RECORD OF DECISION (ROD) OPERABLE UNIT 2 · a subsequent Record of Decision (ROD) will be issued to...

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RECORD OF DECISIONFOR AN

INTERIM REMEDIAL ACTIONAT THE

EASTERN PLUME GROUNDWATEROPERABLE UNIT

NAVAL AIR STATION BRUNSWICK, MAINE

t June 1992

United StatesEnvironmental ProtectionAgency

Off ice ofEmergency andRemedial Response

EPA/ROD/R01 -92/066June 1992PB93-963706 -\

SEPA SuperfundRecord of Decision:

Brunswick Naval Air Station(Operable Unit 2), ME

NOTICEThe appendices listed in the index that are not found in this document have been removed at the request ofthe issuing agency. They contain material which supplement but adds no further applicable information tothe content of the document All supplemental material is, however, contained in the administrative recordfor this site.

50272-101

REPORT DOCUMENTATION 1. REPORT NO. 2.PAGE EPA/ROD/R01-92/066

4. Title and SubtitleSUPERFUND RECORD OF DECISIONBrunswick Naval Air Station (Operable Unit 2), MESecond Remedial Action - Interim

7. Authors)

». performing Organization Name and Address

12. Sponsoring Organization Name and Address

U.S. Environmental Protection Agency401 M Street, S . W .Washington, D.C. 20460

3. Recipient's Accession No.

5. Report Dale

06/16/92Gi

8. Performing Organization Rept No.

10. Project/Task/Work Unit No.

11. ConlrKt(C) Of Grant(G) No.

(C)

<G>

13. Type of Report i Period Covered

800/000

14.

15. Supplementary Note*

PB93-963706

16. Abstract (limit: 200 words)

The 3,094-acre Brunswick Naval Air Station site (NAS Brunswick) is an active militaryfacility located south of the Androscoggin River between Brunswick and Bath, Maine.The primary mission of the Base is to operate and maintain P-3 Orion aircraft for theU.S. Navy's antisubmarine warfare operations in the Atlantic Ocean and MediterraneanSea. Land use in the area surrounding the Base is primarily residential, with anelementary school, hospital, and college located 1 mile west of the site boundary. Thesouthern edge of the Base borders coves and estuaries cf Harpswell Cove. Ground waterunderlying the site is described as a potential source of drinking water, but currentlyNAS Brunswick is serviced by a public water supply system. NAS Brunswick, which firstbecame active in the 1940's during World War II, has many areas onsite that were usedfor past disposal of hazardous materials. Investigations were conducted by the U.S.Navy and EPA beginning in 1983 to determine the contaminated site areas including, Site4, an acid/caustic pit used from 1969 to 1974 for disposal of liquid wastes; Site 11, aformer fire-training area, used over a 30-year period until 1990, where fuels, oils,

(See Attached Page)17. Document Analysis a. Descriptors

Record of Decision - Brunswick Naval Air Station Operable Unit 1), MESecond Remedial Action - InterimContaminated Medium: gwKey Contaminants: VOCs (PCE, TCE)

b. Identifiers/Open-Ended Terms

c. COSAT1 Field/Group

18. Availability Statement 19. Security Class (This Report)None

20. Security Class (This Page)None

21. No. ofPsges

7222. Price

(See ANSI-ZM.18) See Instructions on Reverse OPTIONAL FORM 272 (4-77)(Formerly NDS-35)Department of Commerce

EPA/ROD/R01-92/066Brunswick Naval Air Station (Operable Unit 2) , MESecond Remedial Action - Interim

Abstract (Continued)

and degreasing solvents were used in the fire-training exercises; and Site 13, theDefense Reutilization and Marketing Office (DRMO) area, consisting of three undergroundstorage tanks containing oils, waste fuels, and solvents which were removed in the late1980's. Extensive hydrogeological data from a 1990 study delineated a plume ofVOC-contaminated ground water extending north to south along the eastern boundary of thesite, known as the Eastern Plume. This ROD addresses an interim remedy for Site 2, theEastern Plume, the source of which has been traced to Sites 4, 11, and 13. An additional1992 ROD specified containment of onsite buried wastes and ground water plume management.A future ROD will address a final remedy for the ground water at NAS Brunswick. Theprimary contaminants of concern affecting the ground water are VOCs, including PCE andTCE.

The selected remedial action for this site includes extracting and treating contaminatedground water onsite using precipitation and filtration processes to remove metals such asiron and manganese, and UV/oxidation to remove VOCs, with offsite discharge of thetreated water to a local POTW for final treatment; conducting treatability tests prior todesign of the treatment system; and implementing a Navy monitoring program to ensure thatthe system is effective. Extracted ground water for "his OU will be combined with groundwater from OU1, the subject of a previous ROD, and treated concurrently in a singlesystem. The estimated present worth cost for this remedial action is $4,223,000, whichincludes an O&M cost of $1,845,000 over 5 years.

PERFORMANCE STANDARDS OR GOALS:

Chemical-specific ground water clean-up goals for this site were based on SDWA MCLs andhealth-based standards and include 1,1,1-TCA 200 ug/1; TCS 5 ug/1; PCE 5 ug/1;trans-l,2-DCE 100 ug/1; cis-l,2-DCE 70 ug/1; 1,1-DCA 3,500 ug/1; and 1,1-DCE 7 ug/1. Theinterim action is intended to contain the Eastern Plume and prevent further migration toHarpswell Cove pending final remedial actions.

LLLLLI RECORD OF DECISIONL FOR AN, INTERIM REMEDIAL ACTIONL AT THE

EASTERN PLUME GROUNDWATERI OPERABLE UNITL NAVAL AIR STATION BRUNSWICK, MAINE

L. June 1992

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RECORD OF DECISIONFOR AN

INTERIM REMEDIAL ACTIONAT THE

EASTERN PLUME GROUNDWATEROPERABLE UNIT

NAVAL AIR STATION BRUNSWICK, MAINE

June 1992

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NAVAL AIR STATION BRUNSWICKINTERIM RECORD OF DECISION

TABLE OF CONTENTS

Contents____________________________________Page No.

DECLARATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

DECISION SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6I. SITE NAME, LOCATION, AND DESCRIPTION . . . . . . . . . . . 6D. SITE HISTORY AND ENFORCEMENT ACTIVITIES . . . . . . . 9

A. LAND USE AND RESPONSE HISTORY . . . . . . . . . . . . . . . 9B. ENFORCEMENT HISTORY . . . . . . . . . . . . . . . . . . . . . . n

HI. COMMUNITY PARTICIPATION . . . . . . . . . . . . . . . . . . . . . 14IV. SCOPE AND ROLE OF OPERABLE UNIT . . . . . . . . . . . . . 15V. SUMMARY OF SITE CHARACTERISTICS . . . . . . . . . . . . . 16

A. GROUNDWATER Flow AND SUBSURFACE GEOLOGY . 16B. GROUNDWATER QUALITY . . . . . . . . . . . . . . . . . . . . . 17C. KNOWN OR POTENTIAL ROUTES OF MIGRATION OF

CONTAMINATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22VI. SUMMARY OF SITE RISKS . . . . . . . . . . . . . . . . . . . . . . . . . 24V Q . D E V E L O P M E N T A N D S C R E E N I N G O F

ALTERNATIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26A. S T A T U T O R Y R E Q U I R E M E N T S / R E S P O N S E

OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26B. TECHNOLOGY AND ALTERNATIVE DEVELOPMENT

AND SCREENING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Vm. DESCRIPTION OF ALTERNATIVE . . . . . . . . . . . . . . . . . . . 28LX. SUMMARY OF THE COMPARATIVE ANALYSIS OF

ALTERNATIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29A. OVERALL PROTECTION OF HUMAN HEALTH AND THE

ENVIRONMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29B. COMPLIANCE WITH APPLICABLE OR RELEVANT AND

APPROPRIATE REQUIREMENTS .................. 29C. LONG-TERM EFFECTIVENESS AND PERMANENCE .... 30D. HEDUCTION OF ToxicrrY, MOBILITY, OR VOLUME

THROUGH TREATMENT . . . . . . . . . . . . . . . . . . . . . . . 30E. SHORT-TERM EFFECTIVENESS . . . . . . . . . . . . . . . . . . . 30F. IMPLEMENTABILITY . . . . . . . . . . . . . . . . . . . . . . . . . . 31G. COST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31H. STATE ACCEPTANCE . . . . . . . . . . . . . . . . . . . . . . . . . . 31

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TABLE OF CONTENTS(continued)

Contents ____________________________________ Page No.

I. COMMUNITY ACCEPTANCE . . . . . . . . . . . . . . . . . . . . . 31X. THE SELECTED REMEDY . . . . . . . . . . . . . . . . . . . . . . . . . 33

A. CLEANUP LEVELS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33B. DESCRIPTION OF REMEDIAL COMPONENTS . . . . . . . . . 33

XI. STATUTORY DETERMINATIONS . . . . . . . . . . . . . . . . . . . 39A. THE SELECTED INTERIM REMEDY is PROTECTIVE OF

HUMAN HEALTH AND THE ENVIRONMENT . . . . . . . . . 39B. THE SELECTED INTERIM REMEDY ATTAINS ARARs . 39C. THE SELECTED INTERIM REMEDIAL ACTION is COST-

EFFECTIVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45D. THE SELECTED INTERIM REMEDY UTILIZES

PERMANENT SOLUTIONS AND ALTERNATIVET R E A T M E N T O R R E S O U R C E R E C O V E R YTECHNOLOGIES TO THE MAXIMUM EXTENTPRACTICABLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

E. THE SELECTED INTERIM REMEDY SATISFIES THEP R E F E R E N C E F O R T R E A T M E N T W H I C HPERMANENTLY AND SIGNIFICANTLY REDUCES THETOXICITY, MOBILITY, OR VOLUME OF THEHAZARDOUS SUBSTANCES AS A PRINCIPALELEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

XH. DOCUMENTATION OF NO SIGNIFICANT CHANGES . . . . . 47STATE ROLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

CAPPENDICES

APPENDIX A - Applicable or Relevant and Appropriate RequirementsAPPENDIX B - Responsiveness SummaryAPPENDIX C - MEDEP Letter of ConcurrenceAPPENDIX D - Administrative Record Index and Guidance Documents

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LIST OF FIGURES

Figure_____________________________________Page No.

1 Site Location Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2 Limits of the Eastern Plume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3 Shallow Groundwater Flow-Eastern Plume Area . . . . . . . . . . . . . . . . 18

4 Deep Groundwater Flow-Eastern Plume Area . . . . . . . . . . . . . . . . . . 19

5 Schematic East-West Cross Section of Geology of Eastern Plume . . . . 20

6 Schematic North-South Cross Section of Geology of Eastern Plume . . 21

7 Extraction Wells Water Treatment Plant Location and Process . . . . . . 35

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LIST OF TABLES

Table_____________________________________Page No.

1 VOC Contaminant Concentrations . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

2 List of Contaminants of Concern . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

3 Target Cleanup Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

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! DECLARATION

SITE NAME AND LOCATION

Naval Air Station (NAS) Brunswick, Eastern PlumeBrunswick, Maine

STATEMENT OF BASIS AND PURPOSE

This decision document presents the selected interim remedial action for thehydraulic containment of contaminated groundwater referred to as the Eastern Plumeat NAS Brunswick in Brunswick, Maine. This decision document was developed inaccordance with the Comprehensive Environmental Response, Compensation, andLiability Act as amended by the Superfund Amendments and Reauthorization Actand, to the extent practicable, the National Contingency Plan. Through thisdocument, the Navy plans to remedy, on a interim basis, by hydraulic containment,recovery, and treatment, the threat to human health and the environment posed bycontaminated groundwater. This decision is based on the Administrative Record forthe site. The Administrative Record for the site is located at the Public WorksOffice at NAS Brunswick.

The State of Maine Department of Environmental Protection (MEDEP) and the U.S.Environmental Protection Agency (USEPA) concur with the selected interimremedial action.

A final remedy for the site including both groundwater and source operable units isbeing developed through the Remedial Investigation/Feasibility Study process anda subsequent Record of Decision (ROD) will be issued to address the final siteremedy.

ASSESSMENT OF THE SITE

Actual or threatened releases of hazardous substances from the Eastern Plume, if notaddressed by implementing the interim response action selected in this ROD, maypresent an imminent and substantial endangerment to public health, welfare, or theenvironment

fi- . f - -s.

DESCRIPTION OF THE REMEDY

The interim remedial action will contain the Eastern Plume, preventing furthermigration of the plume and discharge of the plume to the Harpswell Cove estuary.

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The interim remedial action consists of groundwater extraction, treatment, anddischarge of treated groundwater. Wells will be positioned to hydraulically containthe Eastern Plume. Extracted groundwater will be combined with extractedgroundwater from Sites 1 and 3 and treated together. Remediation of Sites 1 and3 is addressed in a separate ROD. Iron and manganese will be removed from theextracted groundwater by precipitation and filtration processes to reduce theirinterference with treatment of the volatile organic compounds (VOCs). The VOCswill be removed from the water using the ultraviolet/oxidation treatment technology.The proposed discharge method is to the Brunswick publicly owned treatment works(POTW), however, another option may be used if approval for discharge to thePOTW cannot be obtained. Ultimate discharge is to the Androscoggin River via aNational Pollutant Discharge Elimination System Permit. Before designing thetreatment system, treatability tests will be conducted to provide information on thecompounds and concentrations likely to be present in the effluent.

Before startup of the extraction well network, the Navy will submit a monitoringprogram for approval by the MEDEP and the USEPA, to confirm that thecontainment system is effective.

The interim remedial action will address the principal threat of discharge ofcontaminated water to Harpswell Cove by containing the Eastern Plume before itreaches Harpswell Cove. The potential threat to human health is not an immediatethreat because water from the contaminated plume is not currently used as adrinking water supply. The final site remedy to address both the source andgroundwater operable units along with future threats to human health and theenvironment will be addressed in a subsequent ROD. This interim remedial actionis expected to be consistent with the final remedy.

STATUTORY DETERMINATIONS

The selected interim remedial action is protective of human health and theenvironment, complies with federal and state applicable or relevant and appropriaterequirements for this limited scope, and is cost-effective. Because this action doesnot constitute the final remedy for the Eastern Plume, the statutory preference forremedies that employ treatment that reduces ioxirity, mobility, or volume as aprincipal element, although partially addressed in this remedy, will be addressed inthe final response action. This remedy uses permanent solutions and alternativetreatment technologies to the maximum extent practicable for this site. Because thisremedy may result in hazardous substances remaining in on-site groundwater abovehealth-based cleanup levels, a review will be conducted by the Navy, the USEPA, andthe MEDEP within five years after startup of the groundwater containment to ensurethat the interim remedy continues to provide adequate protection of human health


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and the environment. This review will be conducted at least every five years as longas hazardous substances remain in on-site groundwater above health-based cleanuplevels or until the ROD for the final site remedy is signed and supersedes this ROD.

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j The foregoing represents the selection of an interim remedial action by theDepartment of the Navy and the U.S. Environmental Protection Agency, Region I,

i with concurrence of the Maine Department of Environmental Protection,i Concur and Recommend for immediate implementation:

Thomas A. Dames

Title: Captain, CEC, U.S. NavyCommanding OfficerNorthern DivisionNaval Facilities Engineering Command

By: i \v~(. (AJU^W*^ Date: 10 June 1992H.M. Wilson

Title: Captain, U.S. NavyCommanding OfficerNaval Air StationBrunswick, Maine


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J1 The foregoing represents the selection of an interim remedial action by the

Department of the Navy and the U.S. Environmental Protection Agency, Region I,with concurrence of the Maine Department of Environmental Protection.

By:

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Title: Regional Administrator, USEPA

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! DECISION SUMMARY

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I. SITE NAME, LOCATION, AND DESCRIPTION

The U.S. Naval Air Station (NAS) Brunswick is a National Priorities List (NPL) site.There are currently 13 areas (Sites) within NAS Brunswick that are underinvestigation. This interim Record of Decision (ROD) relates to the groundwaterplume, known as the Eastern Plume, which is the result of past or currentcontamination at Sites 4, 11, and 13.

NAS Brunswick is located south of the Androscoggin River between Brunswick andBath, Maine, south of Route 1 and between Routes 24 and 123 (Figure 1).Undisturbed topography at the base is characterized by low, undulating hills withdeeply incised brooks; ground surface elevations range from mean sea level (MSL)in lowland drainage areas and the Harpswell Cove estuary, to over 110 feet aboveMSL west and southeast of the southern end of the runways. Topography in thebase's developed areas has been modified by construction, and ground surfaceelevations generally range from 50 to 75 feet above MSL.

NAS Brunswick is an active facility supporting the U.S. Navy's antisubmarine warfareoperations in the Atlantic Ocean and Mediterranean Sea. The primary mission ofthe base is to operate and maintain P-3 Orion aircraft NAS Brunswick first becameactive in the 1940s during World War H, and underwent major expansion in the1950s.

NAS Brunswick is located on 3,094 acres. The operations area (138 acres), east ofthe two parallel runways, consists of numerous office buildings, a ste'am plant, fuelfarm, barracks, recreational facilities, base housing, hangars, repair shops, and otherfacilities to support NAS Brunswick aircraft. Forested areas (approximately48 percent), grasslands (approximately 28 percent), and paved areas (approximately12 percent) comprise most of the base property. Paved areas are mostly flight rampsand runways. The remaining 12 percent of the base includes the operations area(approximately 5 percent) and miscellaneous shrubland, marsh, and open water. Thesouthern edge of the base borders coves and estuaries of Harpswell Cove.

Property usage surrounding "NAS -Brunswick is "primarily suburban tnd ruralresidential, with some commercial and light industrial uses along Routes 1, 24, and123. An elementary school, college, and a hospital are located within 1 mile of thewestern base boundary.

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I[ HARPSWELL

SOURCE: U.S.G.S. QUADRANGLES, BRUNSWICK. AND ORRS BLAND, ME, DATED 1M4,1»7t. 7* MMUTE SERES.

POOR QUALITYORIGINAL

FIGURE 1SITE LOCATION MAP

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t The Eastern Plume, the groundwater operable unit being addressed in this interim1 ROD, is the result of contamination at Sites 4, 11, and 13. Groundwater in the area

of the plume is not currently used for drinking water or other purposes; therefore,there are no human receptors. The plume is predicted to discharge to HarpswellCove in five years, potentially affecting many ecological receptors. Thecontamination of groundwater in the Eastern Plume has not affected the current useof natural resources. Use of groundwater and surface water in this area is verylimited; however, the presence of contaminated groundwater does prevent the useof this natural resource in the future.

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II. SITE HISTORY AND ENFORCEMENT ACTIVITIES

A. LAND USE AND RESPONSE HISTORY

Extensive hydrogeological and analytical data collected during the 1990 field programdelineated a plume of volatile organic compound (VOC)-contaminated groundwaterextending north to south along the eastern boundary of NAS Brunswick. This VOCplume, the result of contamination at Sites 4 (the Acid/Caustic Pit), 11 (the formerFire Training Area), and 13 (the Defense Reutilization and Marketing Office[DRMO] Area), is known as the Eastern Plume (Figure 2). Groundwater in thisplume flows south toward Harpswell Cove. The contaminated groundwater is notflowing toward residential areas east of the base, and it is currently not dischargingto or impacting any surface water bodies. The southern limit of the plume isbelieved to be in the vicinity of New Gurnet Road. The predicted discharge zonefor the Eastern Plume, the tidal area where Mere Brook flows into Harpswell Cove,is approximately 750 feet away from the southern extent of the Eastern Plume (E.C.Jordan Co., 199 Ib). Based on groundwater modeling, the plume is predicted toreach the discharge zone in about five years; however, this interim remedial actionis intended to contain the plume and prevent it from reaching Harpswell Cove.

Surface water contamination has been detected in Mere Brook both above thesouthern part of the Eastern Plume and east of Site 11 in the Picnic Pond Area. TheEastern Plume flows beneath both of these surface waters; however, the presence ofcontaminants in these surface waters are related to other source areas (e.g., Sites 1and 3 and surface runoff). Contaminants detected in the surface water differ fromthe contaminants detected in the Eastern Plume and the Eastern Plume is notbelieved to be hydraulically connected to these surface waters.

Off-base drinking water wells were tested for some residences on Coombs Road inBrunswick to determine if contaminated groundwater from the base had affectedthese wells. Contamination from the Eastern Plume was not expected to impactthese wells and this was confirmed by the testing.

Sites 4, 11, and 13 at NAS Brunswick are believed to be current or past contributorsto groundwater contamination in the Eastern Plume. Site 4, the Acid/Caustic Pit,

^vas used from 1969 to 1974 for the disposal of liquid wastes. -Jne wastes werepoured into the pit, which was approximately 4 feet square and 3 feet deep.Investigations showed that subsurface soils around Site 4 were not contaminated andgroundwater was only contaminated with low levels of trichloroethylene (TCE).Based on these results, it is believed that Site 4 no longer contributes to groundwatercontamination in the Eastern Plume.


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FIGURE 2UMTS OF EASTERN PLUME

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• Site 13, the DRMO Area, consisted of three underground storage tanks located southi - of Site 4. One tank was used for diesel fuel. The other tanks reportedly were used

for storage of waste fuels, oils, and degreasing solvents (R.F. Weston, Inc., 1983). Allthree tanks were removed during the late 1980s and a new fiberglass dieselunderground storage tank was installed. Groundwater sampling downgradient ofSite 13 has shown decreasing VOC contamination since removal of the tanks. Themost recent groundwater samples from this area contained only low levels ofcontamination, indicating that Site 13 is no longer acting as a source ofcontamination for the Eastern Plume.

Site 11 is a former Fire Training Area that was used regularly over a 30-year perioduntil it was closed in the fall of 1990. Waste liquids including fuels, oils, anddegreasing solvents were used as fuel for the fire training exercises. The mostprevalent contaminants in groundwater (i.e., 1,1,1-trichloroethane [TCA] and TCE)are consistent with the wastes used at the Fire Training Area and the soilcontamination at the Fire Training Area. Site 11 is believed to be the primarycontinuing source of groundwater contamination in the Eastern Plume. The FireTraining Area is no longer in use.

A more detailed description of the history of Sites 4, 11, and 13 can be found in theRemedial Investigation Report in Subsections 8.1, 12.1, and 13.1 (E.G. Jordan Co.,1990a).

B. ENFORCEMENT HISTORY

The Navy's cleanup of hazardous wastes at NAS Brunswick falls under the Navy'sInstallation Restoration Program (IRP) and meets the requirements of theComprehensive Environmental Response, Compensation and Liability Act and theSuperfund Amendments and Reauthorization Act (CERCLA). The program wasconducted in several stages:

• In 1983, an Initial Assessment Study (IAS) detailed historicalhazardous material usage and waste disposal practices at NASBrunswick.

• In 1984, a Pollution Abatement Confirmation Study was conducted.These studies recommended further investigation of seven of the ninehazardous waste sites originally identified.

• In 1987, NAS Brunswick was placed on the U.S. EnvironmentalProtection Agency's (USEPA's) NPL,

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• The Remedial Investigation/Feasibility Study (RI/FS) process beganin 1987 for seven sites.

• In February 1988, the first Technical Review Committee (TRC)meeting was held. The TRC meetings have been held quarterly sincethat initial meeting.

• Two sites were added to the RI/FS program in 1989, as well as thetwo additional sites originally identified in the IAS.

• Two other sites were added to the program in 1990. Currently, theNavy is studying 13 sites under the IRP.

• In 1990, the Navy entered into a Federal Facility Agreement (FFA)with the USEPA and the Maine Department of EnvironmentalProtection (MEDEP) regarding the cleanup of environmentalcontamination at NAS Brunswick. The FFA sets forth the roles andresponsibilities of each agency, contains deadlines for the investigationand cleanup of hazardous waste sites, and establishes a mechanism toresolve disputes among the agencies.

• In August 1990, the Navy completed Draft Final RI and Phase I FSReports (E.G. Jordan Co., 1990a and 1990b). The RI described fieldsampling investigations, geology, and hydrogeology, and presentedcontamination and risk assessments. The Phase I FS identifiedremedial action objectives, and developed and screened remedialalternatives for the nine original sites studied in the Draft Final RI.

• The Navy submitted Draft Final Supplemental RI and FS reports foran additional four sites in August and July of 1991, respectively. TheDraft Final Supplemental RI also contained additional field samplingresults for Site 11 and the Eastern Plume.

Each of the stages and documents listed above pertain to Sites 4, 11, and 13 and theEastern Plume. Information on many of the other sites at NAS Brunswick is alsoincluded in these reports.

Because the Navy is committed to providing a timely response to environmentalcontamination at NAS Brunswick, a strategy was developed to expedite the RI/FSprocess. This strategy involves identifying the sites for which enough informationcurrently exists to proceed to the ROD and design phases of the process. Separatetimetables have been established for completing the Final FS reports and RODs for

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these sites. The Navy has identified Sites 1 and 3, and the groundwater associatedwith Sites 4, 11, and 13 (i.e., the Eastern Plume) as distinct areas of contaminationand believes the remedial process can be initiated. Focused Feasibility Studies forSites 1 and 3 and Site 8, and an FS for nine other sites (Sites 2, 4, 5, 6, 7, 9, 11, 12,and 13) have been submitted to the regulatory agencies for review (E.G. Jordan Co.,1991b, 1992a, and 1992b).


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III. COMMUNITY PARTICIPATION

Throughout the site's history, the community has been active and involved. The Navyhas kept the community and other Mterested parties abreast of site activities throughinformational meetings, fact sheets, press releases, public meetings, and TRCmeetings.

In August 1987, the Navy established an information repository for public review ofsite-related documents at the Curtis Memorial Library in Brunswick. OnDecember 3, 1991, the Navy placed the Proposed Plan for the Eastern Plume in theinformation repository at the Curtis Memorial Library. The Administrative Recordfor the Eastern Plume is available for public review at NAS Brunswick in the PublicWorks office. A notice and brief analysis of the Proposed Plan was published in thelocal newspaper, The Times Record on December 3 and 10, 1991.

The TRC has been an important vehicle for community participation. The TRC wasestablished in early 1988 and is made up of Navy, USEPA, MEDEP, and variouscommunity representatives. The community members of the TRC includerepresentatives from Brunswick, Harpswell, and Topsham as well as the BrunswickArea Citizens for a Safe Environment (BACSE). The TRC also has representativesfrom the Brunswick-Topsham Water District The TRC meets quarterly, reviews thetechnical aspects of the program, and provides community input to the program.

In September 1988, the Navy released a Community Relations Plan outlining aprogram to address community concerns and keep citizens informed about andinvolved in remedial activities. On August 16, 1990, the Navy held an informationalmeeting at the Jordan Acres School in Brunswick, Maine, to discuss the results of theRI.

On December 12, 1991, the Navy held an informational meeting to discuss the resultsof the RI and the Navy's Proposed Plan for the interim remedial action for theEastern Plume. During this meeting, the Navy, its consultants, and regulatoryrepresentatives answered questions from the public and accepted formal comments.From December 6, 1991, through January 24, 1992, a public comment period washeld to accept public comments regarding the proposed interim action for theEastern Plume, and on any other documents previously made public. The publiccomments and the responses to the comments are included in Appendix B,Responsiveness Summary.


W0029251.080 6836-0514

I! IV. SCOPE AND ROLE OF OPERABLE UNITiI

An interim remedial action for the groundwater operable unit for Sites 4, 11, and 13,referred to as the Eastern Plume, was developed to control and prevent furthermigration of contaminated groundwater off the NAS Brunswick property and intoHarpswell Cove and to begin to reduce the concentration of contaminants in the

1 groundwater until a final remedy can be chosen. The interim remedial action is notL intended to be a final remedy but should be consistent with the final remedy that is

chosen. This management of migration option is also part of the remedialI alternatives being evaluated in the FS, and will be consistent with the final remedy

chosen for the Eastern Plume and Sites 4, 11, and 13. The final ROD, which. includes the Eastern Plume, may be based in part on the data collected during theI design, operation, and monitoring of the interim remedy. Additional interim

remedial action(s) may be proposed if data collected before the final ROD warrantssuch actions.

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The interim remedy manages migration of the Eastern Plume by extracting, treating,and discharging contaminated groundwater from the Eastern Plume. Extraction wellswill be installed to pump contaminated groundwater from the subsurface where it willbe piped to a treatment plant. The water will be treated using oxidation/filtrationand ultraviolet (UV) light/oxidation and discharged to the public sewer system forconveyance to the local publicly owned treatment works (POTW). Discharge to thePOTW is the preferred discharge option but has not yet been approved. Thisremedial action will hydraulically contain the Eastern Plume and prevent futuredischarge of contaminated groundwater to Harpswell Cove. It is also anticipated thatgroundwater from Sites 1 and 3 will be treated together with groundwater from theEastern Plume. Sites 1 and 3 are being addressed in a separate ROD.


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V. SUMMARY OF SITE CHARACTERISTICS

A focused field investigation of groundwater contamination associated with Sites 4,11, and 13 (i.e., the Eastern Plume) was conducted as part of the Post-ScreeningWork Plan between August and November of 1990. This program was developed tosupplement existing information at these sites and presented in the Draft Final RIReport (E.G. Jordan Co., 1990a). The Post-Screening Field Program consisted of apiezometric cone penetrometer survey, installation of monitoring wells, aquiferpermeability testing, and groundwater sampling and analysis. The results of the fieldinvestigation are presented in the Draft Final Supplemental RI Report (E.C JordanCo., 1991a). The specific objectives of the Eastern Plume field program include:

• characterize the hydrogeologic regime, including the geologic depositsunderlying the study area, the direction arid rate of groundwater flow,and possible discharge to Mere Brook, and Harpswell Cove;

• assess the nature, distribution, and migration of contaminants inshallow and bedrock aquifers;

• assess the degree to which future migration of contaminants may posea threat to public health, welfare, and the environment; and

• obtain groundwater quality data to assess the applicability ofgroundwater treatment technologies for the FS.

The information obtained from the field investigation is summarized in the followingsections.

A. GROUNDWATER FLOW AND SUBSURFACE GEOLOGY

Groundwater in the Eastern Plume occurs in the overburden soil and bedrockformations. The overburden soil at NAS Brunswick is a stratified formationconsisting of a sand layer, a transition layer, and a clay layer. The transition layeris made up of interbedded silt, sand, and a clay layer. The sand, transition, and daysofl layers are all part of the Presumpscot Formation, which was deposited during thelate glacial marine submergence of southern Maine. The variability of soil types in

"the Presumpscot Formation was caused by the glacial retreat and sea level changesthat occurred when the soils were deposited. The saturated thickness of thePresumpscot Formation, or thickness of the overburden saturated with groundwater,varies from 10 to 90 feet across the Eastern Plume area, and generally spans the sandand transition layers.


W0029251.080 683645516

< RI data (E.G. Jordan Co., 1991a) indicate that groundwater flows radially fromSite 11 to the northeast, east, and southeast, and flows southeast from Sites 4 and 13(Figures 3 and 4). Shallow groundwater from Sites 4, 11, and 13 flows toward anddischarges to Mere Brook and its tributaries (see Figure 3). The deep groundwaterflows in a more southerly direction (see Figure 4), and is largely constraintd by thepresence of sand lenses at depth and the eastern limb of the clay trough. The claytrough observed at the site is influenced by an observed bedrock trough alsointerpreted to exist at the site. Figure 5 shows a schematic representation of atypical west-to-east cross section of the trough south of New Gurnet Road. Bedrockalong the eastern boundary of the base forms the eastern limb of a trough. Thebedrock trough is also bounded by a bedrock high to the west (see Figure 5). Theday layer of the Presumpscot Formation lies on top of the bedrock and a deep sandlayer occurs below the transition sediments and above the clay.

Figure 6 shows a schematic north-to-south profile illustrating how the geologicformation influences deep groundwater flow. The deep sand layer within the troughacts to channel groundwater (and contaminant) flow to the south, because the sandyzones are more permeable than the more silty layers of the formation above andbelow the deep sand layer, which may act as a preferred path for groundwater andcontaminant movement within the aquifer (see Figure 6). Groundwater does notflow through the clay layer on top of bedrock due to the clay's low permeability;however, groundwater does flow in the fractures and joints of the bedrock (E.G.Jordan Co., 1991a).

The groundwater flow system located within the Eastern Plume area is interpretedto discharge to the upper portions of the Harpswell Cove watershed area, based ondata presented in the Draft Final Supplemental RI Report (E.C. Jordan Co., 1991a),and shown in Figures 8-14 and 8-18 of that report. Based on groundwater surfacecontour maps, hydraulic conductivity data, current groundwater chemical data, andhydraulic gradients, the southern edge of the Eastern Plume is interpreted todischarge to the Harpswell Cove area in approximately five years.

B. GROUNDWATER QUALITY

-Groundwater contamination is encountered in deep, sand-rich zones above the claylayer, and in shallow groundwater near the source areas. Shallow groundwater away

-from the source area where it discharges to Mere Brook is not contaminated.

Groundwater contamination has not been detected east of the eastern boundary ofthe base, or in water samples collected from monitoring wells in the bedrock aquifer(E.G. Jordan Co., 1991b).

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FIGURESSHALLOW GROUNDWATER FLOW -

EASTERN PLUME AREA

POOR QUALITYORIGINAL

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MII.W1N.TfVtQMOWOWATnow once/ MTIKT OF VOCI COMTJUMATKM

FIGURE 4DEEP GROUNDWATER FLOW -

EASTERN PLUME AREA

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i Data indicate that TCA is the most prevalent contaminant in the Eastern Plume,| although other VOCs (i.e., tetrachloroethylene, TCE, 1,1-dichloroethylene [1,1-DCE],

1,2-dichloroethylene [1,2-DCE], and 1,1-dichloroethane [1,1-DCA]) were alsodetected (E.G. Jordan Co., 199 la). The highest concentrations of several compoundsdetected in the Eastern Plume exceed the Maximum Contaminant Levels (MCLs)established by the USEPA under the 1986 Federal Safe Drinking Water Act and theMaximum Exposure Guidelines (MEGs) outlined in the Maine Drinking WaterRules. A summary of these groundwater data are presented in Table 1.

L A complete discussion of site characteristics can be found in the Draft FinalSupplemental RI Report in Section 8.0 (E.G. Jordan Co., 1991a).

C. KNOWN OR POTENTIAL ROUTES OF MIGRATION OF CONTAMINATION

Shallow groundwater contamination is present in the vicinity of the source areas ofi Sites 4, 11, and 13 and downgradient of Sites 4 and 13. Although the highest levels• of groundwater contamination generally occur in the northwestern portions of the

Eastern Plume, contamination observed in the remaining portions of the EasternI Plume area occurs with a deep, sand-rich layer located within the transition zone.

Therefore, contaminated groundwater flowing from the source areas initially flowssoutheast, and when it becomes entrained in the deeper portions of the aquifer, a

I more southerly flow occurs. The ultimate entrainment of groundwater contaminantsin the deep groundwater (located within sand-rich strata) is further emphasized by

. the lack of shallow groundwater contamination in the downgradient portion of theI plume. The contaminant migration pathway for groundwater contamination at the

Eastern Plume site is generally within a deep sand-rich strata and it is within this uniti that VOCs will migrate to the Harpswell Cove watershed.

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TABLE 1VOC CONTAMINANT CONCENTRATIONS

ROD: EASTERN PLUMENAS BRUNSWICK

L

CONSTITUENT

TCA

TCEPCE

1,1 -DCE

1,2-DCE

1,1 -DCA

Not**:

d)(2)NDMCLMEGTCATCEPCEDCEDCANA

MCL

200

5

5

7

70/100(1)

NA

70/100 denotes theTotal 1,2-DCENot Detected

MEG

200

5

5

7

70/100™

NA

RANGE OF CONCENTRATIONS DETECTEDSHALLOW

WELLS(NEAR

13-

5 -

ND

SOURCE)

1200

770

-42

ND-6

63-

ND

680(2)

-130

DEEP WELLS(DOWNGRADIENT)

11 -

6-

2300

1200

ND-9

ND

ND

ND

-110

-98(2'

-170

OFF-SITE

WELLS

ND

ND

ND

ND

ND

ND

MCL and MEG for cis-1,2-DCE and trans- 1,2-DCE, respectively

Maximum Contaminant Level (Federal Safe DrinkingMaximum ExposuretrichloroethanetrichloroethytenetetracnloroethylenedichloroBthylenedichloroethanenot available

Guideline (State ofWater Act)

Maine Drinking Water Rules)

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! VI. SUMMARY OF SITE RISKS

A risk evaluation estimated the potential for adverse human health effects fromexposure to contaminants associated with the Eastern Plume. The potential riskswere qualitatively evaluated and determined based on a comparison of theconcentration of each contaminant detected at least once in groundwater to federalMCL and Maine MEG concentrations. MCLs and MEGs represent contaminantconcentrations in water considered to be acceptable to human exposure. Therefore,those contaminants detected above their respective standard and criteria values were

I considered to present a potential risk to human health.

The risk evaluation identified several contaminants in the Eastern Plume atconcentrations exceeding their respective MCLs. The MCLs are promulgated federaldrinking water standards and the Maine MEGs are established guidance levels. Thefederal MCL and state MEG values are the same for the contaminants of concernin the Eastern Plume (Table 2). There is currently no risk of exposure to theEastern Plume groundwater; it is not currently used as a water supply on base, andthe plume has not been found to affect off-base private drinking water wells. If, inthe future, residents were to use the groundwater within the Eastern Plume as adrinking water supply, that usage could pose long-term risks to human health. TheEastern Plume is not currently discharging to Harpswell Cove; however, ifcontaminated groundwater were allowed to flow into Harpswell Cove, there wouldbe potential for adverse ecological effects.

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Actual or threatened releases of hazardous substances from the Eastern Plume, if notaddressed by implementing the response action selected in this ROD, may presentan imminent and substantial endangerment to human health, welfare, or theenvironment. The interim action for hydraulic containment and recovery ofgroundwater will prevent future migration and reduce contaminant concentrations ingroundwater from the Eastern Plume.


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TABLE 2LIST OF CONTAMINANTS OF CONCERN


MAXIMUM MCL MEGCONTAMINANT CONCENTRATION (pg/L) 0/g/L) 0*9/1-)

1,1-DCE

1,1 -DCA

cis-1,2-DCE

trans-1,2-DCE

1,1,1-TCA

PCE

TCE

Note*:

MCLMEGN/A* *

//g/L «DCADCEPCETCATCE

110

170

680**

2,300

42

1,200

Maximum Contaminant Level (Federal Safe

7

N/A

70

100

200

5

5

Drinking Water Act)

7

N/A

70

100

200

5

5

Maximum Exposure Guideline (State of Maine Drinking Water Rules)Not Available1,2-DCE was reportedisomer).micrograms per literdichloroethanedichloroethytenetetrachloroethylenetrichloroethanetrichloroethylene

by the laboratory as total (i.e., there was no distinction between the cis- and Vans-

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' VII. DEVELOPMENT AND SCREENING OF ALTERNATIVESi, A. STATUTORY REQUIREMENTS/RESPONSE OBJECTIVES

The primary goal at NPL and similar sites is to undertake remedial actions that areprotective of human health and the environment Sections 120 and 121 of CERCLAestablish several statutory requirements and preferences, including: a requirementthat the remedial action, when complete, must comply with all federal and morestringent state environmental standards, requirements, criteria or limitations, unlessa waiver is invoked; a requirement that the remedial action is cost-effective and usespermanent solutions and alternative treatment technologies or resource recoverytechnologies to the maximum extent practicable; and a preference for remedies inwhich treatment that permanently and significantly reduces the toxicity, mobility, orvolume of hazardous substances as a principal element over remedies not involvingsuch treatment. Response alternatives were developed to be consistent with thesecongressional mandates.

Based on types of contaminants, environmental media of concern, and potentialexposure pathways, remedial action objectives were developed to mitigate existingand future potential threats to human health and the environment. These responseobjectives were:

1. To minimize further migration of the Eastern Plume.2. To minimize any future negative impact to the Haipswell Cove estuary

resulting from discharge of contaminated groundwater.3. To reduce the potential risk associated with ingestion of contaminated

groundwater to acceptable levels.4. To reduce the time required for restoration of the aquifer.

B. TECHNOLOGY AND ALTERNATIVE DEVELOPMENT AND SCREENING

Because the actions described in this ROD are for an interim remedial action,development and screening of remedial action alternatives was not conducted. Asingle alternative to address the Eastern Plume on an interim basis was developed.The Navy's selection of the interim remedial action is the result of a comprehensiveevaluation of different groundwater treatment options. The Draft FS for the site wasconducted to identify and analyze the alternatives considered for addressing bothsource and groundwater contamination. The FS report describes and evaluates fivealternatives: an alternative that offers no action; an alternative that only considersgroundwater extraction and treatment; and three alternatives that each evaluate adifferent source control option in conjunction with groundwater treatment For eachtreatment alternative, the groundwater extraction and treatment strategy is the same.


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The interim remedial action is consistent with the alternatives developed andscreened in the FS for the final site remedy, and it provides a timely response tocontamination in the Eastern Plume until a final remedy can be chosen.


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VIII. DESCRIPTION OF ALTERNATIVE

This section summarizes the interim remedial action developed and evaluated for theEastern Plume. The proposed interim remedial action coL.->ists of extraction,treatment, and discharge of treated groundwater. The extraction system will consistof groundwater extraction wells that will hydraulically contain the plume and reducecontamination throughout the plume. A monitoring program will be developed toensure that the interim remedial action obtains hydraulic capture of the EasternPlume. Changes to the interim remedial action would be made if the monitoringresults determine that the interim remedial action does not achieve hydraulic captureof the plume.

Extracted groundwater will first be treated to remove iron and manganese. If ironand manganese are not removed, they will interfere with the VOC treatmentprocesses. The VOC treatment technology proposed for the interim action isUV/oxidation. The effluent will be sampled to ensure that the water meetsappropriate discharge requirements.

Discharge of the treated water will be through a new sewer connection from the on-site treatment building to the public sewer system for conveyance to the local POTW.Final treatment and disposal will occur at the POTW. A discharge permit will berequired from the Brunswick POTW that will outline specific discharge limitations.The Brunswick POTW has not yet agreed to accept treated groundwater from theEastern Plume. If they do not accept the treated groundwater, an alternativedischarge option (e.g., surface water, groundwater, or the storm sewer system) willbe used.

Estimated Time For Design and Construction: 2 years 5 monthsEstimated Time for Operation: 5 yearsEstimated Capital Cost: $1,223,000Estimated Operation and Maintenance Cost (net present worth): $1,845,000*Estimated Total Cost (net present worth): $4,223,000*

"Net present worth costs are based on a 10 percent discount factor and five years ofoperation.


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! IX. SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES1

Section 121(b)(l) of CERCLA presents several factors that at a minimum must beconsidered in the assessment of alternatives. Building upon these specific s*atutorymandates the National Contingency Plan articulates nine evaluation criteria to beused in assessing the individual remedial alternatives.

For a final remedy, several alternatives are usually developed and evaluated for a siteor operable unit. Because this ROD is for an interim remedial action, only onealternative was developed and its evaluation with respect to the nine criteria ispresented below. A full range of alternatives for Sites 4, 11, and 13 which contributeto the Eastern Plume was developed in the FS and will be presented in the finalROD for the final remedy.

A. OVERALL PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT

Overall Protection of Human Health and the Environment addresses how analternative as a whole will protect human health and the environment This includesan assessment of how human health and environmental risks are properly eliminated,reduced, or controlled through treatment, engineering controls, or institutionalcontrols.

The interim remedial action for addressing groundwater contamination will provideoverall protection of human health and the environment. Protection is provided bycontainment of the plume to prevent the migration of contaminated groundwater tocurrently uncontaminated areas, and by permanent reduction of contaminantconcentrations in the water through treatment and off-site disposal of the sludgeproduced by metals pretreatment

B. COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS

Compliance with Applicable or Relevant and Appropriate Requirements (ARARs)addresses whether or not a remedy complies with all state and federal environmentaland public health laws and/or provides grounds for invoking a waiver. For interimactions, it is appropriate to analyze compliance with only those laws and regulationsthat are applicable or relevant and appropriate to the limited scope of the iUjgaction. However, the interim remedial action proposed for the Eastern Plume wfllbe designed to meet action- and chemical-specific ARARs for the discharge oftreated groundwater and disposal of sludge resulting from the pretreatment process.All location-specific ARARs will also be met In addition, the interim remedialaction proposed for the Eastern Plume will be designed to treat the water to MCLs

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so that this interim action will be consistent with the groundwater component of thefinal site remedy.

C. LONG-TERM EFFECTIVENESS AND PERMANENCE

Long-term Effectiveness and Permanence refers to the ability of an alternative tomaintain reliable protection of human health and the environment over time oncecleanup goals are met.

The interim remedial action is expected to meet the cleanup objectives by preventingmigration of the plume and by removing and treating the water. Residual risk willremain because the source of contamination would not be remediated by the interimremedial action. The final remedy for the site may contain a source controlcomponent to expedite groundwater treatment.

D. REDUCTION OF TOXICITY, MOBILITY, OR VOLUME THROUGH TREATMENT

Reduction of Toxicity, Mobility, or Volume Through Treatment are three principalmeasures of the overall performance of an alternative. The 1986 amendments to theSuperfund statute emphasize that, whenever possible, the USEPA should select aremedy that uses a treatment process to permanently reduce the level of toxicity ofcontaminants at a site, the spread of contaminants away from the source ofcontamination, and the volume or amount of contamination at a site.

The purpose of the interim groundwater extraction and treatment for the EasternPlume is to prevent the further migration of contaminants. Preventing the spread ofcontaminants by pumping to contain the plume may reduce the volume ofcontaminated groundwater. The plume will be contained by controlling migrationwith extraction wells. Extraction wells will also be placed in the northern portion ofthe plume to reduce groundwater contaminant levels. These wells are included tohelp make the interim action consistent with the final remedy for the site and beginto reduce the overall level of contamination of the Eastern Plume. These wells willbe located at the deepest points of the Eastern Plume. Groundwater from theextraction wells will be treated using UV/oxidatiorL Treating the extracted water willpermanently and significantly reduce the toxicity ?nd mobility of contaminants in the•extracted water.

)RT=TERME. SHORT=TERM EFFECTIVENESSShort-term Effectiveness refers to the likelihood of adverse impacts on human healthor the environment that may be posed during the construction and implementationof an alternative until cleanup goals are achieved.

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The community and the environment are not expected to be adversely affectedduring implementation of this action. Workers installing the groundwater extractionsystem and treatment plant operators will wear protective clothing, followappropriate safety procedures to minimize the chance of exposure to contaminantsas outlined in a site-specific health and safety plan, and meet Occupational Safetyand Health Act (OSHA) training requirements.

F. IMPLEMENTABILITY

Implementability refers to the technical and administrative feasibility of analternative, including the availability of materials and services needed to implementthe alternative. The extraction and treatment technologies proposed for the interimaction are implementable and have been successfully demonstrated at other sites.The preferred option of discharging treated water to the POTW must be approvedby the Brunswick Sewer District before it can be implemented. If the application fordischarge to the POTW is not approved, another discharge option would be required.Other discharge options include recycling the water back into the aquifer byupgradient recharge or discharge to surface water on base.

G. COST

Cost includes the capital (up-front) cost of implementing an alternative as well as thecost of operating and maintaining the alternative over a five-year period, and netpresent worth of both capital and operation and maintenance costs. The capital,operation and maintenance, and total cost of the interim action are presented inSection VIII of this ROD.

H. STATE ACCEPTANCE

State Acceptance addresses whether, based on its review of the RI/FS and ProposedPlan, the state concurs with, opposes, or has no comment on the alternative the Navyproposes for the interim action.

As a party to the FFA, the State of Maine has provided comments on the proposedplan and has documented its concurrence with the interim remedial action as statedin Section Xm of this ROD. A copy of the letter of concurrence is presented inAppendix C of this ROD.

I. COMMUNITY ACCEPTANCE

Community Acceptance addresses whether the public concurs with the Navy'sProposed Plan. Community acceptance of the Proposed Plan was evaluated based


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on comments received at the public meetings and during the public comment period.This is documented in the Responsiveness Summaiy presented in Appendix B of this¥•» X-NTXROD.


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f X. THE SELECTED REMEDYi

The interim action for the Eastern Plume addresses only the management of' migration of contaminants in groundwater. The action does not address the sourceI of contamination, and a final remedy for groundwater that will be presented upon

completion of the FS.

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A. CLEANUP LEVELS

Cleanup levels have been established for contaminants of concern identified in therisk evaluation. Cleanup levels have been set equivalent to the appropriate ARARs(e.g., drinking water Maximum Contaminant Levels Goals and MCLs) if available.In the absence of a chemical-specific ARAR, or other suitable criteria to beconsidered, a concentration corresponding to a 10"6 excess cancer risk level forcarcinogenic effects or a Hazard Quotient of 1.0 for noncarcinogenic effects was usedto set cleanup levels. Periodic assessments of the protection afforded by remedialactions will be made as the remedy is being implemented and until a final remedyis chosen to replace the interim action.

Table 3 summarizes the cleanup levels derived based on carcinogenic and• noncarcinogenic effects for the contaminants of concern identified in groundwater.

These cleanup levels are consistent with ARARs for groundwater and attain

I USEPA's risk management goal for remedial actions (carcinogenic risk level between104 and KT6).

B. DESCRIPTION OF REMEDIAL COMPONENTS

The interim remedial action consists of extraction, treatment, and discharge oftreated groundwater with groundwater and effluent monitoring. The extractionsystem would be constructed within the plume to maximize the collection ofcontaminated groundwater. Groundwater extraction wells will contain the southernend of the plume and collect contaminated water from the northern part of theplume (Figure 7). A minimum of one well would be placed at the southern end ofthe plume to prevent contaminated groundwater from migrating further. Additional

-extraction wells would be placed in the deepest parts of the aquifer to ensure thatcontamination in the deep sands is collected. The actual number of wells, pumpingrates, and configuration of the extraction well network will be determined during theremedial design. Monitoring wells will be sampled during the interim remedialaction to confirm the capture of contaminated groundwater. Additional monitoringwells may be installed to supplement the existing monitoring well network.


W00292S1.060 68364533

TABLESTARGET CLEANUP LEVELS


I

TARGETMAXIMUM CLEANUP

CONCENTRATION MCL MEG LEVELCONTAMINANT 0*/M 0/9/L) to/L) fcg/L)

1,1 -DCE

1,1 -DCA

cis-1,2-DCE

trans-1,2-DCE

1,1,1-TCA

PCE

TCE

Not**:

MCLMEGN/AVS/i.DCADCEPCETCATCE(1)

W

(3)

1 1 0 7 7 7

170 N/A N/A S.SOO®

680(1) 70 70 700)

100 100 100

2.300 200 200 200

4 2 5 5 5

1,200 5 5 5

Maximum Contaminant Level (federal Safe Drinking Water Act)Maximum Exposure Guideline (State of Maine Drinking Water Rules)Not Availablemicrograms per literdichloroethanedichloroethylenetetrachloroethylenetrichloroethanetrichloroethylene

RESIDUALRISK01

5x10"5(c)

0.9 (nc)

0.2 (nc)

0.1 (nc)

0.06 (nc)

3x10*(c)

6x10'7(c)

1 ,2-DCE was reported by the laboratory as total (i.e., there was no distinction between the cis- andtrans-tsomer).The Target Cleanup Level for 1,1 -DCA is based on attaining the Reference Dose0.1 mg/kg-day and assumes a 70 kg adult ingests 2 liters of water per day.(c) indicates carcinogenic compound (nc) indicates noncarcinogenic compound

(RfD)of

0r

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LOCATION OFPROPOSEDEXTRACTIONWEU.

I- EXTENT OF VOC\f CONTAMINATION

PROPOSEDDISCHARGELOCATION

PICNIC POND;LOCATION _.

TREATMENT PLANT

WATER TREATMENT PROCESS

WtTCTCTOM _ OniBrnucDcST^ ML

FIGURE 7EXTRACTION WELLS

WATER TREATMENT PLANTLOCATION AND PROCESS

M36-03/910700SO

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A monitoring program will be developed during the design of the interim remedialaction and submitted for regulatory approval. This monitoring program will specifythe number and location of wells to be sampled, the frequency of sampling, and thecompounds to be analyzed. The monitoring program will be developed to ensurethat the interim remedial action is obtaining hydraulic containment of the EasternPlume. Changes to the interim remedial actions would be made if indicated by themonitoring results.

Contaminated groundwater from base landfills (Sites 1 and 3) will be pumped to thegroundwater treatment system for the Eastern Plume and treated concurrently forVOC contamination (see Figure 7). A separate proposed remedial action programhas been prepared for Sites 1 and 3. This scenario is considered feasible because ofthe similar contaminants, the low flow rate of groundwater from Sites 1 and 3, andthe short duration (estimated to be 370 days based on the containment alternativeproposed as the preferred alternative) required to pump and treat the groundwaterfrom Sites 1 and 3. A groundwater flow model will be developed to address thepotential effects of pumping groundwater at both Sites 1 and 3 and the EasternPlume. This modeling effort will be conducted to support the design of the remedialactions selected for both the Eastern Plume interim action and the Sites 1 and 3remedial action.

Several groundwater treatment options to reduce VOC contamination in the EasternPlume were considered. The greatest consideration was given to air stripping withvapor phase carbon (VPC) off-gas treatment and UV/oxidation. Both technologiesare effective in treating VOCs. However, because the groundwater from Sites 1 and3 contains components that are not effectively removed using air stripping and VPC(i.e., methylene chloride and vinyl chloride), UV/oxidation is the preferredgroundwater treatment option for this interim remedial action. A schematic flowdiagram for water treatment is presented in Figure 7.

The proposed treatment process includes removal of metals and VOCs from thewater. Before VOC treatment, dissolved metals in the groundwater (i.e., iron andmanganese) would be removed using a filtration process. The pretreatment processis conducted to remove metals from the groundwater that may interfere with theVOC treatment In this process, a chemical would be added to precipitate thegroundwater by passing the water through sand filters. The filters would bebackwashed periodically to prevent clogging. The solid material cleaned from thefilters would be pressed to remove excess water and then shipped to a hazardouswaste disposal facility if determined to be hazardous, or to an off-site waste landfillif determined to be nonhazardous. The water extracted from the solids would becycled through the on-site groundwater treatment system.


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Ij UV/oxJdation destroys organic compounds in water by exposing them to a chemical

LIIIIICni

oxidant (e.g., hydrogen peroxide) in the presence of UV light. The contaminatedgroundwater would be mixed with the oxidant and pumped into a reactor (or seriesof reactors) where water would be exposed to UV light. The combined effects ofUV light and the oxidant promote rapid breakdown of organic molecules. In theoxidation process, organic contaminants are broken down into simpler, nonhazardoussubstances such as carbon dioxide, water, salts, acetone, sulfates, nitrates, and organicand inorganic acids. Some of these by-products have discharge requirements (e.g.,acetone, sulfates, nitrates) that would need to be met The effluent would besampled to ensure that the water meets appropriate discharge requirements.

A treatability study would be conducted before the final design of the VOCtreatment system to determine the appropriate oxidant and concentration necessaryto destroy the VOCs. In addition, this study would provide information on thecompounds and concentrations likely to be present as by-products in the effluent.The treatability study would also evaluate metals pretreatment and sludgecharacteristics so that suitable disposal options can be evaluated in the design phase.

Several options were evaluated for discharge of treated water:

• surface water (e.g., Mere Brook)• groundwater (e.g., infiltration)• Brunswick Sewer District's POTW• Town of Brunswick storm sewer system

The preferred option for discharge is piping the water to tie into the base sanitarysewer system (Brunswick Sewer District POTW). The Navy would need to obtainpermission from the Brunswick Sewer District to discharge treated effluent to thesystem. The POTWs NPDES permit does not currently have pretreatment standardsfor the compounds that may be detected in the treated water. Pretreatmentstandards are standards that apply to users of the POTW who contribute pollutantsthat interfere with or pass through the POTW. Pretreatment standards then becomeeffluent limits on the user, in this case NAS Brunswick. These standards would bedeveloped by the POTW to ensure that the POTW remains in compliance with itsNPDES permit and sludge use and disposal practices. Regulations for landapplication of sludge have been set for the metals cadmium, chromium, copper, lead,mercury, nickel, and zinc for both maximum permissible concentrations androayjirnim loading limits (on a kilogram/hectare basis). A ma*i"n"n permissibleconcentration level has also been set for PCBs.

The additional flow from the treatment plant would not cause the POTW to exceedits capacity. The design flow rate for the POTW is 3.85 million gallons per day


W00292S1.08037

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(mgd). Average flows are currently 2.8 mgd, or about 73 percent of capacity. Thecost of discharging treated water to the POTW cannot be estimated becausepretreatment requirements are not yet known. Flow from NAS Brunswick iscurrently metered, and there would be a fee for the increased flow.

Some variations to the components described may be necessary during the design andas a result of groundwater flow modeling, treatability studies, and dischargerequirements. The purpose of the interim remedial action is to initiate an earlyresponse action for the Eastern Plume. The Navy, the USEPA, and the MEDEP willreview the collected monitoring data and reevaluate the effectiveness of the interimaction. If the interim action is deemed effective and meets the requirements of thefinal ROD for Sites 4, 11, and 13, the interim action could become part of the overallremedy. If modifications need to be made to the collection or treatment systems tomeet the requirements of the final ROD, those modifications would be incorporatedinto the final ROD for Sites 4, 11, and 13.


38

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XI. STATUTORY DETERMINATIONS

The interim remedial action selected for implementation at NAS Brunswick for theEastern Plume is consistent with CERCLA and, to the extent practicable, theNational Contingency Plan. The selected interim remedy is protective of humanhealth and the environment, attains ARARs for the limited scope of the action, andis cost-effective. The selected interim remedy also satisfies the statutory preferencefor treatment that permanently and significantly reduces the toxicity, mobility, orvolume of hazardous substances as a principal element. Additionally, the selectedinterim remedy uses alternate treatment technologies or resource recoverytechnologies to the maximum extent practicable.

A. THE SELECTED INTERIM REMEDY is PROTECTIVE OF HUMAN HEALTH ANDTHE ENVIRONMENT

The interim remedy at this site will permanently reduce the risks posed to humanhealth and the environment by eliminating, reducing, or controlling exposures tohuman and environmental receptors through treatment; more specifically, protectionis provided by containment of the plume to prevent the migration of contaminatedgroundwater to currently uncontaminated areas, and by permanent reduction ofcontaminant concentrations in the water through treatment and off-site disposal ofthe sludge produced by metals pretreatment. The selected remedy will treatextracted groundwater to levels that are protective of human health, posing humanhealth risks that are within the 10"4 to 10* incremental cancer risk range and that arewithin the Hazard Quotient of 1.0 for noncarcinogens. Finally, implementation ofthe interim action will not pose unacceptable short-term risks or cross-media impacts;there will be little danger to workers or the community during treatment and thecontaminants removed will be destroyed.

B. THE SELECTED INTERIM REMEDY ATTAINS ARARs

This remedy will attain all applicable or relevant and appropriate federal and staterequirements that apply to this limited scope interim action. Generally, ARARs forthe selected interim remedial action are a subset of those found in Tables 2-1, 2-2,and 2-4 of Section 2.0 of the FS (E.C Jordan Co., 1992a). Because the FS

-considered permanent remedial alternatives and the remedy selected is an interimremedy, some of the ARARs outlined in the FS do not apply to this interim action.ARARs that do apply to this interim action are listed in Appendix A and arediscussed below.

When considering interim remedies, it is appropriate to analyze compliance only withthose laws and regulations that are applicable, or relevant and appropriate, to the


39

: limited scope of this interim action. The selected interim remedy would meet the1 following federal and state ARARs for the treatment of groundwater, discharge of

the treated water, and disposal of treatment process sludges:

Chemical-specific ARARs

j • Safe Drinking Water Act (SDWA) - MCLs and non-zero MCLGs

I • Resource Conservation and Recovery Act (RCRA) - MCLs

• Maine Drinking Water Rules

• Clean Water Act (CWA) - Ambient Water Quality Criteria (AWQC)

( • Maine Regulations Relating to Water Quality Criteria for ToxicPollutants

I The following chemical-specific policies, criteria, and guidelines were also considered:

• Maine Department of Human Services Rule 10-144A, CMRI Chapter 233 - Maximum Exposure Guidelines (MEGs)

• USEPA Risk Reference Doses (RfDs)

• • USEPA Human Health Assessment Group Cancer Slope Factors(CSFs)

*- Location-specific ARARs

I • Maine Natural Resources Protection Act

• Natural Resources Protection Act

• Maine Standards for Classification of Minor Drainages

I. • Maine Standards for Classification of Groundwater

p • -Maine Site Location Development Law and Regulations

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1i Action-specific ARARs

| • Resource Conservation and Recovery Act (RCRA) - General Facility( Standards

I • RCRA - Preparedness and Prevention

• RCRA - Contingency Plan and Emergency Procedures

L • RCRA - Miscellaneous Units

| • Maine Hazardous Waste Management Rules

• Occupational Safety and Health Administration (OSHA) - General1 Industry Standards

• OSHA - Safety and Health Regulations

• OSHA - Recordkeeping, Reporting, and Related Regulations

J • Clean Water Act (CWA) - Pretreatment Standards for POTWDischarge

I • CWA - National Pollutant Discharge Elimination System (NPDES)

i • Maine Water Pollution Control Law: Conditions of Licenses

• Maine Water Pollution Control Law: Certain Deposits and Dischargesi Prohibited

• Underground Injection Control Program

I • Maine Rules to Control the Subsurface Discharge of Pollutants byWell Injection

L The following policies, criteria, and guidelines (ie., TBCs) will also be consideredduring the implementation of the remedial action:r

*- • MEDEP, Bureau of Water Quality Control, Policy Number 10: "TheDischarge of Hazardous Substances to Groundwater of the State"

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Federal and State Drinking Water Regulations. The chemical-specific ARARsidentified for the Eastern Plume can be applied to the interim remedy in twomanners In the instance of drinking water standards, MCLs and other guidance andcriteria to be considered (TBCs) were used in the development of target cleanuplevels for the remediation of groundwater at the site. Drinking water standards inayalso be used separately, or in conjunction with surface water standards, in thedevelopment of discharge limits for treated groundwater.

In the development of groundwater cleanup levels, the groundwater in the aquiferunderlying the site is classified by the state as GW-A, a drinking water source. Thequality and safety of drinking water sources is regulated by the SDWA and MaineDrinking Water Rules. MCLs are enforceable standards under the SDWA thatrepresent the maximum level of contaminants that is acceptable for users of publicdrinking water supplies. MCLs are relevant and appropriate because, while thegroundwater on and off site is not currently used as a drinking water source, thegroundwater underlying NAS Brunswick potentially could be used as a drinking watersource in the future.

Target cleanup levels for groundwater within the Eastern Plume were developedbased on results of the baseline risk assessment. Federal and state MCLs were thefirst order of standards used in establishing cleanup levels. For those contaminantsfor which no MCLs were available, other criteria and guidelines (i.e., TBCs) wereused. TBCs used during the risk assessment and in establishing cleanup levelsincluded Maine MEGs, USEPA RfDs, and USEPA CSFs.

The objective of the interim remedial action is to prevent further migration of theEastern Plume. As an interim action, not all ARARs will be attained. Attainmentof groundwater standards and risk-based target cleanup levels will be addressed aspart of the ROD for the final site remedy.

Federal and State Water Quality Criteria. In developing discharge limits for treatedgroundwater, drinking water standards and surface water standards identified underchemical-specific ARARs may be applicable to the interim remedy depending on thechoice of discharge option. The interim remedy considers three options for dischargeof treated groundwater. The Navy's preferred option is discharge of treated waterto the Brunswick POTW. Under this option, discharge limits would be based onfactors regulated by the POTWs NPDES permit, pretreatment regulations, and waterpollution control laws, which will be discussed under action-specific ARARs.Because final discharge from the POTW would be to the Androscoggin River, federalAWQC and Maine Water Quality Criteria are ultimately applicable to this dischargeoption.


42

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Pretreatment standards are being developed with the Brunswick POTW. Both thePretreatment Standards and CWA NPDES will be attained upon successfulestablishment of pretreatment standards for discharge from the groundwatertreatment plant.

Another option for the discharge of treated groundwater would be groundwaterreinjection. As required by Underground Injection Control Programs, to be discussedunder action-specific ARARs, federal and state MCLs and MEGs would apply to thedevelopment of discharge limits. To reinject groundwater, MCLs and MEGs wouldbe attained through treatment of contaminated groundwater.

The final option for discharge of treated groundwater would be directly to a surfacewater source on NAS Brunswick. This action would be governed by NPDES andWater Pollution Control Regulations, to be discussed under action-specific ARARs.However, these regulations would require development of discharge limits thatcomply with federal and state Water Quality Criteria. Compliance with NPDES andWater Pollution Control regulations would be through treatment of contaminatedgroundwater to final discharge limits and regular monitoring of effluent.

State Location-specific Regulations. All the location-specific ARARs that apply tothe interim remedy are related to piping that will need to cross Mere Brook. TheState of Maine location-specific ARARs relate to work conducted within 100 feet ofa stream or wetland. While no significant invasive work wil] be conducted close toMere Brook, construction activities to run piping over the brook are an element ofthe interim remedy.

The Maine Natural Resources Protection Act provides that activities adjacent tostreams must not cause unreasonable soil erosion, cause unreasonable harm tosignificant wildlife habitats, unreasonably interfere with natural water flow, lowerwater quality, or unreasonably cause or increase flooding. Chapter 305 of theMEDEP regulations provides further standards for erosion control and soilexcavation. Implementation of the selected interim remedy would not impact thedrainage or natural flow of Mere Brook, Because the pipeline wfll cross Mere Brookat an existing roadway bridge, minimal effects are expected However, soil erosioncontrols will be employed during excavation along the pipeline.

Portions of the Maine Site Location Development Law, and associated regulations,apply to this site. The law and regulations provide that new development, whichhandles hazardous waste, cannot have an adverse effect on the natural environmentor pose an unreasonable risk of discharge to a significant groundwater aquifer.Applicable portions of Chapter 375, which set forth the no adverse environmentaleffect standards regulation of natural drainageways, runoff, erosion, sedimentation


W00292S1.080 68364543

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, control, and groundwater quality, will be attained by the interim remedy. Asmentioned, implementation of the selected interim remedy would not impact thedrainage or natural flow of Mere Brook. Soil erosion controls will be employedduring excavation along the pipeline to minimize soil entering Mere Brook.Groundwater extraction will remediate groundwater and prevent further impact tothe environment.

Federal and State Hazardous Waste Regulations. The applicability of RCRA andMaine Hazardous Waste Regulations depends on whether the wastes are RCRA-hazardous wastes as defined under these regulations. To date, there is noinformation available (i.e., manifests) to indicate that RCRA-regulated materialswere disposed of at Sites 4, 11, and 13. However, because toxic constituents arepresent in the source materials and groundwater in the Eastern Plume, many portionsof the federal and state hazardous waste regulations are relevant and appropriate tothe interim remedy.

RCRA General Facility Standards, Preparedness and Prevention, and Contingency

I Plan and Emergency Procedures will be attained during construction and operationof the groundwater treatment plant. The treatment plant, which will be secured toprevent access by unauthorized personnel. The facility will be designed, maintained,

I constructed, and operated to minimize the possibility of an unplanned release thatcould threaten human health or the environment During remedial construction,safety and communication equipment will be installed at the site, and local

I authorities will be familiarized with site operations. Contingency plans will be' developed and implemented during site work and treatment plant operation. A

program will be developed for handling, storage, and recordkeeping, in accordanceI with Maine Hazardous Waste Management Rules.

During treatment of contaminated groundwater, sludges containing some toxicconstituents will be produced. A component of groundwater treatment includeslaboratory analysis of this sludge, including Toxicity Characteristic LeachateProcedure (TCLP) testing. If the sludge fails TCLP testing, this material will beconsidered hazardous. As a characteristic hazardous waste, RCRA regulations,including Land Disposal Restrictions will apply and the sludge will be treated anddisposed of in a RCRA Subtitle C facility.

Ircrir

Because toxic constituents are present on site, OSHA regulations protecting workerhealth and safety at hazardous waste sites are applicable to the implementation andlong-term operation of the interim remedy. Site workers will have completedtraining and will have appropriate health and safety equipment on site. Contractorsand subcontractors working on site will follow health and safety procedures.


W0029251.060 6836-QS44

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I Federal and State NPDES, Water Pollution Control, and Underground InjectionJ Regulations. As mentioned, many action-specific ARARs will regulate the discharge

of treated groundwater. The three discharge options for the interim remedy include:(1) Brunswick POTW, (2) reinjection to groundwater, and (3) direct discharge tosurface water. Discharge of treated groundwater to the Brunswick POTW is theNavy's preferred option; however, final approval has not been obtained from thePOTW. CWA Pretreatment Standards for POTW Discharge would be attainedthrough treatment of the groundwater to these standards. Indirectly, CWA NPDESis an applicable regulation because the final discharge is to the Androscoggin River,

I and the Brunswick POTW has a current NPDES permit.

If discharge to the POTW is not acceptable, a second alternative is to reinject treatedwater back to groundwater. The federal Underground Injection Control Programand Maine Rules to Control the Subsurface Discharge of Pollutants by Well Injectionare applicable to this discharge option. These regulations would require and beattained through establishment of standards for the treatment of groundwater thatattain federal and state drinking water standards and guidance values.

IIIIILIICC

The third discharge option would be to send treated groundwater directly to asurface water source on NAS Brunswick. The CWA NPDES and Maine WaterPollution Control Laws would apply to this method of discharge. Under this option,an NPDES permit would need to be obtained. In the course of obtaining thatpermit, discharge limits for the treatment plant effluent would be established.Federal and state water quality criteria would be used in the development of finaldischarge limits.

C. THE SELECTED INTERIM REMEDIAL ACTION is COST-EFFECTIVE

The selected interim remedy is cost-effective; that is, the remedy affords overalleffectiveness proportional to its costs. The Navy evaluated the overall effectivenessof the interim action by assessing the relevant three criteria: long-term effectivenessand permanence; reduction in toxicity, mobility, and volume through treatment; andshort-term effectiveness, in combination. The relationship of the overall effectivenessof this remedial alternative was determined to be proportional to its costs. The costsof this remedial alternative are:

-Estimated Capital Cost: $1,223,000Estimated Operation and Maintenance Costs (net present worth): $1,845,000*Estimated Total Cost (net present worth): $4,223,000*

'Net present worth costs are based on a 10 percent discount factor and five years ofoperation.


W00292S1.060 6836-0545

1 D. THE SELECTED INTERIM REMEDY UTILIZES PERMANENT SOLUTIONS AND' ALTERNATIVE TREATMENT OR RESOURCE RECOVERY TECHNOLOGIES TO THE

MAXIMUM EXTENT PRACTICABLE

The selected interim remedy uses permanent solutions and alternative treatmenttechnologies or resource recovery technologies to the maximum extent practicable.The interim action was evaluated for the balance of trade-offs in terms of: (1) long-term effectiveness and permanence; (2) reduction of toxicity, mobility, or volumethrough treatment; (3) short-term effectiveness; (4) implementability; and (5) cost.The balancing test emphasized long-term effectiveness and permanence and thereduction of toxicity, mobility, and volume through treatment; and considered thepreference for treatment as a principal element, the bias against off-site land disposalof untreated waste, and community and state acceptance. The interim remedialaction provides the best balance of trade-offs among these criteria prior todetermination of a final remedy.

E. THE SELECTED INTERIM REMEDY SATISFIES THE PREFERENCE FORTREATMENT WHICH PERMANENTLY AND SIGNIFICANTLY REDUCES THETOXICITY, MOBILITY, OR VOLUME OF THE HAZARDOUS SUBSTANCES AS APRINCIPAL ELEMENT

• The principal element of the selected interim remedy is the extraction ofgroundwater and treatment with UV/oxidation. This element addresses the primarythreat of the Eastern Plume-discharge of contaminated water to Harpswell Cove.The interim remedial action satisfies the statutory preference for treatment as aprincipal element by destroying contaminants in the extracted groundwater withUV/oxidation.

This interim ROD will be followed by a final ROD that will determine what furtheractions, if any, will be necessary to meet the preference for treatment which willpermanently and significantly reduce toxicity, mobility, or volume of hazardoussubstances.

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W00292S1.080 6836-0546

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' XII. DOCUMENTATION OF NO SIGNIFICANT CHANGESi

f The Navy presented a Proposed Plan (preferred alternative) for the interim remedialj action for the Eastern Plume on December 12, 1991. The interim remedial action

consisted of the same components described in this ROD. No significant changesI have been made to the interim action described in the proposed plan and presented{ to the public.

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XIII. STATE ROLE

MEDEP has reviewed the interim remedial action and indicated its support for theselected remedy. As party to the FFA, the state has also reviewed the RI, RemedialAction, FS, and Proposed Plan to determine if the selected remedy is in compliancewith ARARs. MEDEP concurs with the selected remedy for the Eastern Plume atNAS Brunswick. A copy of the letter of concurrence is presented in Appendix C ofthis ROD.


W0029251.080 68364648

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ARARATSDRAWQC

BACSE

CERCLA

CSFCWA

DCADCEDNAPLDRMO

.FFAFS

gpm

IASmpMCLMEDEPMEGmgdMSL

NASNPDESNPL

OSHA

POTWppb

ACRONYMS

Applicable or Relevant and Appropriate RequirementAgency for Toxic Substances and Disease RegistryAmbient Water Quality Criteria

Brunswick Area Citizens for a Safe Environment

Comprehensive Environmental Response, Compensation, and LiabilityActcancer slope factorClean Water Act

dichloroethanedichloroethylenedense nonaqueous phase liquidDefense Reutilization and Marketing Office

Federal Facility AgreementFeasibility Study

gallons per minute

Initial Assessment StudyInstallation Restoration Program

Maximum Contaminant LevelMaine Department of Environmental ProtectionMaximum Exposure Guidelinemillion gallons per daymean sea level

Naval Air StationNational Pollutant Discharge Elimination SystemNational Priorities List

Occupational Safety and Health Act

publicly owned treatment worksparts per billion


W0029251.080 6836-5

ACRONYMS

L

RCRA Resource Conservation and Recovery ActRfD reference doseRI Remedial InvestigationROD Record of Decision

SDWA Safe Drinking Water Act

TBC to be consideredTCA trichloroethaneTCE trichloroethyleneTCLP Toxicity Characteristic Leachate ProcedureTRC Technical Review Committee

USEPA U.S. Environmental Protection AgencyUV ultraviolet

VOC volatile organic compoundVPC vapor phase carbon

cpr

W00292S1.080


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_______________________________________REFERENCES

E.G. Jordan Co., 1990a. "Draft Final Remedial Investigation Report NAS. Brunswick"; Portland, Maine; August.

E.G. Jordan Co., 1990b. "Phase I Feasibility Study Development and Screening of• Alternatives NAS Brunswick"; Portland, Maine; August.

E.G. Jordan Co., 199 la. "Draft Final Supplemental Remedial Investigation ReportI NAS Brunswick"; Portland, Maine; August.

E.G. Jordan Co., 1991b. "Focused Feasibility Study Sites 1 and 3 NAS Brunswick";I Portland, Maine; October.

E.C. Jordan Co., 1992a. "Feasibility Study NAS Brunswick"; Portland, Maine; March.

1 E.C Jordan Co., 1992b. "Focused Feasibility Study Site 8 NAS Brunswick"; Portland,Maine; March.

I R.F. Weston, Inc., 1983. "Initial Assessment Study of Naval Air Station, Brunswick,Maine"; Westchester, Pennsylvania; June.

ICCrI Installation Restoration Program

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APPENDIX A

APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS

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[ RESPONSIVENESS SUMMARY

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APPENDIX B

RESPONSIVENESS SUMMARY

OVLKVIEW

At the time of the public comment period, the U.S. Navy had selected a preferredalternative for interim remediation to address groundwater contamination at theEastern Plume at NAS Brunswick. This preferred alternative was selected incoordination with the USEPA and the MEDEP. Other members of the TRC for thisproject were also involved in discussions and planning of the groundwater extractionand treatment alternative. Technical details of the alternative have been discussed,and no fundamental objections to its selection have been raised.

The sections below describe the background of community involvement with theproject and the U.S. Navy's responses to verbal and written comments receivedduring the public comment period.

BACKGROUND OF COMMUNITY INVOLVEMENT

Prior to the public comment period in December 1991 and January 1992, there wereseveral presentations to the public regarding the RI/FS activities at NAS Brunswick.Two meetings to inform the public on the general status and process for the RI/FSoccurred in February and March of 1990. A technical forum occurred in August1990 where the status and understanding of site-specific studies was also presentedto the public. In November 1991, newspaper announcements were placed for apublic meeting presented by the U.S. Navy in Brunswick to discuss the results of theRI/FS and the Preferred Alternative.

Local input to the selection of the preferred remedy for interim remediation hascome predominantly through the TRC, established by the U.S. Navy. Meetings heldapproximately quarterly since early 1988 have brought together local representativesof the towns of Brunswick, Harpswell, and Topsham. The TRC also has includedrepresentatives from the Brunswick-Topsham water district and a local citizens group(Le., BACSE). This involvement has facilitated remedial planning by the U.S. Navyand has alerted affected local groups to the proposed activities.


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SUMMARY OF COMMENTS RECEIVED DURING PUBLIC COMMENT PERIOD

During the public comment period, written comments were received from citizensand several special interest groups. At the public meeting on December 12, 1991,several questions and comments were also raised.

eo

1. Comment (written):

Response:

Groundwater modeling is proposed to simulatepumping and determine effects on the plume fromthe remediation efforts at Sites 1 and 3, I amconcerned about the possible interactions betweenthe two sites and would encourage you to back upthe modeling results with significant on-sitemonitoring once the proposed plans areimplemented. In addition, monitoring should takeplace outside the plume edge to insure that thecontamination is not advancing during groundwaterextraction. It is anticipated that the leading edge ofthe phime could reach Harpswell Cove in 1996 andthe remedial action will take 2 years and 5 monthsto implement. Considering the elapsed time beforeactual construction begins, it is realistic to assumethat pumping will begin sometime in early 1995.Therefore, it is essential that monitoring outside theplume edge be performed in the interim prior toimplementation to predict any potential impacts toHarpsweU Cove. The results of the groundwatermodel should also be used in the placement of theextraction wells in the eastern plume.

The groundwater modeling program is designed toanswer several questions including the interactionbetween the groundwater at Sites 1 and 3 and theEastern Plume. The modeling will also provideinformation on the potential location and pumpingrates for extraction wells. The remedial action atthe Eastern Plume will also include a RemedialAction -Monitoring Plan. The -Remedial ActionMonitoring Plan will describe a Tnonitoring programthat will evaluate the effectiveness of the remedialaction and will specify sampling locations, intervals,and compounds to be analyzed This monitoringplan will support the model by sampling monitoring


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wells located downgradient of the existing plume(i.e., wells in the path of the plume that have testedclean) to make sure that the extraction wells arelocated to effectively capture the advancing plume.The Remedial Action Monitoring Plan will bereviewed by regulators and the public during theconstruction process. The Remedial ActionMonitoring Plan will not be finalized until the designeffort is complete. This will allow the RemedialAction Monitoring Plan to incorporate the mostappropriate design.

2. Comment (written): The proposed method of discharge is to theBrunswick Sewer District. Although I feel this is thepreferred option, I do have a concern over removingwater from one watershed (Harpswell Cove) anddischarging it to another (AndroscogginRiver/Merrymeeting Bay). The effects on bothwatersheds should be addressed prior toimplementation of this option. The report statesthat "the treated water would meet pretreatmentrequirements or other applicable standards beforeentering the sewer system." At the December 12,1991 public meeting, it was stated that the waterwould be cleaned up to MCL levels prior todischarge to the sewer system. POTW pretreatmentstandards and National Pollutant DischargeElimination System (NPDES) permit requirements(if surface water discharge is implemented) areusually far less stringent than MCLs. The reportleaves these cleanup levels as an option, howeversince MCLs were stated as the cleanup level prior todischarge at the public meeting. I would hold you tousing the MCL values. Also, please address thedischarge requirements for acetone, sulfates, and

-nitrates generated as byproducts during thegroundwater treatment The groundwater shouldalso be tested for radon prior to treatment Ifdischarge to the POTW is not feasible, public

ni should be soh'cJted for the other options ofgroundwater recharge or surface •water discharge.


B-3

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I Response: With regard to the amount of water that normallyflows into the Casco Bay estuary; an overall water

r balance for the Harpswell cove watershed area was| performed using a general area of the watershed

area (ft2} x an average infiltration rate of18-inches/year. Of the approximately 4,151 gallonsper minute (gpm) flowing into lids watershed, theEastern Plume and Site 1 and 3 extraction rates

( (approximately 130 gpm) represents less than3 percent of the overall flux into the system. Whenthe Sites 1 and 3 extraction is completed

[ (approximately 1 to 2 years) the Eastern Plumeextraction represents less than 2 percent of theoverall flux. Given the significant area over which

I the Kennebec/Sheepscott bay watershed occurs, the1 addition of this volume of water is expected to be

negligible compared to the overall flux through theI watershed area.

The POTW's current NPDES permit does not haveI effluent standards for many of the contaminants that

will be in the NAS Brunswick treated water. Forpreliminary design and cost-estimating purposes,

I discharge limits equal to MCLs were assumed.However, in order to discharge to the POTWpretreatment, standards for a user such as a militaryinstallation (NAS Brunswick) will have to beestablished. These pretreatment standards arelimitations that will be placed on the effluent fromthe NAS Brunswick treatment system such that theintroduction of the NAS Brunswick effluent to thePOTW waste stream will not cause the POTW to bein violation of its NPDES permit The design of thetreatment plant will be determined by thepretreatment requirements (these pretreatment

^standards may be determined by Ambient WaterQuality Criteria [AWQCs], MCLs, or some otherappropriate rationale). The pretreatment standardswill be developed to be protective of receptors in theAndroscoggin River, human or environmental

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The POTW will be requi red to submit apretreatment program as an amendment to itsNPDES permit. This program (which will includethe standards themselves and a compliance schedule)will be submitted to the Wastewater ManagementBranch of USEPA Region I and be subject toapproval. Pretreatment standards may includelimitations on compounds such as acetone, sulphates,nitrates and any other possible by-products of thetreatment system as well as the contaminantsoriginating from Sites 1 and 3 groundwater.Treatability tests conducted during the design of thesystem will provide information on effluent

' constituents and their concentrations. The processof applying for pretreatment standards and anamended NPDES permit will require cooperationbetween the Navy and POTW officials.

If discharge to the POTW of treated groundwater isnot chosen as the discharge option, the Navy will useone of the other discharge options includingupgradient infiltration or discharge to surface water.These other discharge options are included in theProposed Plan for the Eastern Plume and additionalpublic comment is not required The final choice fordischarge of treated groundwater may also beevaluated using the design groundwater model.

Radon testing is not anticipated to be included inthe Remedial Action Monitoring Plan. Thepresence of radon would not be the result of site-related contamination.

3. Comment (written): More information on the extent of contamination ofthe solid residue from the groundwater treatment

^and its ultimate disposal site is needed. If it is notdeclared a hazardous waste, will disposal optionsinclude the Brunswick sanitary landfill or landapplication? I encouraged you to solicit publiccomments prior to any decision on a disposal she.

installation Restoration ProgramW0029251.080 6836-5

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Response:

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Response:

The metals sludge from the pretreatment processwill be tested for characteristics (i.e., ignitability,corrosivity, reactivity, and toxicity) of ResourceConservation and Recovery Act (RCRA) hazardouswaste. It will either be disposed of in a securehazardous waste landfill or a landfill for non-hazardous solid waste depending on the results ofthe tests. It is not likely that the sludge would besuitable for land application.

While we jinArcfanH {haf the purpose of the interjmremedial action is to begin to clean up contaminatedgroundwater in the Eastern Plume, it is not clearhow the interim measures fit with the final remedialactions, including source removal. How will thepotential for DNAPLs (dense nonaqueous phaseliquid contaminants) be evaluated? Theimplementation of the interim groundwaterextraction should provide an opportunity to gatherdata concerning water levels and water chemistrythat can be used to design the final remedialmeasures.

Although the proposed remedial action at theEastern Plume is currently a interim action, it maybe consistent with the final proposed action for thedowngradient groundwater operable unit The DraftFinal FS (E.C Jordan Co., 199 la) describes a seriesof remedial alternatives for the source area. Therange of proposed alternatives for the source areavaries from no action through source removal andtreatment. The presence or absence of densenonaqueous phase liquids (DNAPLs) was evaluatedas part of the RI study, and DNAPLs are notobserved in the Eastern Plume area.

Additional data concerning water levels and waterchemistry will be gathered as part of the RemedialAction Monitoring Plan (see Response toComment 1).

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Comment (written):

Response:

Comment (written):

Response:

According to tbe plan, the southern limit of theplume is "believed to be in the vicinity of NewGurnet Road." What measures will be taken tomore closely define the extent, both vertically andhorizontally, of the contaminant plume?

Based on sampling results from the fall of 1990reported in the Draft Final Supplemental Rl Report(E.G. Jordan Co., 1991a), the southern limit of the.Eastern Plume was determined to be in the vicinityof New Gurnet Road, and the vertical and horizontaldistribution of contamination within the EasternPlume was well characterized. Monitoring wellsestablished along the plume boundaries, anddowngradient of the plume will allow futurecharacterization of the plume. A Remedial ActionMonitoring Plan will be developed to evaluate theeffectiveness of the remedial action and monitorpotential contaminant migration. The RemedialAction Monitoring Plan will receive regulatory andpublic review.

The Plan indicates that the main potential effect ofthe proposed remedial action of Sites 1 and 3 on theEastern Plume remediation will be the diversion ofclean groundwater upgradient of the sites toward thesouthern portion of the Eastern Plume, and thatdesign-level groundwater modeling studies willquantitatively evaluate this interaction. What if themodel does not show this interaction? How andwhere will field data be gathered to test thepotential effect?

The effects of the remedial action at Sites 1 and 3on the Eastern Plume will be evaluated using field=data and the design-level groundwater model These

-modeling results will be included in the evaluation offinal locations and pumping rates for extractionwells. Additional field data are not anticipated to berequired to finally^, iVdgn of the Eastern Plumegroundwater extraction system; however, treatabilitystudies will be performed on contaminated


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groundwater from both Sites 1 and 3 and theEastern Plume. The treatability studies will provideinput for both extraction rates and groundwatertreatment design.

The long-term Remedial Action Monitoring Planwill include provisions for assessing the field dataand modeling results to evaluate the interactionbetween the extraction program at the EasternPlume and the diversion of groundwater from Sites 1and 3.

7. Comment (written): There are not enough data points to substantiatethat groundwater does not flow from the clay intothe underlying bedrock at the facility. Furthermore,while the clay may have a relatively lowpermeability, it cannot be assumed to be acontinuous impermeable barrier to contaminantmigration. Additional hydrogeologic data is neededto better characterize the current clay-bedrock flowregime and how it will be affected by the proposedremedial action at Sites 1 and 3 and the EasternPlume.

Response: Extensive explorations have been conducted at thesite to characterize the geology and hydrogeology,including the clay-bedrock flow regime. The sitecharacterization included 55 cone penetrometer testexplorations and 119 monitoring well/piezometerexplorations. The data collected at the base indicatethat an upward gradient exists between the bedrockaquifer and the overlying aquifer in theunconsolidated sediments. Although existing dataindicates that an upward vertical component of flowmay exist at the site, it is estimated to be minimal(Draft Final Supplemental RI Report, E.C JordanCo., 1991a). Investigations conducted at the siteindicate that the clay unit ranges in thickness from20 to 60 feet and permeability tests conducted onshelby tube samples obtained from this unit indicatea hydraulic conductivity on the order of 10'7 cm/sec.Upward vertical gradients were also observed to

————— installation Restoration Program

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Response:

exist between the overburden soils located above theclay and bedrock unit located below the clay.Although the bedrock has been shown to occurabove the day in two locations, the bulk of theobservations demonstrates that this is the exception.The large extent and low permeability of the claywill minimi** upward seepage. As part of the designmodeling task, sensitivity analyses will be utilized toevaluate the amount of upward vertical seepagethrough the clay. However, given the very lowhydraulic conductivity of the clay, potential seepageis anticipated to be only a very small fraction of thewater available through surface recharge ofprecipitation and the total water mass balance.

What is the hydrogeologic relationship between the"coarse sand" shown on Figure 6 and the "sand" or"deep sand" shown on Figure 5?

The hydrogeologic relationship between the coarsesands shown in Figure 6 and the deep sand shown inFigure 5 is that they represent the samehydrogeologic unit. Figure 5 shows th ishydrogeologic unit in cross section, and Figure 6shows a longitudinal section of this hydrogeologicunit.

How were the locations of the extraction wells andthe pumping rates determined?

The location and pumping rates for the extractionwells were developed from the results ofgroundwater modeling presented in the Draft FinalFS (E.C Jordan Co., 199la), and the location of the

-deep pockets of contaminated groundwater within"the Eastern Plume. The design-level groundwatermodel will further refine the well locations andextraction rates.

10. Comment (written): Since groundwater cannot be effectively isolatedbetween cleanup sites, and since there is evidencethat plumes from several sites are already merging,



Response:

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Response:


the treatment of all discharged ground-water shouldbe based upon the presumptive presence of toxicmaterials currently identified as being present at anyof the sites.

The interaction between Sites 1 and 3 and theEastern plume will be evaluated with a design-levelgroundwater model. The current understanding ofthe interaction of contamination from Sites 1 and 3and the Eastern Phrme indicates that the two plumesdo not interact With the construction of the slurrywall at Sites 1 and 3, a potential exists foruncontaminated groundwater to flow into thesouthern portion of the Eastern Plume. Thisinteraction will be evaluated with the groundwatermodel. Considerable time has been spent studyingthe nature and distribution of contamination at thevarious sites at NAS Brunswick. This informationhas been used to evaluate risk to human health andthe environment, and to set target cleanup levels.This information is site-specific and will be used toset target cleanup levels as appropriate for each site.Because extracted groundwater from Sites 1 and 3and the Eastern Plume will likely be combined inthe treatment process, treatability studies will beconducted on the combined flows in order to designthe system to treat contaminants from both plumes.

We note with concern that the proposed treatmentcriteria are essentially based upon standards fordrinking water (the EPA standard, which is lessstringent than those of many states), although it isgenerally recognized that the criteria for theprotection of plant and animal life are morestringent Since we know that toxic elementsaccumulate and become more dangerous as theymove up the food chain, it is illogical to use drinkingwater standards. We do not drink the waters of theAndroscoggin • they are used by simple and thenincreasingly complex organisms that reach us onlymuch later in the food chain. Moreover, evenminute quantities of some of the toxic materials, like


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rResponse:

However, in order to discharge to the POTWpretreatment, standards for a user such as a militaryinstallation (NAS Brunswick) will have to beestablished. These pretreatment standards arelimitations that will be placed on the effluent fromthe NAS Brunswick treatment system such that theintroduction of the NAS Brunswick effluent to thePOTW waste stream will not cause the POTW to bein violation of its NPDES permit The design of thetreatment plant will be determined by thepretreatment requirements (these pretreatmentstandards may be determined by AWQCs, MCLs, orsome other appropria te rationale). Thepretreatment standards will be developed to beprotective of receptors in the Androscoggin River,human or environmental.

The POTW will be required to submit apretreatment program as an amendment to itsNPDES permit. This program (which will includethe standards themselves and a compliance schedule)will be submitted to the Wastewater ManagementBranch of USEPA Region I and subject to approvalPretreatment standards may include limitations oncompounds such as acetone, sulphates, nitrates, andany other possible byproducts of the treatmentsystem as well as the contaminants originating fromSites 1 and 3 groundwater. The process of applyingfor pretreatment standards and an amended NPDESpermit will require cooperation between the Navyand POTW officials.

The State of Maine amended 38 MRSA Section 420to adopt EPA's national water quality criteria.Inasmuch as these criteria impose more restrictive

-standards than EPA drinking water standards, theyappear to be the legal minimum requirements fordischarge of water to the Androscoggin River atBrunswick, Maine.

The actual cleanup levels for contaminants in thegroundwater from Sites 1 and 3 will be determined

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I 13. Comment (written):

Recommendation A:

Response:

Recommendation B:

based on the final disposal of the treated water.Three discharge options were developed anddiscussed in the Proposed Plan and the FocusedFeasibility Study for Sites 1 and 3 and include:upgradient recharge, discharge to surface water, ordischarge to the POTW. Each discharge option hasspecific requirements that must be met prior to theimplementation of the proposed alternative. Asstated in the response to Comment 11, dischargedwater will be required to comply with federal andstate regulations applicable to the receiving waterbody.

Recommendation

Recharge water into ground on the base.

Upgradient infiltration of groundwater has beenconsidered as a potential discharge option. Thepotential effectiveness of this discharge option willbe evaluated with the design-level groundwatermodel.

This option is not preferred for discharge of treatedwater from the Eastern Plume, because agroundwater divide exists north of the EasternPlume. Reinjecting water "upgradient" of the plumemay actually recharge another aquifer system.

If A is not possible, and discharge to theAndroscoggin is required, then accomplish thefollowing:

Lr

Recommendation B-l: Strengthen groundwater cleanup levels, based uponfish and wildlife species criteria.

The environmental standards needed to protect thefish and wildlife in our rivers are no longer a matterof speculation; there is adequate documentation inthe criteria used in many states; i.e., New Jersey,Maryland and EPA also promulgates minimumrequirements. We would hope to see the NAS

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Response:

assume leadership in giving Maine waters the samelevel of protection.

See response to Comment 11.

Recommendation B-2: Department of the Navy should fund some of theservices of an independent toxicologist to review thefinal requirements from the mission requirementpoint of view of the Friends of Merrymeeting Baybecause the subject matter of toxicant levels for fishand wildlife habitat is too complex and beyond thenormal expertise of informed sports enthusiasts.

Response: Technical Assistance Grants (TAGs) are availablefor technical support to the public. The BACSEgroup has received such a grant and may have fundsto support this study.

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Recommendation B-3: Identify the specific legal authority and enablinglegislation that permits piping large quantities ofwater which normally flow to the Casco Bay estuaryinto the Kennebec/Sheepscott Bay estuary.

Response: No specific legislation restricting or limiting thegroundwater flow between watersheds wereidentified during the identification or ARARs. TheNavy does not consider the discharge of treatedwater to the Kennebec/Sheepscott estuary to besignificant. See response to Comment 2.

Recommendation B-4: Prevent the intermixing of sludge from the NAScleanup with domestic sludge. This is of concern tous if the NAS cleanup wastewater is dischargedthrough the Brunswick Sewage Treatment Plant,because the domestic sludge is, at this time, used by

farmers in the Merrymeeting Bay watershed asfertilizer. In addition to the obvious environmentalquestions raised by this issue, there is a question oflegal responsibility. The intermixing of the ~twosources in sludge could generate a rrightmare of legalentanglements should one of the NAS toxicants bethe source of a lawsuit.

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Response:

Recommendation C:

Response:

rf

Sludge from the POTW used as a soil additive issubject to the MEDEP Rules for Land Applicationof Sludge and Residuals. These standards have beendeveloped for several inorganic elements andpolychlorinated biphenyls (PCBs). The standardsspecify maximum permissible concentrations (massof contaminant per mass of sludge applied) andmaximum loading limits (mass of contaminant perarea applied). The pretreatment standards willtherefore be developed so that the maximumpermissible concentrations in the sludge from thePOTW are not exceeded.

Sludge from the POTW will be completely separatefrom and a much different composition than thesludge from the metals pretreatment processes of theNAS Bnmswick treatment plant The POTW sludgehas a much higher organic content (making it usefulto fanners) than the metals sludge from the NASBrunswick treatment plant and the two would not bemixed. The metals sludge from the pretreatmentprocess will be tested for characteristics of RCRAhazardous waste. It will either be disposed of in asecure hazardous waste landfill or a landfill for non-hazardous solid waste depending on the results ofthe tests. Available options for disposal of thesludge from metals pretreatment will be evaluatedduring the design phase.

We have received verbal assurance that there will bea pilot project for water treatment. We request thatthis pilot project be followed by a full-stop reviewand a public comment period.

Pilot tests for the water treatment system will bedeveloped during the pre-design phase. The specificpilot tests will be described in a design work plan.The design work plan will receive regulatory andTRC review.

14. Comment (written): Recommendation


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Recommendation 1:

Response:

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The groundwater treatment include all toxicantscurrently identified as being present at any site.

The groundwater treatment for the PreferredAlternative for the Eastern Plume was designed tospecifically treat or remove the constituents detectedin the groundwater downgradient of the sourceareas. The Preferred Alternative includestreatments for metals and VOC contaminants. Thetreatment option will be designed to meet the finaldischarge requirements for all constituents detectedin the effluent.

Designing a treatment system for contaminants thatare not detected at or likely to be present in theinfluent is not possible, as is suggested in thecomment. Three areas of groundwatercontamination have been detected at NASBrunswick and include Sites 1 and 3, the EasternPlume, and groundwater beneath Site 9. Similarcontaminants of concern have been identified atSites 1 and 3 and the Eastern Plume making itpossible to design a single cost-effective andimplementable groundwater treatment. However,the contaminants of concern at Site 9 includecompounds that have different chemical and physicalproperties than those identified at Sites 1 and 3.This results from the different historical land useand disposal practices at these site. Because of thedifferent properties of the contaminants of concern;separate and different treatment technologies needto be considered. Each site must be evaluatedseparately to ensure proper treatment and/orremoval of the site-specific contaminants of concern.

The final treatment of contaminated groundwater atSite 9 will be decided using the same process as the

-JEastern Plume. The public will have the sameopportunity to review and comment on the finalplan.

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Recommendation 2:

Response:


Response:

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The groundwater treatment levels be strengthenedand be based upon fish and wildlife species criteria.The attached list of monitoring elements containssample recommended water treatment levels basedon these criteria, incorporating drinking waterstandards where appropriate (Table B-l).

See response to Comment 11.

Our final interest concerns die overall biological andecological threat posed by the sites. We applaudwhat appears to be a very thorough hydrogeologicalevaluation of the site but we believe the surfaceterrestrial and aquatic biotic components have beenneglected. We wish to see a more complete analysisof the threat of dispersal of hazardous materials bybiotic -means through toe food web and within andbeyond the confines of the Mere Brook watershedand associated aquifers. An analysis of this son iscritical in evaluating the effectiveness of anycontainment or extraction/treatment remedialactions.

The proposed long-term monitoring for thePreferred Alternative includes surface water andsediment sampling locations along Mere Brook;soil/sediment samples at the current leachatelocations and groundwater samples from locationsdowngradient of the landfill areas. Analytical resultsfrom these samples will provide informationregarding the transport of contaminants from thelandfill to the Mere Brook environment. Currentsampling results do not show the transport ofcontaminants beyond the region of Mere Brookdirectly adjacent to Sites 1, 2, and 3. Therefore, nocontaminant migration is expected after theimplementation of remedial actions.

A biological food chain model was used to providean appropriate ecological cleanup level for mercury.This value (1 milligram per kilogram) will be used aspart of the Remedial Action Monitoring Plan to

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TABLE B-1FRIENDS OF MERRYMEETING BAY CLEANUP RECOMMENDATIONS


MONITORING ELEMENT

Arsenic

Vinyl chloride

Methylene chloride

Chromium (total)

Lead

Nickel

Zinc

Mercury

1.1 -DCE

1,1 -DCA

1,1,1-TCA

1,2-DCE (cis)

1,2-DCE (trans)

Asbestos

PCE

TCE

AlcoholPCB

2-Butanone:J(ylene

ODD

DDE

DOT

CyanideOR

MINIMUM CLEANUP LEVEL(micrograms per liter)

50.2

4.7

0.06

0.9

0.04

0.03

0.03

6

0

200

70

100

10

0

0

data unavailable0.014

data unavailable0.8

0.01

0.0006

0.012

1

0.01

RATIONALE127

7

6

7

6

7

4

5

2,3

2,3

2,3

5

5

5

8

8

7

6

7

7

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continued

TABLE B-1AMENDS OF MErmvMEErmG BAY CLEANUP RECOMMENDATIONS

ROD: EASTERN PLUMEMAS BRUNSWICK

tfV^hMW^B^^P* d ^ ^ MiV IIflUNI lUnlNu CU.lfU.l1l

Solvents

pH

Oxygen

temperature

MINIMUM CLEANUP LEVELiiiivi wyiBlllv | » HM51J

data unavailable

6-8.5

>7 ppm

ambient

RATIONALE

-2

2

2

Sources for rationale:

1. University of Maine Coop Extension Service2. State of Maine recommended levels3. MCL (USEPA)4. Current levels shall not be exceeded5. MCLG (EPA)6. ISBN 0 521 22495 (Pg. 291, based on application factor for fish)7. EPA Region IV, Toxic Substance Spreadsheet data as modified by the State of Maine8. Handbook of Acute Toxictty of Chemicals, U.S. Department of the Interior (modified for chronic

criteria)

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16. Comment (verbal):

Response:


Response:

r18. Comment (verbal):

Response:

compare sampling results and evaluate theeffectiveness of the remedial action and/or need foradditional remedial actions.

Please explain the proposed discharge locationshown on the map (see Figure 7 of the EasternPlume Proposed Plan, December 1991).

Please explain why the target dean up level for1,1-DCA is 3,500 parts per bfflion (ppb) -when themaximum concentration in the Eastern Plume is130 ppb.

The discharge point on that map is a potentiallocation where a connection could be made to thebase sewer system.

The target cleanup level for the compound DCAchanged midstream. The target cleanup level is notbased on an MCL, as there is no MCL or MEGavailable for 1,1-DCA. The Navy had alreadyidentified this compound as being a contaminant ofconcern. The target cleanup level of 3,500 ppb wasdeveloped using current toxicity information in theliterature.

How strong is the upward gradient in the bedrockgroundwater?

There are several bedrock monitoring wells withoverburden monitoring wells adjacent to them. Atthese locations, there was a foot or two of upwardgradient in that relationship.

"With this foot difference, how far apart were thosepoints?

The vertical distance between the two screenedintervals is typically 20 to 40 feet and is a function ofthe clay thickness.


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23.

Action Monitoring Plan is developed in the samemanner as all other plans, with concurrence from theUSEPA, the MEDEP, and TRC members.

The Remedial Action Monitoring Plan will set up astrategy to monitor the sites over a long period oftime. In the Remedial Action Monitoring Plan, thetarget cleanup levels that are written in the RODare addressed. The Remedial Action MonitoringPlan discusses the approach, the sampling frequency,and when remediation is to be considered complete.

If the USEPA concurs that the Navy has obtainedthe cleanup goal, then a delisting process isundertaken.

Did you identify any denser than water contaminantsat Sites 1 and 3 or the Eastern Plume?

We did identify various solvent compounds that dohave densities greater than water. However, wenever identified them at concentrations that wouldbe indicative of the formation of an immisciblephase that would then have a density greater thanwater.

A solubilized plume, that is, a plume that containssolvent concentrations at the saturated limit, doesnot have a density difference great enough to allowfor downward migration. In all of the investigations,there is no evidence for the presence of a separatephase.

General Comment (verbal):What is the risk for the children coming in contactwith any of the carcinogens? Can asthma be

'developed from the toxic waste at that base?


Response:

Response: There is currently no exposure to the contaminantsin the Eastern Plume and, therefore, there are norisks to children. Future exposure to thecontaminated groundwater is also considered


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•unlikely. This interim remedial action has beendeveloped to limit contaminant migration andprotect against future potential exposure.

Risks were evaluated specifically for Girl Scouts andBoy Scouts coming on the base. As mentionedearlier. Sites 1 and 3 has a unique current land usein that Boy Scouts or Girl Scouts that do access orcome on base do not use that particular area. Thereis no exposure, and there likely will never be anyexposure in that area. The risks from exposure atother sites (i.e., Site 8 and Site 9), were evaluatedand are discussed in the respective Risk Assessmentand Feasibility Study reports.

24. Comment (verbal): Have there been any studies on the community tosee if any diseases due to exposure to toxins at thebase are developing in the city at a raster rate thansurrounding areas?

Response: There is an ongoing study by the Agency for ToxicSubstances and Disease Registry (ATSDR). ATSDRis a federal agency that is involved in the Superfundprogram at the NAS Brunswick. Representativesfrom ATSDR have attended a TRC meeting(April 11, 1991) and are involved in the remediationof the base. However, they have not reviewedinformation related to the Eastern Plume or initiatedany studies related specifically to NAS Brunswick.

The role of ATSDR is to develop lexicologicalprofiles of chemicals found at Superfund sites and todetermine if a large enough population has beenexposed. If so, ATSDR would conduct healthstudies and report to the USEPA The public wouldhave the opportunity to comment on the report

25. General Comment (verbal):Has there been any testing done at the old radarstation off Old Bath Road or in the TopshamAnnex? Unauthorized dumping may have occurred


W0029251.080 6836-5B-24

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Response:

there. Would you visit the site to see if there isanything going on?

To our knowledge and during the Initial AssessmentStudy, we did not receive or identify any reports orknowledge of dumping or other activity at the oldradar station. To date there have been no studiesconducted at that site.

The Navy willbase.

this area of concern with the


Response:

•27.

I heard that this present contamination on the basewas just individuals dumping things.

Sites 1 and 3 and the Eastern Plume are specificsites where there was a clear indication that somesort of disposal or leakage had occurred, or somepractice that gave rise to environmentalcontamination.

General Comment (verbal):J went to the Curtis Memorial Library on Tuesday,looked at the reference desk and found no study. Itwas not readily available.

Response: You need to go to the front desk and ask to see theinformation repository for the Navy. The person incharge of reference material will direct you to it.

28. General Comment (verbal):Can we get an extension of time for comments?

Response: There is a legal and acceptable extension that'savailable. The comment period wfll be extended forone week.

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APPENDIX C

MEDEP LETTER OF CONCURRENCE

W0029251.080 «36-05

STATE OF MAINE

Department of Environmental ProtectionMAIN OFFICE: BAY BUILDING. HOSPITAL STREET. AUGUSTA

MAIL ADDRESS: Suit HouM Sltl»n 17. Augusu. 0*333

K7-Z89-TSM

JOHN X. McKERNAN. JR.GOVERNOR

DEAN C MAftftlOTTCOMMISSIONER

June 4, 1992

Thomas A. DanesCaptain, CEC, U.S. NavyCommanding OfficerDepartment of the Navy, Northern DivisionNaval Facilities Engineering CommandBuilding 77-LPhiladelphia Naval ShipyardPhiladelphia, PA 19112-5094

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RE: Naval Air Station Brunswick Superfund Site, Brunswick,Maine

Dear Captain Dames:

The Maine Department of Environmental Protection (MEDEP) hasreviewed the June 1992 Draft Record of Decision (ROD)regarding the Interim Remedial Action for the Eastern Plumefor the Naval Air Station Brunswick Superfund Site locatedin Brunswick, Maine.

Based on that draft the MEDEP concurs with the selectedinterim remedial action. This action seeks to control andprevent further migration of the contaminant plume emanatingfrom Sites 4, 11, and 13 until a final remedy for thesesites and the Eastern Plume is chosen. This interim remedywill operate in conjunction with the remedial actionselected for Sites 1 and 3. The interim remedial actioninvolves the extraction, treatment and discharge ofgroundwater from the Eastern Plume area as outlined in thefollowing:

I. Groundwater Extraction Wells

A. Groundwater extraction veils will be installed ±oremove contaminated groundwater from the designatedplume-area and to limit further migration of the

' plume towards Harpswe11 Cove.B. The number of wells, pumping rates, and location of

the wells will be determined during the designphase.

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Portland •REGIONAL OFFICES

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II. Groundwater Treatment

. A. Extracted groundwater will be pumped to a centraltreatment plant.

B. Groundwater will be pretreated to remove inorganiccompounds.

C. Groundwater will be treated to reduce or eliminatevolatile organic compounds through the use ofUV/oxidation technology.

D. Treatment levels will be based on the PublicOperated Treatment Work's (POTW) National PollutionDischarge Elimination System permit and/or MCLs.

E. Treatability studies will be conducted prior tofull-scale design.

III. Discharge of Treated Water

A. Discharge of treated water is expected to be to thebase sanitary sewer systein which connects to theBrunswick Sewer District, Public Operated TreatmentWorks (POTW).

B. Flow from the NABS treatment facility will not causethe POTW to exceed its capacity.

TV. Clean-up levels

A. Groundwater clean-up levels for contaminants havebeen set at the MCL.

B. In the absence of an MCL, groundwater clean-uplevels have been based on a excess cancer risk levelof 10"6 to 10~4 as set by USEPA policy or at aHazard Index of 1.0 for non carcinogenic compounds.

V. Environmental monitoring

A. Monitoring wells will be sampled to confirm theeffectiveness of the Interim action.

B. A monitoring program will be developed during "thedesign phase and will require regulatory approval.

VI. Other remedial actions

-'" ,A. Changes in the interim remedial action will bedeveloped if necessary.

B. This interim action may be incorporated into orsuperseded by a comprehensive remedial action ofthe Site 4, 11, and 13 source areas.

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}. This concurrence is based upon the State's understandingi

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that:

A. The MZDZP will continue to participate in theFederal Facilities Agreement dated October 19, 1990ard in the review and approval of operationaldesigns and monitoring plans.

B. Groundwater extraction wells established within theplume area will be maintained and sampled on aregular basis.

C. Selection and development of a final remedial actionfor the Eastern Plume source areas will continue.

The MEDEP looks forward to working with the Department ofthe Navy and the USEPA to resolve the environmental problemsposed by this site. If you need additional information, donot hesitate to contact myself or members of my staff.

Sincerely,

Dean C. MarriottCommissioner

cc: Alan Prysunka, Director, BHMSWCMichael Barden, Director, DSIR4?MarkTHyla~nd.;5,Directory.;IFFt7

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APPENDIX D

ADMINISTRATIVE RECORD INDEXiL AND

GUIDANCE DOCUMENTS

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W0029251.080 «83fr«5

EASTERN PLUME

ADMINISTRATIVE RECORD

INDEX

Prepared forI Naval Air Station Brunswick

Brunswick, Maine

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W0029251.080 6836-05

SECTION I

INTRODUCTION

This document is the Index to the Administrative Record for the Record of Decisionfor the Naval Air Station (NAS) Brunswick National Priorities List (NPL) site(Fasff»m Plume). Section I of the Index cites site-specific documents, and Section Hcites guidance documents used by Navy staff in selecting a response action at the she.

Although not expressly listed in this Index, all documents contained in the Recordof Decision Administrative Record (Sites 1 and 3) are incorporated by referenceherein, and are expressly made a part of the Administrative Record for the Recordof Decision Administrative Record (Eastern Plume).

The Administrative Record is available for public review at NAS Brunswick PublicWorks Office, Brunswick, Maine. Questions concerning the Administrative Recordshould be addressed to Lt. Cmdr. Michael J. L'Abbe at NAS Brunswick PublicAffairs Office (207) 921-2340, Brunswick, Maine.

The Administrative Record is required by the Comprehensive EnvironmentalResponse, Compensation, and Liability Act (CERCLA), as amended by theSuperfund Amendments and Reauthorization Act (SARA).

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W0029251.080 683645

Administrative Record Brunswick Naval Air StationEastern Plume

RI/FS Correspondence

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1

1

1

1

1

1

1

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DATE

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20-Sep-91

23-Sep-91

31-Oct-91

6-Nov-91

tteSI

Mar 92

2-Apr-92

VOLUME TO

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VOLUME 7E

Apr 91

VOLUME 7F

Apr 91

TITLE AUTHOR

EPA Comments on EPADraft FinalSupplemental RemedialInvestigation Report

DEP Gownwots on DEPDraft FS

EPAandNOAA EPAvOvwiwntB on (Mvft <S

EPA Comments on EPADraft Proposed PlanEastern Plume

DEP Comments on DEPDraft Proposed PlanEastern Plume

ffTDpoaajQ rttn cejeiem tw <JDVOBJRPlume

Draft ROD Eastern EC JordanPlume

EPA Comments on EPADraft ROD EasternPlume

Draft Supplemental EC JordanRemedial Investigation& Comments, Vol. 1

Draft Supplemental Rl EC JordanReport, Vol. 2

Draft Final EC JordanSupplemental RemedialInvestigation

ADOfE&sEE Doc TYPE Pos . FEE REMARKS

NorthDiv latter 5 RI/FS

NorthDiv Utter 6 RI/FS

NorthDiv Letter 35 RI/FS

NorthDiv Utter 4 Proposed Plan

NorthDiv Utter 3 Proposed Plan

NorthDiv Report Pmpoaad Plan

NorthDiv Report ROD

J. Shafer Utter 13 ROD

NorthDiv RI/FS Report



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! SECTION IIi

| _ GUIDANCE DOCUMENTS

EPA guidance documents may be reviewed at EPA Region I, Boston, Massachusetts.

Genera Site-Secific EPA G u D o c u m e n t s

1. "National Oil and Hazardous Substances Pollution Contingency Plan." Code, of Federal Regulations (Title 40, Part 300), 1985.

2. U.S. Environmental Protection Agency. Comprehensive Environmental

J Response Compensation and Liability Act of 1980. as Amended October 17,1986.

1 3. U.S. Environmental Protection Agency. Office of Emergency and RemedialResponse. Guidance for Conducting Remedial Investigations and FeasibilityStudies Under CERCLA (Comprehensive Environmental Response.

I Compensation, and Liability Act) (Interim Final) (EPA/540/G-89/004,I OSWER Directive 9355.3-1), October 1988.

{ 4. U.S. Environmental Protection Agency. Office of Emergency and RemedialResponse. Guidance on Remedial Actions for Contaminated Ground Water

"- at Superfund Sites (EPA/540/G-88/003), December 1988.

• 5. U.S. Environmental Protection Agency. Office of Emergency and RemedialResponse. Interim Final Guidance on Preparing Superfund Decision

I Documents (OSWER Directive 9355.3-02), July 1989.

6. U.S. Environmental Protection Agency. Office of Solid Waste and EmergencyI Response. Ground Water Issue - Performance Evaluation of Pump-and-Treat1 Remediations (EPA/540/4-89/005), October 1989.

I ] 7. U.S. Environmental Protection Agency. Office of Emergency and RemedialResponse. Risk Assessment Guidance for Superfund - Volume I: Human

r Health Evaluation Manual (Part A - Interim Final) (EPA/540/1-89/002),I December 1989.

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W0029251.080 6836-05

I:I 8. U.S. Environmental Protection Agency. Risk Reduction Engineering

Laboratory. Technology Evaluation Report: SITE Program Demonstration. of the Ultrox International Ultraviolet Radiation/Oxidation Technology[ (EPA/540/5-89/012), January 1990.

1 9. "National Oil and Hazardous Substances Pollution Contingency Plan," FederalRegister (VoL 55, No. 46), March 8, 1990.

L 10. U.S. Environmental Protection Agency. Office of CommnnuaFinns and PublicAffairs. Glossary of Environmental Terms and Acronyms list (EPA19K-1002), December 1989.

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