicinity of the site, it is possible that elevated concentrations of contaminants have leached into the shallow groundwater beneath the site. The construction of a series of shallow boreholes into the Taplow Gravels will enable PB to assess any risks to this minor aquifer.



2.2.2 All site works were undertaken in accordance with BS10175: 2001 (‘Investigation of

Potentially Contaminated Sites’), and the LBTH document ‘Technical Guidance for Site Investigation and Remediation’ (September 2004). All works were completed without incident.

2.2.3 A total of 264 No. soil samples were taken during the site works, from 158 No. hand excavated pits (including 10 duplicates). The positions of all exploratory locations are illustrated within Figure 2.

2.2.4 Where conditions allowed, a total of 5 No. soil samples were collected from each private garden (3 samples at 0.1 m BGL and 2 samples from 0.5 m BGL). All 264 No. samples were submitted for laboratory analysis, and were analysed for the following determinands:

• Metals and metalloids (As, Cd, Cr, Pb, Hg, Ni, Cu, Zn, Se, WSB); • Total Cyanide; • Water Soluble Sulphate; • Water Soluble Chloride; • Total Monohydric Phenols; • pH; • Soil Organic Matter; • Speciated Polycyclic Aromatic hydrocarbons (PAH); • Speciated Total Petroleum Hydrocarbons (TPH); and • BTEX.

2.2.5 A total of 5 No. boreholes were installed to 6.0 m BGL. Groundwater samples were subsequently collected from 4 No. boreholes during 4 No. monitoring visits, with a total of 19 No. water samples (including 3 duplicates) scheduled for the following determinands:

• Metals and metalloids (As, Cd, Cr, Pb, Ni, Cu, Zn, Hg, Se, WSB); • Total Cyanide; • Sulphate; • Chloride; • Total Phenols; • pH; • TOC; • Speciated Polycyclic Aromatic hydrocarbons (PAH); • Speciated Total Petroleum Hydrocarbons (TPH); and • BTEX.

2.2.6 All soil and groundwater samples were analysed by The Environmental Laboratory Ltd, Hastings, a UKAS and MCerts accredited laboratory. Additional soil samples were submitted to ALcontrol Geochem Ltd, Chester (a UKAS and MCerts accredited laboratory) as inter-laboratory duplicates. Full schedules of sample analysis are detailed within the chain of custody forms provided in Appendix C.

2.2.7 A total of 19 No. soil vapour samples were collected from gas wells installed into hand excavations within private gardens (including 1 No. field blank).



2.2.8 Samples were analysed for the following determinands:

• BTEX compounds; and • Total Petroleum Hydrocarbons.

2.2.9 All soil vapour samples were analysed by Scientific Analysis Laboratories (SAL) Ltd, Manchester, a UKAS accredited laboratory.

2.2.10 Analytical results for soil, groundwater and vapour samples are provided within Appendix C, and summarised in Tables 3.28 – 3.39.

2.3 General Ground Conditions

2.3.1 Ground conditions have been logged in accordance with the requirements of BS5930:1999. Detailed logs for the hand dug pits and boreholes are provided in Appendix B, along with photographs of exploratory locations.

2.3.2 A summary of the ground conditions identified during the investigation is given below.

Made Ground

2.3.3 Made Ground was encountered within all exploratory locations across the site, ranging in thickness from 1.6 m (BH B) to 2.2 m (BH C). The base of the Made Ground was not encountered within any hand excavated pits.

2.3.4 The uppermost Made Ground across the site ranged from grass cover, patio paving slabs and tarmacadam. Below the immediate surface, the Made Ground was primarily encountered as gravely, clayey/silty sands (topsoil). The gravel primarily comprised fragments of red brick and chert.

2.3.5 Although there were no olfactory indicators of potential contamination identified during the investigation, visual indicators were identified in several hand dug pits, as illustrated in Table 2.2:

Table 2.2: Visual evidence of potential contaminants Potential Contaminants Exploratory Location (Made Ground) Unidentified black vesicular material

BH101, BH107, BH108, BH110, BH123, BH125, BH126, BH128, BH135, BH140, BH146, BH147, BH1551, BH156 & BH171

Unidentified black laminar material

BH141

Unidentified white vesicular material

BH122

Coal/coke BH105, BH111, BH113, BH117, BH162, BH172, BH204, BH212, BH230, BH232, BH233, BH237, BH238, BH256, BH258, BH260, BH263, BH265, BH268, BH269 & BH275



Natural Ground

2.3.6 Natural ground at the site comprised light brown, gravelly to very gravelly sands, and brown, very clayey gravels (Taplow Gravels). The Taplow Gravels ranged in thickness from 3.5 m (BH A) to >4.4 m (BH B), and were underlain by the London Clay. The London Clay was encountered as a firm, grey/brown mottled clay.

2.3.7 There was no visual or olfactory evidence of potential contamination identified within the natural ground.

2.4 Groundwater Observations

2.4.1 A total of 5 No. boreholes were constructed during the site works to monitor shallow groundwater quality beneath the site. Boreholes were installed into the Taplow Gravels, classified as a minor aquifer.

2.4.2 Depths to the groundwater surface within these monitoring wells are given within Table 2.3.

Table 2.3: Results of Groundwater Monitoring Visits

Depth to Groundwater Surface (m BGL) Location

6/07/2006 12/07/2006 20/07/2006 2/08/2006

BH A 2.97 2.97 2.98 2.99

BH B 2.28 2.26 2.27 2.28

BH C 3.40 3.39 3.40 3.40

BH E 3.19 3.18 3.18 3.20 2.4.3 Groundwater monitoring visits were undertaken by a PB engineer on 5-6th July, 12th

July, 20th July and 2nd August 2006. A total of 21 No. water samples (including 3 No. duplicates) were submitted for laboratory analysis. The results of the water analysis are given in Appendix C.

2.5 Vapour Monitoring

2.5.1 Vapour samples were collected from 15 No. monitoring wells, within the private gardens of the Glamis Estate, in order that potential vapour risks to residents could be assessed.

2.5.2 The vapour monitoring was undertaken in accordance with the in-house methodology recommended by Air Sampling Instruments Ltd and Scientific Analysis Laboratories (SAL) Ltd, who provided the calibrated pumps and sampling tubes for the works. The sampling methodology involved the collection of 20 litre samples, using low flow pumps, into charcoal tubes. Details of flow rates for sampling are provided within Appendix B.

2.5.3 Analytical results for vapour samples are provided within Appendix C, and summarised in Table 3.35.



2.6 Photo Ionisation Detector

2.6.1 A Photo Ionisation Detector (PID) was used on site during the works to screen samples for the presence of volatile organic compounds. Soil samples were bagged, and screened for a minimum period of 60 seconds at 0.1 m and 0.5 m BGL. Both peak and average readings were recorded (PID calibrated to isobutylene).

2.6.2 Screening results are provided within Appendix B.

2.7 Soil Gas Emissions (CH4, CO2 and O2)

2.7.1 Fifteen hand excavated inspection pits across the site were installed for soil gas and vapour monitoring. Two rounds of soil gas monitoring were undertaken within these boreholes, in order that potential soil gas risks to residents could be assessed.

2.7.2 Results of soil gas measurements (methane, carbon dioxide and oxygen) are given in Appendix B.

2.8 Quality Assurance / Quality Control

2.8.1 A total of 264 No. soil samples were submitted for analysis following exploratory works on the Glamis Estate. In accordance with LBTH guidance, a total of 10 duplicate samples were analysed. 5 samples were submitted to ELAB, the principle laboratory used throughout this project, and a further 5 samples were submitted to ALcontrol Geochem, as inter-laboratory duplicates.

2.8.2 A total of 19 No. groundwater samples were submitted for analysis, following 4 rounds of monitoring. Duplicate samples were collected during the 2nd, 3rd and 4th monitoring rounds, and were subsequently submitted for laboratory analysis.

2.8.3 A total of 19 No. vapour samples were collected and submitted for laboratory analysis. A single ambient air sample was collected during the monitoring works, to check that there were no elevated background concentrations of vapours at the site, and this sample was also submitted for laboratory analysis.

2.8.4 A total of 2 No. equipment blanks (rinsate samples) were collected during the drilling works undertaken at the site. These samples were taken in order to check the cleanliness of the drilling equipment, and to confirm the adequacy of field decontamination procedures.

2.8.5 The data collection, storage and preparation of this report has been undertaken in accordance with PB’s Integrated Management System which operates within the standards outlined in ISO 9001 (BSI Certificate No. Q06143) and ISO 14001 (BSI Certificate No. A12283).


SECTION 3

GENERIC QUANTITATIVE RISK ASSESSMENT

SECTION 3 GENERIC QUANTITATIVE RISK ASSESSMENT

3 GENERIC QUANTITATIVE RISK ASSESSMENT


3.1.1 This section makes use of the site investigation findings, as described in the previous section, to evaluate further the potential pollutant linkages identified in Section 1. A combination of qualitative and quantitative techniques is used, as described below.

3.2 Numerical Assessment Criteria - Soils

3.2.1 Various numerical assessment criteria have been used to interpret the chemical testing results, as described in this section. These criteria are generally set to be highly conservative and in the event that they are exceeded a further level of analysis is typically required.

3.2.2 The assessment criteria used for the screening of determinands within soils are identified within Table 3.1. Details of input parameters are given within the footers to Tables 3.28 – 3.34.

Table 3.1: Selected Assessment Criteria – Contaminants in Soils Substance Group Determinand(s) Assessment

Criteria Selected Organic Substances

Toluene, Ethylbenzene SGV Reports Volatile Organic Compounds (VOC’s) Benzene, Xylenes Draft SGV Reports

Total Phenols SGV Report Non-halogenated hydrocarbons Total Petroleum Hydrocarbons

(TPHCWG banded) CLEA UK (beta) Risc (for vapours)

Polycyclic Aromatic Hydrocarbons (PAH’s)

Naphthalene, Acenaphthylene, Acenaphthene, Fluorene, Phenanthrene, Anthracene, Fluoranthene, Pyrene, Benz(a)anthracene, Chrysene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(a)pyrene, Indeno(1,2,3-cd)pyrene, Dibenz(a,h)anthracene, Benzo(ghi)perylene

CLEA UK (beta)

Inorganic Substances Arsenic, Cadmium, Lead, Nickel, Selenium, Mercury, Chromium

SGV Reports Heavy metals and metalloids

Copper, Zinc CLEA UK (beta) Cyanides Total Cyanide. CLEA UK (beta)

Risc

3.2.3 Risc has been used to model the soil vapour at the site. In an independent review commissioned by the EA, Risc air models were considered to be more flexible and applicable than those contained within CLEA and SNIFFER.



CLEA UK

3.2.4 In November 2005 the Environment Agency released CLEA UK (beta version), the updated version of the CLEA 2002 model. The CLEA 2002 model and supporting CLR technical package was originally released by the Department of Environment Food and Rural Affairs (DEFRA) in 2002 to provide a scientifically based framework for assessing chronic risks to human health posed by land contamination in the United Kingdom.

3.2.5 On 9th October 2006 the Environment Agency formally withdrew the CLEA 2002 software, stating it lacked the versatility of CLEA UK (beta version). Furthermore, the Environment Agency also recommended the use of CLEA UK in human health risk assessments.

3.2.6 Analytical results for soils will be compared against published SGV’s where available. SGV reports for benzene and xylenes are currently in consultation. These ‘proposed’ SGV’s are yet to be published, but have been incorporated into the generic risk assessment within this study.

3.2.7 All remaining contaminants are to be screened against criteria derived using the CLEA UK model. All model assumptions and input parameters (both toxicological and fate & transport), in addition to full CLEA UK report summaries, are provided within Appendix D.

CLEA UK Input Criteria

3.2.8 The input criteria used for the development of Generic Assessment Criteria (GAC) within CLEA UK, and where appropriate, those required for selection of the correct screening criteria from SGV reports, are provided within Tables 3.2a, 3.2b and 3.2c.

Table 3.2a: CLEA UK Input Criteria – Residential with Plant Uptake Input Details Value Land Use Residential with plant uptake Building Type Typical House Receptor Female Age Class 1 – 6 Exposure Duration 6 years Averaging Time 6 years

Direct Soil Ingestion Direct Soil Derived Indoor Dust Ingestion Consumption of Site Grown Vegetables

Oral

Consumption of Soil Attached to Site Grown Vegetables Skin Contact with Soil Derived Indoor Dust Dermal Skin Contact with Soil Inhalation of Soil Derived Indoor Dust Inhalation of Soil Dust Inhalation of Soil Vapours Indoors

Inhalation

Inhalation of Soil Vapours Outdoors



Table 3.2a: CLEA UK Input Criteria – Residential with Plant Uptake Input Details Value Soil Type Sandy pH 7 Soil Organic Matter 5%

Table 3.2b: CLEA UK Input Criteria – Residential without Plant Uptake Input Details Value Land Use Residential without plant uptake Building Type Typical House Receptor Female Age Class 1 – 6 Exposure Duration 6 years Averaging Time 6 years

Direct Soil Ingestion Oral Direct Soil Derived Indoor Dust Ingestion Skin Contact with Soil Derived Indoor Dust Dermal Skin Contact with Soil Inhalation of Soil Derived Indoor Dust Inhalation of Soil Dust Inhalation of Soil Vapours Indoors

Inhalation

Inhalation of Soil Vapours Outdoors Soil Type Sandy pH 7 Soil Organic Matter 5%

Table 3.2c: Input Criteria – Published SGV Determinand Value Cadmium (SGV Report 3) pH 7 Phenols (SGV Report 8) 5 % SOM Benzene (Draft SGV Report 12) 5 % SOM Toluene (SGV Report 15) 5 % SOM Ethylbenzene (SGV Report 16) 5 % SOM Xylenes (Draft SGV Report 18) 5 % SOM

3.2.9 A pH value of ‘7’ has been used for the derivation of all generic screening criteria, and

is considered to be representative of the prevailing soil conditions across the site. This value has been obtained by converting all pH values to hydrogen ion concentrations, averaging them, and then using the product to complete the average pH. Full calculations are provided within Appendix D.



3.2.10 The actual pH value obtained for the Glamis Estate is 7.15. As the CLEA UK model

(and SGV report 3) only offer the option of selecting a pH value of 6, 7 or 8, the averaged value of 7.15 has been rounded down to a pH of 7.

3.2.11 The average soil organic matter across the site is 4.08 %. As the CLEA UK model (and SGV reports 8, 12 15, 16 & 18) only offer the option of selecting an SOM value of 1 %, 2.5 % or 5 %, the averaged value of 4.08 % has been rounded up to 5 % for use in the generation of generic assessment criteria.

Naphthalene Sensitivity Analysis

3.2.12 It should be noted that a draft SGV report for naphthalene (SGV 19) is also currently in consultation. The proposed SGV given within this draft report for the ‘residential and allotments’ land use is 34 mg/kg (for 5 % SOM).

3.2.13 The screening criteria derived for naphthalene using CLEA UK are as follows:

• For a ‘residential with plant uptake’ land use (pH7, 5 % SOM), the GAC derived is 17.3 mg/kg; and

• For a ‘residential without plant uptake’ land use (pH7, 5 % SOM), the GAC derived is 33.6 mg/kg.

3.2.14 Therefore, the criteria derived using CLEA UK for naphthalene, as opposed to the proposed SGV, are used throughout the remainder of this risk assessment. They are considered to be more conservative than the draft SGV value.

3.3 Numerical Assessment Criteria - Groundwater

3.3.1 The assessment criteria used for the screening of determinands within groundwater are detailed within Table 3.3. Details of input parameters are given within the footers to Tables 3.36 – 3.39.

Table 3.3: Selected Assessment Criteria – Contaminants in Water Substance Group Determinand(s) Assessment Criteria

Selected Organic Substances

Benzene, Toluene, Xylenes EQS Volatile Organic Compounds (VOC’s) Ethylbenzene WHO Health Non-halogenated hydrocarbons

Total Phenols EQS

Polycyclic Aromatic Hydrocarbons (PAH’s)

Naphthalene EQS



Table 3.3: Selected Assessment Criteria – Contaminants in Water Substance Group Determinand(s) Assessment Criteria

Selected Polycyclic Aromatic Hydrocarbons (PAH’s)

Acenaphthylene, Fluorene, Phenanthrene, Anthracene, Fluoranthene, Pyrene, Benz(a)anthracene, Chrysene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(a)pyrene, Dibenz(a,h)anthracene, Benzo(ghi)perylene

LEC

Inorganic Substances Arsenic, Cadmium, Lead, Nickel, Mercury, Chromium, Copper, Zinc, Boron

EQS Heavy metals and metalloids

Selenium WHO Health

Cyanides Total Cyanide WHO Health

3.3.2 A brief discussion of each source of criteria is provided below.

EQS

3.3.3 Environmental Quality Standards (EQS) have been released by the EA for dangerous substances, as identified by the EC Dangerous Substances Directive. EQS can vary for each substance, and can be different for fresh, estuarine or coastal waters.

Lowest Effect Concentration (LEC)

3.3.4 These criteria relate to the concentrations of polycyclic aromatic hydrocarbons in groundwater. They are taken from the Environment Agency R&D Technical Report P45 – Polycyclic Aromatic Hydrocarbons (PAH): Priorities for Environmental Quality Standard Development (2001).

3.3.5 They represent the lowest concentration below which the PAH compounds is not toxic to aquatic organisms.

WHO Health

3.3.6 These screening criteria have been taken from the World Health Organisation Guidelines for Drinking Water Quality (1984). The health value is a guideline value representing the concentration of a contaminant that does not result in any significant risk to the receptor over a lifetime of exposure.

3.4 Identification of Unacceptable Risks

3.4.1 The aim of this section is to determine which pollutant linkages represent unacceptable risks, and thereby require further investigation, further risk assessment or that remedial works be undertaken.



Soils

3.4.2 When undertaking site investigation works, it is not feasible to sample the entire soil mass. A limited number of soil samples are collected, in order to represent an area of interest (in accordance with P5-066/TR). The soil samples collected during the site works on the Glamis Estate have been divided into four zones of similar characteristics, as follows;

• Property Code 1A;

• Property Code 2H;

• Property Code 3A; and

• Property Code 4A.

3.4.3 The positions of all zones are illustrated within Figure 2.

3.4.4 Due to the variety of land uses encountered across the Glamis Estate, generic assessment criteria have been developed for two different exposure scenarios:

• Residential with plant uptake; and

• Residential without plant uptake.

3.4.5 All samples from data sets 1, 2 and 3 have initially been screened against both sets of assessment criteria, and this data has been included within Tables 3.4, 3.5 and 3.6 for comparison, with exceedences illustrated in Figures 3A, 3B and 3C (for residential with plant uptake), and Figures 4A, 4B and 4C (for residential without plant uptake).

3.4.6 However, all residents on the Estate have the potential to grow vegetables and edible plants within their gardens, should they wish. Therefore, we have assumed a ‘residential with plant uptake’ exposure scenario for all private gardens across the site for the purposes of this risk assessment, regardless of the observations made during the site investigation works.

3.4.7 The samples from the communal areas have initially been screened against criteria derived for a ‘residential without plant uptake’ scenario, and exceedences are illustrated within Figure 4D.

3.4.8 Where samples have exceeded the selected screening criteria, mean value and maximum value tests have been undertaken in accordance with the guidance set out within EA R&D Document CLR 7. Statistical tests have been applied to data sets representing the aforementioned zones of similar characteristics (paragraph 3.4.2). Full workings are set out within Tables 3.12 – 3.27, included within Appendix D, where these tests have been undertaken.



3.4.9 It should be noted that whilst screening criteria have been derived for all 16 USEPA

‘Priority’ PAH compounds, toxic equivalence to benzo(a)pyrene has been used as the basis for index dose derivation for all carcinogenic PAH’s (full justifications are provided within Appendix D).

3.4.10 Samples exceeding these TEF derived criteria are illustrated within Figures 3A - 3C and 4A - 4D, but are not discussed within the remainder of this risk assessment. Whilst these screening criteria are considered to be the most appropriate available at this time, they are not considered robust enough for use during the assessment of pollutant linkage significance.

3.4.11 Full soil results are included in Appendix C.

Data Set 1

3.4.12 This data set comprises a total of 91 No. soil samples, which exceeded selected generic screening criteria as follows:

Table 3.4: Data Set 1 – Exceedences of Selected Generic Assessment Criteria Determinand Screening Criteria No. of

Exceedences Residential with plant uptake land use Arsenic 20 mg/kg

Published SGV 64 of 91

Cadmium 2 mg/kg Published SGV

68 of 91

Chromium 130 mg/kg Published SGV

1 of 91

Lead 450 mg/kg Published SGV

68 of 91

Nickel

59 of 91

Nickel (1 outlier removed)

50 mg/kg Published SGV

58 of 90

Copper 241 mg/kg CLEA UK (beta)

66 of 91

Zinc 292 mg/kg CLEA UK (beta)

73 of 91

Benzene 0.109 mg/kg Draft SGV

2 of 91

Benzo(a)pyrene 62 of 90 Benzo(a)pyrene (1 outlier removed)

1.09 mg/kg CLEA UK (beta) 61 of 89

Aliphatic EC8-10

1 of 91

Aliphatic EC8-10 (2 outliers removed)

7.92 mg/kg CLEA UK (beta)

0




Exceedences Residential without plant uptake land use (included for comparison) Arsenic 20 mg/kg



68 of 91

Nickel 37 of 91 Nickel (1 outlier removed)

75 mg/kg Published SGV 36 of 90

Benzene 0.168 mg/kg Draft SGV

2 of 91



Aliphatic EC8-10 7.92 mg/kg CLEA UK (beta)

1 of 91

3.4.13 Soils from Data Set 1 contain concentrations of heavy metals (arsenic, cadmium,

chromium, lead, nickel, copper and zinc), benzene, benzo(a)pyrene and aliphatic EC8-10 in excess of the selected generic assessment criteria. Therefore, in accordance with procedures set out within CLR 7, statistical tests for contaminated soils have been applied to this data set.

3.4.14 Data Set 1 fails the mean value test for arsenic, cadmium, lead, nickel, copper, zinc and benzo(a)pyrene (i.e. the US95 value for each determinand exceeds the selected screening criteria). The mean value test was passed for chromium, benzene and aliphatic EC8-10.

3.4.15 The maximum value test was then undertaken, in order to determine if all samples belonged to the same population, or if there were any statistical outliers present.

3.4.16 A single outlier was identified for nickel (1,478.48 mg/kg) and for benzo(a)pyrene (51.61 mg/kg). These outliers were subsequently removed from the data set, and the mean value test was run again. In both instances, even with the outliers removed, the mean value test was still failed for nickel and for benzo(a)pyrene.

3.4.17 Although the mean value test was passed for aliphatic EC8-10, a single outlier (10.33 mg/kg) was still identified following completion of the maximum value test. This outlier is to be treated as a ‘hotspot’ (as it exceeds the selected screening criteria).



Data Set 2





Cadmium 10 of 92 Cadmium (1 outlier removed)



23 of 92

Nickel 2 of 92 Nickel (1 outlier removed)


Copper 241 mg/kg CLEA UK (beta)

3 of 92

Zinc 4 of 92 Zinc (1 outlier removed)

292 mg/kg CLEA UK (beta) 3 of 91

Benzo(a)pyrene 35 of 92 Benzo(a)pyrene (2 outliers removed)


Residential without plant uptake land use (included for comparison) Arsenic 20 mg/kg



23 of 92



3.4.19 Soils from Data Set 2 contain concentrations of heavy metals (arsenic, cadmium,

lead, nickel, copper and zinc) and benzo(a)pyrene in excess of the selected generic assessment criteria. Therefore, in accordance with procedures set out within CLR 7, statistical tests for contaminated soils have been applied to this data set.

3.4.20 Data Set 2 fails the mean value test for benzo(a)pyrene (i.e. the US95 value exceeds the selected screening criteria). The mean value test was passed for arsenic, cadmium, lead, nickel, copper and zinc.




3.4.22 Two outliers were identified for benzo(a)pyrene (37.06 mg/kg and 21.35 mg/kg).

These outliers were subsequently removed from the data set, and the mean value test was run again. Even with the outliers removed, the mean value test was still failed for benzo(a)pyrene.

3.4.23 Although the mean value test was passed for all metals, outliers were still identified following completion of the maximum value test. Single outliers were identified for cadmium (6.31 mg/kg), for nickel (55.7 mg/kg) and for zinc (702.4 mg/kg), and three outliers were identified for copper (508.35 mg/kg, 325.84 mg/kg and 275.83 mg/kg). These outliers were then removed from the data set, and are to be treated as ‘hotspots’ (as they all exceed the selected screening criteria).

Data Set 3






3 of 50

Zinc 292 mg/kg CLEA UK (beta)

7 of 50



Residential without plant uptake land use (included for comparison) Arsenic 20 mg/kg



3 of 50



3.4.25 Soils from Data Set 3 contain concentrations of heavy metals (arsenic, lead and zinc)

and benzo(a)pyrene in excess of the selected generic assessment criteria. Therefore, in accordance with procedures set out within CLR 7, statistical tests for contaminated soils have been applied to this data set.

3.4.26 Data Set 3 fails the mean value test for benzo(a)pyrene (i.e. the US95 value exceeds the selected screening criteria). The mean value test was passed for arsenic, lead and zinc.




3.4.28 A single outlier was identified for benzo(a)pyrene (8.44 mg/kg). This outlier was

subsequently removed from the data set, and the mean value test was run again. Even with the outlier removed, the mean value test was still failed for benzo(a)pyrene.

Communal Areas


Table 3.7: Communal Areas – Exceedences of Selected Generic Assessment Criteria Determinand Screening Criteria No. of

Exceedences Residential without plant uptake land use Arsenic 20 mg/kg



10 of 26

Nickel 75 mg/kg Published SGV

2 of 26



3.4.30 Soils from the Communal Areas data set contain concentrations of heavy metals

(arsenic, lead and nickel) and benzo(a)pyrene in excess of the selected generic assessment criteria. Therefore, in accordance with procedures set out within CLR 7, statistical tests for contaminated soils have been applied to this data set.

3.4.31 The Communal Areas data set fails the mean value test for arsenic and for benzo(a)pyrene (i.e. the US95 value exceeds the selected screening criteria). The mean value test was passed for lead and nickel.


3.4.33 A single outlier was identified for benzo(a)pyrene (12.74 mg/kg). This outlier was subsequently removed from the data set, and the mean value test was run again. With the outlier removed, the mean value test was then passed for benzo(a)pyrene. The outlier is to be treated as a ‘hotspot’, as it exceeds the selected screening criteria.

Buildings and Building Foundations

3.4.34 Sulphate attack on building foundations occurs where sulphate solutions react with the various products of hydration in Ordinary Portland Cement (OPC) or converted High-Alumina Cement (HAC). The reaction is expansive, and therefore disruptive, not only due to the formation of minute cracks, but also due to loss of cohesion in the matrix.

3.4.35 Elevated concentrations of water soluble sulphate were recorded at a number of sample locations, as detailed within Table 3.45.



Table 3.45: Selected Water Soluble Sulphate Results Location Sample Depth

(m BGL) Measured

Concentration (g/l SO4)

Data Set 1 BH261 (Property Code 1E) 0.1 37.0 Data Set 2 BH220 (Property Code 2F) 0.1 1.47 BH202 (Property Code 2G) 0.5 1.23 BH117 (Property Code 2D) 0.5 6.7 Data Set 3 BH274 (Property Code 3B) 0.4 1.34

3.4.36 These elevated concentrations are a potential risk to buildings and building

foundations on the Glamis Estate.

Soil Gas and Vapour

3.4.37 Vapour samples were scheduled for a suite of volatile organic compounds, comprising TPH, benzene, toluene, ethylbenzene and xylenes. Results are presented in Appendix C, and are summarised within Table 3.35.

3.4.38 All samples analysed for TPH were either below or marginally exceeded the laboratory reported limit of detection, and samples analysed for BTEX compounds were all below laboratory reported limits of detection. TPH concentrations have been screened against criteria derived using Risc, and full details of model input parameters are provided within Appendix D.

Table 3.8: Summary of Reported TPH Vapour Results Vapour Results

(mg/m3) Screening Criteria (SSTL)

(mg/m3) Minimum Maximum TPH Fraction Outdoor Air Indoor Air

Aliphatic EC8-10 35,000 A 7,500 Aliphatic EC10-12 4,400 A 4,400 A

Aliphatic EC12-16 410 A 410 A

Aliphatic EC16-35 8.3 A 8.3 A

<0.5

1.7

Aromatic EC8-10 32,000 A 1,500 Aromatic EC10-12 3,500 A 1,500 Aromatic EC12-16 310 A 310 A

Aromatic EC16-21 6.6 A 6.6 A

<0.5

1.7

Aromatic EC21-35 0.0045 A 0.0045 A

A The SSTL was set equal to the saturated vapour concentration, and therefore the target level (SSTL) could not be exceeded.



3.4.39 Screening criteria have been developed for all TPH fractions above EC8, as the TPH

vapour results received from SAL are not speciated.

3.4.40 No vapour results exceeded the screening criteria derived using Risc (see footnote to Table 3.8), and the ‘ambient air’ sample did not contain any reported concentrations of either TPH or BTEX compounds above the limit of detection. Risks to the residents of the Glamis Estate from the inhalation of organic vapours are therefore considered to be minimal.

3.4.41 All soil samples taken from across the site were subjected to an initial on site screening with a PID, as per the criteria outlined within Section 2.6, for the presence of volatile organic compounds. Results are included within Appendix B. All peak and average readings were below 100 ppm, and are therefore determined to present a minimal risk to site users.

3.4.42 Soil gas measurements were taken from gas wells, installed within selected private gardens across the Glamis Estate. A total of 2 monitoring rounds were undertaken, for the presence of methane, carbon dioxide and oxygen. Monitoring results are included within Appendix B.

3.4.43 No methane was detected over the two monitoring rounds from any of the installations, and the maximum detected concentration of carbon dioxide was 1 %.

3.4.44 The gassing situation on site has been characterised in accordance with CIRIA Report 149 as ‘characteristic setting’ 2 (Table 3.9).

Table 3.9: Site Classification Criteria (amended from CIRIA 149) Methane (% by volume in air)

Carbon dioxide (% by volume in air)

Gas Protection Measures

Characteristic Situation 1 < 0.1 < 1.5 No special precautions

Groundwater Contaminants

3.4.45 A comparison of the results from the sampled boreholes against the assessment criteria outlined in Table 3.3 is presented in Tables 3.36 – 3.39. Full analytical results for groundwater samples are provided in Appendix C.

3.4.46 No determinands were identified at concentrations in excess of the selected groundwater screening criteria.

3.5 Identification of Pollutant Linkages not to be Considered Further

3.5.1 On the basis of the comparison of the detected chemical concentrations with the criteria described above, Table 3.10 lists the pollutant linkages, with justifications, that are considered insignificant within the context of this risk assessment.



Table 3.10: Pollutant Linkages not to be Considered Further Contaminant(s) Pathway(s) Receptor(s) Justification

Ingestion, inhalation or

rmal contact h

aminated il and wind

blown dust.

dewitcontso

Property Code 4A.

No soil concentrations from the Communal Areas data set were reported in excess of the selected generic assessment criteria.




No concentrations were reported in excess of the selected groundwater assessment criteria (following 4 rounds of borehole monitoring & sampling).



Property Code 5.

Although 2 No. benzene samples from Data Set 1 exceeded the proposed SGV criteria, the mean value test was passed for this data set, and the exceedences were not identified as outliers following completion of the maximum value test. All gas wells, installed into private gardens across the site, were monitored using a PID. Vapour samples were also collected from each location, which were subsequently analysed for TPH and for BTEX compounds. No vapour concentrations were reported in excess of the selected assessment criteria.

Non-halogenated hydrocarbons within Made Ground and shallow surface waters across the site.


Property Code 4A.

No soil concentrations from the Communal Areas data set were reported in excess of the selected generic assessment criteria.



Table 3.10: Pollutant Linkages not to be Considered Further Contaminant(s) Pathway(s) Receptor(s) Justification Non-halogenated hydrocarbons within Made Ground and shallow surface waters across the site.




Ingestioinhdermw

n, alation or

al contact ith

contaminated soils, shallow groundwater and wind blown dust. Consumption of edible plants.

Property Code 5.


Property Code 4A.

No soil concentrations of cyanide were reported in excess of the selected generic assessment criteria.

Cyanides within Made Ground and shallow surface waters across the site.








Heavy metals and metalloids within Made Ground and shallow surface waters across the site.






3.6 Remaining Pollutant Linkages

3.6.1 Following the generic quantitative risk assessment detailed above, Table 3.11 details the remaining pollutant linkages identified as requiring further action.

Table 3.11: Remaining Pollutant Linkages Contaminant(s) Pathway(s) Receptor(s) Action Aliphatic EC8-10. Ingestion, inhalation

or dermal contact with contaminated soils, shallow groundwater and wind blown dust. Consumption of edible plants.

Property Code 1C. Progress to detailed quantitative risk assessment (DQRA).


Property Code 5. Progress to DQRA.

Benzo(a)pyrene.


Property Code 4B. Progress to DQRA.

Arsenic. Ingestion, inhalation or dermal contact with contaminated soil and wind blown dust.

Property Code 4A. Schedule for bioaccessability testing, followed by DQRA.

Arsenic, Lead and Nickel.

Ingestion, inhalation or dermal contact with contaminated soil and wind blown dust. Consumption of edible plants.


Cadmium, Copper, Zinc

Consumption of edible plants.


Cadmium. Consumption of edible plants.

Property Code 2B. Schedule for bioaccessability testing, followed by DQRA.



Table 3.11: Remaining Pollutant Linkages Contaminant(s) Pathway(s) Receptor(s) Action Nickel and Zinc. Consumption of

edible plants. Property Code 2A. Schedule for

bioaccessability testing, followed by DQRA.

Copper. Consumption of edible plants.

Property Codes 2B, 2C and 2E.

Schedule for bioaccessability testing, followed by DQRA.




Foundation Assessment.

3.7 Foundation Assessment

3.7.1 The potential risks to buildings and building foundations highlighted within Table 3.45 are not actual risks if the foundations of the Glamis Estate were constructed using sulphate resisting concrete. If sulphate resisting concrete was not used, however, concrete testing works (foundation assessment) may be required.

3.7.2 Such works would establish if sulphate resisting concrete was used during the construction of the Estate, and would identify if the concrete was suffering from sulphate attack. Foundation core sampling works would need to be undertaken, in accordance with BS1881: Part 204 (1988), and the resulting materials would be scheduled for the following laboratory analysis:

• Determination of cement type;

• Sulphate content of concrete; and

• Petrographic examination of hardened concrete.

3.7.3 This programme of works would only need to be considered if the foundations of the Estate were considered to be constructed of non-sulphate resisting concrete.


SECTION 4

DETAILED QUANTITATIVE RISK ASSESSMENT

SECTION 4 DETAILED QUANTITATIVE RISK ASSESSMENT

4 DETAILED QUANTITATIVE RISK ASSESSMENT


4.1.1 This section provides detailed evaluation of the pollutant linkages identified in Section 3.6 (Table 3.11) as requiring detailed quantitative risk assessment.

Table 4.1: Identified Pollutant Linkages for Detailed Quantitative Risk Assessment Contaminant(s) Pathway(s) Receptor(s) Aliphatic EC8-10. Ingestion, inhalation or

dermal contact with contaminated soils, shallow groundwater and wind blown dust. Consumption of edible plants.

Property Code 1C.


Property Code 5. Benzo(a)pyrene.


Property Code 4B.

Identified Pollutant Linkages for Detailed Quantitative Risk Assessment, following Bioaccessability Analysis: Contaminant(s) Pathway(s) Receptor(s) Arsenic. Ingestion, inhalation or

dermal contact with contaminated soil and wind blown dust.

Property Code 4A.

Arsenic, Lead and Nickel.


Property Code 1A.

Cadmium, Copper, Zinc

Consumption of edible plants. Property Code 1A.

Cadmium. Consumption of edible plants. Property Code 2B.

Copper. Consumption of edible plants. Property Codes 2B, 2C and 2E.

Nickel and Zinc. Consumption of edible plants. Property Code 2A.



4.2 Aliphatic EC8-10

4.2.1 Although the mean value test for Data Set 1 was passed for aliphatic EC8-10, a single outlier (10.33 mg/kg) was still identified following completion of the maximum value test (Section 3.4). This outlier, from Property Code 1C, is to be treated as a ‘hotspot’, as it exceeds the selected Tier 1 screening criteria of 7.92 mg/kg.

4.2.2 Therefore, a site specific assessment criteria (SSAC) has been derived using CLEA UK. The input criteria used for the development of this SSAC are provided within Table 4.2, and full CLEA UK report summaries are in Appendix D.

Table 4.2: CLEA UK Input Criteria – Aliphatic EC8-10 SSAC Input Details Value Land Use Residential with plant uptake Building Type Typical House Receptor Female Age Class 1 – 6 Exposure Duration 6 years Averaging Time 6 years

Direct Soil Ingestion Direct Soil Derived Indoor Dust Ingestion Consumption of Site Grown Vegetables

Oral

Consumption of Soil Attached to Site Grown Vegetables Skin Contact with Soil Derived Indoor Dust Dermal Skin Contact with Soil

Soil Type Loam pH 7 Soil Organic Matter 5%

4.2.3 The private garden to Property 1C is primarily paved with decorative slabs, and

therefore the inhalation pathways within CLEA UK are not considered appropriate. Furthermore, the maximum PID value recorded during the excavation works within this garden was 1.4 ppm (full data contained within Appendix B).

4.2.4 The soil type of ‘loam’ has been selected, as this is considered to be the most appropriate for the soil conditions encountered within boreholes BH161, BH162 and BH162.

4.2.5 The SSAC has been compared with the Aliphatic EC8-10 data from BH161 in Table 4.3:

Table 4.3: Tier 2 Aliphatic EC8-10 Screening Criteria (against BH161 data) Location Tier 2 Criteria

mg/kg Measured Concentration

mg/kg BH161 (Property Code 1C)

1,320

10.33



4.3 Benzo(a)pyrene

Background

4.3.2 For non-threshold contaminants, health criteria values (HCV’s) are based upon excess lifetime cancer risks (ELCR). The ECLR is the additional risk of developing cancer, due to exposure to a toxic substance over an individual’s lifetime (i.e. an upper bound estimate of the probability of developing cancer due to exposure to a particular substance). The HCV for benzo(a)pyrene recommended by the EA for SSGV calculation is in the region of 10-5.

4.3.3 The CLEA UK model and its inputs are based on calculating an acceptable or minimum level of risk from pollutants within soil. However, in order to satisfy the legal definition of contaminated land, an unacceptable level of risk must be established. This can be achieved by increasing the ELCR on which the benzo(a)pyrene HCV is based. There is no set mechanism for choosing an ELCR, it is intangible, a scientific and political choice.

4.3.4 The toxicological data for benzo(a)pyrene recommended within DEFRA Tox Report 2 is based upon the WHO Drinking Water Standard (DWS) of 700 ng/L, which relates to an ELCR of 1x10-5. Whilst the WHO selected guideline values based on an upper bound ELCR of 10-5, they also considered concentrations associated with ELCR of 10-4 and 10-6, suggesting that such values may be acceptable for the derivation of DWS.

4.3.5 Sword et. al. undertook an extensive literature review, including information sourced from the USEPA, the National Institute of Public Health and the Environment in the Netherlands, the New Zealand Ministry for the Environment and the HSE. They concluded that the lower bound or minimal risk levels for benzo(a)pyrene are generally in the region of 1x10-6 and 1x10-5, whilst upper bound risk levels are more difficult to equate.

4.3.6 Many countries and organisations use an ELCR of 1x10-4 as an upper bound level of ‘acceptable risk’, and guidance from the EA also suggests that there may be some consensus in using this risk level where it is determined appropriate. The use of an ELCR of 1x10-3 is generally regarded as unacceptable, and therefore the risk range of 1x10-5 to 1x10-4 may be regarded as representing a tolerable risk region.

4.3.7 There are large uncertainty factors currently applied in the drinking water and air quality standards used to derive the Index Doses presented within the TOX 2 Report (in particular the factors of safety as detailed in section 3.32). This, coupled with the acknowledgement that 1x10-4 is used by countries outside the UK, makes this ELCR a reasonable choice for inclusion as part of the assessment.

Calculation of an SSGVtrigger for the Glamis Estate

4.3.8 Using an amended ELCR of 1x10-4, we have derived the following SSGV for benzo(a)pyrene:

• 10.7 mg/kg (residential with plant uptake); and

• 13.6 mg/kg (residential without plant uptake).

4.3.9 Full CLEA UK report summaries are provided within Appendix D. These screening criteria may be considered to represent a trigger of the potential for significant harm.



4.3.10 Risc (RBCA approach) was also used to generate screening values for

benzo(a)pyrene. A direct comparison can not be made between the values, as the RBCA methodology uses cancer slope factors for the assessment of non-threshold behaviour. It is, however, a useful guide to the confidence in the criteria produced with CLEA UK.

Table 4.11: Comparison of CLEA UK and Risc Screening Criteria for Benzo(a)pyrene (Residential with Plant Uptake) Risk Assessment Tool Tier 1 Criteria

mg/kg Tier 2 value

mg/kg CLEA UK 1.07 10.7 Risc 0.84 8.4

4.3.11 Full details of model input parameters are provided within Appendix D.

Tier 2 benzo(a)pyrene assessment – for residents with private gardens

4.3.12 The new screening criteria for residential with plant uptake has been compared against the US95 values for Data Sets 1, 2 and 3.

Table 4.4: Tier 2 Benzo(a)pyrene Screening Criteria (against US95 values) Location Tier 2 Criteria

mg/kg US95 value

mg/kg Property Code 1A. 10.7 3.56 Property Code 2H. 10.7 3.27 Property Code 3A. 10.7 1.75

4.3.13 The US95 values for benzo(a)pyrene, derived for data sets 1, 2 and 3 (and thereby

encompassing all residences with private gardens within the Glamis Estate) do not exceed the Tier 2 assessment criteria.

4.3.14 Although this means the mean value test is now ’passed’ for these data sets, several benzo(a)pyrene ‘outliers’ were identified following completion of the maximum value test (Section 3.4). These outliers must be treated as deemed to be ‘hotspots’ of benzo(a)pyrene contamination, if they now exceed the Tier 2 assessment criteria:

Table 4.5: Tier 2 Benzo(a)pyrene Screening Criteria (against ‘outliers’) Location Tier 2 Criteria


mg/kg BH123 (Property Code 1B)

10.7

51.61

BH101 (Property Code 2E)

10.7

37.06

BH117 (Property Code 2D)

10.7

21.35



4.3.15 The benzo(a)pyrene concentrations within these 3 residences do not belong to the

underlying sample populations, and exceed the Tier 2 screening criteria.

4.3.16 It is worth noting that unidentified black, vesicular materials were identified within the Made Ground from BH123 (Property Code 1B) and from BH101 (Property Code 2E), whilst coal/coke was identified within the Made Ground from BH117 (Property Code 2D).

4.3.17 These materials may be responsible for the elevated concentrations of benzo(a)pyrene recorded at these three locations.

Tier 2 benzo(a)pyrene assessment – users of communal areas

4.3.18 Although the mean value test was passed for benzo(a)pyrene for the Communal Areas data set (Section 3.4), a single ‘hotspot’ was identified in the vicinity of BH170. However, the concentration of benzo(a)pyrene (12.74 mg/kg) did not exceed the Tier 2 assessment criteria of 13.6 mg/kg.

Table 4.6: Tier 2 Benzo(a)pyrene Screening Criteria (Communal Areas) Location Tier 2 Criteria


mg/kg BH170 13.6 12.74

4.4 Bioaccessability (PBET) Testing

4.4.1 Risk assessment for potentially contaminated land is currently based upon estimates of intake, rather than actual uptake by an exposed population. Intake is the amount of a chemical entering the body, whereas uptake is the amount of a chemical that is absorbed into the blood stream.

4.4.2 This can invariably lead to overly conservative assumptions concerning risks to human health, as the human gastrointestinal tract only makes a fraction of a potentially harmful chemical entering the body accessible for absorption.

4.4.3 Bioaccessability testing serves to estimate the fraction of a contaminant that is soluble in the gastrointestinal tract, and therefore available for absorption into the blood stream.

TOTAL SOIL METAL CONCENTRATION

BIOACCESSIBLE FRACTION

BIOAVAILABLE FRACTION

TOTAL CONCENTRATION ≥ BIOACCESSIBLE FRACTION ≥ BIOAVAILABLE FRACTION



4.4.4 In accordance with the recommended actions identified within Table 3.11, a total of 23

No. soil samples were scheduled for bioaccessability testing. Samples were scheduled from locations across the study site, where elevated heavy metal concentrations were reported. Chain of custody forms are provided within Appendix C.

4.4.5 Samples were analysed by the Analytical Geochemistry Laboratories of the British Geological Survey (UKAS and MCerts accreditation currently undergoing validation), following PBET (Physiologically Based Extraction Test) extraction methodologies. The PBET test includes stomach and small intestinal phases and has been validated using the gastrointestinal tract parameters for a number of animal species for bioaccessible arsenic.

4.4.6 The PBET test determines the bioaccessible fraction of a particular element within soil, i.e. the fraction of the element that is soluble under each of the PBET test conditions. It should therefore not be interpreted as bioavailability.

4.4.7 BAF denotes the bioaccessible fraction of metal in the sample, based on the highest bioaccessability value following extractions (from either ‘stomach’, ‘intestine 1’ or ‘intestine 2’). It is calculated by:

BAF (%) = Element (bioaccessible) / Element (total) X 100

4.4.8 Samples were analysed for the bioaccessible fraction of arsenic, cadmium, copper, lead, nickel and zinc.

4.4.9 Full details of sample preparation and analysis methodologies are provided within Appendix C.

Incorporation of PBET data into DQRA; SNIFFER

4.4.10 SNIFFER is recognised as using the same algorithms as CLEA, and has been produced by the Scottish and Northern Ireland Forum for Environmental Research. It allows for the incorporation of the oral bioaccessability data provided by BGS (for the assessment of intake via soil and indoor dust ingestion).

4.4.11 SNIFFER has been used to generate Site Specific Assessment Criteria (SSAC) for Arsenic, Cadmium, Copper, Nickel and Zinc, both for residential with plant uptake and residential without plant uptake exposure scenarios.

4.4.12 A total of 23 No. samples have been scheduled for PBET testing, and the maximum BAF value for each contaminant has been used in all subsequent risk estimation. No guidance is currently available on the application of bioaccessability data into risk assessment, though in his talk at the BARGE Special Session at Consoil 2005, Mr. Paul Nathanial of LQM stated that “usually, at least 10 samples per site, zone or material are tested and the maximum bioaccessability used in risk estimation”.

4.4.13 A SNIFFER print-out for each contaminant (including the highest reported BAF) and exposure scenario is included in Appendix D, in order that all SNIFFER input parameters are transparent.

4.4.14 A summary of all PBET results, and the corresponding SNIFFER-derived assessment criteria for each sample, is provided in Tables 4.7 – 4.11. Full BGS PBET data is also provided, within Appendix C.



Re-assessment of Identified Pollution Linkages (from Table 4.1) against SNIFFER-derived Assessment Criteria

Table 4.12: Re-assessment of Identified Pollution Linkages against SNIFFER-derived SSAC (incorporating PBET data) Contaminant Pathway(s) Receptor(s) US95

(mg/kg) SSAC

(mg/kg) Arsenic. Ingestion, inhalation

or dermal contact with contaminated soil and wind blown dust.

Property Code 4A.

21.12 121.8

4.4.15 The SNIFFER-derived SSAC of 121.8 mg/kg is based upon a residential without plant

uptake exposure scenario, and a BAF of 25 %. A total of 23 No. soil samples from the Glamis Estate were analysed for bioaccessible arsenic, and results ranged between 8.17 % and 25 % BAF. This results in assessment criteria that range between 121.8 mg/kg and 372.7 mg/kg (full details within Table 4.7).

4.4.16 For the purpose of this assessment, the lowest SSAC has been selected, as this is considered to represent the most conservative assessment of on-site bioaccessability. The US95 value of 21.12 mg/kg does not exceed the screening criteria of 121.8 mg/kg.


(mg/kg) SSAC

(mg/kg) Arsenic Ingestion, inhalation

or dermal contact with contaminated soil and wind blown dust. Consumption of edible plants.

Property Code 1A. 29.32 45.2

4.4.17 The SNIFFER-derived SSAC of 45.2 mg/kg is based upon a residential with plant

uptake exposure scenario, and a BAF of 25 %. A total of 23 No. soil samples from the Glamis Estate were analysed for bioaccessible arsenic, and results ranged between 8.17 % and 25 % BAF. This results in assessment criteria that range between 45.2 mg/kg and 62.7 mg/kg (full details within Table 4.7).





(mg/kg) SSAC

(mg/kg) Nickel (1 outlier removed)




uptake exposure scenario, and a BAF of 13.3 %. A total of 23 No. soil samples from the Glamis Estate were analysed for bioaccessible nickel, and results ranged between 3.71 % and 13.3 % BAF. This results in assessment criteria that range between 90.2 mg/kg and 99.7 mg/kg (full details within Table 4.10).


4.4.21 A single nickel outlier was identified within Data Set 1 (1,478.48 mg/kg, BH149 at 0.1 m BGL; Property Code 1D). The bioaccessible fraction of nickel this sample was determined to be 6.76 % (nickel PBET data is summarised within Table 4.10), and this resulted in SSAC values of 96.5 mg/kg (residential with plant uptake) and 1,501 mg/kg (residential without plant uptake).


(mg/kg) SSAC

(mg/kg) Cadmium 4.35 1.68

Copper 701.82 227.5

Zinc

Consumption of edible plants.

Property Code 1A.

956.13 231.3 4.4.22 The SNIFFER-derived assessment criteria for copper, cadmium and zinc (for a

residential with plant uptake scenario) are exceeded by the US95 values.

4.4.23 For the residential with plant uptake exposure scenario, for these three determinands, the ingestion of soil and indoor dust contributes no more than 5 % of total exposure from soil. Therefore, the incorporation of the (oral) bioaccessability data has not significantly changed the screening criteria derived for a residential with plant uptake scenario.

4.4.24 The US95 values for cadmium, copper and zinc do not exceed the generic assessment criteria for a residential without plant uptake scenario (refer to Table 3.29).



Table 4.16: Re-assessment of Identified Pollution Linkages against SNIFFER-derived SSAC (incorporating PBET data) Contaminant Pathway(s) Receptor(s) Conc.

(mg/kg) SSAC

(mg/kg) Cadmium Consumption of

edible plants. Property Code 2B. 6.31 1.68

Copper Consumption of edible plants.

Property Codes 2B 2C 2E.

276 326 508

227.5 227.5 227.5

Zinc Consumption of edible plants.


4.4.25 The SNIFFER-derived assessment criteria for copper, cadmium and zinc (for a

residential with plant uptake scenario) are exceeded by the soil concentrations.

4.4.26 For the residential with plant uptake exposure scenario, for these three determinands, the ingestion of soil and indoor dust contributes no more than 5 % of total exposure from soil. Therefore, the incorporation of the (oral) bioaccessability data has not significantly changed the screening criteria derived for a residential with plant uptake scenario.

4.4.27 The soil concentrations for cadmium, copper and zinc do not exceed the generic assessment criteria for a residential without plant uptake scenario (refer to Table 3.31).

Table 4.17: Re-assessment of Identified Pollution Linkages against SNIFFER-derived SSAC (incorporating PBET data) Contaminant Pathway(s) Receptor(s) Conc.

(mg/kg) SSAC

(mg/kg) Nickel Consumption of

edible plants. Property Code 2A. 55.7 90.2


uptake exposure scenario, and a BAF of 13.3 %. A total of 23 No. soil samples from the Glamis Estate were analysed for bioaccessible nickel, and results ranged between 3.71 % and 13.3 % BAF. This results in assessment criteria that range between 90.2 mg/kg and 99.7 mg/kg (full details within Table 4.10).

4.4.29 For the purpose of this assessment, the lowest SSAC has been selected, as this is considered to represent the most conservative assessment of on-site bioaccessability. The nickel concentration of 55.7 mg/kg does not exceed the screening criteria of 90.2 mg/kg.



Incorporation of PBET data into DQRA; Lead

4.4.30 The residential with plant uptake SGV for lead (450 mg/kg) is based upon the model derived by SEGH (Society for Environmental Geochemistry and Health 1993, within DEFRA R&D Publication SGV 10). The SGV depends upon;

• The target blood lead concentration and the degree of compliance within the overall population;

• The blood lead attributable to sources other than on site soil exposure; and

• The slope of empirical relationship between blood lead concentration and soil lead concentration (δ value).

4.4.31 SEGH considered that the reasonable range of δ values was between 2 and 5 µg/dL per 1,000 µg/g, but that this value should be adjusted in light of particular knowledge about a given situation (‘site specific considerations’).

4.4.32 DEFRA have selected a default value for δ of 5 µg/dL per 1,000 µg/g for the derivation of the published SGV (5 is the most conservative value within the ‘reasonable range’ of δ values reported by SEGH).

4.4.33 In deriving a Tier 2 site specific assessment criteria for lead, it is considered that a low δ value is suitable for use at the Glamis Estate. In accordance with the advice set out in paragraph 3.9 of the DEFRA R&D Publication SGV 10, the δ value is only being changed following detailed assessment of on-site lead bioaccessability.

4.4.34 A total of 23 No. soil samples from the Glamis Estate were analysed for bioaccessible lead, and results ranged from between 1.4 % and 5.31 % BAF. This is considered sufficient data upon which to justify lowering the δ value for calculating the Tier 2 SSAC for lead.

Table 4.18: Re-assessment of Identified Pollution Linkage against Tier 2 Lead SSAC (incorporating amended δ value) Contaminant Pathway Receptor Lead Ingestion, inhalation or

dermal contact with contaminated soil and wind blown dust. Consumption of edible plants.

Property Code 1A.

Selected δ Value

Calculated Tier 2 SSAC (mg/kg)

Log(SSAC) Data Set 1 US95

(log) 4 577 2.761 3 770 2.886 2 1,155 3.063

2.837



4.4.35 SSAC have been calculated using δ values of 2, 3 and 4 (Table 4.18). Once the δ

value is reduced to 3 (still within the ‘reasonable range of δ values’ as reported by SEGH), the US95 value for lead (Data Set 1) does not exceed the derived Tier 2 assessment criteria. Due to the low on-site lead bioaccessability (ranging from 1.4 % to 5.31 % BAF), the selection of a δ value of ‘3’ is considered justifiable.

4.5 Identification of Pollutant Linkages not to be Considered Further

4.5.1 Following completion of the Tier 2 (detailed) quantitative risk assessment, Table 4.19 lists the pollutant linkages, with justifications, that are now considered insignificant within the context of this risk assessment.

Table 4.19: Pollutant Linkages not to be Considered Further Contaminant(s) Pathway(s) Receptor(s) Justification Aliphatic EC8-10 Ingestion,

inhalation or dermal contact with contaminated soils, shallow groundwater and wind blown dust. Consumption of edible plants.

Property Code 1C.

The aliphatic EC8-10 concentration within BH161 (10.33 mg/kg) does not exceed the Tier 2 SSAC criteria of 1,320 mg/kg.


Property Code 3A.

The US95 value for Data Set 3 does not exceed the Tier 2 assessment criteria. A single outlier (8.44 mg/kg) was identified, but this falls below the Tier 2 assessment criteria (10.7 mg/kg).

Benzo(a)pyrene


Property Code 4B.

The benzo(a)pyrene concentration reported from BH170 (12.74 mg/kg) does not exceed the Tier 2 screening criteria of 13.6 mg/kg.

Lead Ingestion, inhalation or dermal contact with contaminated soil and wind blown dust. Consumption of edible plants.

Property Code 1A.

The US95(log) value of 2.837 does not exceed the selected Tier 2 Log(SSAC) of 2.886.



Table 4.19: Pollutant Linkages not to be Considered Further Contaminant(s) Pathway(s) Receptor(s) Justification


Property Code 4A.

The US95 value of 21.12 mg/kg does not exceed the selected Tier 2 assessment criteria of 121.8 mg/kg.

Arsenic


Property Code 1A.

The US95 value of 29.32 mg/kg does not exceed the selected Tier 2 assessment criteria of 45.2 mg/kg.

Nickel Consumption of edible plants.

Property Code 2A.

The nickel concentration of 55.7 mg/kg does not exceed the selected Tier 2 assessment criteria of 90.2 mg/kg.

4.6 Remaining Pollutant Linkages

4.6.1 Following completion of the Tier 2 detailed quantitative risk assessment, Table 4.20 details the remaining pollutant linkages identified as being theoretically of concern at the site. A conceptual cross section illustrating these linkages is presented as Figure 5.

Table 4.20: Remaining Pollutant Linkages Contaminant(s) Pathway(s) Receptor(s) Action Benzo(a)pyrene Ingestion,

inhalation or dermal contact with contaminated soils, shallow groundwater and wind blown dust. Consumption of edible plants.

Property Codes 1B, 2D and 2E.

To be confirmed.

Property Code 1A. Cadmium Consumption of edible plants. Property Code 2B.

To be confirmed.

Property Code 1A. Copper Consumption of edible plants. Property Codes 2B,

2C and 2E.

To be confirmed.

Nickel Consumption of edible plants.

Property Code 1D. To be confirmed.



Table 4.20: Remaining Pollutant Linkages Contaminant(s) Pathway(s) Receptor(s) Action

Property Code 1A. Zinc Consumption of edible plants. Property Code 2A.

To be confirmed.




Foundation Assessment.


REFERENCES

REFERENCES

References Model Procedures for the Management of Contaminated Land, Contaminated Land Report 11, Environment Agency, September 2004; Environment Agency Technical Report P45 “Polycyclic Aromatic Hydrocarbons (PAH): Priorities for Environmental Quality Standard Development; Code of Practice for Site Investigations BS5930: 1999; Investigation of Potentially Contaminated Sites – Code of Practise BS10175: 2001; BRE Special Digest 1, Concrete in Aggressive Ground, 2001; ISO 9001 (BSI Certificate No. Q06143); ISO 14001 (BSI Certificate No. A12283); Protecting development from methane, CIRIA Report 149, 1995; Historic Maps of Tower Hamlets. Bethnal Green and Stepney (accessed 13th July 2006) www.mernick.co.uk/elhs/mapgallery.htm; Development of fraction specific reference doses (RfDs) and reference concentrations (RfCs) for total petroleum hydrocarbons (TPHs). TPHCWG Volume 4. March 1997; RISC Workbench v. 4.03 October 2003; USEPA online toxicity and chemical parameters database http://risk.lsd.ornl.gov/cgi-bin/tox/TOX_9801; Re-evaluation of human-toxicological maximum permissible risk levels. RIVM Report 711701025. March 2001; Massachusetts Department of Environment Protection, Policy #WSC-02-411. October 31, 2002; Soil Guideline Values For Lead Contamination, DEFRA R&D Publication SGV 10, 2002; EA R&D Publication CLR 9. Contaminants in soil: collation of toxicological data and intake values for humans. October 2001; LQM Report No LQ01. Method for deriving site-specific human health assessment criteria for contaminants in soil. April 2003; EA Draft Technical Report P5-079/TR1. Review of the fate and transport of selected contaminants in the soil environment. September 2003; Travis, C. and A.Arms (1988). Bioconcentration of organics in beef, milk and vegetation. Environmental Science & Technology 22: 271-274; Malcolm HM & Dobson S (1994) The calculation of an environmental assessment level (EAL) for atmospheric PAHs using relative potencies. London, Department of the Environment, 34 pp (Report No. DoE/HMIP/RR/94/041);


REFERENCES

McClure P & Schoeny R (1995) Evaluation of a component-based relative potency approach to cancer risk assessment for exposure to PAH. In: Fifteenth international symposium on polycyclic aromatic compounds: Chemistry, biology and environmental impact, Belgirate, Italy, 19-22 September 1995. Ispra, Joint Research Centre European Commission, p 161; Nisbet ICT & LaGoy PK (1992) Toxic equivalency factors (TEFs) for polycyclic aromatic hydrocarbons (PAHs). Regul Toxicol Pharmacol, 16: 290-300; Swords. C, Harker. P & Hallas. A, Determination of Contaminated Land – A Science or an Art? Royal Haskoning; Grubb, F. E. et al, Extension of Samples Sizes and Percentage Points for Significance Tests of Outlying Observation. Technometrics, Vol 14, No. 4, November 1972; CLEA UK Handbook (Draft). EA October 2005. ISBN 1844325016; CLEA Briefing Note 1: Version 1.1 (March 2005); CLEA Briefing Note 2: Version 1.1 (July 2004); CLEA Briefing Note 3: Version 1.1 (July 2004); and CLEA Briefing Note 4: Version 1.0 (November 2005).


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