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Superfund Records CenterSITE:BREAK: BOTHER:

Five-Year Review ReportNaval Air StationBrunswick, Maine

U.S. NAVAL AIR STATIONBRUNSWICK, MAINE

Prepared by

Department of the NavyNorthern Division

Naval Facilities Engineering Command10 Industrial Highway

Mail Stop No. 82Lester, Pennsylvania 19113-2090

March 2000Revision: FINAL

UNITED STATES ENVIRONMENTAL PROTECTION AGENCYREGION 1

I 1 CONGRESS STREET, SUITE 1100BOSTON, MASSACHUSETTS 02114-2023

March 3 1,2000

Mr. Art Coccoli ([email protected])Northern Division, Naval Facilities Engineering CommandCode 1822/AC10 Industrial Highway, Mailstop 82Lester, PA 191 13-2090

Re: Five- Year Review Report, Naval Air Station, Brunswick, Maine

Dear Mr. Coccolia:

Thank you for the opportunity to review Five-Year Review Report for Naval Air Station,Brunswick, Maine dated March 2000. Upon review, the EPA concurs with the finding that allremedies as implemented, or in the process of being implemented, by the Navy are protective ofhuman health and the environment.

The Report includes reviews for sites 1, 2, 3, 4, 9, 11, 13 and the Eastern Plume and is consistentwith EPA's Five Year Review Guidance, Office of Solid Waste and Emergency Response(OSWER) Directive 9355. 7-02 (May 1991 and Supplemental Five-Year Review Guidance,(OSWER) Directive 9355-02A (August 1994). The selection of a Type I A review is alsoconsistent with the above guidance. For those sites which that are still in the investigative orremedy selection phases, EPA is pleased that the Navy has reiterated it's commitment tocontinuing the CERCLA cleanup process to a successful conclusion. Access to these sites isrestricted to minimize potential threats to human health.

EPA fully concurs with the findings and recommendations for further action in the review. Oncethese recommendations are carried out, they will ensure full protectiveness of the remediesimplemented. Key recommended actions EPA specifically endorses are:

• Adding groundwater institutional controls to the OU5 ROD and documentingthem in the NAS Brunswick Base Instructions for OU1, OU5, OU6 and OU7.

• Verification of the southern boundary of the eastern plume (OU5).

Though not explicitly required for remedy protectiveness, we also support the Navy'srecommendations to optimize the eastern plume remedy as they should reduce the time requiredto meet the ROD objectives.

As indicated in EPA's letter of April 2, 1999, this five-year review was triggered by the Sites 1

Toll Free • 1-888-372-7341Internet Address (URL) • http://www.epa.gov/region1

Recycled/Recyclable • Printed with Vegetable Oil Based Inks on Recycled Paper (Minimum 30% Postconsumer)

and 3 (OU1) Remedial Action start of December 6, 1994 and was therefore due December 6,1999. Consistent with Section 121 (c) of CERCLA and (OSWER) Directive 9355-02A, the nextstatutory required five-year review must be finalized prior to December 6, 2004.

Sincerely,

Patricia L. Meaney, DirectorOffice of Site Remediation and Restoration

cc. Mike Barry/EPA ([email protected])Al Easterday/EA ([email protected])Emil Klawitter/NORTHDIV ([email protected])Carolyn LePage/LePage Environmental ([email protected])Betsy Mason/EPA ([email protected])Mary Sanderson/EPA ([email protected])Claudia Sait/ME DEP ([email protected])Tony Williams/NASB ([email protected])

Revision: FINALContents

Northern Division, Naval Facilities Engineering Command March 2000

CONTENTS

Page

LIST OF FIGURESLIST OF TABLES

1. INTRODUCTION 1-1

1.1 Organization of Report 1-11.2 Next Five-Year Review 1-2

2. SITE 1 ORION STREET LANDFILL - NORTH AND SITE 3 HAZARDOUSWASTE BURIAL AREA 2-1

2.1 Site Description 2-1

2.1.1 Significant Events 2-1

2.2 Discussion of Remedial Objectives 2-22.3 Areas of Non-Compliance 2-22.4 Recommendations 2-32.5 Statement of Protectiveness 2-4

3. SITE 2 ORION STREET LANDFILL - SOUTH 3-1




4. SITE 9 NEPTUNE DRIVE DISPOSAL AREA 4-1



4.2 Discussion of Remedial Objectives 4-14.3 Areas of Non-Compliance 4-2

Naval Air Station, Brunswick, Maine Five-Year Review Report

Revision: FINALContents (Continued)


Page

4.3.1 Natural Attenuation 4-34.3.2 Long-Term Monitoring 4-34.3.3 Institutional Controls 4-4

4.4 Recommendations 4-44.5 Statement of Protectiveness 4-4

5. EASTERN PLUME OPERABLE UNIT 5-1


5.1.1 Soils 5-15.1.2 Ground-Water Operable Unit (Eastern Plume) 5-25.1.3 Significant Events 5-2


6. REFERENCES 6-1

APPENDIX A: RESPONSE TO COMMENTS ON THE DRAFT FIVE-YEAR REVIEWREPORT RECEIVED FROM THE U.S. ENVIRONMENTAL PROTECTIONAGENCY AND THE MAINE DEPARTMENT OF ENVIRONMENTALPROTECTION


Northern Division, Naval Facilities Engineering Command

Revision: FINALList of Figures/List of Tables

March 2000

LIST OF FIGURES

Number Title

1 Site location map, Sites 1 and 3 and Eastern Plume, Naval Air Station,Brunswick, Maine.

2 Long-term monitoring network, Sites 1 and 3 and Eastern Plume, Naval AirStation, Brunswick, Maine.

3 Site location map, Site 2, Naval Air Station, Brunswick, Maine.

4 Site 2 site plan, Naval Air Station, Brunswick, Maine.

5 Site location map, Site 9 (Neptune Drive Disposal Site), Naval Air Station,Brunswick, Maine.

6 Site plan, Site 9 (Neptune Drive Disposal Site), Naval Air Station, Brunswick,Maine.

7 Site location map, Sites 1 and 3 and Eastern Plume, Naval Air Station,Brunswick, Maine.

8 Site plan for Sites 1 and 3 and Eastern Plume, Naval Air Station, Brunswick,Maine.

9 Long-term monitoring network, Sites 1 and 3 and Eastern Plume, Naval AirStation, Brunswick, Maine.

LIST OF TABLES

Number Title

1 Active sites not included in first five-year review.

2 Inactive closed sites not included in five-year review.


Revision: FINALPage 1-1


1. INTRODUCTION

A statutory five-year review has been conducted by the U.S. Department of the Navy (Navy)pursuant to Section 121(c) of the Comprehensive Environmental Response, Compensation, andLiability Act; Section 300.400(f)(4)(ii) of the National Oil and Hazardous SubstancesContingency Plan; Executive Order 12580; and U.S. Environmental Protection Agency(U.S. EPA) Office of Solid Waste and Emergency Response Directive 9355.7-02 (23 May 1991),Office of Solid Waste and Emergency Response Directive 9355.7-02A (26 July 1994), andOffice of Solid Waste and Emergency Response Directive 9355.7-03A (21 December 1995).The purpose of this five-year review is to ensure that the remedial actions selected for the NavalAir Station (NAS) Brunswick National Priorities List sites remain protective of human healthand the environment, and are functioning as designed.

This review is a Type la review, which is applicable at sites where response is ongoing.According to U.S. EPA guidance, a Type la review consists of a document review (includingRecord of Decision [ROD] declarations and monitoring information) and preparation of a reportthat provides a discussion of remedial objectives, areas of non-compliance with those objectives,recommendations for improvements, and a statement of whether the remedy/remedies remainprotective. This report will become part of the Site File (Administrative Record).

The Federal Facilities Agreement for NAS Brunswick, Maine, dated 19 October 1990, alsorequires a five-year review. The trigger date for this statutory review was determined by theremedial action on site construction of the first operable unit giving rise to a five-year review.For NAS Brunswick, the trigger site was the remedial action onsite construction date of the Sites1 and 3 Landfill. The guidance further states that sites subject to five-year reviews with multipleremedies or operable units should conduct a five-year review for the entire site and all operableunits.

1.1 ORGANIZATION OF REPORT

This document presents the first five-year review of NAS Brunswick. The following operableunits have ongoing remedial actions as of the date of the five-year review documented in thisreport:

• Chapter 2—Site 1 Orion Street Landfill - North and Site 3 Hazardous Waste BurialArea.

• Chapter 3—Site 2 Orion Street Landfill - South.

• Chapter 4—Site 9 Neptune Drive Disposal Area.

• Chapter 5—Eastern Plume Operable Unit (Site 4 - Acid/Caustic Pit, Site 11 - FireTraining Area, and Site 13 - Defense Reuse and Marketing Office Area).

• Chapter 6—References.




• Appendix A—Response to comments on the draft Five-Year Review Report receivedfrom the U.S. Environmental Protection Agency and the Maine Department ofEnvironmental Protection.

Table 1 provides a summary of the status of the remaining active sites in the NAS BrunswickInstallation Restoration Program. These sites will be addressed in the next five-year review.The next five-year review shall be completed by 6 December 2004.

Table 1 is a summary of active sites not included in the first five-year review. Table 2 is asummary of inactive sites that will not be addressed in the five-year reviews.

1.2 NEXT FIVE-YEAR REVIEW

The next five-year review shall be completed by 6 December 2004.




2. SITE 1 ORION STREET LANDFILL - NORTH AND SITE 3 HAZARDOUSWASTE BURIAL AREA

2.1 SITE DESCRIPTION

Sites 1 and 3 are closed hazardous waste landfills within the same operable unit and are locatedwithin a restricted portion of NAS Brunswick (Figures 1 and 2). Reportedly, these landfillsreceived a variety of waste material, such as garbage, food, oils, solvents, pesticides, petroleumproducts, paint, aircraft and automobile parts, and various chemicals. Field activities did notindicate a clear boundary between these sites although they were regarded as separate disposalareas. Compounds/analytes that were detected above background concentrations during previousinvestigations include: polycyclic aromatic hydrocarbons and pesticides in soil; volatile organiccompounds (VOCs) and inorganics in ground water; VOCs, inorganics, and semivolatile organiccompounds (SVOCs) in leachate; VOCs, SVOCs, polycyclic aromatic hydrocarbons, andinorganics in stream sediment; and inorganics in surface water.

2.1.1 Significant Events

• 1992 ROD was signed (U.S. Department of the Navy 1992a).

• 1994 Remedial Action started.

• 1995 Long-Term Monitoring initiated.

• 1995 Remedial Action Closure Report.

• 1998 Cessation of Pumping from Landfill Extraction Wells—Operation of the landfillextraction wells had been intermittent since the water level fell below the extraction wellscreen.

• 1999 Slurry Wall Demonstration Completed—U.S. Department of Energy, FederalEnergy Technology Center through Science and Engineering Associates, Inc. requestedthe landfill cap slurry wall be used to demonstrate a vadose zone barrier monitoringsystem. Only a portion of the slurry wall was used for the demonstration.

• 1999 Completion of Erosion Repairs—The 1998 visual inspection of the landfill capnoted erosion of the protective cap, although a small portion of the underlying landfillliner was exposed but undamaged. Corrective measures to correct the landfill cap erosionwere completed in 1999.

• 1999 NAS Brunswick Restriction on Excavation Activities Instruction (NASBINST5090.1 A).

• 2000 Final Long-Term Monitoring Plan (EA 2000a).




2.2 DISCUSSION OF REMEDIAL OBJECTIVES

In the 1992 ROD, the remedial objectives were set as follows:

• Reduce the generation and mitigation of contaminated ground water.

• Reduce the potential risk associated with ingestion of contaminated ground water.

• Minimize future negative impacts to Mere Brook and the sediment in the leachate seepsresulting from the discharge of contaminated ground water and leachate.

• Reduce the concentrations of metals (iron and zinc) discharging to Mere Brook.

To accomplish these objectives, the following components were implemented:

• A slurry wall was placed around the landfill (with the exception of the WeaponsCompound Area) to divert clean ground-water flow around the site, preventing contactwith the waste material. The slurry wall is sealed into the underlying silty clay and,therefore, minimal volumes of water flow beneath or through the wall.

• A low permeability cap was placed over the landfill area and slurry wall to reduce theamount of rainfall infiltration, thereby reducing leachate production.

• A ground-water extraction system was installed to remove contaminated ground watertrapped beneath the cap and within the slurry wall system. Capturing this contaminatedwater prevented it from discharging to Mere Brook. These extraction wells facilitated thecollection of the ground water remaining within the limits of the slurry wall after theconstruction of the landfill cap and reduced the time required to lower ground-waterlevels below the waste.

• This alternative requires the implementation of institutional controls and land userestrictions to prevent future invasive reuse of the landfills or underlying ground water.

2.3 AREAS OF NON-COMPLIANCE

Any substantial aspect of the remedial action that fails to conform to remedial objectives wouldbe considered an area of non-compliance. Based on the information evaluated as part of theType la five-year review, all areas currently comply with the ROD remedial objectives.

A comparison of water elevation data collected prior to emplacement of the slurry wall in March1995 and subsequent long-term monitoring gauging data indicates that water elevations havedecreased significantly within the landfill. Water surface elevations within the landfill havestabilized and have not shown significant rebound after cessation of pumping the landfillextraction wells in November 1997 (EA 2000b).




Monitoring wells located outside of the Sites 1 and 3 landfill have detected inorganic elements(arsenic, manganese, and chromium) in the ground water exceeding the Maximum ContaminantLevel (MCL) and/or the Maximum Exposure Guideline (MEG). However, most of the detectedconcentrations of these inorganics are exhibiting a general decreasing trend.

VOCs have been detected at increasing concentrations in the ground water at monitoring wellswithin the landfill. No VOCs have been detected at concentrations above MCLs or MEGsdowngradient and outside the landfill, except at SEEP-04.

Potentiometric heads in the shallow and deep monitoring wells downgradient of the landfill inthe vicinity of the Weapons Area Compound and Mere Brook show a trough in water elevations.The interpreted 21 -ft contour potentiometric surface lines in the deep interval downgradient ofthe landfill are deflected towards the southern end of the Sites 1 and 3 landfill. This is attributedto the presence of the low permeability cap and previous ground-water extraction activity, inaddition to the slurry wall at the Sites 1 and 3 landfill have acted to limit infiltration and ground-water movement in the capped area. The presence of these remedial structures has resulted in anarea of lower head downgradient of Sites 1 and 3 (EA 2000b).

Ground water is below the known bottom elevation of waste material at monitored locationswithin the Sites 1 and 3 landfill, with the exception of MW-234R (EA 2000b). At this location,less than 1.0 ft of waste material was saturated in 1998. Based on the comparison to waste andwater elevations, the landfill cap and slurry wall are successfully minimizing the saturation ofwaste within the Sites 1 and 3 landfill (EA 2000b).

Iron and zinc have been monitored in seep samples as part of the Long-Term MonitoringProgram. The ROD reported maximums (maximum detected concentration) of 2,510,000 Jig/kgand 2,770 |ig/kg for iron and zinc, respectively. Since the monitoring began, iron has onlyexceeded these maximums in Monitoring Events 8, 10, and 11. Exceedance of the maximum forzinc has not been reported in any monitoring event report to date.

The operable unit remains within the restricted area of the base and, as such, the institutionalcontrols remain effective. However, ground-water institutional controls will be added toOperating Instruction NASBINST 5090.1 A, "Restriction on Excavation Activities" in the nextannual revision.

2.4 RECOMMENDATIONS

No further response actions are required at this time.

An institutional control to restrict ground-water use will be added in the next revision ofOperating Instruction NASBINST 5090.1 A, "Restriction on Excavation Activities." Thenext revision of NASBINST 5090.1 A is scheduled for September 2000. Ground-waterinstitutional controls are not documented in the ROD, and need to be added to the ROD.


Revision FINALPage 2-4


• Ongoing operation and maintenance activities should continue and be summarized inannual reports. Annual reports and event monitoring reports will continue to besubmitted to U.S. EPA and Maine Department of Environmental Protection (MEDEP).

2.5 STATEMENT OF PROTECTIVENESS

The purpose of the five-year review is to ensure that the selected remedy remains protective ofhuman health and the environment and is functioning as designed. The source control remedyselected for Sites 1 and 3 Operable Unit has been successfully implemented, and remainsprotective of human health and the environment as long as the area maintains restricted access.If the area were to become freely accessible, institutional controls would have to be imposed onthe site. Long-term operation and maintenance activities are ongoing. Operational activities alsoinclude ground-water, surface water, sediment, and landfill gas sampling.




3. SITE 2 ORION STREET LANDFILL - SOUTH


Site 2 Orion Street Landfill is a closed hazardous waste landfill located south and across MereBrook from Sites 1 and 3 Landfill within the restricted area in the central portion of NASBrunswick (Figures 3 and 4). Site 2 was used as the primary landfill for NAS Brunswick from1945 to 1955, although actual operation may have been less than 10 years because NASBrunswick was closed from 1946 to 1951. The base was occupied by non-military tenants from1946 to 1951, and it is not known if the landfill was utilized during that period.

The landfill occupies approximately 2 acres of soil covered land that currently supports a densestand of conifers. Prior to remedial actions, miscellaneous debris items such as drums,containers, office furniture, and domestic wastes were exposed along the eastern side of thelandfill. Other wastes reportedly disposed at the landfill were solvents, paint, oil, toluene,methyl ethyl ketone, and medical supplies. Solid wastes were incinerated (openly burned) at thesite and a substantial component of the landfill material could be ash and partially burnedmaterials. The Site 2 Landfill was closed by capping the area with soil and planting pine trees ontop of the cap.

Based on the available sample results, environmental contamination at Site 2 was evident insurface waters, stream sediments, ground-water seeps, and surface soils associated with seeplocations. During the Remedial Investigation in 1990 (E.G. Jordan 1990), lead was detected inthe ground-water samples at concentrations ranging from 80 to 180 |lg/L that exceeded theFederal MCL of 5 |lg/L. The lead detection in site ground water is consistent with historic use ofthe site. Ash would have been produced by incineration (open burning) at the landfill, and ashtypically contains inorganic constituents that would not be destroyed by burning. The shallowground water in this area is not used for a potable supply.

No unacceptable risk to human health was identified under the future residential use scenario.A quantitative exposure assessment for ingestion of ground water was not developed for Site 2since there is no exposure along this pathway. Future use of ground water is not consideredlikely because this property is under control of the Navy, and the shallow aquifer between Site 2and Mere Brook is not likely to be used as a drinking water source (U.S. Department of the Navy1998a).


• 1998 ROD was signed (U.S. Department of the Navy 1998a).• 1999 Remedial Action - Debris removal and bank stabilization completed.• 1999 NAS Brunswick Operating Instruction NASBINST 5090.1 A, "Restrictions on

Excavation Activities."• 2000 Final Long-Term Monitoring Plan (EA 2000c).


Revision1 FINALPage 3-2



In accordance with the 1998 ROD, remedial objectives were not developed for this site becauseno risk to human health or the ecological receptors was indicated by the baseline risk assessment.The selected remedy for Site 2 was Minimal Action. Implementation of the Minimal ActionAlternative includes the following components:

• Implementation of institutional controls to include maintenance of the existing fence,installation of warning signs, and land use restrictions. Land use restrictions areincorporated in Operating Instruction NASBINST 5090.1 A, "Restriction on ExcavationActivities."

• Removal of surface debris that was visible in the depression immediately south and eastof the landfill.

• Installation of an additional ground-water monitoring well.

• Implementation of an environmental monitoring program that includes collection andanalysis of ground-water, seeps, surface water, and sediment samples.

• Five-year site reviews.

• Modifications to the selected remedy, if necessary.


Although no remedial objectives were established for Site 2, the ROD indicated a long-termmonitoring plan would be implemented to confirm the protectiveness of the selected remedy.Data collected during the monitoring program will be evaluated as part of the five-year reviewcycle.

Long-term monitoring has not commenced since the plan is currently being implemented.Monitoring is expected to start in 2000.

The operable unit remains within the restricted area of the base and, as such, the institutionalcontrols remain effective. However, institutional controls for restriction of use and contact withground water will be included in the next revision of Operating Instruction NASBINST 5090.1 A,"Restriction on Excavation Activities." The next revision of NASBINST 5090.1 A is scheduledfor September 2000.

3.4 RECOMMENDATIONS

• No additional response actions are required at this time.

• Implement the Long-Term Monitoring Plan and commence monitoring.




• The sampling event reports and annual reports will be submitted to U.S. EPA andMEDEP.

• Based on the annual reports, the Long-Term Monitoring Plan will be refined as needed.

• Amend the Operating Instruction NASBINST 5090.1A "Restriction on ExcavationActivities" to include a restriction of use and physical contact with the ground water.


The purpose of the five-year review is to ensure that the selected remedy remains protective ofhuman health and the environment and is functioning as designed. Environmental monitoringhas not been performed since 1990. A determination for success of Minimal Actions cannot bemade at this time because the activities necessary for implementation of the Minimal ActionAlternative have not been completed. However, restricted access to the site and restrictions onexcavation activities have reduced the potential for human exposure, thereby providing partialprotection of human health. Implementation of the recommended sampling actions will providethe data necessary to determine if the environment is protected. Long-term monitoring will beongoing.




4. SITE 9 NEPTUNE DRIVE DISPOSAL AREA


The Neptune Drive Disposal Site (Site 9) was the former location of an incinerator and ashlandfill/dump area, located north of Neptune Drive (Figures 5 and 6). Hazardous materialdisposal reportedly occurred south of Neptune Drive at unspecified locations. The site has theseareas of concern:

• Vinyl chloride was detected in ground-water samples collected as part of the Long-TermMonitoring Program at several monitoring wells. A septic system east of Building 201was thought to be a possible source of VOCs in ground water; however, results from anadditional source investigation indicate that this area is not a likely source for the vinylchloride contamination in ground water.

• An incinerator was located at what is currently the northeast corner of Building220, and an ash landfill/dump area is located in the current area of Buildings 218and 219. There are no exact data detailing the location or types of wastes handledor disposed at these locations, although wastes may have included solvents thatwere burned on the ground, paint sludge, and metal shop wastes. Inorganics andsemivolatile compounds have been detected in soils and the ground water at thisarea.

• The unnamed stream and impoundment ponds located near Building 201 receive waterfrom the Site 9 area and the central portion of NAS Brunswick. Surface waterimpoundment ponds were constructed in 1997 to capture stormwater runoff from airfieldpavements, parking lots, and roads in the developed central portion of the base.Construction of the surface water impoundments has flooded the former southernunnamed stream and partially flooded the northern unnamed stream.


• 1994 Interim Record of Decision (U.S. Department of the Navy 1994).• 1995 Long-Term Monitoring initiated.• 1999 Final Record of Decision was signed (EA 1999a).• 1999 Final Long-Term Monitoring Plan (EA 1999b).• 1999 NAS Brunswick Restriction on Excavation Activities Instruction (NASBENST

5090.1 A).


The objectives developed in the Final Site 9 ROD are as follows:

• To reduce contaminant concentrations in Site 9 ground water to below Federal MCL andState MEG target cleanup levels.




• To prevent human exposure and ecological exposure (i.e., ingestion, dermal contact) toSite 9 ground water.

• To prevent human exposure and ecological exposure (i.e., ingestion, dermal contact) tothe contents of the inactive landfill at Site 9.

• To prevent any migration of the Site 9 ground-water plume offsite or of contaminantsfrom the inactive landfill to ground water and/or surface water.

To accomplish these objectives within a 20-year time period, the following components wereimplemented:

• Natural Attenuation—This remedy will be used to allow degradation of contaminants inthe ground water at the site to concentrations sustained at or below Federal MCLs andState MEGs. Ground-water monitoring results showing contaminant concentrations willbe compared to these remediation goals, and the selected remedy will be continued untilsite goals are achieved.

• Long-Term Monitoring—Long-term monitoring will be implemented to:

— Assess variations in the concentrations of contaminants in ground water, leachatesurface water, and sediment to determine the effectiveness of natural attenuation.

— Assess whether ground water downgradient of the ash landfill is impacted byinorganics from the site.

— Assess whether contamination is migrating offsite.

— Assess variations in ground-water flow patterns.

— Monitor structural integrity of the ground-water monitoring wells.

• Institutional Controls—Institutional controls will be used to prevent use of and contactwith impacted ground water, and to prevent the disturbance of or contact with thecontents of the ash landfill without prior written approval from the U.S. EPA andMEDEP. These controls will primarily consist of ground-water and land use restrictions.

• Five-Year Review—Data collected from the Long-Term Monitoring Program will bereviewed and recommendations for modifications will be made as part of annual reportsand in the five-year reviews.






March 2000

4.3.1 Natural Attenuation

Vinyl chloride was reported at concentrations greater than the corresponding Federal MCL orState MEG in samples taken from several monitoring wells. Assessed indicators of naturalattenuation include vinyl chloride trends in the Long-Term Monitoring Program and the ratio ofvinyl chloride to 1,2-dichloroethene with time.

The 1998 Annual Report (EA 1999c) illustrates total VOC and vinyl chloride trends for long-term monitoring data collected between 1995 and 1998 for the 7 monitoring wells that havereported vinyl chloride concentrations in this time period. Regression analyses of vinyl chloridedata are presented in the 1998 Annual Report for 1995 through 1998, and also presentedseparately for 1998 data to illustrate changing trends with time. The table below summarizes thetrends as indicated by the least-mean square regressions:

Vinyl Chloride TrendsWell

MW-NASB-069MW-NASB-071MW-NASB-072MW-NASB-074MW-NASB-075MW-NASB-076MW-NASB-080

1995-1998 1998Increasing IncreasingSteady at non-detection Steady at non-detectionSteady DecreasingDecreasing Steady at non-detectionDecreasing Steady at non-detectionIncreasing IncreasingSteady Increasing

Assessment of the vinyl chloride/dichloroethene ratio provides a measure of whetherdechlorination is occurring in ground water by noting the changes in concentrations of parent-daughter compounds. A decreasing concentration of total dichloroethene and an increasingconcentration of vinyl chloride (a breakdown product of dichlorethene) indicates that thedechlorination process is occurring. The table below summarizes trends in the vinyl chlorideto total dichloroethene ratios at Site 9:

Vinyl Chloride to Dichloroethene RatioWell 1995-1998 Trend

MW-NASB-069MW-NASB-072MW-NASB-074MW-NASB-075MW-NASB-076MW-NASB-080

StableIncreasingStableIncreasingIncreasingIncreasing

The trends indicate the dechlorination process is occurring and therefore demonstrating thatnatural attenuation is in progress.

4.3.2 Long-Term Monitoring

In 1994, a Long-Term Monitoring Plan was established for Site 9 (ABB-ES 1994). The LTMPwas finalized for Site 9 on 16 August 1999 (EA 1999b). The goals of the final 1999 LTMP areas follows:




• Monitor changes in the plume boundaries and potential migration pathways.

• Monitor effectiveness of the remedial action for the protection of human health and theenvironment.

• Evaluate whether the inactive landfill contents are impacting ground water.

• Monitor the VOC concentration to evaluate the effectiveness of natural attenuation anddetermine trends with time.

• Monitor impacts to the environment due to Site 9.

4.3.3 Institutional Controls

Institutional controls at Site 9 consist of ground-water and land use restrictions that apply to theentire Site 9 area east of Orion Road and Avenue F, east of MW-NASB-073, and south ofBuilding 52. However, institutional controls to prohibit ground-water use and physical contactwith ground water must be incorporated into the next revision of Operating InstructionNASBINST 5090.1 A, "Restriction on Excavation Activities." The next revision of NASBINST5090.1 A is scheduled for September 2000. This program was shown to be effective by NASBrunswick's recent request for concurrence with the proposed Bachelor Enlisted QuartersMilitary Construction Project.

4.4 RECOMMENDATIONS

• No additional remedial actions are required at this time; however, if sampling trendsindicate sustained increases in vinyl chloride concentrations in ground water, additionalfield work may be required to better delineate a potential plume of deep-seated vinylchloride. U.S. EPA and MEDEP will be consulted to establish a specific trigger level forthis action.

• Ongoing operation and maintenance activities will continue and will be summarized inannual reports. Annual reports and monitoring event reports will continue to besubmitted to U.S. EPA and MEDEP.

• The Long-Term Monitoring Plan will be refined as needed based on the annual reports.

• Amend the Operating Instruction NASBINST 5090.1A "Restriction on ExcavationActivities" to include a restriction of use and physical contact with the ground water.


The purpose of the five-year review is to ensure that the selected remedy remains protective ofhuman health and the environment and is functioning as designed. The Natural Attenuation andInstitutional Control remedy selected for Site 9 has been successfully implemented to date, andremains protective of human health and the environment. Long-term monitoring is ongoing.




5. EASTERN PLUME OPERABLE UNIT

The Eastern Plume Operable Unit consists of the following sites:

• Site 4—Acid/Caustic Pit• Site 11—Fire Training Area• Site 13—Defense Reuse and Marketing Office Area.

Figure 7 provides the location of the Eastern Plume Operable Unit.


Site 4: Acid/Caustic Pit—Under the eastern portion of Building 584, this pit was used from1969 to 1974 to dispose of acidic and caustic liquid wastes. The wastes were poured into the pit,which was approximately 4 feet square and 3 feet deep. In 1975, Building 584 was constructedon top of the pit.

Site 11: Fire Training Area—This area was used regularly over a 30-year period until it wasclosed in the Fall of 1990. Waste liquids, including fuels, oils, and degreasing solvents, wereused as fuel for the fire training exercises.

Site 13: Defense Reuse and Marketing Office Area—This area consisted of the formerlocations of three underground storage tanks south of Site 4. One underground storage tank wasused for diesel fuel; the other two tanks were reportedly used for storage of waste fuels, oils, anddegreasing solvents. All three tanks were removed during the late 1980s.

5.1.1 Soils

In 1998, a ROD was signed for No Further Action for soils at Sites 4, 11, and 13. The decisionwas based on the Feasibility Study (E.G. Jordan 1992) that concluded the only risk remaining atthese sites is from the continuing impacts to ground water from soils at Site 11. Removal actionsfor metallic debris, drums, and contaminated soils were completed at Site 11 following theFeasibility Study. The metallic debris and drums were disposed off-base, and contaminated soilswere used for subgrade fill beneath the Sites 1 and 3 Landfill cover (U.S. Department of theNavy 1998b).

Subsurface soils at Building 584 at Site 4 did not contain detectable quantities of VOCs;however, subsurface soil samples were not collected directly from the suspected pit location dueto the presence of Building 584 at that location. Therefore, no soils were removed from thislocation. If the building is ever removed, further investigations and remedial actions may berequired.

During the Remedial Investigation (E.G. Jordan 1990), fuel oil contamination was detected in thesoil and was believed to have been related to the diesel fuel oil underground storage tanks atSite 13. The underground storage tanks were removed from the site, but no soils were removed.

Naval Air Station, Brunswick Five-Year Review Report



Ground-water wells were installed and sampled for VOCs. The ground-water VOC data indicatea decrease in VOC concentrations as the result of the underground storage tank removals.

5.1.2 Ground-Water Operable Unit (Eastern Plume)

The Eastern Plume has been attributed to past solvent disposal practices from Sites 4, 11, and 13.The plume of VOC-impacted ground water extends along the eastern boundary of the base, asshown on Figure 8. The presently mapped southern boundary of the Eastern Plume is locatednear New Gurnet Road (Figure 9).

As an initiative to determine if the plume was discharging to wetlands area, the U.S. EPA,MEDEP, and the Navy installed vapor diffusion samplers in the Summer of 1999. This actionwas used to assess the possibility for discharge of the Eastern Plume contaminants to wetlandareas of Mere Brook and Merriconeag Stream. Diffusion sampler results showed no EasternPlume contaminants of concern in the sampled wetland areas.

In 1999, a separate "Remedial Action Operation Optimization Case Study" was accomplished toreview the Eastern Plume (Radian 1999). The primary purpose of this case study was to evaluateand assess the ongoing remedial action objectives program and provide recommendationsresulting in attainment of site remedial action objectives and closure for optimal life cycle costs.Specific elements evaluated for the Eastern Plume pump and treat system include:

1. Overall site remediation strategy and approach.

2. Best operation and management practices already in place.

3. Extraction system network, including all wells, screen intervals, and piping.

4. Performance of treatment system components, including control systems.

5. Operation, maintenance, and control for the treatment units.

6. Treatment system data collection, analysis, and reporting.

7. Effluent discharge options.

8. Appropriate exit strategy for site closeout, including recommendations for the use ofalternative technologies, as appropriate.

9. Total estimated cost avoidance/savings from optimized operations.


• 1992 Interim ROD (U.S. Department of the Navy 1992b) was signed.• 1995 Remedial Action started.• 1995 Long-Term Monitoring initiated.




• 1998 Final ROD and Remedial Action (U.S. Department of the Navy 1998b).• 1999 Remedial Action Operation Optimization Case Study (Radian 1999).• 1999 Two-Day Technical Workshop on Outstanding Regulator Concerns.• 2000 Final Long-Term Monitoring Plan (EA 2000a).


In the 1998 ROD, the remedial objectives were set as follows:

• Minimize further migration of the Eastern Plume.

• Minimize any future negative impact to surface water resulting from discharge ofcontaminated ground water.

• Reduce the potential risk associated with ingestion of contaminated ground water toacceptable levels.

• Restore the aquifer.

To accomplish these objectives within a 17- to 72-year timeframe, the following componentswere implemented:

• Ground-Water Extraction and Treatment—Continuance of the existing extractionsystem. In 1992, an Interim ROD was signed for extraction and treatment of thecontaminated ground water. The system, operating since May 1995, providespretreatment to remove turbidity and inorganics, ultraviolet-oxidation to destroy VOCs,discharge of treated water to the local publicly-owned treatment works, and periodicdisposal of filter press sludge from the inorganics treatment process. An additionalextraction well (EW-2A) was added to the extraction system in July 1998. EW-2A wasdesigned to prevent further movement of migration towards surface water, and recovermore mass of contaminants located in an area of the plume found to have a greateraccumulation of VOCs.

• Monitoring—The goals of the plan are as follows:

— Provide a tiered approach to attain the requirements of MEDEP water qualitystandards

— Monitor changes in the plume boundaries and potential migration pathways

— Monitor changes in ground-water contamination




— Monitor the effectiveness of the remedial action for the protection of human healthand the environment

— Monitor the treatment plant effluent.

• Five-Year Reviews—Since the remedy will result in hazardous substances(contaminants of concern listed in the Final 1998 ROD) remaining in place, five-yearreviews will continue to be conducted. In addition, conditions at Sites 4, 11, and 13 willbe evaluated to determine whether additional response actions may be necessary at thosesites.



Institutional Controls

The operable unit remains within the restricted area of the base and, as such, the institutionalcontrols are effective. However, ground-water institutional controls are not documented in theROD and need to be added to the ROD. In addition, institutional controls for restriction of useand contact with ground water need to be included in the next revision of Operating InstructionNASBINST 5090.1 A, "Restriction on Excavation Activities." The next revision of NASBINST5090.1 A is scheduled for September 2000.

Further Migration of the Eastern Plume

In the latest revision of the Long-Term Monitoring Plan, sentinel wells were located outside thearea of known contamination and are used to warn of plume migration. The 1998 Annual Reportsummarized that "Ground-water samples collected from shallow and deep sentinel wells did notdetect VOCs above MEG or MCL" (EA 2000b).

Future Negative Impact to Surface Water Resulting from Discharge of ContaminatedGround Water

No Eastern Plume contaminants of concern have been detected in surface water with theexception of anomalies involved with Monitoring Event 13. Trichloroethene was reported inassociated method blanks, trip blanks, and equipment rinsate blanks and are consideredlaboratory or sampling artifacts. Based on these results, VOCs from the Eastern Plume do notappear to be significantly impacting surface water, although the potential impact to surface watercannot be fully evaluated due to the presence of trichloroethene in the sample method blanksduring Monitoring Event 13. Additional surface water sample results have confirmed that nosurface water impacts are caused by Eastern Plume contaminants of concern.


Revision- FINALPage 5-5


Reduce the Potential Risk Associated with Ingestion of Contaminated Ground Water toAcceptable Levels

The majority of the Eastern Plume remains within the restricted area of NAS Brunswick and, assuch, placement of potable water wells is restricted.

Restore the Aquifer

The Eastern Plume system removed approximately 536 Ibs. of VOCs during an operationalperiod of July 1996 through May 1999. Mass removal averages approximately 15 Ibs. permonth.

While the current system is in compliance with the ROD, improvements can be made in theoptimization of the system. A separate "Remedial Action Operation Optimization Case Study"was accomplished to review the Eastern Plume (Radian 1999). The primary purpose of this casestudy was to evaluate and assess the ongoing remedial action objectives program at the EasternPlume system at NAS Brunswick, and provide recommendations resulting in attainment of siteremedial action objectives and closure for optimal life cycle costs. Specific elements that wereevaluated for the Eastern Plume pump and treat system include:

• Overall site remediation strategy and approach.

• Best operation and management practices already in place.

• Extraction system network, including all wells, screen intervals, and piping.

• Performance of treatment system components, including control systems.

• Operation, maintenance, and control for the treatment units.

• Treatment system data collection, analysis, and reporting.

• Effluent discharge options.

• Appropriate exit strategy for site closeout, including recommendations for the use ofalternative technologies, as appropriate.

• Total estimated cost avoidance/savings from optimized operations.

5.4 RECOMMENDATIONS

No further response actions are required to be protective of human health and the environment atthis time. However, optimization of the treatment system should continue and the final Long-Term Monitoring Plan should be implemented. The following recommendations are prioritizedas follows:


Revision' FINALPage 5-6


• Enhance mass removal of contaminants in the Eastern Plume. Mass removal would beimproved by replacement of existing extraction wells EW-4 and EW-5 with wells that arescreened solely in the lower sand unit "hotspots." In order to ensure appropriate pipingsize and treatment system capacity, determine ground-water flow rates and mass removalfrom these new extraction wells prior to making any modifications to the abovegroundtreatment system (Radian 1999).

• Add ground-water institutional controls to the ROD and amend Operating InstructionNASBINST 5090.1 A "Restriction on Excavation Activities," to add a restriction on useand physical contact with contaminated ground water.

• Modify the aboveground treatment system to allow effluent discharge to surface water orto an infiltration gallery after confirming the most effective and efficient option based ona detailed technical review and lifecycle cost analysis (Radian 1999).

• Determine if the southern terminus sentinel wells are adequately placed, and initiate workto correct the situation if necessary.

• Begin a formal evaluation for Monitored Natural Attenuation for the Eastern Plume. Inparticular, determine whether natural wetland biodegradation and/or natural attenuationprocesses are occurring at acceptable rates in the aquifer zone. Also, verify that theplume is stable. Ground-water monitoring results indicate that the downgradient extentof the plume apparently has not changed since at least 1995; however, additionalremedial actions may be warranted in the area of the southern terminus of the EasternPlume prior to formal initiation of monitored natural attenuation.

• Pursue negotiations with the regulatory agencies to establish risk-based cleanup levels forthe entire Eastern Plume and alternate concentration limits for any ground waterdischarging to Mere Brook. Ground water at the Eastern Plume is not a drinking watersource, thus cleanup to MCLs or State of Maine standards is not necessary for the remedyto remain protective of human health. In particular, begin discussions with the regulatoryagencies to establish definitive criteria for discontinuing active ongoing operation andmaintenance activities.

Long-term operations and maintenance activities will continue and will be summarized in annualreports. Annual reports and monitoring event reports will continue to be submitted to theU.S. EPA and MEDEP. The Long-Term Monitoring Plan will be refined as needed.


The purpose of the five-year review is to ensure that the selected remedy remains protective ofhuman health and the environment and is functioning as designed. The ground-water extractionand treatment system and the ground-water monitoring program have been only partiallysuccessful as implemented; but given the current data, these remedies appear to be protective ofhuman health and the environment with the existing institutional controls as exercised by theNavy (restricted access area surrounded by fencing). The addition of institutional controls in the




ROD to restrict ground-water use will better ensure the protection of the selected remedy in thefuture and formalize the controls implemented by NASBINST 5090.1 A. Long-term operationand maintenance of the extraction and treatment system is ongoing in addition to the long-termmonitoring program.


Revision- FINALPage 6-1


6. REFERENCES

ABB Environmental Services. 1993. Site Inspection Report, Swampy Road Debris Site,Merriconeag Extension Debris Site. Portland, Maine. October.

ABB Environmental Services. 1994. Long-Term Monitoring Plan, Building 95, Sites 1 and 3and Eastern Plume, Naval Air Station, Brunswick, Maine. August.

ABB Environmental Services. 1995. Site Inspection, West Runway Study Area. Portland,Maine. January.

EA Engineering, Science, and Technology. 1999a. Record of Decision for Site 9, Brunswick,Maine. Newburgh, New York. September.

EA Engineering, Science, and Technology. 1999b. Final Long-Term Monitoring Plan, Site 9(Neptune Drive Disposal Area), Naval Air Station, Brunswick, Maine. Newburgh, NewYork. August.

EA Engineering, Science, and Technology. 1999c. Final 1998 Annual Report MonitoringEvents 11 through 13, Site 9: Neptune Drive Disposal Area, Naval Air Station, Brunswick,Maine. Newburgh, New York. August.

EA Engineering, Science, and Technology. 2000a. Final Long-Term Monitoring Plan Sites 1and 3 and Eastern Plume, Naval Air Station, Brunswick, Maine. Newburgh, New York.February.

EA Engineering, Science, and Technology. 2000b. Final 1998 Annual Report MonitoringEvents 11 through 13, Sites 1 and 3 and Eastern Plume, Naval Air Station, Brunswick,Maine. January.

EA Engineering, Science, and Technology. 2000c. Final Long-Term Monitoring Plan, Site 2,Naval Air Station, Brunswick, Maine. Newburgh, New York. February.

E.G. Jordan Co. 1990. Draft Final Remedial Investigation Report. Volumes 1 through 4.August.

E.G. Jordan Co. 1992. Feasibility Study, NAS Brunswick. Portland, Maine. March.

OHM Remediation Services Corporation (OHM). 1996. Final Report, Remediation of Sites 1,3, 5, 6, and 8. Volumes I through IV. July.

Radian International. 1999. Eastern Groundwater Plume, Naval Air Station, Brunswick,Remedial Action Operation (RAO) Optimization Case Study. Morrisville, North Carolina.December.




U.S. Department of the Navy. 1992a. Record of Decision for a Remedial Action at Sites 1and 3, Brunswick, Maine. June.

U.S. Department of the Navy. 1992b. Record of Decision for an Interim Remedial Action at theEastern Plume Operable Unit, Naval Air Station, Brunswick, Maine. June.

U.S. Department of the Navy. 1993a. Record of Decision for a Remedial Action at Sites 5and 6, Naval Air Station, Brunswick, Maine. August.

U.S. Department of the Navy. 1993b. Record of Decision for a Remedial Action at Site 8,Naval Air Station, Brunswick, Maine. August.

U.S. Department of the Navy. 1994. Interim Record of Decision for the Ground Water OperableUnit at Site 9, Naval Air Station, Brunswick, Maine. September.

U.S. Department of the Navy. 1998a. Record of Decision for Site 2, Brunswick, Maine.September.

U.S. Department of the Navy. 1998b. Record of Decision for No Further Action at Sites 4, 11,and 13 and a Remedial Action for the Eastern Plume, Naval Air Station, Brunswick, Maine.February.

U.S. Environmental Protection Agency. 1991. Office of Solid Waste and Emergency Response(OSWER) Directive 9355.7-02, Structure and Components of Five-Year Reviews. 23 May.

U.S. Environmental Protection Agency. 1994. Office of Solid Waste and Emergency Response(OSWER) Directive 9355.7-02A Supplemental Five-Year Review Guidance. 26 July.

U.S. Environmental Protection Agency. 1995. Office of Solid Waste and Emergency Response(OSWER) Directive 9355.7-03A Second Supplemental Five-Year Review Guidance.21 December.


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SOURCE MAPS USGS ORRS ISLAND (1978) AND BRUNSWICK (1980) 7 5 MINUTE QUADRANGLES

EA ENGINEERING,SCIENCE, ANDTECHNOLOGY

SITES I AND 3 ANDEASTERN PLUME

NAVAL AIR STATION, BRUNSWICK, MAINE

FIGURE ISITE LOCATION MAP

PROJECT MGR

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SURFACE WATER GAUGING POINTINFERRED AREA ABOVE STATEMEG/FEDERAL MCL CONCENTRATIONFENCE

APPROXIMATE LIMITS OF SLURRY WALL

APPROXIMATE LIMITS OF SITES 1 AND 3

APPROXIMATE LIMITS OF FORMER DISPOSAL TRENCHES

APPROXIMATE BOUNDARY OF SITE 2 LANDFILL

APPROXIMATE LIMITS OF EASTERN PLUME IN 1999

INFERRED EXTENT OF EASTERN PLUME ABOVE MEG/MCL

NOTE-

1. SITE PLAN TAKEN FROM THE INTEGRAPH VERSION 5 BASE-WIDE PLANPROVIDED BY NAS BRUNSWICK PUBLIC WORKS DEPARTMENT ON13 OCTOBER 1995.

2. SW-1B LOCATED APPROXIMATELY 1.000 FTUPSTREAM OF SITES 1 AND 3.

3. APPROXIMATE SAMPLE LOCATIONS SHOWN.

4. INFERRED EXTENT OF EASTERN PLUME ABOVE MEG/MCLBASED ON MONITORING EVENT 13 DATA (NOVEMBER 1998).

ORAPHtt KALE IN TOT

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NOTES

Base map from 1998 ROD Site 2 (HLA 1998)Surface water sample locations SW-04 and SW-07 and streamsediment sample locations SED-17 through SED-19 are sampledas part of the Long-Term Monitoring Program for Sites 1 and 3 andEastern Plume (approximate locations shown)

LEGEND

A SW-04 Surface water sample• LT-201 Leachate sampleSMW-213 Monitoring well* SED-17 Sediment sample

10 ft surface contoursRoads and buildingsSurface water features

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SITE PLAN TAKEN FROM THE INTEGRAPH VERSION 5BASE-WIDE PLAN PROVIDED BY HAS BRUNSWICKPUBLIC WORKS DEPARTMENT ON 13 OCTOBER 1995.

THE TWO STREAM GAUGE STATIONS (SG-1 AND SG-2)WERE FOUND TO BE MISSING ON 2 APRIL 1999, ANDWERE REPLACED IN THE SAME LOCATION AND SURVEYEDAS PART OF MONITORING EVENT 14. THE TWO NEWSTATIONS WERE DESIGNATED AS SG-1 A AND SG-2A.

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INFERRED AREA ABOVE STATEMEG/FEDERAL UCL CONCENTRATION

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APPROXIMATE LIMITS OF SLURRY WAUL

APPROXIMATE LIMITS OF SITES 1 AND 3

APPROXIMATE LIMITS OF FORMER DISPOSAL TRENCHES

APPROXIMATE BOUNDARY OF SfTE 2 LANDFILL

APPROXIMATE LIMITS OF EASTERN PLUME IN 1999

INFERRED EXTENT OF EASTERN PLUME ABOVE MEC/MCL

NOTE:

1. SITE PLAN TAKEN FROM THE INTEGRAPH VERSION 3 BASE-WIDE PLANPROVIDED BY NAS BRUNSWICK PUBLIC WORKS DEPARTMENT ON13 OCTOBER 1995.

2. SW-16 LOCATED APPROXIMATELY 1,000 FTUPSTREAM OF SITES 1 AND 3.

3. APPROXIMATE SAMPLE LOCATIONS SHOWN.

4. INFERRED EXTENT OF EASTERN PLUME ABOVE MEG/MCLBASED ON MONITORING EVENT 13 DATA (NOVEMBER 1998).

GfWPHK SCALE IN FEET

Kit7 MARCH 2000

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SITES 1 AND 3 AND EASTERN PLUMENAVAL AIR STATION, BRUNSWICK. MAINE

FIGURE 9

LONG-TERM MONITORING NETWORK


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Revision: FINALTable 1

March 2000

TABLE 1 ACTIVE SITES NOT INCLUDED IN FIRST FIVE-YEAR REVIEW

Site No.Site?

Site 12

Site 14

Site 15

Site 16

Site 18

Building 95

Site NameOld Acid/Caustic Pit

EOD Training Area

Old Dump #3

MerriconeagExtension Debris Site

Swampy Road DebrisSite

West Runway StudyArea

Former PesticideShop

Summary Description of Site EventsFeasibility Study (E.G. Jordan 1992) recommendedmonitoring ground water for metals. Navyinvestigating need for monitoring or possible sourceremoval. Record of Decision scheduled forDecember 2001.Feasibility Study (E.G. Jordan 1992) indicated noaction, control, or monitoring for the site, andrecommended a no further action Proposed Plan andRecord of Decision.Site Investigation activities concluded that the dumpno longer exists, or was removed during runwayconstruction in the early 1950s. Only a No- ActionAlternative was evaluated in the Feasibility Study(E.G. Jordan 1992). A Consensus Statement isneeded to close the site and is scheduled forSeptember 2000.The Site Inspection (ABB-ES 1993) recommended nofurther action, and the site was not included in theFeasibility Study. A Consensus Statement is neededto close the site and is scheduled for September 2000.The Site Inspection (ABB-ES 1993) recommended nofurther action, and the site was not included in theFeasibility Study. A Consensus Statement is neededto close this site.

The Site Inspection (ABB-ES 1995) recommended nofurther action, and the site was not included in theFeasibility Study. A Consensus Statement is neededto close the site and is scheduled for September 2000.This site was designated Site 17 for tracking purposesonly, and is not part of the National Priorities List.There is no final agreed remedial action for this site.Site is not subject to five-year reviews required byComprehensive Environmental Response,Compensation, and Liability Act; however, the Navyagreed to review it under the same process.

Site StatusNo Further ActionRecord of Decisionplanned for December2001 if successfulremoval action.No Further ActionRecord of Decisionplanned for December2001.Site pending closurebased on a SiteInspection leading toNo Further Action.

Site pending closurebased on a SiteInspection leading toNo Further Action.Additional surveywork planned for lateSpring 2000, thenConsensus Statementby September 2000.Site pending closurebased on a SiteInspection leading toNo Further Action.Additional ground-water investigations in2000, institutionalcontrols andConsensus Statementplanned forcompletion byDecember 2002.



Revision: FINALTable 2

March 2000

TABLE 2 INACTIVE CLOSED SITES NOT INCLUDED IN FIVE-YEAR REVIEW

Site No.SiteS

Site 6

SiteS

Site 10

Site NameOrion StreetAsbestos Disposal

Sandy Road Rubbleand AsbestosDisposal Site

Perimeter RoadDisposal Site

Harpswell FuelDepot

Summary Description of Site EventsAsbestos was successfully removed and placed atSites 1 and 3 Landfill. Record of Decision signedAugust 1993 (U.S. Department of the Navy 1993a)indicates five-year reviews would not be required.Rubble and asbestos were successfully removed andplaced at Sites 1 and 3 Landfill. Record of Decisionsigned August 1993 (U.S. Department of the Navy1993a) indicates five-year reviews would not berequired.Soil was removed and placed at Sites 1 and 3Landfill. The Record of Decision (U.S. Departmentof the Navy 1993b) indicated monitoring would berequired if soil was not satisfactorily removed. Nomonitoring was required subsequent to soil removal(OHM 1996). Record of Decision signed in 1993.Not part of Naval Air Station, Brunswick. Site islocated in Harpswell, Maine, and remediation wascompleted by the Defense Energy Supply Center.Site 10 (Harpswell Fuel Depot) was not included onthe National Priorities List due to petroleumexclusion.

Site StatusSite was closed based on aRecord of Decision withremoval action completed.

Site was closed based on aRecord of Decision withremedial actioncompleted.

Site was closed based on a1993 Record of Decisionfollowing a remedialaction.

Transferred to DefenseEnergy Supply Center.Remedial action andclosure is beingperformed by DefenseEnergy Supply Center.


Appendix A

Response to Comments on theDraft Five-Year Review Report

Received from theU.S. Environmental Protection Agency and

Maine Department of Environmental Protection

RESPONSE TO COMMENTS FROM THEU.S. ENVIRONMENTAL PROTECTION AGENCY

ON THE FIVE-YEAR REVIEWNAVAL AIR STATION, BRUNSWICK, MAINE

COMMENTOR: Michael Barry DATED: 9 February 2000

The U.S. Environmental Protection Agency has reviewed the above report, dated 5 January 2000and received on 11 January 2000. Based on EPA's Supplemental Five-Year Review Guidance,Office of Solid Waste and Emergency Response (OSWER) Directive 9355.7-02A (August 1994)and our knowledge of the site, we concur that a Level la review is appropriate for Naval AirStation (NAS) Brunswick for this review. Additionally, based on EPA's Structure andComponents of Five-Year Reviews, OSWER Directive 9355.7-02 (May 1991), we also concurthat the review includes the required information and level of detail. The review also readsclearly and concisely.

We largely concur with the finding and recommendations of the draft review. However, in orderto concur that all remedies are protective of human health and the environment, ground-waterinstitutional controls need to be added to the Eastern Plume Record of Decision (ROD) and fullydocumented for the Eastern Plume, Sites 1 and 3, and 9.

We appreciate the improvements already taken and underway by the Navy. The monitoringnetwork was much improved in the last 2 years and we look forward to further improving it withthe recommended verification of the southern terminus of the plume. The addition of extractionwell EW-2A has resulted in improved Eastern Plume mass removal. We concur with all theextraction and treatment system recommendations presented and look forward to improved andmore optimal performance with their implementation.

Though we remain concerned about potential bedrock exposure, we believe that there is neithersufficient evidence nor clear or imminent threat to human health or the environment to justifypressing the Navy to perform any additional action to address this specific concern at this time.We will be working with Maine Department of Environmental Protection (MEDEP) to resolveour concerns in this area and will keep you informed of any new information.

Please see more specific general and specific comments in the attachment. Per EPA's extensionrequest approval letter dated 2 December 1999, the due date of the final review is 2 March 2000.In order to allow a 30-day period, we consent to a final review due date of 10 March 2000. Ifyou have any questions, please contact me at 617-918-1344 or [email protected].

To aid in response, general and specific comments are referenced and all comments codedsimilarly a recent MEDEP letter.

(RR) Means response requested, generally is a substantive comment.

(F) Means a format comment. Though not a substantive issue, we feel a change is needed toconform to EPA format or policy or adds information that would greatly improve thereview. Response only requested if the Navy disagrees.

(NR) Means no response required, usually an observation, note, non-substantive comment, orsubstantive but response is more appropriate to another comment to avoid repetition.

(ED) Means editorial comment or suspected typographical error.

GENERAL COMMENTS

1. Ground- Water Institutional Controls

(a) (RR) Eastern Plume. Although the Eastern Plume remedy does not include ground-water use restrictions (no use/contact as in the 1999 Site 9 ROD), it should, given that itcontains contaminant concentrations that pose an unacceptable risk under CERCLA,while the active remedy operates to meet the cleanup goals. Also, under Maine law, allground water in the state shall be considered a potential source of drinking water (asClass GW-A). Though ground-water institutional controls (ICs) are de facto in effectbecause the Eastern Plume is contained on Navy property (most of it in the weaponscompound), EPA cannot concur to the protectiveness of the remedy in the reviewwithout a recommendation to add ICs to the ROD. We acknowledge that EPAconcurred with the ROD in 1998 and regard this as an administrative matter that can beeffected with a minor ROD change or included with the Explanation of SignificantDifferences (ESD) to change the ground-water treatment method and discharge tosurface water. (See Specific Comment Nos. 28b, 29a, and 30a).

Response—Institutional controls will be added to the Eastern Plume ROD as part of theESD. This ESD is scheduled to be completed by Fall of 2000. The language used forground-water institutional controls developed for the Site 9 ROD will be used as amodel for the ESD.

The Navy will implement institutional controls to prevent the use of and contactwith impacted ground water at the Eastern Plume without prior written approvalfrom EPA and MEDEP. These institutional controls will consist of ground-waterand land use restrictions that would apply to the entire Eastern Plume area(Figure X). They will be implemented and enforced by the Navy or otherdesignated agency. The Navy will have ultimate responsibility for ensuring thatthese controls, as components of the selected remedy, continue to be in place andeffective, and protective of human health and the environment.

These controls will be documented as ground-water and land use restrictions in thecurrent NAS Brunswick Operations Instructions in effect, which are used to identifyand screen environmental areas for inappropriate construction or developmentactivities. Within a reasonable time after signature of the Explanation ofSignificant Differences, the Navy will provide a draft version of these userestrictions to EPA and MEDEP for review and comment. The Navy shall revisethe draft use restrictions in accordance with EPA and MEDEP comments to ensurethat the restrictions adequately protect human health and the environment. Whenfinalized, the ground-water and land use restrictions will be incorporated into theOperations Instructions and placed in the Administrative Record for the EasternPlume. The Operations Instructions will not be modified in any way that affectsthese use restrictions or the Eastern Plume remedy.

Should the Navy transfer or lease any real property affected by Eastern Plume,whether or not as a result of base closure, the Navy will notify EPA and MEDEP ofthe transfer or lease and will include in all documents evidencing the transfer orlease appropriate provisions (i.e., restrictive covenants or other use restrictions)preventing use of and contact with site ground water without prior written approvalfrom EPA and MEDEP. If the property is transferred, or the lease allows capitalimprovements, a technical evaluation of the effectiveness and appropriateness ofthe remedy will be undertaken considering long-term monitoring results to date, theproposed land use, and the fact that the Navy may no longer actively own oroperate the property.

(b) (RR) 1C Documentation. Regardless if ground-water environmental risks are containedon Navy property and effectively controlled by Navy access control, they must beexplicitly documented. Though ground-water use may effectively be prevented by theprohibitions on excavation activities in the NAS Restriction on Excavation ActivitiesInstruction, NASBINST 5090.1 A, it misses the point of directly stating this 1C that isstated in the Sites 1 and 3, 2, and 9 RODs and should be in the Eastern Plume ROD.NASBINST 5090.1 A concisely and completely covers soil exposure; adding a line aboutground-water restrictions in Paragraph 5 would be suitable to EPA. We request theNavy add a recommendation to revise the 1C accordingly so that EPA can concur to thereview. Adding the 1C for Site 2 could be deferred pending monitoring results toconfirm if lead is still above the Maximum Contaminant Level. Since the Navy controlsall affected property and NAS Brunswick is an operating base, it would be satisfactoryto EPA to put off adding the ground-water ICs to NASBINST 5090.1 A until the nextroutine revision. We also regard this as an area of non-compliance, albeit a minor one,for Sites 1 and 3, Site 9, and the Eastern Plume. (See Specific Comment Nos. 13c, 14,23b, 18,29a, and 30a.)

Response—We agree. The addition of ground-water use prohibitions will be included inthe next revision of the Operating Instruction NASBINST 5090.1 A, "Restriction onExcavation Activities" for inclusion of ground-water institutional controls. The revisedexcavation text will be forwarded to EPA prior to finalizing NASBINT 5090.1A toreceive EPA comments on the revised text. The next scheduled revision will be inSeptember 2000. This response applies to EPA Comment Nos. 13c, 14, 18, 23b, 28, 29,and 30.

2. Section 1

(a) (F) Section 1.0 doesn't quite fit model language. (See Specific Comment No. 7.)

Response—The first and second paragraphs have been revised as follows:

A statutory five-year review has been conducted by the U.S. Department of the Navy(Navy) pursuant to Section 121(c) of the Comprehensive Environmental Response,Compensation, and Liability Act; Section 300.400(f)(4)(ii) of the National Oil andHazardous Substances Contingency Plan; Executive Order 12580; and U.S.Environmental Protection Agency (U.S. EPA) Office of Solid Waste and Emergency

Response Directive 9355.7-02 (23 May 1991), Office of Solid Waste and EmergencyResponse Directive 9355.7-02A (26 July 1994), and Office of Solid Waste andEmergency Response Directive 9355.7-03A (21 December 1995). The purpose ofthis five-year review is to ensure that the remedial actions selected for the NavalAir Station (NAS) Brunswick National Priorities List sites remain protective ofhuman health and the environment, and are functioning as designed.

This review is a Type la review, which is applicable at sites where response isongoing. According to U.S. EPA guidance, a Type la review consists of adocument review (including Record of Decision [ROD] declarations andmonitoring information) and preparation of a report that provides a discussion ofremedial objectives, areas of non-compliance with those objectives,recommendations for improvements, and a statement of whether theremedy/remedies remain protective. This report will become part of the Site File(Administrative Record).

(b) (F) Table 1 is confusing. We concur that these sites not be included in the first five-year review for the reasons stated, but they should be reorganized into three tables fordifferent categories. (See Comment No. 11 for specifics.)

Response—The tables have been revised to include a column in each table in theFive-Year Review with the heading "Site Status." This column will allow for thespecific comments outlined in Comment No. 11 to be addressed without adding tables.

(c) (F) Table 2. We concur that these sites not be included in this or subsequent five-yearreviews, but Sites 5, 6, and 7 should be split apart from Site 10. (See Specific CommentNo. 12.)

Response—Please see response to Comment No. 2b.

3. (F) Section 3, Site 2. We regard the remedy as in the process of being implementedbecause the Long-Term Monitoring Plan is not yet finalized, new monitoring well is to beinstalled and 1C mot fully implemented. (See Specific Comment No. 20.)

Response—The remedy is in the process of being implemented, a new monitoring well isscheduled to be installed in March 2000, and the Final Site 2 Long-Term Monitoring Planwas distributed on 29 February 2000 to the EPA and MEDEP.

4. Section 4, Site 9

(a) (F) We regard the remedy as in the process of being implemented because not allcomments to the LTMP have been resolved. (See Specific Comment No. 24.)

Response—The remedy is in the process of being implemented. The Final Site 9 Long-Term Monitoring Plan was distributed to EPA and MEDEP on 16 August 1999.

(b) (NR) Natural attenuation is clearly taking place at Site 9, yet VOC concentrations areincreasing at some wells. We concur with continued monitoring and are not overlyconcerned at present because VOC concentrations at the outlet monitoring wells aredeclining. If present absolute concentration levels continue rising in MW-69 or if theremedy doesn't succeed within its expected duration, subsequent five-year reviews mayindicate that more active remedial or source control measures are required.

(c) (NR) The mention of phytoremediation is interesting. This technology could be veryappropriate for Site 9 to address concerns noted in the previous comment. Toimplement beyond a treatability study would require some type of ROD modification.

5. Section 5, Eastern Plume

(a) (NR) Recommendations 1 and 2. Concur, the remedy appears to be operating asdesigned, but the recommendations will make it much more effective in attainingremedial goals which include aquifer restoration.

(b) (NR) Recommendation 3. Strongly concur. We are very concerned that the southernwells are placed properly in the deep overburden sand and that this could be giving us"false" data to support a stalled leading front of the plume.

(c) (NR) Recommendation 4. We look forward to the Navy's study, especially after ourconcerns about the plume southern overburden terminus are resolved.

(d) (NR) Recommendation 5. We will consider the Navy's proposal. This would requirean BSD to the ROD and concurrence by MEDEP and the EPA Region 1 ARARs panel.Under Maine law, all ground water in the state must be considered a potential drinkingwater source. Another approach the Navy may consider is proposing a "complianceboundary" such as was concurred upon at Loring Air Force Base.

(e) (NR) Bedrock and DNAPL. As voiced at several meetings and in our comments to the1998 annual monitoring report, and presented at the November 1999 technical meeting,we are still concerned of possible bedrock exposure at a bedrock ridge or knoll near thesource area. This concern is somewhat mitigated by the lack of confirmed DNAPLfound and upward gradients in the bedrock. Thus, though we are certain bedrockexposure occurred to at least dissolved VOCs and certain fractures in the bedrock, thepotential exposure risk to receptors does not appear imminent nor is easily quantifiable.Thus, we feel there is insufficient data to compel the Navy to perform bedrockinvestigations at this time. We are concerned about downgradient environmentalreceptors and possible private deep well downgradient and will proceed with MEDEP toresolve this concern. This directly relates to the ROD objective of monitoring all plumemigration pathways.

6. (RR) Public information requirements. Per CERCLA, it is required to inform the public ofthe review scope, results, actions taken as a result of it, and location of the report (this isalso in the 1991 guidance). This is not required to be before the final review is published.

We recommend this be conveyed by means of a newspaper ad and also that the RestorationAdvisory Board and public be invited to the March technical meeting for an informalpresentation and opportunity to submit oral comments.

Response—A notice regarding the Five-Year Review will be published in the localnewspaper. A presentation of the Five-Year Review Report will be made at a RestorationAdvisory Board meeting followed by a public comment period. The Response toComments have been provided as an appendix to the Final Five-Year Review Report.

SPECIFIC COMMENTS - SECTION 1

7. (F) Section 1.0, Paragraphs 1 and 2—Recommend substituting the below wording tobetter fit model language:

The U.S. Department of the Navy (Navy) conducted this review pursuant to Section121(c) of the Comprehensive Environmental Response, Compensation and Liability Act(CERCLA), Section 300.400(f)(4)(ii) of the National Oil and Hazardous SubstancesContingency Plan (NCP), Executive Order 12580, EPA OSWER Directive 9355.7-02(May 23, 1991), OSWER Directive 9355.7-02A (June 23, 1994), and OSWER Directive9355.7-03A (December 21, 1995). It is a statutory review. The purpose of this five-yearreview is to ensure that the remedial actions (RAs) selected for the Naval Air StationBrunswick (NASB) National Priorities List site (Site) remain protective of human healthand the environment and are functioning as designed.

This review is a Type la review, which is applicable at sites where response is ongoing.According to EPA guidance, a Type la review is to consist of a document review(including ROD declarations and monitoring information) and preparation of a reportthat is to include a discussion of remedial objectives and any areas of noncompliancewith those objectives, recommendations, and a statement of whether the remedy/remediesremain protective. This report will become part of the Site File

Response—Please see Response to General Comment No. 2a.

8. (ED) Section 1.0, Third Paragraph, Second line—Recommend deleting "be performedafter the initiation of the selected RA each site."

Response—The text has been deleted as suggested.

9. Section 1.1, Organization of Report

(a) (ED) In the 2nd sentence of the 1st paragraph, recommend replacing "implemented aspart of this writing" with "ongoing as of the date of the five-year review documented inthis report."

Response—The second sentence of the first paragraph of Section 1.1 has been revised asfollows:

The following operable units have ongoing remedial actions implemented as part ofthe writing of this five-year review, as of the date of the five-year reviewdocumented in this report.

(b) (F) The statement of when the next five-year review is required is usually its ownsection, such as Section 1.2, Next Review.

Response—The following text has been added as Section 1.2:

1.2 Next Five-Year Review

The next five-year review shall be completed by 6 December 2004.

10. Table 1, Specifics to Comment No. 2b

(a) (ED) Recommend the "Active" in the title be deleted for brevity and to preventconfusion between CERCLA, RCRA, and BRAC programs.

Response—Per an e-mail from EPA dated 13 March 2000, Item 3, "active" will remainon Table 1.

(b) (F) Sites 7 and 12 should be split of by themselves in a table called "Sites in ProgressPending RODs."

Response—Please see Response to General Comment No. 2b.

(c) (ED) For Site 7, change the last sentence to "ROD scheduled for ...."

Response—The text has been revised as suggested.

(d) (F) Sites 14, 15, 16, and 18 should be in a table called "Sites Pending Closure Based ona Site Inspection Leading to No Further Action."


(e) (F) Building 95 should be in a separate table called "sites under investigation and to bedetermined.".


1 1 . Table 2, Specifics to Comment 2c

(a) (F) Alter the title to "Closed Sites " to be clear that action at these sites is complete.


(b) (F) Sites 5, 6, 7 should be in a table called "Sites Closed Based on a ROD withRemoval Action Completed"

Response—Based on investigations in 1999, it was determined that there may be a needfor additional monitoring or source removal at Site 7. Therefore, Site 7 will remain onTable 1 (Sites Not Included in First Five-Year Review.) Text has been added to Table 1,in the "Site Status" column as follows:

No further action ROD anticipated, pending successful removal action.

(c) (F) Sites 5 and 6 should have some reference to a successful removal action as doesSite 8.

Response—The clarification to the sentence will be made to address the success of theremoval action. Sites 5 and 6 descriptions, "successful" will be added prior to"removed" in each of the appropriate columns for the sites.

(d) (F) Site 10 should have more information such as citing that it isn't part of the NASBrunswick NPL site because it was deferred to the Defense Logistics Agency and theState program due to petroleum exclusion to CERCLA (if all true).

Response—See Response to MEDEP Comment No. 6b.

SPECIFIC COMMENTS - SECTION 2, SITES 1 AND 3

12. Section 2.1, Significant Events

(a) (F) Add the 1995 RA closure report and the 1999 Base 1C instruction (NASBINST5090.1 A) as these are key remedy documents.

Response—The documents have been added to Section 2.1, Significant Events, asrequested.

(b) (ED) Erosion Repairs Bullet. Add that the corrective measure were completed in 1999.

Response—The last sentence of the seventh bullet of Section 2.1, Significant Events,has been revised as follows:

Corrective measures to correct the landfill cap erosion were completed in 1999.

13. Section 2.3, Areas of Non-Compliance

(a) (F) Ground Water—This paragraph should mention the general VOC trends observedand that arsenic is also still above the MCL in MW-318, but has a clear downward trendand, thus, the objectives of the ROD regards to ground-water concentrations are in theprocess of being met.

Response—The following text has been added to Section 2.3 between the 2nd and 3rdparagraphs:

Monitoring wells located outside of the Sites 1 and 3 landfill have detectedinorganic elements (arsenic, manganese, and chromium) in the ground waterexceeding the Maximum Contaminant Level (MCL) and/or the Maximum ExposureGuideline (MEG). However, most of the detected concentrations of theseinorganics are exhibiting a general decreasing trend.

VOCs have been detected at increasing concentrations in the ground water atmonitoring wells within the landfill. No VOCs have been detected at concentrationsabove MCLs or MEGs downgradient and outside of the landfill, except at SEEP-04.

(b) (F) Seeps—The trend of iron and zinc should be briefly mentioned and by what basis(maximum sample, average, etc). For example, the maximum zinc at SW-1 is trendingdownward but was above the ambient water quality criteria of Monitoring Events 1through 6 and 11, thus, the remedy is effective in returning levels to meet the ambientwater quality criteria.

Response—The following text has been added as the fifth paragraph on Page 2-3:

Iron and zinc have been monitored in seep samples as part of the Long-TermMonitoring Program. The ROD reported maximums (maximum detectedconcentration) of 2,510,000 JUg/kg and 2,770 fig/kg for iron and zinc, respectively.Since the monitoring began, iron has only exceeded these maximums in MonitoringEvents 8, 10, and 11. Exceedance of the maximum for zinc has not been reported inany monitoring event report to date.

(c) (RR) ICs—Ground-water ICs are not documented. (See Comment No. Ib.)

Response—Please see Response to General Comment Nos. la and Ib.

14. (RR) Section 2.4 Recommendations. We believe ground-water ICs should be added toNASBINST 5090.1 A. (See Comment No. Ib.)

Response—Please see Response to General Comment No. Ib. The following text has beenadded to Section 2.4, Recommendations:

An institutional control to restrict ground-water use will be added in the next revision ofOperating Instruction NASBINST 5090.1 A, "Restriction on Excavation Activities." The

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next revision ofNASBINST 5090.1A is scheduled for September 2000. Ground-waterinstitutional controls are not documented in the ROD, and need to be added to the ROD.

SPECIFIC COMMENTS - SECTION 3, SITE 2

15. (F) Section 3.1, Significant Events—Insert "RA start" after "1999" to the debris removalbullet and add the 1999 Base 1C instruction as these are key parts of the RA at Site 2.

Response—Text will be revised as requested.

16. Section 3.1

(a) (F) In the last paragraph, note that lead was above the MCL in a monitoring well in thelandfill prior to the explanation on why this is not an issue.

Response—The following text has been added to Section 3.1:

Based on the available sample results, environmental contamination at Site 2 wasevident in surface waters, stream sediments, ground-water seeps, and surface soilsassociated with seep locations. During the Remedial Investigation in 1990 (E.G.Jordan 1991), lead was detected in the ground-water samples at concentrationsranging from 80 to 180 JUg/L that exceeded the Federal MCL of 5 JUg/L. The leaddetection in site ground water is consistent with historic use of the site. Ash wouldhave been produced by incineration (open burning) at the landfill, and ash typicallycontains inorganic constituents that would not be destroyed by burning. Theshallow ground water in this area is not used for a potable supply.

(b) (ED) In the first paragraph, recommend calling the landfill "closed" vice "inactive" andstate that it was closed by capping with soil and pine trees planted.

Response—The word "inactive" will be replaced with "closed" in the first sentence of thefirst paragraph of Section 3.1. The following text has been added at the end of the secondparagraph of Section 3.1:

The Site 2 Landfill was closed by capping the area with soil and planting pine trees ontop of the cap.

17. (F) Section 3.2—Though there are no objectives, the RA components documented in theROD should be mentioned as at the other sites evaluated in the review, i.e., long-termmonitoring, debris removal, ICs, and five-year reviews.

Response—Remedial action components will be summarized in this section of theFive-Year Review.

18. (RR) Section 3.3—Non-compliance may result if monitoring indicates that lead is stillabove the MCL and ground-water ICs are not documented in the base excavationinstruction. (Refer to General Comment No. Ib.)

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Response—Please see Response to General Comment No. Ib. The following text has beenadded to Section 3.3:

Although no remedial objectives were established for Site 2, the ROD indicated a long-term monitoring plan would be implemented to confirm the protectiveness of the selectedremedy. Data collected during the monitoring program will be evaluated as part of thefive-year review cycle.

Long-term monitoring has not commenced since the plan is currently beingimplemented. Monitoring is expected to start in 2000.

The operable unit remains within the restricted area of the base and, as such, theinstitutional controls remain effective. However, institutional controls for restriction ofuse and contact with ground water will be included in the next revision of OperatingInstruction NASBINST 5090.1 A, "Restriction on Excavation Activities." The nextrevision of NASBINST 5090.1 A is scheduled for September 2000.

19. (F) Section 3.4, First Line—Recommend substituting "No additional..." for "No further...".No further action conflicts with the long-term monitoring planned and ICs established.


20. (F) Section 3.5—The RA at Site 2 is in the process of being successfully implemented.EPA cannot close the RA until the LTMP is final and the new monitoring well installed.(See General Comment No. 3.)

Response—Please see Response to EPA Comment No. 20. The text has been revised toindicate that no monitoring has been undertaken since 1990. Therefore, it cannot bedetermined if the remedial action has been successful.

SPECIFIC COMMENTS - SECTION 4, SITE 9

21. (F) Section 4.1, Significant Events—Recommend adding the 1999 Base 1C instruction asthis is a key element of the remedy.

Response—The 1999 Base institutional control instruction has been added to the list ofsignificant events for Site 9.

22. (F) Section 4.2 Remedial Objectives—Denoting the expected time frame of up to 20 yearsas stated in the ROD would help put expected results in perspective in the bullet on naturalattenuation.

Response—The following text has been added to the sentence prior to the bullet regardingnatural attenuation:

To accomplish these objectives "within a 20-year time period, " the...

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23. Section 4.3 Areas of Non-Compliance

(a) (NR) Natural Attenuation—Data from the two rounds in 1999 should be included if atall possible. It looks like it will bear out the trends from 1995 to 1998. In any case, thiswas a concise analysis and we concur that natural attenuation is occurring due to thehigh level of DCE.

(b) (RR) ICs—Ground-water ICs are not documented. (See Comment No. Ib.) Weappreciate the expeditious implementation NASBINST 5090.1 A long before requiredby the ROD and that it was effectively used when EPA and MEDEP were consultedduring the recent BEQ project. (See General Comment No. Ib.)

Response—Please see Response to General Comment No. Ib. The following text has beenadded to Section 4.3.3:

Institutional controls at Site 9 consist of ground-water and land use restrictions thatapply to the entire Site 9 area east of Orion Road and Avenue F, east ofMW-NASB-073,and south of Building 52. However, institutional controls to prohibit ground-water useand physical contact with ground water must be incorporated into the next revision ofOperating Instruction NASBINST 5090.1A, "Restriction on Excavation Activities." Thenext revision of NASBINST 5090.1A is scheduled for September 2000. This program wasshown to be effective by NAS Brunswick's recent request for concurrence with theproposed Bachelor Enlisted Quarters Military Construction Project.

24. (F) Section 4.5, Third Line—Request "to date" be inserted after "has been successfullyimplemented" (See Comment No. 4a.)


SPECIFIC COMMENTS - SECTION 5, SITES 4,11, AND 13, AND THE EASTERNPLUME

25. (ED) Section 5.1, Ground-Water Operable Unit—Request insert "Monitoring data to dateindicates" in the beginning of the last sentence.

Response—The third sentence, first paragraph, of Section 5.1.2 has been revised as follows:

The presently mapped southern boundary of the Eastern Plume is located near NewGurnet Road (Figure 9).

26. (F) Section 5.1, Significant Events—Request adding RA complete to the Final ROD bullet;remedial action for final ROD was the same as Interim ROD regarding ground water.

Response—The remedial action will be added to the Final ROD bullet.

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27. Section 5.2, Discussion of Remedial Objectives

(a) (ED) Mention of the expected time frame of 17-72 years to meet remedial objectivesnoted in the ROD will help put results in context of expectations.

Response—The following text was added to the last sentence in Section 5.2 after the 4thbullet:

To accomplish these objectives within a 17- to 72-year timeframe, the...

(b) (ED) Ground-Water Extraction and Treatment—Installation of EW-2A was asignificant improvement and worthy of mention.

Response—The following sentence has been added as the second to last sentence of theGround-Water Extraction and Treatment paragraph of Section 5.2:

An additional extraction well (EW-2A) was added to the extraction system inJuly 1998.

28. Section 5.3, Areas of Non-Compliance

(a) (ED) Second Line—"Are" should be "Area."

Response—"Are" has been replaced with "Area."

(b) Section on ..risk associated with ingestion of contaminated ground water...Lack ofground-water ICs in the ROD is an area of non-compliance. (See Comment No. la.)

Response—Please see Response to General Comment No. Ib. The following text hasbeen added to Section 5.3:

Institutional Controls

The operable unit remains within the restricted area of the base and, as such, theinstitutional controls are effective. However, ground-water institutional controlsare not documented in the ROD and need to be added to the ROD. In addition,institutional controls for restriction of use and contact with ground water need tobe included in the next revision of Operating Instruction NASBINST 5090.1 A,"Restriction on Excavation Activities." The next revision of NASBINST 5090.1Ais scheduled for September 2000.

29. Section 5.4, Recommendations

(a) Ground-water ICs need to be added as a component of the ROD and documented inNASBINST 5090.1A. (See General Comment Nos. la and Ib.)

Response—Please see Response to General Comment Nos. Ib and 29b below.

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(b) (ED) Adding ground-water ICs would be an additional action and thus requireredrafting this sentence.

Response—Please see Response to General Comment No. Ib. The following text hasbeen added to the second bullet on Page 5-6 in Section 5.4:

• Add ground-water institutional controls to the ROD and amend OperatingInstruction NASBINST 5090.1 A "Restriction on Excavation Activities," to add arestriction on use and physical contact with contaminated ground water.

30. Section 5,5, Statement of Protectiveness

(a) (RR) Addition of ground-water ICs to the ROD will make the remedy fully protective.(See General Comment Nos. la and Ib.)

Response—Please see Response to General Comment No. Ib. The following text hasbeen added to Section 5.5:

The purpose of the five-year review is to ensure that the selected remedy remainsprotective of human health and the environment and is functioning as designed.The ground-water extraction and treatment system and the ground-watermonitoring program have been only partially successful as implemented; but giventhe current data, these remedies appear to be protective of human health and theenvironment with the existing institutional controls as exercised by the Navy(restricted access area surrounded by fencing). The addition of institutionalcontrols in the ROD to restrict ground-water use will better ensure the protection ofthe selected remedy in the future and formalize the controls implemented byNASBINST 5090.1 A. Long-term operation and maintenance of the extraction andtreatment system is ongoing in addition to the long-term monitoring program.

(b) (ED) Third line—Insert "implemented" after "successfully."

Response—The text has been revised as requested.

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RESPONSE TO COMMENTS FROMMAINE DEPARTMENT OF ENVIRONMENTAL PROTECTION

ON THE FIVE-YEAR REVIEWNAVAL AIR STATION, BRUNSWICK, MAINE

COMMENTOR: Claudia Sait DATED: 3 February 2000

The Maine Department of Environmental Protection (MEDEP or Department) has reviewed thedraft report entitled Five-Year Review, Naval Air Station, Brunswick, Maine, dated 5 January2000, prepared by EA Engineering, Science, and Technology. Based on that review, theDepartment has the following comments and issues.

Each of our comments is followed with a code that indicates whether a response is required(RR), no response is required (NR), editorial correction needed (ED); or meeting discussionrequested (MTG). No response is required for editorial corrections unless the Navy disagreeswith the correction.

GENERAL COMMENTS:

1. Concerning the assessment of "areas of noncompliance," the task is to report if the remedialaction fails to conform to remedial objectives. This language is found in EPA OSWERDirective 9355.7-02A (our copy is stamped July 1994). In OSWER's August 1996"Guidance for Evaluation of Federal Agency Demonstrations that Remedial Actions areOperating Properly and Successfully Under CERCLA Section 120(h)(3)," the phrase "failsto conform to remedial objectives" is apparently replaced by "operating properly andsuccessfully." The Department would like to have the newer phrase used in this five-yearreview, as it is a lot more meaningful yardstick. Moreover, although EPA has used thephrase "area of noncompliance," the word "area" was defined as "any substantial aspect." Ifthe Navy keeps this older terminology, "area" must be defined as an aspect, so as not toconfuse it as a locality. (RR)

Response—The newer phase "operating properly and successfully" will not replace "fails toconform to remedial objectives" for this five-year review. The use of "area" with regards toan aspect and not a locality will be defined where appropriate within the five-year review.These are Base Realignment and Closure terms.

2. According to EPA's "Structure and Components of Five-Year Reviews," OSWER Directive9355.7-02, dated 23 May 1991, there is a public participation component to the five-yearreview. How is the Navy proposing to handle the public participation portion of the five-year review? (RR)

Response—A notice will be published in a local newspaper and a presentation of the FinalFirst Five-Year Review will be made at the April Restoration Advisory Board meeting.A 30-day public comment period will follow the presentation of the First Final Five-YearReview Report. The response to comments have been provided as an appendix to the FinalFive-Year Review Report.

3. It has come to the Department's attention during the review process that the Record ofDecision for a Remedial Action at Sites 1 and 3 (1992) did not include provision forrestricting excavation. Similarly, there is no restriction preventing the contact with andextraction of ground water within the Eastern Plume in the "Sites 4, 11, and 13 No FurtherAction and a Remedial Action for the Eastern Plume" (1998). Without these restrictions,the question of protectiveness is called into question. These oversights must be corrected.(RR)

Response—The restrictions of excavations at these sites will be made during the nextrevision of Operating Instruction NASBINST 5090.1 A, "Restriction on ExcavationActivities." The next revision of NASBINST 5090.1 A is scheduled for September 2000.The revised excavation text will be forwarded to EPA/MEDEP prior to finalizing NASBINT5090.1 A to receive EPA/MEDEP comments on the revised text. The restriction will beexplained in an Explanation of Significant Differences.

4. The Five-Year Review should identify the actual Institutional Control document whereverinstitutional controls are cited as part of the remedy.

Response—Where appropriate, the institutional control document will be cited andreferenced in the Five-Year Review Report.

SPECIFIC COMMENTS

Introduction

5. Table 1, Page 2, Active Sites Not Included in the Five-Year Review

(a) While Building 95 was not included in the Federal Facilities Agreement, the Navycommitted to including it in the five-year reviews. However it is MEDEP'sunderstanding that it is not included in this five-year review because the agencies havenot agreed upon the final remedial action objectives for this site. Since this is aCERCLA removal action, please identify what upcoming document will include thefinal remedial objectives. (RR)

Response—This site was designated Site 17 for tracking purposes only, and is not partof the National Priorities List. There is no final agreed remedial action on this area.Although it is not subject to CERCLA required five-year reviews, the Navy agrees toreview it under the same process. A draft final Long-Term Monitoring Plan (LTMP) isbeing completed for Building 95 and will be issued by the end of March 2000, whichwill include the remedial objectives for the site. A Consensus Statement andinstitutional controls are planned for completion by December 2002.

(b) One of the issues to be resolved for Building 95 is the matter of institutional controls.If the site is not appropriate for unrestricted use, then institutional controls will berequired and this site must be included in the five-year reviews to ensure that theinstitutional controls remain in effect. (NR)

6. Table 2, Page 3, Inactive Sites Not Included in Five-Year Reviews

(a) The Navy should provide more information as to why these inactive sites are notincluded in the five-year review. More information in the third column would also allayany concern on the part of the public regarding these sites. (RR)

Inclusion of the following information outlining would be helpful:

• Sites 5, 6, and 8 were landfills transported to Landfills 1 and 3. Becausecontaminated soils and non-hazardous debris were removed from theses sites, theRecords of Decision stated that no long-term controls were necessary and that thefive-year review would not apply.

• Confirmation sampling cited in the Remedial Action Final Report of Sites 1, 3, 5, 6,and 8 (August 1996) indicated that the response objectives of the Records ofDecision had been achieved.

Response—A fourth column (Site Status) has been added to the tables (Tables 1 and 2)to summarize site activities. The recommended text above will be summarized andadded to the 3rd column of Table 2 as follows:

Site 5 - Asbestos was successfully removed and placed at Sites 1 and 3 Landfill.Record of Decision signed August 1993 (U.S. Department of Navy 1993a)indicates five-year reviews would not be required.

Site 6 - Rubble and asbestos were successfully removed and placed at Sites 1 and3 Landfill. Record of Decision signed August 1993 (U.S. Department of the Navy1993a) indicates five-year reviews would not be required.

Site 8 - Soil was removed and placed at Sites 1 and 3 Landfill. The Record ofDecision (U.S. Department of the Navy I993b) indicated monitoring would berequired if soil was not satisfactorily removed. No monitoring was requiredsubsequent to soil removal (OHM 1996). Record of Decision signed in 1993.

(b) The Harpswell Fuel Depot is identified in the Initial Assessment Study as Site 10; thistitle follows through into the Federal Facility Agreement, therefore, for consistency,please use the same name for the facility. Also to close this loop, please provideaddition information as to the resolution of this site. For example, it is located inHarpswell, Maine and remediation is being handled by the Defense Energy SupplyCenter. If it was not included on the National Priorities List site, this should also benoted. (RR)

Response—The name of Site 10 on Table 2 has been revised as requested. Thefollowing text has been added to column 3 of Site 10:

Not part of Naval Air Station, Brunswick. Site is located in Harpswell, Maine,and remediation was completed by the Defense Energy Supply Center. Site 10(Harpswell Fuel Depot) was not included on the National Priorities List due topetroleum exclusion.

Sites 1 and 3

7. Section 2.1, Page 1, Site Description, 1st Sentence—Sites 1 and 3 would be more aptlyidentified as hazardous waste landfills. Please correct. (ED)

Response—The first sentence of Section 2.1 has been revised as follows:

Sites 1 and 3 are closed hazardous waste landfills within the same operable...

8. Section 2.1, Page 1, Site Description, Last Bullet—The correct title of the Long-TermMonitoring Plan is Draft Final Long-Term Monitoring Plan. (ED)

Response—The Long-Term Monitoring Plan was issued Final in February 2000 and the titlehas been corrected as suggested.

9. Section 2.2, Page 2, Discussion of Remedial Objectives, 2nd Bullet—Does the Navy mean"Reduce the concentrations of metals (iron and zinc) discharging the to Mere Brook? Pleasecorrect. (ED)

Response—The fourth bullet has been revised as suggested.

10. Section 2.2, Page 2, Discussion of Remedial Objectives, 4h Bullet—"The cap extends overthe slurry wall to prevent rainfall within the slurry wall limits."

MEDEP recommends the following language: "The cap extends over the slurry wall toprevent the infiltration of rainfall within the slurry wall limits." (ED)

Response—The second bullet of the second set of bullets has been revised as follow:

• A low permeability cap was placed over the landfill area and slurry wall to reducethe amount of rainfall infiltration, thereby reducing leachate production.

11. Section 2.2, Page 2, Discussion of Remedial Objectives, 5th Bullet—This bullet is poorlywritten. Please consider: Capturing this contaminated water will prevented it fromdischarging to Mere Brook. These extraction wells facilitated the collection of the groundwater remaining beneath the landfill cap following installation of the slurry wall within thelimits of the slurry wall after the construction of the landfill cap and reduced the timerequired to lower ground-water levels below the waste. (ED)

Response—The third bullet of the second set of bullets has been revised as suggested.

12. Section 2.2, Page 2, Discussion of Remedial Objectives, (>h Bullet—The way this bullet iswritten indicates that the institutional controls and land use restrictions have not beenimplemented. Institutional controls do not appear to have been a component of this Recordof Decision. Please clarify. While the Naval Air Station includes Sites 1 and 3 on its baseinstructions 5090.1 A, excavation within the landfills is not prohibited by the Record ofDecision. This oversight must be corrected. (RR)

Response—The institutional controls will be added to the ROD.

13. Section 2.3, Page 3, Areas of Noncompliance, Paragraph 2—"Since the monitoring begin..." This should read "Since the monitoring began... (ED)

Response—The sentence in Paragraph 5 on Page 3 has been revised as suggested.

14. Section 2.3, Page 3, Areas of Noncompliance, Page 3, Top of Page—"The presence ofthese remedial structures has resulted in an area of lower head downgradient of Sites 1 and 3(EA 1999b)."

What is actually needed is just the opposite: higher head that surrounds the site creatinginward gradients preventing the escape of contaminated ground water. The area of lowerhead has always been naturally present because it is downgradient. The shallow and deep

potentiometric contours downgradient of the landfill do not show that the landfill groundwater is captured. The Department has commented a number of times in monitoring eventreviews that contouring in this area is not properly drawn. When properly drawn, landfillground water is not captured, as indicated by the elevated arsenic concentrations that persistin monitoring well MW-218.

Record of Decision objectives (Bullets 3 and 4 in the five-year review) are not being met,because leachate seeps and ground-water concentrations of metals and vinyl chloride havenot been reduced or minimized. Arsenic (seeps and MW-218) and vinyl chloride (SEEP-04and MW-217B) concentrations are well above Maximum Exposure Guidelines(MEGs)/Maximum Contaminant Levels (MCLs), and would present a potential humanhealth problem if the area were to become unrestricted to the public. The arsenic and zinc inSEEP-05 water rose to 1 and 7 ppm, respectively (see 1998 Annual Report). Therefore, itmust be noted in the five-year review that downgradient seeps still have arsenic, zinc, andvinyl chloride which have not been reduced and are not meeting the objectives of theremedy. (ED)

Response—The following text has been added as the second paragraph on Page 2-3:

VOCs have been detected at increasing concentrations in the ground water at monitoringwells within the landfill. No VOCs have been detected at concentrations above MCLs orMEGs downgradient and outside the landfill, except at SEEP-04.

15. Section 2.4, Page 3, Recommendations, Paragraph 3—"The Draft Final Long-TermMonitoring Plan should be finalized."

The Navy must commit to finalizing the Long-Term Monitoring Plan. The Navy hasreceived a number on concessions, such as the cessation of pump if the criteria forresumption of pumping was provided. This criteria has never been finalized although thepumping ceased in November 1998. The Navy must commit to a date to finalize the Long-Term Monitoring Plan. (RR)

Response—The Long-Term Monitoring Plan was finalized and distributed on 29 February2000. The last bullet of Section 2.1 Significant Events has been revised as follows:

• 2000 Final Long-Term Monitoring Plan (EA 2000a).

The third paragraph of Section 2.4 has been removed.

16. Section 2.5, Page 3, Statement of Protectiveness—The remedy is protective of humanhealth solely because of the restricted access. The remedy is only partially successful,because landfill-contaminated ground water above MEGs/MCLs is seeping into MereBrook, and would pose a human health threat if the area were accessible. This paragraphmust be revised. (RR)

Response—Section 2.5 has been revised as follows:

The purpose of the five-year review is to ensure that the selected remedy remainsprotective of human health and the environment and is functioning as designed. Thesource control remedy selected for Sites 1 and 3 Operable Unit has been successfullyimplemented, and remains protective of human health and the environment as long asthe area maintains restricted access. If the area were to become freely accessible,institutional controls would have to be imposed on the site. Long-term operation andmaintenance activities are ongoing. Operational activities also include ground-water,surface water, sediment, and landfill gas sampling.

Site 2 (Orion Street Landfill-South)

17. Section 3.1, Page 2, Site Description, 1st Sentence—Please identify Site 2 Orion StreetLandfill as an inactive hazardous waste landfill. (ED)

Response—The text has been revised to indicate that Site 2 Orion Street Landfill is a closedhazardous waste landfill.

Site 2 Orion Street Landfill is a closed hazardous waste landfill located south...

18. Section 3.4, Page 2, Areas of Non-Compliance, 2nd Paragraph—Please indicate when theLong-Term Monitoring Plan will be finalized. (ED)

Response—The last bullet of Section 3.1, Significant Events, has been revised to indicatethe Long-Term Monitoring Plan has been finalized as follows:

• 2000 Final Long-Term Monitoring Plan (EA 2000c).

The fourth paragraph of Section 3.4 has been removed.

19. Section 3.4, Page 2, Recommendations—Another action item that the Navy has agreed todo is install an additional monitoring well as part of the Long-Term Monitoring Program.Please add this to the second sentence. Also, state that metallic surface debris was removedfrom the site in 1999. (ED)

Response—The installation of an additional monitoring well was previously agreed to by allinterested parties and removal of surface debris has already occurred. Therefore, it is notnecessary to add these as action items for recommendations, as they are already discussed inthe Final Long-Term Monitoring Plan (EA 2000c), which has been referenced.

20. Section 3.5, Page 2, Statement of Protectiveness—This statement is premature becauseenvironmental monitoring has not been undertaken since 1990. It is not currentlydeterminable that the Minimal Action remedy is successful, and any statement to that effectmust be deleted. (ED)

Response—The second and third sentences of Section 3.5, Statement of Protectiveness,have been revised as follows:

Environmental monitoring has not been performed since 1990. A determination forsuccess of Minimal Actions cannot be made at this time because the activities necessaryfor implementation of the Minimal Action Alternative have not been completed.

Site 9 (Neptune Drive Disposal Area)

21. Section 4.1, Page 1, Significant Events—Please add the year that long-term monitoring wasinitiated. (ED)

Response—The following text has been added as the second bullet of Section 4.1.1:Significant Events:

• 7995 Long-Term Monitoring initiated.

22. Section 4.2, Page 2, Discussion of Remedial Objectives, 1st Bullet—The remedialobjectives in the Record of Decision, Bullet 1 (Page 2-24) does not specify vinyl chloride,therefore, please remove the reference to vinyl chloride from this sentence. (ED)

Response—The reference to vinyl chloride in the first bullet of Section 4.1 has beenremoved as suggested and replaced with contaminant.

23. Section 4.2, Page 2, Discussion of Remedial Objectives, Bullet 4—Under long-termmonitoring, a stated objective component is to "assess whether contamination is migratingoffsite."

This task is only partially addressed by the Long-Term Monitoring Program. Only onecurrent monitoring well (MW-NASB-77) is located at or beyond the site boundary. Thiswell may be retained for a limited time in order to demonstrate, through re-instituting a verylow level sensitivity analytical method, that the August 1996 detection of vinyl chloride atthe MEG concentration (0.15/^g/L) is not re-occurring.

Prior to flooding of the small drainage demarcating the site boundary, wells MW-NASB-077 and MW-NASB-078 located across the drainage from Site 9 were considereddowngradient of the site. It appears now that detention ponds have deflected thedowngradient pathway near the ponds eastward. Restoration Advisory Board membersgenerally agree that the detention ponds should behave as a hydraulic barrier and are themajor receptors of the shallow contaminated ground water. Therefore, the current thinkingis that contamination can not migrate offsite, unless it does so in a very diluted surface waterenvironment. As a consequence, the importance of offsite wells in the Long-TermMonitoring Program has been minimized. The single surface water monitoring station(SW-010) is upstream on the north branch from where the bulk of volatile organiccompound-contaminated ground water would enter the ponds and, therefore, mostlymonitors for contaminants from the ash landfill.

It should clearly state in this five-year review document that monitoring to detect offsitemigration of vinyl chloride is very limited, and a new interpretation that virtually all shallowground water discharges into the ponds has alleviated this concern. However, monitoringdoes address any offsite contaminant migration from the ash landfill. (RR)

Response— There are two wells located offsite (MW-NASB-077 and MW-NASB-078).Currently, only MW-NASB-077 is being sampled during monitoring events. However, bothmonitoring wells have had no detection of VOCs and that was why MW-NASB-078 wasdropped from the monitoring program. Current monitoring wells in the LTMP are sufficientto evaluate if offsite migration is occurring.

24. Section 4.2, Page 2, Discussion of Remedial Objectives, tfH Bullet — Please recheck the firstsentence. MEDEP recommends: Institutional controls will be used to prevent use of andcontact... (ED)

Response — The sentence has been revised as suggested.

25. Section 4.3, Page 3, Areas of Non-Compliance — It is the Department's view that the firstobjective on Page 2 (a reduction in vinyl chloride concentrations) is not being met. Thesummary table on Page 3-2 (1998 Draft Annual Report) indicates an increasing trend at 3 of7 wells in 1998. The table also indicates that during the period 1995-1998, only 2 of 7 wellsshowed decreasing trend in vinyl chloride. What this discussion on natural attenuation doesnot present is that one well (MW-NASB-069) is responsible for the bulk of measured vinylchloride, and the trend is distinctly increasing. The September 1999 concentration doubledthe previous highest concentration, reaching approximately 45 /^g/L (well above the MCL of

Therefore, the statement that "all areas currently comply with the ROD's remedialobjectives" appears to be in jeopardy if the data from 1999 is included. The rate ofdechlorination of the parent compound may be accelerating or perhaps vinyl chloride isaccumulating in the clay depression that MW-NASB-069 draws water samples from.Possibly, natural attenuation is working too rapidly at the site. Because vinyl chloride is anextremely toxic compound in ground water and its source has not been discovered, theDepartment has growing concerns and would like to discuss when alternative remediesshould be considered. This statement must be qualified to acknowledge recent trends. (RR)

Response — The text of the first bullet in Section 4.2, Discussion of Remedial Objectives,will be revised to state the remedial objective stated in the Final ROD (Section V1HRemediation Objectives). The text has been revised in Section 4.2, first bullet as follows:

• To reduce contaminant concentrations. . .

The increasing vinyl chloride concentrations are an indicator that the natural attenuation isoccurring at the site. Monitored natural attenuation is the selected remedy for this site andthe amount to time required to complete the goal of the remedial objective is estimated to beup to 20 years. Currently, the short term vinyl chloride concentration trend is increasing,

which is evidence that continued natural degradation of the COCs is occurring. The topic ofalternative remedies for this site will be discussed at the April 2000 Technical Meeting.

26. Section 4.3, Page 4, Areas of Non-Compliance—The second sentence refers to DCE as theparent compound of vinyl chloride. It is very unlikely that DCE was released to theenvironment, either on Site 9 or upgradient. It is much more likely that PCE or TCE wasreleased, which degraded to DCE, and subsequently to vinyl chloride. Levels of TCE up to3 ̂ g/L have been consistently detected at some Site 9 wells. The Department recommendsthat DCE not be called the parent compound of vinyl chloride. Please correct this statement.(ED)

Response—The second sentence of the third paragraph on Page 4-3 has been changed to thefollowing:

...of total dichloroethene and an increasing concentration of vinyl chloride (abreakdown product of dichloroethene) indicates...

27. Section 4.3, Page 4, Areas of Non-Compliance, Long-Term Monitoring—State the natureof changes in the pre-existing long term monitoring plan that were implemented and why thenew plan better addresses the goals of the ROD. (RR)

Response—The text has been revised as follows:

In 1994, a Long-Term Monitoring Plan was established for Site 9 (ABB-ES 1994). TheLTMP was finalized for Site 9 on 16 August 1999 (EA 1999b). The goals of the final1999 LTMP are as follows:

• Monitor changes in the plume boundaries and potential migration pathways.• Monitor effectiveness of the remedial action for the protection of human health

and the environment.• Evaluate whether the inactive landfill contents are impacting ground water.• Monitor the VOC concentration to evaluate the effectiveness of natural

attenuation and determine trends with time.• Monitor impacts to the environment due to Site 9.

28. Section 4.3, Page 4, Institutional Controls—The copy of the operation instructions (NASB1999) must be modified to incorporate MEDEP comments as required by the Record ofDecision, therefore, the institutional controls (base operations instructions) cannot beconsidered final. Please rewrite. (ED)

Response—The text has been revised as stated below:

Institutional controls at Site 9 consist of ground-water and land use restrictions thatapply to the entire Site 9 area east of Orion Road and Avenue F, east ofMW-NASB-073,and south of Building 52. However, institutional controls to prohibit ground-water useand physical contact with ground water must be incorporated into the next revision ofOperating Instruction NASBINST 5090.1A, "Restriction on Excavation Activities. " The

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next revision ofNASBINST 5090.1A is scheduled for September 2000. This program wasshown to be effective by NAS Brunswick's recent request for concurrence with theproposed Bachelor Enlisted Quarters Military Construction Project.

29. Section 4,4, Page 5, Recommendations, Paragraphs 2 and 3—The use of the verb "should"expresses probability or an expectation, not an absolute. Therefore, please replace "should"with shall or will. (ED)

Response—The verb "should" has been replaced with "will" in paragraphs two and three ofSection 4.4, Recommendations.

30. Section 4.4, Page 5, Recommendations Paragraph 1—The first sentence needs to beexpanded to address the non-compliance noted by MEDEP above. A suggestedmodification is:

No additional remedial actions are required at this time, however, if the monitoringevents in 2000 result in further increases in vinyl chloride in ground water, additionalfield work may be required to better delineate a potential plume of deep-seated vinylchloride. EPA and MEDEP will be consulted to establish a specific trigger level forthis action. (ED)

Response—The first bullet of Section 4.4, Recommendations, has been revised as follows:

31. Section 4.4, Page 5, Recommendations, Paragraph 4—It is unclear if this is a proposal ornot. Please clarify. (RR)

Response—Paragraph 4 will be removed from the document.

32. Section 4.5, Page 5, Statement of Protectiveness—The natural attenuation remedy appearsto be generating anaerobic biodegradation as it should, but is producing a larger mass of thetoxic daughter compound, vinyl chloride, than expected. The Department believes that theremedial air sparging activities at the former NEX Service Station, located upgradient ofSite 9, may have enhanced this situation. The Department also believes that it is possiblethat residual TCE may reside in fine-grained soils within or immediately underlying theshallow saturated sand at Site 9, and that the mass of vinyl chloride in site ground water mayincrease further. To date, no evidence has been collected that indicates surface water atSite 9 has been adversely impacted. Therefore, to date, the natural attenuation/institutionalcontrol remedy appears to be protective of human health and the environment. However,Restoration Advisory Board members must continue to reassess the vinyl chloride situationin each forthcoming annual report. (NRR).

Eastern Plume Operable Unit

33. Section 5.0, Page 1, Site Description—Additional information on the resolution of the soilsat Site 13 must be included. (RR)

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Response—Additional text will be added to Site 13 in Section 5.1.1 to provide a descriptionof the resolution of the soils at Site 13, as follows:

In 1998, a ROD was signed for No Further Action for soils at Sites 4, 11, and 13. Thedecision was based on the Feasibility Study (E.C. Jordan 1992) that concluded the onlyrisk remaining at these sites is from the continuing impacts to ground water from soils atSite 11, Removal actions for metallic debris, drums, and contaminated soils werecompleted at Site 11 following the Feasibility Study. The metallic debris and drums weredisposed off-base, and contaminated soils were used for subgradefill beneath the Sites 1and 3 Landfill cover (U.S. Department of the Navy 1998b).

Subsurface soils at Building 584 at Site 4 did not contain detectable quantities of VOCs;however, subsurface soil samples were not collected directly from the suspected pitlocation due to the presence of Building 584 at that location. Therefore, no soils wereremoved from this location. If the building is ever removed, further investigations andremedial actions may be required.

During the Remedial Investigation, fuel oil contamination was detected in the soil andwas believed to have been related to the dieselfuel oil underground storage tanks at Site13. The underground storage tanks were removed from the site, but no soils wereremoved. Ground-water wells were installed and sampled for VOCs. The ground-waterVOC data indicate a decrease in VOC concentrations as the result of the undergroundstorage tank removals.

34. Section 5.0, Page 1, Site Description, Paragraph 5—"Removal actions completed as Site11..." Please change "as" to "at." (ED)


35. Section 5.1, Page 1, Ground-Water Operable Unit (Eastern Plume)—"The southernboundary of the Eastern plume is located near New Gurnet Road."

Recent technical discussions with the Navy and EPA have illuminated the likelihood thatthis boundary could be a function of the existing well network. Because additional work isprobable, please insert "presently mapped' before "southern boundary."

Response—The text has been revised as recommended.

36. Section 5.1, Page 2, Significant Events—Please add the following event: 1999 Two-DayTechnical Workshop on Outstanding Regulator Concerns. (ED)

Response—The text has been added as requested.

37. Section 5.2, Page 3, Discussion of Remedial Objectives, Ground Water Monitoring—"Thegoals of the plan is as follows: provide a tiered approach to attain the requirements ofMEDEP water quality standards."

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(a) While this statement is included under Ground-Water Monitoring in the Record ofDecision, the tiered approach is actually for surface water quality not ground water.This could be clarified in the five-year review by changing this heading to Monitoring.(RR)

Response—The heading "Ground Water Monitoring" has been revised to "Monitoring"as suggested.

(b) The verb should be "are." (ED)


38. Section 5.2, Page 3, Discussion of Remedial Objectives, Five-Year Reviews—Under "Five-Year Reviews," identify the hazardous substances that will remain in place. How willconditions at Sites 4, 11, and 13 be evaluated at the three source areas when the Long-TermMonitoring Program includes very few monitoring wells near these sources? TheDepartment endorses a concept that pockets of residual soil contamination may continue tokeep the dissolved plume from shrinking, and if so, such pockets would require specialattention. These pockets may, or may not, be located at former source areas. Please bemore specific.

Response—The text in Section 5.2, "Five-Year Reviews" has been revised.

...in hazardous substances (contaminants of concern listed in the Final 1998 ROD)remaining in place..

The conditions will be evaluated and monitored in accordance with the objectives and goalsof the 1998 ROD and 2000 Final LTMP for the Eastern Plume.

As per EPA Comment No. 27(a), the following text has been added as the second paragraphin Section 5.2:

• To accomplish these objectives within a 17- to 72-year timeframe, the following....

39. Section 5.3, Pages 3 and 4, Areas of Non-Compliance—

(a) Please reread the first sentence and check for typographical errors and clarity. (ED)

Response—The first sentence of Section 5.3 has been revised as follows:

Any substantial aspect of the remedial action that fails to conform to remedialobjectives would be considered an area of non-compliance.

(b) The Department does not agree that "all areas currently comply with the ROD'sremedial objectives," and has elaborated our reasons in the bullets that follow.

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• Concerning further migration of the southern edge of the Eastern Plume, four deepsentinel wells (MW-230A, MW-231A, MW-333, and MW-334) and three shallowsentinel wells (MW-231B, MW-313, and MW-318) are being monitored in thelong-term program. Two deep sentinel wells (MW-230A and MW-333) haveconsistently had detections of DCA and/or DCE. One shallow sentinel well(MW-313) showed 1 jig/L of TCE in November 1998 and up to 2 /u.g/L of 1,1-DCA(September 1999).

As MEDEP and EPA discussed at the November 1999 Technical Meeting, thecross-gradient distances between MW-231A, MW-230, and MW-334 (600 ft and450 ft, respectively) are too large to confidently say where the leading edge of theEastern Plume really is located. The above-noted detections of chlorinatedhydrocarbons, although below the MCLs/MEGs, suggest that contaminates havemigrated beyond the 1995 mapped edge of the plume. Therefore, it is unknown atthis time if the plume advanced during the last 5 years, or that the edge may havebeen further advanced than mapped in 1995. Furthermore, an accurate assessmentcannot be made whether the remedial pumping system has minimized furthermigration of the Eastern Plume, however, existing data would indicate that ground-water flow gradients have not been reversed inward along much of the southernfringe of the known plume extent. More monitoring wells are needed to answerthese questions.

• With respect to negative impacts to surface water, the reversal of pre-pumpingupward gradients by EW-2A beginning in late 1998 has likely mitigated what theDepartment believes was slow seepage of contaminants upward through the shallowconfining sandy silt bed along Mere Brook in the vicinity of its confluence withMerriconeag Stream. Natural attenuation in wetland soils and dilution by streamflow may be adequate for downgradient reaches of Mere Brook to protect theenvironment, however, this potential needs to be field tested if the plume is found tohave migrated further southward than currently mapped.

• Even though an approximate 500 Ib of volatile organic compounds have beenremoved to date, the extent of contamination has not changed significantly, and highconcentrations of 1,1,1-TCA and TCE remain within the plume. As the Navyrealizes, the existing extraction well system has been slow in achieving any degreeof restoration of the aquifer. Tentative plans to reconfigure the extraction wellsshould help this situation greatly, provided that chlorinated hydrocarbons are not yetbeing dissolved into aquifer water from the original contaminant source areas orpossibly from a dense, non-aqueous phase liquid source downgradient of theoriginal source areas.

These areas of non-compliance must be noted. (RR)

Response—The remedial objectives are in progress to reach remedial objectives of theROD within a 17- to 72-year timeframe. The text for Section 5.3 (Areas of No-Compliance) has been modified to address this comment.

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40. Section 5.4, Page 5, Recommendations

(a) While the Department does not know of any additional response actions needed at thistime to be protective of human health and the environment, the rate of aquiferrestoration has to be improved if the Record of Decision objective of aquifer cleanupis to occur in a reasonable timeframe. Questions raised by MEDEP and EPAconcerning the leading edge of the Eastern Plume and the potential for dense, non-aqueous phase liquid should be addressed by additional field work. The results ofsuch work may require additional response actions well before the next five-yearreview. (NR)

(b) "However it is strongly recommended optimization of the treatment system and Long-Term Monitoring Plan continue."

First the draft final Long-Term Monitoring Plan must be finalized. MEDEPrecommends the following language: "However it is strongly recommended thatoptimization of the treatment system continue and that the draft final Long-TermMonitoring Plan be finalized and implemented.'1'' (ED)

Response—The Long-Term Monitoring Plan has been finalized. The sentence will berevised as follows:

However, optimization of the treatment system should continue and the final Long-Term Monitoring Plan should be implemented.

(c) Please modify Recommendation 3 to read:

Determine if the southern terminus sentinel wells are adequately placed, andinitiate work to correct the situation if they are not adequately placed. (ED)

Response—Recommendation 4 has been modified as follows:

Determine if the southern terminus sentinel wells are adequately placed, andinitiate work to correct the situation if necessary.

(d) The Department supports the initiation of a formal evaluation for monitored naturalattenuation, but cautions the Navy that until concentrations in the Eastern Plume aresubstantially lowered by remedial pumping, heavy reliance on monitored naturalattenuation will not be acceptable. Any consideration of monitored natural attenuationwill include assessing the timeframe for restoration of the aquifer and the potential forground water to degrade surface water. As the Navy is aware, all of Maine's groundwater is designated as GW-A. Also, MEDEP requests that the last sentence ofRecommendation 4 be deleted, or highly qualified per our concerns expressed inComment 39b. (RR)

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.. .the plume apparently has not changed since at least 1995; however, additionremedial actions may be warranted in the area of the southern terminus of theEastern Plume prior to formal initiation of monitored natural attenuation.

(e) "Pursue negotiations with the regulatory agencies to establish risk-based cleanup..."

The Navy should be aware before undertaking this recommendation that all groundwater in Maine is classified as GW-A under the Water Classification Program (Title38 section 465-C), whether or not it is used for drinking water, and the MaineExposure Guidelines are risk based.

Response—The Navy is aware of this.

41. Section 5.5, Page 6, Statement of Protectiveness—

The Department disagrees with the statement that includes the ground-water extraction partof the system as being successful. The Eastern Plume wells have moved huge volumes ofclean shallow ground water through the treatment plant due to flawed screen placements.The extraction wells have not been effective in attaining an EPA Core Criteria of "operatingproperly and successfully" which specifies that "ground-water elevation data show inwardgradients throughout plume for all affected aquifers'" (OSWER guidance of August 1996).The wells appear to be functioning as designed with ground water being captured from bothshallow and deep sand aquifers, but continuous areal drawdown in the deep sand has notoccurred as modeled by the Navy's consultant. Maintenance problems with the extractionwells has often caused reductions in total extraction rates, further reducing plume capture.

The Department recommends that the second sentence be replaced with the following:

The ground-water extraction and treatment system and monitoring have been onlypartially successful, but given the current data, appears to be protective of humanhealth and the environment under the existing institutional controls (military securedarea within fencing). (ED)


The ground-water extraction and treatment system and the ground-water monitoringprogram have been only partially successful as implemented; but given the current data,these remedies appear to be protective of human health and the environment with theexisting institutional controls as exercised by the Navy (restricted access areasurrounded by fencing).

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