subj: loring air force base - record -q-f decision v ,. .. . … of decisions summary - sept....

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U.S. ENVIRONMENTAL PROTECTION AGENCY^REGION l'" . , " ,,

FEDERAL BUILDING', BOSTd^; ,MA O22.()3~2211

MEMORANDUM • '•,>.. ' " ' . - ••.:.,-' ' '^

DATE: September 25, 1996 " '•'.'.;, • -..'^ .v_ '" /-.

SUBJ: Loring Air Force Base - Record -Q-f Decision v ,. " .. .-,_.yOU 4 - Landfill Groundwater •• / • • - . ';. • j "' • "V : •-.'•'

FROM: Michael Nalipinski, RPM, OSRR 'M / !"/% {(A : J^Robert DiBiccaro, Case Attorney, ORCHfcj&W'\r

TO: Linda M. Murphy, Director ^Office of Site Remediation and Restoration

Attached for your review are the ROD Summary, CommunicationsStrategy, and Draft Air Force Press Release for the OU 3 Loring AirForce Base Superfund Site in Aroostock County, Maine. Attached foryour signature is the ROD.

If you have any questions regarding the ROD, please contact MichaelNalipinski at 223-5503 or Mary Sanderson at 537-5711.

The ROD has been signed by the Air Force and the State of Maine hasconcurred with the ROD. This ROD should be signed by September 30,1996, to meet our commitment date.

Attachments: ROD SummaryCommunications StrategyDraft Air Force Press ReleaseROD

cc: Mary Sanderson

Record of Decisions Summary - Sept. '96

Loring Air Force Base - Limestone, Maine

Remedial Project Manger: Michael Nalipinski

Section Chief Mary Sanderson

ORC Contact: Bob DiBiccaro

Community Relations: Sarah White

Congressional Relations: Al Frezza

BACKGROUND:

The former Loring Air Force Base (LAFB) is located in northeastern Maine and is approximately3 miles west of the United States/Canadian border and approximately 450 miles northeast ofBoston, Massachusetts. The main base covers approximately 9,000 acres and was used by the AirForce from the late 1940's until closure in September 1994. Activities at LAFB includedoperations and maintenance of fighter, heavy bomber, and support aircraft. Additional baseactivities involved corrosion control, munitions storage and maintenance, and fire trainingexercises.

The sites at LAFB are organized into Operable Units (OUs) according to geographic location,disposal type, or affected media, i.e., groundwater, surface water, or soils. Together, 53 specificsites have been identified and divided into 15 OUs which are being investigated under theInstallation restoration Program by the BRAC Cleanup Team (BCT). The BCT comprises the AirForce Base Conversion Agency, the US Environmental Protection Agency, and the MaineDepartment of Environmental Protection and operates in accordance with the three-party FederalFacilities Agreement (FFA).

OU 9/11 - South Flightline Soils/Tank Farm Maintenance Areas

OU 9 - South Flightiine Soils: OU 9 is located in the south central portion of the base andincludes four sites: the Auto Hobby Shop (AHS), the Snow Barn (SB), the Power Plant DrainagePipe (PPDP), and the Former Vehicle Motor pool (FVMP).

Due to successful removal excavations at the SB, PPDP, and FVMP, which were consolidatedinto Landfill 2 (OU 2), and the installation of bioventing systems to address UST issues "NoFurther CERCLA" actions are recommended for these areas. The approximate costs for theaforementioned removal actions is $289,000. Currently, a $130,000 bioventing system isoperating at the AHS to address VOC and petroleum contaminated soils. See Table I for asummary of the OU 9 sites.

OU 11 - Tank Farm Maintenance Area: This OU is located on the southern edge of the baseand comprises the: Fuels Tank Farm (FTF), Refueling Maintenance Shop Area (RMSA), VehicleMaintenance Building (VMS), Coal Storage Pile/Fly Ash Disposal (CSP/FAD), and BaseLaundry (BL).

See Table II for a summary of the removal actions and status of the OU 11 sites relative to thisROD or future actions.

Removal actions at the OU 11 sites have expended approximately $422,000, to date.

OU 3 - Debris Disposal Areas

OU 3 consists of 17 sites spread across LAFB. This ROD codifies the position that "No FurtherCERCLA Action" is required for 14 sites, further investigation is necessary for the EOD Rangeand Outdoor Firing Range, and remedial action is appropriate for the Contract Storage Shed. SeeTable III for a summary of the removal actions, state regulated sites and recommended actions.

Upon completion of the RI, the 14 "No Further CERCLA Action" sites either did not pose a riskto human health or the environment, were addressed using State authorities, or the risks weremitigated via minimal excavations conducted using removal authorities.

The EOD Range and Outdoor Firing Range require additional investigations because confirmationsampling of the removal actions revealed areas of greater contamination than originally identified.The additional field work will be conducted in October 1996. The final CERCLA determinationfor these two areas will be made in 1997.

The Contract Storage Shed was used for the storage and staging of electrical transformers, wasteoil, and waste chemical drums. The storage shed was demolished and the area is now used as aparking area for grounds keeping equipment. The contaminated soils/sediments pose a risk toboth human health and the environment. The compounds of concern include fuel oils, PAHs,pesticides, and metals.

OU 4 - Landfill Groundwater

In September 1994 the EPA and the Air Force signed the OU 2 CERCLA ROD, withconcurrence from the State of Maine and the community, to install a RCRA C cap on Landfills 2& 3. The OU 2 ROD indicated that the groundwater component of the landfill area would beevaluated and addressed as part of OU 4. The post closure and monitoring plans from OU 2 andOU 4 would be combined.

REMEDIAL ACTIONS

Refer to Tables I - III for the identification of the "No Further CERCLA Action" sites and thejustification for those determinations.

OU 3 - Contract Storage Shed Remedial Action:

The action for the Contract Storage Shed consists of:

• Excavating approximately 1,500 cubic yards of contaminated soils for placement inLandfil l3;

• In-site capping of approximately 200 cubic yards chlordane contaminated soil with aminimum of 2 feet of clean cover;

• A Maintenance Plan to ensure maintenance and institutional controls of the cappedchlordane soils; and,

• . Five year reviews will be required for this remedy.

The estimated cost for the remedial action, maintenance, and Five year reviews for the ContractStorage Shed is approximately $65,000.


The ROD for this OU is designated as Minimal Action with an option for a Contingency Action.The Minimal Action component includes groundwater monitoring beneath Landfills 2 & 3 todetermine the effectiveness of the RCRA C caps which are currently being constructed. If theMCLs or State MEGs are exceeded at the compliance boundary, the Contingency Action will beevaluated.

The first phase of the Contingency Action would be to evaluate risks posed by the excedences andthe proximity of the contaminants to the receptors. Depending upon the risk evaluation,additional actions may be required. If a limited action is necessary, i.e., repairing the landfill cap,connection to public water, or off-base institutional controls those actions can be accomplishedwithin the scope of this ROD. If a major remedial action is required, i.e., installation of a pumpand treat system or construction of a slurry wall, an additional CERCLA decision will be required.

The Minimal Action remedy will require groundwater monitoring for a minimum of 30 years,which is the required period of monitoring per the States'landfill regulations. The estimatedcapital cost is $87,000 and the estimated O&M costs are $810,000. >

ISSUES:

OU 3 - Contract Storage ShedThe primary risk drivers at the Contract Storage Shed were metals and PAHs. However, theprimary "remedy driver" was chlordane. Because RCRA designates chlordane as a "special listedwaste" the remedial options available were shipment to an off-site licenced hazardous wastedisposal facility or cap in place with two feet of cover material to mitigate the ecological risks.The chlordane did not represent a human health risk. Factoring in the cost difference, $65,000

compared to $310,000, the onsite capping option was selected.


The State of Maine initiated the Dispute Resolution process per the Federal Facilities Agreementduring review of the Final ROD. The State believes that their groundwater standards (MEGs)should be considered as relevant and appropriate ARARs. Accepting this determination wouldhave dramatic implications on the OU 4 ROD as well as all future groundwater RODs in the Stateof Maine because 19 elements/compounds on the State MEG list are below MCLs. The mostdramatic is the State's MEG for vinyl chloride which has a value of 0.15 ppb compared to theMCLof2.0ppb.

Last week during Informal Dispute Resolution the BCT concluded that:

• The OU 4 ROD would use the MEGs as action levels at the compliance boundary and ifthe MEGs were exceeded the Contingency Action would be initiated; and,

• The determination as to whether the State MEGs should be relevant and appropriate asARARs would be tabled. Thfc ORC is currently researching this issue and will provide theprogram an opinion by November 1, 1996, prior to the Draft OU 12 (base widegroundwater) FS.

PUBLIC INVOLVEMENT/COMMENTS

The Maine Department of Environmental Protection has provided letters of concurrence for theOU 9/11 and OU 3 RODs. The State has also indicated that they are intending to provide aconcurrence letter for the OU 4 ROD.

The Restoration Advisory Board (RAB) has reviewed the three RODs and concurred with theselected actions. No formal comments were received for any of the RODs from the community.

MEDIA/CONGRESSIONAL INVOLVEMENT

Briefings for the Maine Congressional delegation regarding the Loring Air Force Base activitiesoccur quarterly. During these discussions all aspects of the base closure program are discussedfrom employment opportunities for local citizens, to cleanup, to future use options/plans.

Media attention regarding cleanup activities at the base have been limited due to related storiesregarding future land use options, employment, and impact of reuse on the local economy. •

OU 9 SOUTHFLIGHTLINESOILS

Auto Hobby Shop -AHS

Snow Barn - SB

Power Plant DrainagePipe - PPDP

Former VehicleMotor Pool - FVMP

Bioventing

yes

no

yes

no

Soil RemovalConducted

yes

yes

yes

yes

Included in ROD

NO

yes

yes

yes

OU 11 TANKFARMMAINTENANCEAREA

Fuel Tank Farm -FTF

RefuelingMaintenance ShopArea - RMSA

Vehicle MantenanceBuilding - VMB

Coal StoaragePile/Fly Ash Disposal

Base Laundry - BL

Bioventing, SoilVapor Extraction, orBioslurping

Bioslurping

Bioventing

Bioventing

no

Soil VaporExtraction


yes

yes

yes

no

yes

Included in ROD

yes

NO

NO

yes

NO

JDZ.OU 3 DEBRISAREAS

Ohio Road

Oklahoma Road

KC-135 Crash Site

Dumpster CleaningArea/ Bid 8741

Explosive OrdinanceDisposal Cylinders

Golf Course Shed

Chapman Pit Debris

9000 Derbis Area

Solvent Paint Dock

Prime Beef Area

Bids. 8951/8960DRMO

Old PX Gas Station

F- 106 A Crash Site

DemineralizationPlant

EOD Range

Outdoor FiringRange

Contract StorageShed


yes

yes

yes

no

no

yes

no

yes

yes

no

no

yes

yes

yes

no

yes

no

State Regulated

no

no

yes

no

no

no

no

yes

no

no

no

yes

yes

no

no

no

no

NFA under CERCLA

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

NO - Add'l RI worknecessary

NO - Add'l RI worknecessary

NO - RemedialAction necessary

COMMUNICATIONS STRATEGY FOR

LORING AIR FORCE BASE RODs (Sept '96)

Message: The EPA agrees with the Air Force determination of "No Further CERCLA Action"for:

• OU 9: Snow Barn, Power Plant Drainage Pipe, Former Vehicle Motor Pool;

• OU 11: Fuel Tank Farm, Coal Storage Pile/Fly Ash Disposal; and,

• OU 3: The first 14 sites listed on Table III of the ROD Summary.

The EPA agrees and the State of Maine and the community concur that:

• OU 3: Excavation with on-site disposal, in-situ capping, and institutional controls areappropriate;

• OU 4: Groundwater for Landfills 2 & 3 warrants a Minimal Action ROD which includelong term monitoring and an option for a Contingency Action if MEGs are exceeded at thecompliance boundary.

Reuse Issues: No short or long term leases have been initiated for "No Further CERCLA Action"sites identified in these RODs. However, the Job Corps has signed a federal to federal permit forthe Auto hobby Shop and has initiated modification to the building. The Job Corps activities havebeen coordinated with the BCT cleanup program because a bioventing system is operating at thissite and no final CERCLA determination has been made. The Base Laundry SVE system wasinstalled ahead of schedule in order to accommodate a commercial laundry tenant. The lease forthe Base Laundry is scheduled to be signed in October and occupancy is scheduled for this winter.The SVE will continue to operate until the remediation goals are accomplished and a finalCERCLA determination can be made.

The Loring Reuse ROD was signed in April 1996 and designated the western area of LAFB,including Landfills 2 & 3, for future transfer to the USFWS. These areas will remain open spacevia institutional controls.

The Air Force continues to facilitate hiring local Maine contractors to perform remedial activities.To date, the Air Force has spent approximately $100 million on the Loring project, $60 million onconstruction activities and of the $60 million, $25 million have been contracted to Maine smallbusinesses.

Remedy Issues: The OU 4 ROD is a groundwater monitoring ROD with a contingency foradditional remedial activity i|the State MEGs are exceeded at the compliance boundary.

207 328 713109/30/98 09:38 ©207 328 7131 AFBCA/OL-M (21001

NEWS RELEASEOFFICE OF THE ENVIRONMENTAL COORDINATOR

AIR FORCE BASE CONVERSION AGENCY(AFBCA)/OPERATING LOCATION-MAINELORING AIR FORCE BASE

RR 1 Box 1719, LIMESTONE, ME 04750-0523TEL: (207) 328-7109/FAX 328-7131

FOR IMMEDIATE RELEASESeptember 30,1996

BASE ENVIRONMENTAL TEAM ANNOUNCES CLEANUPCOMPLETE FOR SEVERAL MORE SITES AT LORING

LIMESTONE - The environmental cleanup work at Loring Commerce Centrecontinues at a fast pace as the Air Force Base Conversion Agency (AFBCA) announcesthe recent completion of three more Records of Decision (RODs), for several sites at the

former active military base.To date, just over $90 million has been spent on the cleanup and restoration of Loring,

with about $20 million projected to be spent during the next three years, according to-%sf,David Strainge, BRAC (Base Realignment and Closure) Environmental Coordinator atLoring.

According to the AFBCA, the three RODs completed include 17 debris disposalareas in Operable Unit (OU) 3; the groundwater associated with five different sites in OU4; and nine cleanup sites included hi OU's 9 and 11.

Completion of these three decision documents brings the total to eight RODs issued atLoring since the cleanup began in 1994.

__ Q 9 ft 7 1 ^ 1 A T7R C1 A / n T \f l«l n O ?id^g . » j j ^ &.^ C. t> r ^\ £ n I I A I * * H r % l . > * / I J I . — 1*1 [-T!

5 9 : 3 9 Q207 328 7131 AFBCA/OL-M 81002

Cleanup sites at Loring are organized for management purposes into OUs according togeographic location, disposal type or affected media, i.e. groundwater, soils or surfacewater. Altogether, 53 specific sites divided into 15 OUs are being investigated as part ofLoring's Installation Restoration Program (IRP).

The issuance of a ROD is one Of the many steps in the overall environmental cleanupprocess, including site investigation, evaluation of cleanup options, selection of thepreferred cleanup alternative and finally completion of the remedial (cleanup) work.RODs are public documents that explain which cleanup alternatives have beendetermined as the most appropriate and chosen for each site by the Base Cleanup Team(BCT).

Responsible for the environmental cleanup at the former bomber base, the BCT orTeam Loring, is comprised of the Remedial Project Managers from the AFBCA, the USEnvironmental Protection Agency and the Maine Department of EnvironmentalProtection.

OU 3 consists of the Ohio and Oklahoma Roads; the Chapman Pit, 9000, and PrimeBeef Debris Areas; the KC-135 Crash Site; the Dumpster Cleaning Area; the ExplosiveOrdnance Disposal (EOD) Area-Cylinders Site; the Golf Course Maintenance Shed Area;the Solvent/Paint Dock Area; Buildings 8951 and 8960; the Old PX Gas Station; the F-106A Crash Site; the Outdoor Firing Range Area; the Demineralization Plant (Building7321); the EOD Range and the Contract Storage Shed Area,

According to the OU 3 ROD, as a result of site investigations and several isolated

removal actions at 14 of the sites, low levels of contamination are not expected to resultin adverse human health or ecological effects. Therefore, no further action under thefederal Comproraisive Environmental Response, Compensation and Liability Act(CERCLA), isrecommended for these sites.

Further investigation however is being recommended at both the EOD and OutdoorFiring Ranges. The 40-acre EOD Range was previously used for disposal of ammunitionby detonation and burning, and for burial of munitions residue, spent cartridges andconstruction debris. Because another older EOD Range within the site was discovered butnot investigated during the Cleanup Team's initial Remedial Investigation, further

'Cf2Q7 7131 AFBCA/OL-M 31003

investigation is recommended for this site. The Outdoor Firing Range was used for smallarms training for military personnel. During removal of lead contaminated soil at this siteadditional contamination was found, therefore further investigation is also planned forthis area.

The Contract Storage Shed Area was used for the storage and staging of electricaltransformers, waste oil and waste chemical drums. The storage shed was demolished, andthe site is now being used as a parking lot and storage area for groundskeepingequipment. Risk assessment results at the site indicates that elevated risk to human healthand the environment exists by exposure to contaminated soils and sediments. TheRemedial Action Plan includes excavation and on-base disposal of certain contaminatedsediments/soils, and the placement of two feet of clean soil cover and erosion protectionover portions of the site.

Total projected cost of the remedial actions to date and planned for OU 3 are$215,000.

OU 4 manages the groundwater associated with five sites known as Landfills 1,2 and3 (LF-1, LF-2, & LF-3), the Chapman Pit Debris Area (CPDA), and the Coal Ash Pile(CAP) at Loring. Landfill contents and soils associated with these five sites were studiedseparately from OU 4.

According to this ROD, No Further Action under CERCLA is required forgroundwater at LF-1 and the CPDA, and Minimal Action for groundwater at LF's 2 and3, and the CAP.

The CPDA was mined for its sand and gravel during construction of the base. Oldconstruction equipment and debris, and old concrete and asphalt pavement werepreviou8j|gOored in the sand and gravel pit. LF-1 was used as a gravel pit during runway

"**sS**'

construction at Loring. The excavated area, which is approximately 3.3 acres, was usedprimarily for disposal of construction debris.

Results of the groundwater investigation for both sites indicates risks do not exceedthe USEPA target risk range or hazard index, therefore the Air Force recommends NoFurther Action for groundwater at these two sites.

0 9 : 4 0 ©207 328 7131 AFBCA/OL-M 121004

LF-2 was excavated for sand and gravel prior to being used as a landfill. The landfilloperated from 1956 to 1974 for base refuse and flightline wastes. Approximately 300,000cubic yards of wastes are buried in LF-2, and in 1994-95 nonhazardous contaminatedsoils and debris from removal actions at other Loring sites were placed as subgrade fillfor a cover system here.

LF-3 was also excavated for sand and gravel prior to being used as a landfill. Thelandfill operated between 1974 and 1991 for receiving domestic garbage from basehousing and flightline areas. Over 350,000 cubic yards of wastes are buried in LF-3.Nonhazardous contaminated soils and debris from removal actions are being placed assubgrade fill for use in the cover system at this landfill.

The Air Force conducted a removal action in accordance with CERCLA in 1994-95 atthe Coal Ash Pile. Approximately 184,000 cubic yards of coal ash, contaminated soil,concrete rubble, miscellaneous debris and refuse were removed from the area and placedat LF-2 and LF-3 as subgrade fill for cover systems at these two sites.

According to the ROD, the risks for groundwater contamination at LF-2, LF-3 and theCAP only slightly exceed the USEPA target risk range or hazard index. Therefore the AirForce has proposed Minimal Action for groundwater at these three sites. The MinimalAction includes controls to restrict groundwater use, provide for groundwater monitoring,and allows for the selected cleanup alternative to be reviewed by the Air Force at leastonce every five years to ensure that the action continues to be protective of human healthand the environment.

Total cost of the minimal action alternative for OU 4, including operations andmaintenance costs for 30 years, is estimated at $897,000.

OUs 9 and 11 comprise several sites at Loring. OU 9 includes the Auto Hobby Shop(AHS), the Snowbara, (SB), the Power Plant Drainage Pipe (PPDP), and the FormerVehicle Motorpool (FVMP). Five sites comprise OU 11 including the Fuels Tank Farm(FTF), the Refueling Maintenance Shop (RMSA), the Vehicle Maintenance Building(VMS), the Coal Storage Pile/Fly Ash Disposal Area (CSP/FAD), and the former BaseLaundry.

13005

Because of ongoing remedial or cleanup actions at three sites in OU 9, includingexcavation and disposal of contaminated soils at the SB and PPDP, and the installation ofbioventing systems at the PPDP and FVMP, no further action under CERCLA isrecommended for these areas.

A Corrective Action Plan, in accordance with MEDEP guidelines, was developed forthe AHS including the installation of a bioventing system to treat contaminated soil.

In OU 11, no further action under CERCL A is proposed for the FTP and theCSP/FAD. But, three sites will remain in the CERCLA cleanup process, including theRMSA, Base Laundry and the VMB, because of ongoing CERCLA cleanup actions stillcurrently in progress.

The approximate total cost for cleanup action in OU's 9 and 11 is $1.3 million.The Records of Decision for OU 3, OU 4 and OUs 9 and 11 are available for public

review at the AFBCA offices, 5100 Texas Road, Loring Commerce Centre. For moreinformation, interested persons are asked to contact Dave Strainge at 328-7109.

1111.11. It Jt JjjtiIl'it if'it ttTtrf

DECLARATION

DECLARATION FOR THE RECORD OF DECISION

SITE NAME AND LOCATION

Operable Unit 4 (OU 4) addresses groundwater associated with Landfill 1 (LF-1),Landfill 2 (LF-2), Landfill 3 (LF-3), the Coal Ash Pile (CAP), and Chapman PitDebris Area (CPDA) at the former Loring Air Force Base (LAFB), located inAroostook County, Maine.

STATEMENT OF BASIS AND PURPOSE

This decision document presents the final remedies for OU 4:

• No Further Action (NFA) for groundwater associated with LF-1 andthe CPDA

• Minimal Action for groundwater associated with LF-2 and LF-3/CAP,in conjunction with the source control remedy selected for LF-2 andLF-3 as described in the OU 2 Record of Decision (ROD) (ABBEnvironmental Services, Inc., [ABB-ES], 1994b).

This decision document was developed in accordance with the ComprehensiveEnvironmental Response, Compensation, and Liability Act (CERCLA) of 1980, asamended by the Superfund Amendments and Reauthorization Act (SARA) of 1986,and to the extent practicable, the National Oil and Hazardous Substances PollutionContingency Plan (NCP). This decision is based on the administrative record forOU 4, which was developed in accordance with Section 113(k) of CERCLA, and isavailable for public review at the Air Force Base Conversion Agency, 5100 TexasRoad, Limestone, Maine. Through the combined source control remedy for OU 2(ABB-ES, 1994b) and this groundwater mitigation remedy for OU 4, the U.S. AirForce (USAF) plans to remedy the threat to human health posed by the presence ofcontaminated groundwater at LF-2 and LF-3/CAP.

The Maine Department of Environmental Protection (MEDEP), concurs with theselected remedy for OU4.

CONCURRENCES

SYMBOL [

SURNAME '

DATE I

//firEPA Form 1320-1 (12-70) OFFICIAL FILE CC

• U.S.GPO: l gsa-O-lOK.A-

DECLARATION

ASSESSMENT OF OU 4

The USAF has determined that NFA is necessary for the groundwater associatedwith LF-1 and the CPDA, since risk estimates for domestic use of groundwater arebelow U.S. Environmental Protection Agency (USEPA) target risk levels. Risksassociated with bedrock groundwater at LF-1 exceed the MEDEP cancer riskguidance value of IxlO"5. However, a soil cover system has been installed as requiredby Maine State Solid Waste Regulations.

Actual or potential releases of hazardous substances from LF-2 and LF-3/CAP, if notaddressed, may pose a risk to human health and the environment. This risk will beaddressed by implementing the Minimal Action groundwater remedy selected in thisROD, in conjunction with the source control remedy outlined in the OU 2 ROD.

DESCRIPTION OF THE SELECTED REMEDY

The USAF has determined that NFA is appropriate for groundwater associated withLF-1 and the CPDA.

The selected remedy for groundwater associated with LF-2 and LF-3/CAP isMinimal Action. In addition to the low permeability cover systems, 30-year landfillpost-closure monitoring, and deed restrictions for Landfill 2 and Landfill 3 containedin the OU 2 ROD, implementation of the OU 4 Minimal Action alternative wouldinclude the following activities:

• institutional controls;• groundwater monitoring;• five-year site reviews; and• contingency action, if necessary.

If results of monitoring show landfill-related contaminants are detected at thecompliance point at concentrations above the action levels, a contingency action willbe implemented. The contingency action is discussed in Subsection 10.2 of thisROD.

Installation Restoration Program

W0039621.080 8741-16D-2

DECLARATION

STATUTORY DETERMINATIONS

The statutory requirements of CERCLA Section 121 for remedial actions are notapplicable to the NFA decision for groundwater associated with LF-1 and the CPDATherefore, no five-year review will be undertaken for these sites.

The remedy selected by the USAF for LF-2 and LF-3/CAP is protective of humanhealth and the environment, complies with applicable or relevant and appropriaterequirements (ARARs) for this action, and is cost-effective. This remedy usespermanent solutions and alternative treatment technologies to the extent practicable.The selected remedy does not, however, satisfy the statutory preference for remediesthat employ treatment that reduces toxicity, mobility, or volume as a principalelement. Mobility of contaminants is expected to be reduced through thecontainment features of the landfill cover systems under OU 2, which will also reducerainwater infiltration, leachate generation, and associated groundwater contamination.Institutional controls will restrict human exposure to contaminated groundwater inthe vicinity and downgradient of the landfills.

installation Restoration Program

W0039621.080 8741-16D-3

SENT'BY: 9-30-96 ; 13:44 ; AFBCA/DB/DC/DD/LD-> 9916175739662;* 3/ ;

DECLARATION

DECLARATION

This ROD represents NFA under CERCLA for LF-1 and the CPDA and theselection of a remedial action under CERCLA for LF-2 and LF-3/CAP. Theforgoing represents the selection of a remedial action by the Department of the AirForce and the United States Environmental Protection Agency Region 1 with theconcurrence of the Maine Department of Environmental Protection.

Concur and recommend for immediate implementation:

Department if the/KV/Force

By: U^.A^Vt-jgW^_______ Date:Alan K. OlsenDirectorAir Force Base Conversion Agency

United States Environmental Protection Agency

By: _____________________ Date:Linda M. MurphyDirectorOffice of Site Remediation and RestorationRegion I

installation Restoration ProgramW003%21.080

D-4

DECLARATION

DECLARATION

This ROD represents NFA under CERCLA for LF-1 and the CPDA and theselection of a remedial action under CERCLA for LF-2 and LF-3/CAP. Theforgoing represents the selection of a remedial action by the Department of the AirForce and the United States Environmental Protection Agency Region I with theconcurrence of the Maine Department of Environmental Protection.


Department of the

By: l £ ^ t £ ___ Date:Alan K. (MserT "DirectorAir Force Base Conversion Agency


B y : ( J L > • t-^s Date:Linda M. Murphy ^/DirectorOffice of Site Remediation and RestorationRegion I


W0039621.080 8741-16D-4

Final

Operable Unit 4 (OU 4)Record of Decision

September 1996

TheAir Force

Rebuilding OurEnvironment

Installation Restoration ProgramLoring Air Force Base, Maine

FINAL

Loring Air Force Base

Operable Unit 4 (OU 4)Record of Decision

September 1996

Prepared for:

Air Force Base Conversion AgencyLoring Air Force Base, Maine

(207) 328-7109

Prepared by:

Service Center: Hazardous Waste Remedial ActionsOak Ridge, Tennessee 37831-7606

Contractor: ABB Environmental Services, Inc.Portland, Maine 04101

Job No. 8741-16W

OPERABLE UNIT 4 RECORD OF DECISIONLORING AIR FORCE BASE, MAINE

TABLE OF CONTENTS

Section__________________Title_________________Page No.

DECLARATION FOR THE RECORD OF DECISION . . . . . . . . . . . . . . . D-l

1.0 SITE NAME, LOCATION AND DESCRIPTION . . . . . . . . . . . . . . . . . 1-1

2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES . . . . . . . . . . . . 2-12.1 LAND USE AND SITE HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12.2 RESPONSE AND ENFORCEMENT HISTORY . . . . . . . . . . . . . . . . . . 2-3

3.0 COMMUNITY PARTICIPATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

4.0 SCOPE AND ROLE OF OPERABLE UNIT OR RESPONSEACTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

5.0 SUMMARY OF SITE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . 5-1

6.0 SUMMARY OF SITE RISKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16.1 HUMAN HEALTH RISK ASSESSMENT . . . . . . . . . . . . . . . . . . . . . . 6-2

6.1.1 Landfill 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-26.1.2 Landfill 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-26.1.3 Landfill 3/Coal Ash Pile . . . . . . . . . . . . . . . . . . . . . . . . 6-66.1.4 Chapman Pit Debris Area . . . . . . . . . . . . . . . . . . . . . . . 6-8

6.2 UNCERTAINTY EVALUATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-86.3 CONCLUSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10

7.0 DEVELOPMENT AND SCREENING OF ALTERNATIVES . . . . . . . . 7-17.1 STATUTORY REQUIREMENTS/RESPONSE OBJECTIVES . . . . . . . . . 7-17.2 TECHNOLOGY AND ALTERNATIVE DEVELOPMENT AND

SCREENING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2

8.0 DESCRIPTION OF ALTERNATIVES . . . . . . . . . . . . . . . . . . . . . . . . . 8-18.1 No ACTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-18.2 MINIMAL ACTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-28.3 GROUNDWATER COLLECTION/TREATMENT/DISCHARGE . . . . . . 8-3

W0039621.080 8741-16


TABLE OF CONTENTS(Continued)

Section__________________Title_________________Page No.

9.0 SUMMARY OF THE COMPARATIVE ANALYSIS OFALTERNATIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-19.1 EVALUATION CRITERIA USED FOR DETAILED ANALYSIS . . . . . . 9-1

9.1.1 Threshold Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-19.1.2 Primary Balancing Criteria . . . . . . . . . . . . . . . . . . . . . . . 9-19.1.3 Modifying Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2

9.2 SUMMARY OF COMPARATIVE ANALYSIS . . . . . . . . . . . . . . . . . . . 9-39.2.1 Overall Protection of Human Health and the

Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-39.2.2 Compliance with Applicable or Relevant and

Appropriate Requirements . . . . . . . . . . . . . . . . . . . . . . 9-39.2.3 Long-term Effectiveness and Permanence . . . . . . . . . . . . 9-39.2.4 Reduction of Mobility, Toxiciry, or Volume through

Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-59.2.5 Short-term Effectiveness . . . . . . . . . . . . . . . . . . . . . . . . . 9-59.2.6 Implementability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-59.2.7 Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-59.2.8 State Acceptance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-69.2.9 Community Acceptance . . . . . . . . . . . . . . . . . . . . . . . . . 9-6

10.0 THE SELECTED REMEDY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-110.1 ACTION LEVELS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-110.2 DESCRIPTION OF REMEDIAL COMPONENTS . . . . . . . . . . . . . . . 10-6

11.0 STATUTORY DETERMINATIONS . . . . . . . . . . . . . . . . . . . . . . . . . 11-111.1 THE SELECTED REMEDY is PROTECTIVE OF HUMAN

HEALTH AND THE ENVIRONMENT . . . . . . . . . . . . . . . . . . . . ll-l11.2 THE SELECTED REMEDY ATTAINS ARARs . . . . . . . . . . . . . . . 11-211.3 THE SELECTED REMEDIAL ACTION is COST-EFFECTIVE . . . . . 11-211.4 THE SELECTED REMEDY UTILIZES PERMANENT SOLUTIONS

AND ALTERNATIVE TREATMENT OR RESOURCE RECOVERYTECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICABLE .. 11-4

W0039621.080 8741-16ii


TABLE OF CONTENTS(Continued)

Section_________________Title________________Page No.

11.5 THE SELECTED REMEDY DOES NOT SATISFY THEPREFERENCE FOR TREATMENT WHICH PERMANENTLY ANDSIGNIFICANTLY REDUCES THE TOXICITY, MOBILITY ORVOLUME OF THE HAZARDOUS SUBSTANCES AS A PRINCIPALELEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-5

12.0 DOCUMENTATION OF NO SIGNIFICANT CHANGES . . . . . . . . . 12-1

13.0 STATE ROLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1

GLOSSARY OF ACRONYMS AND ABBREVIATIONS

REFERENCES

APPENDICES

APPENDIX A - TRANSCRIPT OF THE PUBLIC MEETING(JUNE 11, 1996)

APPENDIX B - RESPONSIVENESS SUMMARYAPPENDIX C - LETTER OF CONCURRENCE

W0039621.080 8741-16iii


LIST OF FIGURES

Figure___________________Title_________________Page No.

1-1 Location of OU 4 Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-210-1 Compliance and Institutional Control Boundaries . . . . . . . . . . . . . . . 10-710-2 Interpreted Water Table and Groundwater Monitoring Wells . . . . . . 10-11

W0039621.080 8741-16iv


LIST OF TABLES

Table___________________Title_________________Page No.

6-1 Contaminants of Concern for Landfill 1 . . . . . . . . . . . . . . . . . . . . . . . 6-36-2 Chemicals of Concern for Landfill 2 . . . . . . . . . . . . . . . . . . . . . . . . . . 6-56-3 Contaminants of Concern for Landfill 3/Coal Ash Pile . . . . . . . . . . . . 6-76-4 Contaminants of Concern for Chapman Pit Debris Area . . . . . . . . . . . 6-96-5 Quantitative Risk Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-119-1 Comparative Summary of Remedial Alternatives . . . . . . . . . . . . . . . . 9-410-1 LF-2 Bedrock Groundwater Action Levels . . . . . . . . . . . . . . . . . . . . 10-210-2 LF-3 Bedrock and Overburden Groundwater Action Levels . . . . . . . 10-310-3 Groundwater Action Levels and Risk Summary . . . . . . . . . . . . . . . . 10-411-1 Chemical-Specific ARARs, Criteria, Advisories, and Guidance

Minimal Action Alternative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3

* -»'

W0039621.080 8741-16

DECLARATION

DECLARATION FOR THE RECORD OF DECISION

SITE NAME AND LOCATION

Operable Unit 4 (OU 4) addresses groundwater associated with Landfill 1 (LF-1),Landfill 2 (LF-2), Landfill 3 (LF-3), the Coal Ash Pile (CAP), and Chapman PitDebris Area (CPDA) at the former Loring Air Force Base (LAFB), located inAroostook County, Maine.

STATEMENT OF BASIS AND PURPOSE

This decision document presents the final remedies for OU 4:

• No Further Action (NFA) for groundwater associated with LF-1 andthe CPDA

• Minimal Action for groundwater associated with LF-2 and LF-3/CAP,in conjunction with the source control remedy selected for LF-2 andLF-3 as described in the OU 2 Record of Decision (ROD) (ABBEnvironmental Services, Inc., [ABB-ES], 1994b).

This decision document was developed in accordance with the ComprehensiveEnvironmental Response, Compensation, and Liability Act (CERCLA) of 1980, asamended by the Superfund Amendments and Reauthorization Act (SARA) of 1986,and to the extent practicable, the National Oil and Hazardous Substances PollutionContingency Plan (NCP). This decision is based on the administrative record forOU 4, which was developed in accordance with Section 113(k) of CERCLA, and isavailable for public review at the Air Force Base Conversion Agency, 5100 TexasRoad, Limestone, Maine. Through the combined source control remedy for OU 2(ABB-ES, 1994b) and this groundwater mitigation remedy for OU 4, the U.S. AirForce (USAF) plans to remedy the threat to human health posed by the presence ofcontaminated groundwater at LF-2 and LF-3/CAP.

The Maine Department of Environmental Protection (MEDEP), concurs with theselected remedy for OU4.

Installation Restoration ProgramW0039621.080 8741-16

D-l

DECLARATION

ASSESSMENT OF OU 4

The USAF has determined that NFA is necessary for the groundwater associatedwith LF-1 and the CPDA, since risk estimates for domestic use of groundwater arebelow U.S. Environmental Protection Agency (USEPA) target risk levels. Risksassociated with bedrock groundwater at LF-1 exceed the MEDEP cancer riskguidance value of IxlO"5. However, a soil cover system has been installed as requiredby Maine State Solid Waste Regulations.

Actual or potential releases of hazardous substances from LF-2 and LF-3/CAP, if notaddressed, may pose a risk to human health and the environment. This risk will beaddressed by implementing the Minimal Action groundwater remedy selected in thisROD, in conjunction with the source control remedy outlined in the OU 2 ROD.

DESCRIPTION OF THE SELECTED REMEDY

The USAF has determined that NFA is appropriate for groundwater associated withLF-1 and the CPDA.

The selected remedy for groundwater associated with LF-2 and LF-3/CAP isMinimal Action. In addition to the low permeability cover systems, 30-year landfillpost-closure monitoring, and deed restrictions for Landfill 2 and Landfill 3 containedin the OU 2 ROD, implementation of the OU 4 Minimal Action alternative wouldinclude the following activities:

• institutional controls;• groundwater monitoring;• five-year site reviews; and• contingency action, if necessary.

If results of monitoring show landfill-related contaminants are detected at thecompliance point at concentrations above the action levels, a contingency action willbe implemented. The contingency action is discussed in Subsection 10.2 of thisROD.


W0039621.080 8741-16D-2

DECLARATION

STATUTORY DETERMINATIONS

The statutory requirements of CERCLA Section 121 for remedial actions are notapplicable to the NFA decision for groundwater associated with LF-1 and the CPDATherefore, no five-year review will be undertaken for these sites.

The remedy selected by the USAF for LF-2 and LF-3/CAP is protective of humanhealth and the environment, complies with applicable or relevant and appropriaterequirements (ARARs) for this action, and is cost-effective. This remedy usespermanent solutions and alternative treatment technologies to the extent practicable.The selected remedy does not, however, satisfy the statutory preference for remediesthat employ treatment that reduces toxicity, mobility, or volume as a principalelement. Mobility of contaminants is expected to be reduced through thecontainment features of the landfill cover systems under OU 2, which will also reducerainwater infiltration, leachate generation, and associated groundwater contamination.Institutional controls will restrict human exposure to contaminated groundwater inthe vicinity and downgradient of the landfills.

installation Restoration ProgramW0039621.080 8741-16

D-3

DECLARATION

DECLARATION

This ROD represents NFA under CERCLA for LF-1 and the CPDA and theselection of a remedial action under CERCLA for LF-2 and LF-3/CAP. Theforgoing represents the selection of a remedial action by the Department of the AirForce and the United States Environmental Protection Agency Region I with theconcurrence of the Maine Department of Environmental Protection.


Department of the Air Force

By: ______________________ Date: ________________Alan K. OlsenDirectorAir Force Base Conversion Agency


By: ______________________ Date:Linda M. MurphyDirectorOffice of Site Remediation and RestorationRegion I


W0039621.080 8741-16D-4

SENT BY: 9-30-96 ; 13=44 ; AFBCA/DB/DC/DD/LCH 9916175739662;* 3/ ,

DECLARATION

DECLARATION

This ROD represents NFA under CERCLA for LF-1 and the CPDA and theselection of a remedial action under CERCLA for LF-2 and LF-3/CAP. Theforgoing represents the selection of a remedial action by the Department of the AirForce and the United States Environmental Protection Agency Region 1 with theconcurrence of the Maine Department of Environmental Protection.

Concur andj-ecommend for immediate implementation:

Alan K. OlsenDirectorAir Force Base Conversion Agency


Date: .3dLffida M. Murphy ff ' /DirectorOffice of Site Remediation and RestorationRegion I

Installation Restoration ProgramW003!Ki21.080 8741-16 f

D-4 *-* *

SECTION 1

1.0 SITE NAME, LOCATION AND DESCRIPTION

The former LAFB, in northeastern Maine, is bordered on the south and east by theTown of Limestone, on the north by the towns of Caswell and Connor, and on thewest by the City of Caribou. The base is approximately 3 miles west of the UnitedStates/Canadian border and covers approximately 9,000 acres.

LAFB is a NPL site. There are currently several areas of concern underinvestigation within LAFB, which have been organized into Operable Units (OUs)for investigation and remediation purposes. This ROD relates to OU 4, whichconsists of groundwater associated with LF-1, LF-2, LF-3, the CAP, and the CPDA.Soils/sources for LF-2 and LF-3 were addressed under OU 2; soils/sources for LF-1and the CAP were addressed under OU 2A; and soils/sources for the CPDA wereaddressed under OU 3. Figure 1-1 shows the location of the five OU 4 sites andtheir relationship to features at the western boundary of LAFB.

Landfill 1. LF-1 covers approximately 3.3 acres and is located in the southwesternpart of the base west of West Virginia Road and north of Green Pond. Site featureshave changed since the Remedial Investigation (RI) as a result of grubbing andgrading in preparation for cover system construction. For more detailed informationon LF-1, including pre-construction conditions, see Section 7.1 of the OU 4 RIReport (ABB-ES, 1995) and the OU 2A ROD (ABB-ES, 1996a).

Landfill 2. LF-2 covers nine acres approximately one mile west of the West Gateon Nebraska Road and is surrounded by a densely wooded area. Site features havechanged since the RI as a result of grading during on-going cover systemconstruction. For more detailed information on LF-2, including pre-constructionconditions, see Section 5.1 of the OU 4 RI Report (ABB-ES, 1995) and the OU 2ROD (ABB-ES, 1994b).

Landfill 3. LF-3 covers approximately 17 acres, is located on Sawyer Road, aboutone half mile southwest of the West Gate, and is approximately 1,000 feet south ofLF-2. Site features have changed since the RI as a result of grading during on-goingcover system construction. For more detailed information, including pre-constructionconditions, see Section 6.1 of the OU 4 RI Report (ABB-ES, 1995) and the OU 2ROD (ABB-ES, 1994b).


W0039621.080 8741-161-1

LANDFILLS

COALASHPILE

[LANDFILL 3|

LANDFILL 11

i CHAKMANHI""' 'DEBRIS AREA

LEGEND

I I SlTE

FIGURE -

LOCATION OFOU 4 SITES

0 500 1000 2000 FEET

SCALE: 1=1000 ' LORING AIR FORCE BASELIMESTONE, MAINE

SECTION 1

Coal Ash Pile. The CAP was located northeast of LF-3 and south of Nebraska Road,about one-half mile southwest of the West Gate. The CAP consisted of threedistinct areas where uniform types of waste were identified. These areas have beenprovided unofficial names to allow them to be distinguished from one another. Theyare the Coal Ash Disposal Area (CADA), the Drum Disposal Area (DDA), and thePaint Can Disposal Area (PCDA). These three disposal areas combined occupiedfive acres: The CADA is 4.1 acres; the DDA is 0.9 acres; and the PCDA is lessthan 0.1 acres. For more detailed information, see Section 6.1 of the OU 4 RIReport (ABB-ES, 1995) and the OU 2A ROD (ABB-ES, 1996a).

Chapman Pit Debris Area. The CPDA is located approximately 500 feet west ofLF-1, south of Chapman Pit Pond. The area is a relatively flat wooded area,approximately two acres in size. The north side of the debris area is bounded by anunimproved road and Chapman Pit Pond. The east and south sides of the debrisarea slope steeply to wet areas. To the west, the debris area slopes steeply to a smallstream that ultimately drains into Greenlaw Brook. For more detailed information,see Section 8.1 of the OU 4 RI Report (ABB-ES, 1995) and the OU 3 RI Report(Law Environmental, Inc. [Law], 1996).


W0039621.080 8741-161-3

SECTION 2

2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES

This section summarizes the land use, response history, and enforcement history foreach of the five OU 4 sites.

2.1 LAND USE AND SITE HISTORY

Landfill 1. Sand and gravel from the LF-1 site was mined for construction at thebase until 1952. The area reportedly was used for base waste disposal from 1952 to1956. It was suspected that during its operation, the landfill received hazardouswaste generated by flightline activities. However, evidence of such wastes were notencountered during RI explorations. This waste was reportedly burned and buriedon site (CH2M Hill, 1984). Based on reconnaissance and subsurface explorationactivities, the landfill area contains construction debris including asphalt, concreteand rebar. The site has been inactive since 1956, although some dumping ofconstruction debris at the surface was reported to have occurred since that time. Asoil cover system has been designed for LF-1 in accordance with Maine Solid WasteRegulations. Construction of the soil cover system was completed in 1996.

Landfill 2. The LF-2 area was quarried for gravel during construction of the base.Waste disposal began in 1956 after the gravel had been exhausted, and continueduntil 1974. The landfill was covered with approximately one foot of clean soil andwas closed in 1974. The LF-2 area soils settled over time, leaving a depression in theLF-2 surface. In 1994 and 1995, nonhazardous contaminated soil and debris fromvarious removal actions were placed on LF-2 as subgrade for a cover system,designed in accordance with Resource Conservation and Recovery Act (RCRA)Subtitle C and Maine Hazardous Waste Regulations, and constructed in 1996.

Wastes buried or burned at the site include: domestic garbage, construction rubble,flightline wastes, and sewage sludge. There are no records of waste segregation atthe landfill and waste was reportedly distributed evenly. Flightline wastes disposedof at this site reportedly included oil, hydraulic fluids, solvents, thinners, and paints.Disposal of hazardous substances at this site reportedly ended by 1968. Noadditional information is available concerning daily operations at LF-2 or the buriallocations of different types of waste.


2-1

SECTION 2

In accordance with the response action specified in the OU 2 ROD (ABB-ES,1994b), the selected source control remedial action for LF-2 is containment using alow permeability cover system. The cover system has been designed in accordancewith RCRA Subtitle C and Maine Hazardous Waste Regulations. Site preparationfor the cover system began in 1994, and the cover system was completed in 1996.

Landfill 3. The area occupied by LF-3 was quarried extensively for gravel duringconstruction of the airfield runway and the Flightline Area. Gravel quarryingcontinued as late as 1994 in the northwestern portion of the site. The landfillreceived waste from 1974 to 1991, and eventually was covered with six inches ofnative soil. Between 1994 and 1996, nonhazardous contaminated soil and debrisfrom various removal actions were placed on LF-3 as subgrade for a cover system.

Waste brought to this site included base refuse such as domestic garbage, contentsof dumpsters from the flightline shops, and mess hall wastes. Hazardous wastes arenot known to have been placed at LF-3. However, it is suspected that smallquantities of hazardous substances such as partially-filled solvent cans, oily-waterwastes, and fuel-saturated soil are buried at this landfill. No additional informationabout daily operations at LF-3 is available.

In accordance with the response action specified in the OU 2 ROD (ABB-ES,1994b), the selected source control remedial action for LF-3 is containment using alow permeability cover system. The cover system has been designed in accordancewith RCRA Subtitle C and Maine Hazardous Waste Regulations. Site preparationfor the cover system began in 1994 and the cover system scheduled to be completedin 1998.

Coal Ash Pile. The CAP was used as a source of gravel during base construction.Following depletion of the gravel in this area, the excavation appeared to have beenfilled with coal ash and some construction debris. The time period during which theCAP was active is not known. According to the "Master Plan for Limestone AFB"dated 1957, coal ash had been dumped in an abandoned gravel pit outside the WestGate during the early 1950s.

Coal ash generated from industrial and domestic sources comprised most of thewaste in the CAD A, along with some construction debris. The PCDA was locatedsouth of the CADA and the DDA. Although it is not known how long this disposal


W0039621.080 8741-162-2

SECTION 2

area was active, paint cans are the only wastes known to have been disposed of atthis location.

The CAP was eliminated in a removal action conducted in 1994 and 1995.Approximately 184,000 cubic yards of coal ash, contaminated soil, concrete rubble,and miscellaneous debris and refuse were removed from the area and placed at LF-2and LF-3 as subgrade material for the cover systems.

Chapman Pit Debris Area. The CPDA was previously mined for sand and gravelduring construction of the base. After mining activities ceased, an earthen dam wasconstructed across the southern portion of the pit, creating Chapman Pit Pond northof the dam. During construction of the dam, fill was deposited in the southernportion of the pit (i.e., CPDA), and unauthorized dumping may have occurred (Law,1996).

Bituminous asphalt and concrete materials were reportedly disposed of in this area.Equipment and construction supplies may also have been placed in the pit andcovered over with fill. Small amounts of household and construction debris wereencountered during field investigations, but there is no evidence of widespread debrisdumping.

2.2 RESPONSE AND ENFORCEMENT HISTORY

The response and enforcement history of OU 4 sites is summarized as follows:

• In 1984, a Preliminary Assessment (PA) was completed detailinghistorical hazardous material usage and waste disposal practices atLAFB (CH2M Hill, 1984).

• Initial Site Investigation (SI) field work was conducted in 1985 todetermine if contaminants were present at the OU 4 sites (Weston,1988).

• The RI process commenced in 1988 and continued into 1994 (ABB-ES,1995).

• LAFB was added to the NPL in February 1990.


W0039621.080 8741-162-3

SECTION 2

• The USAF entered into a Federal Facilities Agreement (FFA) (FFA,1991) with the USEPA and MEDEP in 1991, to address the cleanupof environmental contamination at LAFB. The FFA was revised inDecember 1993 to address base closure related issues, such as realestate property transfer, and to revise the cleanup schedule. The FFAwas further modified in January 1995 to allow the Remedial ProjectManagers to make minor modifications, such as schedule adjustmentsand removal of petroleum-contaminated sites from the agreement.

• A Feasibility Study (FS) (ABB-ES, 1996b) was completed in 1996 forOU 4 to determine remedial alternatives for LF-2 and LF-3 based oninformation presented in the RI report; and

• A Proposed Plan (ABB-ES, 1996c) was submitted for public review inMay 1996.

• Public comment period from May 17, 1996 to June 15, 1996.

The following additional key milestones at LAFB indirectly relate to OU 4:

• Non-hazardous contaminated soils from other sites on base wereexcavated and placed on LF-2 and LF-3 in 1994 and 1995 as subgradematerial for the cover systems. LF-3 will receive non-hazardouscontaminated soils from other sites on base in 1996 and 1997.

• A removal action was conducted at the CAP in 1994 and 1995 in whichexcavated materials were placed at LF-2 and LF-3 as subgradematerial for the cover systems.

• Construction of a soil cover system at LF-1 was completed in 1996.

• Construction of LF-2 cover system was completed in 1996.

• Construction of LF-3 cover system is scheduled for completion in 1998.


W0039621.080 8741-162-4

SECTION 3

3.0 COMMUNITY PARTICIPATION

Throughout LAFB's history, the community has been active and involved in baseactivities at a high level. The USAF and USEPA have kept the community andother interested parties apprised of LAFB activities through informational meetings,fact sheets, press releases, public meetings, site tours and open houses, as well asRestoration Advisory Board (RAB) meetings. The RAB is chaired by USAF andcommunity representatives.

The LAFB Community Relations Plan (CRP) was released in August 1991 andrevised in May 1995. The CRP outlined a program to address community concernsand keep citizens informed and involved during remedial activities. The CRP canbe found in the Administrative Record.

On June 24, 1992, the USAF made the LAFB Administrative Record available forpublic review. The Administrative Record is currently available for public review atthe Air Force Base Conversion Agency Office, 5100 Texas Road, Limestone, Maine.The USAF published a notice and brief analysis of the OU 4 Proposed Plan in theBangor Daily News, the Aroostook Republican, and the Fort Fairfield Review onMay 15, 1996, and made the Proposed Plan available to the public at the Air ForceBase Conversion Agency Office.

From May 17, 1996 through June 15, 1996, the USAF held a 30-day public commentperiod to accept public input on the alternatives presented in the FS and theProposed Plan, as well as other documents previously released to the public. OnJune 11, 1996, LAFB personnel and regulatory representatives held a public meetingto discuss the Proposed Plan and to accept any oral comments. A transcript of thismeeting is included as Appendix A, and a Responsiveness Summary is included asAppendix B. The Air Force received no verbal or written comments on the OU 4Proposed Plan at a public hearing held on June 11, 1996, or during the 30 day publiccomment period.


W0039621.080 8741-163-1

SECTION 4

4.0 SCOPE AND ROLE OF OPERABLE UNIT OR RESPONSE ACTION

The USAF has determined that NFA under CERCLA is appropriate for groundwaterassociated with LF-1 and the CPDA. The concentrations of organic and inorganiccompounds detected in groundwater at these sites do not pose risks in exceedanceof USEPA target risk levels.. A determination by the USAF not to pursue furtheraction under CERCLA for groundwater associated with LF-1 and the CPDA is nota determination that no action is warranted for source control under otherregulations and statutes. The State of Maine's statutory authority is not limited byNFA under CERCLA A soil cover system at LF-1, in accordance with Maine SolidWaste Management Regulations, was completed in 1996.

The selected remedy for LF-2 and LF-3/CAP was developed by combiningcomponents of source control and groundwater mitigation alternatives to obtain acomprehensive approach for groundwater remediation. The selected remedy forgroundwater associated with LF-2 and LF-3/CAP is Minimal Action in conjunctionwith the source control remedy for LF-2 and LF-3 as outlined in the OU 2 ROD(ABB-ES, 1994b). In addition to the low permeability cover systems, 30-year landfillpost-closure monitoring, and deed restrictions for LF-2 and LF-3 contained in theOU2 ROD, implementation of the selected alternative for OU 4 would include thefollowing activities:

• institutional controls;• groundwater monitoring;• five-year site reviews; and• contingency action, if necessary (see Subsection 10.2).

The Minimal Action alternative utilizes institutional controls to protect againsthuman exposure to contaminated groundwater. Groundwater monitoring will beused to assess contaminant migration and to measure performance of the OU 2 coversystems in reducing leachate generation and associated groundwater contamination.The combination of OU 2 cover systems and application of activities under OU 4Minimal Action remedy will achieve the following remedial response objectives forgroundwater at LF-2 and LF-3/CAP:

• prevent human exposure to contaminated groundwater, and• protect downgradient groundwater from contamination.


W0039621.080 8741-164-1

SECTION 5

5.0 SUMMARY OF SITE CHARACTERISTICS

Section 2.0 of the FS (ABB-ES, 1996b) contains an overview of the OU 4 RI at LF-2and LF-3/CAP, including discussions on the geology, hydrogeology, and nature anddistribution of contaminants. The RI Report (ABB-ES, 1995) gives the results of theinvestigations at all five OU 4 sites. The significant findings of the RI aresummarized below.

Landfill 1. The site geology at LF-1 is characterized by fill material consisting oflandfill waste and granular soil, ablation till underlain by ice-contact deposits, basaltill, and bedrock consisting of dark gray, pellitic limestone. The ablation till, ice-contact deposits, and basal till consist generally of fine to coarse sands and gravelswith varying amounts of silty materials. In general, the overburden thickness at LF-1is about 15 feet, but increases significantly toward the southwest portion of the sitedue to a steep drop-off in the bedrock surface. The upper 15 feet of bedrock istypically highly weathered and fractured, but becomes more competent with depth.

Groundwater in the area of LF-1 is interpreted to be flowing to the southwest anddischarging to Green Pond. Downward vertical gradients near the northeastern edgeof the landfill suggest downward groundwater movement, or recharge, in this area.At the southeastern edge of the landfill near Green Pond, the vertical gradients areupward, suggesting groundwater discharge into Green Pond.

Upgradient of the landfill, the water table is typically just above the top of thebedrock surface. The saturated overburden thickness increases steadily toapproximately 40 feet at the downgradient or southwestern edge of the landfill. Theincrease in saturated thickness is a function of the rapid drop in the bedrock surfaceacross the site from northeast to southwest. It does not appear that overburdengroundwater extends into the landfill debris, with the possible exception of the toeof the landfill.

A comparison of upgradient and downgradient groundwater samples does not suggestan impact on groundwater from the landfill. Landfill leachate parameters indicatedno change in groundwater conditions upgradient to downgradient. Manganese andaluminum were the only inorganics reported above maximum exposure guidelines(MEGs) for unfiltered analyses; however, no exceedances of MEGs or MCLs werenoted in low-flow samples collected subsequent to the RI (ABB-ES, 1996b). Vinyl


5-1

SECTION 5

chloride was detected twice in one well at concentrations exceeding maximumcontaminant levels (MCLs)/MEGs.

Landfill 2. LF-2 geology is characterized as glaciofluvial, with associated depositsconsisting of ablation till underlain by ice-contact deposits, a discontinuous layer ofbasal till, and dark gray, weathered, pellitic Limestone. Overburden thickness rangesfrom negligible in the central area of the landfill to about 60 feet at the northwesternportion of the site, outside the area of landfilled wastes. In most cases, landfilledwastes were placed on ice-contact deposits; however, they were also placed directlyon the bedrock surface in some areas.

Based on interpretive bedrock contours, it appears that a northwest to southeasttrending bedrock trough exists beneath LF-2. The topographic high of the trough islocated near the northwestern end of LF-3. The trough plunges northwest in thevicinity of LF-2.

The bedrock trough beneath LF-2 apparently influences groundwater flow in boththe shallow bedrock and overburden soils. Groundwater flow at LF-2 is to the north-northwest, subparallel to the trend of the bedrock trough. This direction of flowindicates that water flowing across LF-2 may also have flowed through the northernportion of LF-3. Potentiometric head data for two overburden bedrock well pairsshow weak overall upward gradients in the area of LF-2.

The discontinuous shallow overburden aquifer and the fractured-bedrock aquiferappear to form one groundwater system throughout the LF-2 area, due to thepermeable nature of the sand and gravel, and the weathered and fractured nature ofthe bedrock. The water table is located in the overburden soils over the majority ofthe LF-2 site. Therefore, it can be concluded that groundwater comes into contactwith some of the waste throughout the year.

Volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs),pesticides, inorganics above background concentrations, total petroleum hydrocarbons(TPHs), and oil and grease were detected in groundwater in and around LF-2. Inaddition, several miscellaneous parameters which are typical indicators of landfillplume contamination were detected in groundwater samples collected in 1993 and1994.


W0039621.080 8741-165-2

SECTION 5

Contaminants detected in overburden wells inside the landfill perimeter include fuel-related VOCs and chlorobenzenes, SVOCs (including bis(2-ethylhexyl)phthalate[BEHP] above the MCL), pesticides, and inorganics. Concentrations of contaminantsdetected in perimeter wells completed in the overburden adjacent to or downgradientfrom LF-2 were generally lower than concentrations within the limits of the waste.No significant organic contaminants were detected in overburden groundwater inperimeter wells.

Based on the most recent sampling results, inorganics above backgroundconcentrations were detected in all bedrock monitoring wells around LF-2. TheSVOC BEHP was detected, and the VOC vinyl chloride was detected above itsMEG, but not in excess of its MCL. Tetrachloroethene (PCE) was detected aboveits MEG but not its MCL. The only inorganics identified as chemicals of potentialconcern during low-flow sampling (LFS) were arsenic, barium, iron, and manganese.

Landfill 3/CAP. Because of the proximity of LF-3 and the CAP, these two OU 4sites will be discussed concurrently in this section. LF-3/CAP overburden geologyis characterized as a former esker deposit, consisting of ablation till underlain by ice-contact deposits, and highly weathered, pellitic limestone. Thickness of the soilsoutside the landfilled material ranges from about 5 feet on the northern side to amaximum of 55 feet southeast of the site in the bedrock trough. Wastes appear tohave been placed directly on the ice-contact sand and gravel deposits.

Bedrock in the LF-3/CAP area is a gray pellitic limestone. The northwest-to-southeast-trending bedrock trough present beneath LF-2 appears to continue beneathLF-3, narrowing and rising to a saddle in the northwestern area of LF-3, thendeepening again to the southeast of the landfill. Bedrock is interpreted to be morefractured within the trough axis than on the trough walls.

The water table was typically encountered above the bedrock surface within theperimeter of LF-3 and the CAP. LF-3 waste appears to be partially saturated bygroundwater throughout the year. The groundwater system is bounded to the eastand west of LF-3 by the bedrock trough, and data indicate that the water table entersbedrock in the axis of the trough south of LF-3. To the north of the divide,groundwater flows northward toward LF-2, whereas south of the divide, groundwaterflow is interpreted to be southeast. Calculated vertical gradients suggest thatdownward groundwater movement exists on the flanks of the bedrock trough, and


W0039621.080 8741-165-3

SECTION 5

limited upward groundwater movement exists in the central areas of the bedrocktrough.

VOCs, SVOCs, pesticides, and inorganics above background concentrations weredetected in groundwater in and around LF-3. Oil and grease were also detected ingroundwater samples collected within the LF-3 boundary during 1993 sampling.

Concentrations of VOCs (including benzene, trichloroethene [TCE], PCE, and vinylchloride), SVOCs (including polynuclear aromatic hydrocarbons [PAHs]), andinorganics (including lead, nickel, and cadmium) were detected above MEGs and/orMCLs within the LF-3 boundary. The only exceedance for pesticides was heptachlorin a single well. Concentrations of VOCs, SVOCs, and inorganics are generallyhighest in wells within the southern half of the landfill.

Concentrations of contaminants in overburden outside the perimeter of the landfillwere generally much lower than concentrations within the landfill. There were noexceedances of MEGs and/or MCLs for VOCs and pesticides/polychlorinatedbiphenyls (PCBs). Only one SVOC, BEHP, was detected above MEGs and/orMCLs. Arsenic, barium, iron, and manganese were identified above backgroundconcentrations in overburden groundwater low-flow samples collected outside theperimeter of the landfill.

VOCs (i.e., PCE, benzene, and vinyl chloride) were detected sporadically above theMEGs and/or MCLs in bedrock wells, generally south, east, and west of LF-3.SVOCs have been detected in several bedrock monitoring wells. The only SVOCconcentrations above MCLs or MEGs were for BEHP, which was detected in threemonitoring wells. Pesticides have been detected in most samples, althoughconcentrations were generally extremely low. No pesticides or PCBs were detectedabove MEGs and/or MCLs in wells around LF-3. Inorganics above backgroundconcentrations have been detected in bedrock wells in the vicinity of LF-3.

Chapman Pit Debris Area. The site geology at the CPDA is characterized as fillmaterial overlying native glacial and post-glacial deposits, which in turn are underlainby pellitic Limestone. The two fill materials present consist of silts, sands, and gravelsplaced during LAFB gravel mining activities, and during construction of the damafter mining activities ceased. The post-glacial deposits consist of peat, silt and claypond deposits, and medium to coarse sand and gravel stream channel deposits. Thebasal till, a mixture of varying amounts of silt, sand, and clay, lies directly over a


W0039621.080 8741-165-4

SECTION 5

highly fractured, pellitic limestone. Overburden thickness ranges from 10 to 20 feetover much of the site, to as much as 42 feet at the southern boundary of the area.

The groundwater system associated with the CPDA is bounded to the north by arecharge boundary (Chapman Pit Pond), to the east, south, and west by unnamedstreams and swamps that act as discharge boundaries. These boundaries are assumedto control both overburden, and bedrock groundwater flow in the CPDA.Groundwater flow is generally south and southwest away from Chapman Pit Pond.

Organic contaminants at this site are present only at very low concentrations.Methylene chloride was the only reported VOC at estimated concentrations abovethe MCL in 1993 samples, but it was not detected in 1994 samples. BEHP was theonly SVOC detected above its MCL. Metals appear to be the primary constituentspresent, with aluminum and manganese consistently exceeding regulatory criteria.Lead exceeded MEGs in one overburden groundwater sample, but not at aconcentration that would cause exceedance of the blood lead level, which wouldcause risk.


W0039621.080 8741-165-5

SECTION 6

6.0 SUMMARY OF SITE RISKS

A baseline human health risk assessment (RA) was performed as part of the OU 4RI Report (ABB-ES, 1995). A revised RA was performed as part of the OU 4 FS(ABB-ES, 1996b). The revised RA focused on the recalculation of risk based on theseparation of OU 4 groundwater into bedrock and overburden samples for each ofthe sites, and the incorporation of LFS results for inorganic analytes, as available.The assessment was performed in accordance with USEPA guidance documents(USEPA, 1989a,b,c,d; 1991a,b), MEDEP Guidance Manual (MEDEP/DHS, 1994)and the Loring Air Force Base Risk Assessment Methodology (Hazardous WasteRemedial Actions Program [HAZWRAP], 1994). The RA estimates the probabilityand magnitude of potential adverse human health effects from exposure togroundwater contaminants associated with the OU 4 sites. The human health riskassessment followed a four step process:

1) contaminant identification identified those hazardous substanceswhich, given the specifics of the site, were of significant concern;

2) exposure assessment identified actual or potential exposure pathways,characterized the potentially exposed populations, and determined theextent of possible exposure;

3) toxicity assessment considered the types and magnitude of adversehealth effects associated with exposure to hazardous substances; and

4) risk characterization integrated the three previous steps to summarizethe potential and actual risks posed by hazardous substances at thesite, including carcinogenic and non-carcinogenic risks.

Although groundwater is not currently used on the former base, and residentialdevelopment will be restricted, the RA assumed domestic use of groundwater.Exposure to residual contamination in the groundwater present at or migrating fromthe OU 4 sites is assumed to occur through residential use (i.e., drinking, cooking,washing, and showering). For more detail on the data sets used, contaminantidentification, exposure assessment, toxicity assessment, and risk characterization, seeSection 3 of the Final OU 4 FS (ABB-ES, 1996b).


W0039621.080 8741-166-1

SECTION 6

Carcinogenic and noncarcinogenic risks are quantitatively evaluated for each site.Carcinogenic risks are compared to the USEPA target carcinogenic risk range ofIxlO-4 to lxlO'6 and the MEDEP cancer risk guidance value of IxlO'5.Noncarcinogenic risks are compared to the USEPA noncarcinogenic Hazard Index(HI) of 1.0 (USEPA, 1989a).

6.1 HUMAN HEALTH RISK ASSESSMENT

A summary of the results of the human health risk assessment for LF-1, LF-2, LF-3/CAP, and the CPDA groundwater is presented in the following subsections and aretabulated on Table 6-5.

6.1.1 Landfill 1

Risks from exposure to bedrock and overburden groundwater at LF-1 were evaluatedseparately. The contaminants of concern identified for each data set are presentedon Table 6-1.

Lead was not detected in either the bedrock or overburden data sets.

LF-1 Bedrock Groundwater. The total cancer risks for the average (i.e., mostprobable case) and maximum (i.e. reasonable maximum exposure [RME]) scenariosare 4xlO~5 and 1x10"*, respectively. These risks exceed the MEDEP cancer riskguidance value of IxlO"5, but are within the USEPA carcinogenic risk range of Ixlfr4

to IxlO'6. The noncancer risks are less than an HI of 1. The HI for the averageexposure is 0.02, and for the maximum exposure is 0.06.

LF-1 Overburden Groundwater. The total cancer risks for the average and maximumscenarios are 7xlO"7 and IxlO'6, respectively. These risks are less than the MEDEPcancer risk guidance value of IxlO"5, and less than the USEPA carcinogenic riskrange of 1x10 to bclO"6. The noncancer risks are less than an HI of 1. The HI forthe average exposure is 0.006, and the HI for the maximum exposure is 0.009.

6.1.2 Landfill 2

Risks from exposure to bedrock and overburden groundwater at LF-2 were evaluatedseparately. Because of distinct differences in the nature of contamination, shallow


W0039621.080 8741-166-2

TABLE 6-1CHEMICALS OF CONCERN FOR LANDFILL 1

HUMAN HEALTH RISK ASSESSMENT

OPERABLE UNIT 4 RECORD OF DECISIONLORINQ AIR FORCE BASE

CApiuiwfiJiiHiti "x:x-x:x-:::-i:x-:- :•:•:• :-:::-;-: ":: :-:'::x:x:x ::::;;:::->;-:;:;::::::::x::: ::;:: : :: •:•:•:•:•:•iWf* ••»•?*•**•.•:•:-:•:•:•:•:•:•:•:•:•:• :->;-:-x :::•:•:•: •:•:•:•:•:•:•:•:• •:•:•:•:•:•:•:•:•:•:•:•:•:•:•:•: :•:•. • •: :-:-:•:•:•iiiiiiiiiiiiiii 1111 iiiiiiii i i ;i 11LF-1 BEDROCK GROUNDWATER

ChloroformVinyl Chloride

Aluminum

LF-1 OVERBURDEN 6ROUNDWATER

bis<2-EthylhexyOphthalat»

••^^^^^i-iiii^fftjftiiif^^^^-foi^^i^y^t^^l-^-^: ^-^^:i:::^

0.009 0.009 0.0027 1 / 5

0.00211 0.00211 0.000822 1 / 5

0.0641 0.177 0.09467 5 / 5

0.001 0.005 0.00325 2 / 2

NOTE: For information on data cats (walk, analyra, and sample data*) uaad in tha RA. aaa Table 3-1 of the Brefe Final FS (ABB-ES. 1996a).

6-3

OU4-COC.XLS 6/13/96

SECTION 6

bedrock (less than 200 feet bgs) and deep bedrock (greater than 200 feet bgsgroundwater were evaluated separately. Similarly, overburden groundwater fromwithin the landfill boundary was evaluated separately from overburden groundwateroutside the landfill boundary. The contaminants of concern identified for each dataset are presented on Table 6-2.

Lead was detected in the data sets for both shallow and deep bedrock groundwater.Lead was evaluated using the Integrated Exposure Uptake Biokinetic (IEUBK)Model only in the data set for deep bedrock, where concentrations exceeded theUSEPA Action Level of 15 micrograms per liter (/xg/L). IEUBK results indicatethat blood lead levels due to consumption of lead at both average and maximumconcentrations in drinking water would exceed the USEPA guidance blood lead levelof 10 micrograms per deciliter

LF-2 Shallow Bedrock Groundwater. The total cancer risks for the average andmaximum scenarios are IxlO"4 and 2xl(r*, respectively. These risks exceed theMEDEP cancer risk guidance value of IxlO"5. The maximum exposure risk exceedsthe USEPA carcinogenic risk range of 1x10"* to IxlO"6, and the average risk equalsthe upper end of the risk range. The primary contributors to the carcinogenic riskare arsenic, vinyl chloride, and 2,6-dinitrotoluene. The noncancer risks exceed an HIof 1. The HI for both the average and maximum exposure scenario is 3. Theprimary contributors to the noncancer risk are manganese, iron, and arsenic.

LF-2 Deep Bedrock Groundwater. The total cancer risks for the average andmaximum scenarios are 6xlO~5 and IxlO"4, respectively. These risks exceed theMEDEP cancer risk guidance value of IxlO"5, but are within the USEPA carcinogenicrisk range of 1x10^ to IxlO"6. The primary contributor to the carcinogenic risk isarsenic. The noncancer risks exceed an HI of 1. The HI for the average exposureis 5, The HI for the maximum exposure is 9. The primary contributors to thenoncancer risk are iron, cadmium, and zinc.

LF-2 Overburden Groundwater Outside the Perimeter of the Landfill. The totalcancer risks for the average and maximum scenarios are 6x10"* and IxlO"5,respectively. These risks are less than or equal to the MEDEP cancer risk guidancevalue of IxlO"5, and within the USEPA carcinogenic risk range of 1x10^ to IxlO"6.The noncancer risks are less than an HI of 1. The HI for both the average andmaximum scenario is 0.1.


W0039621.080 8741-166-4

TABLE 6-2CHEMICALS OF CONCERN FOR LANDFILL 2


OPERABLE UMT 4 RECORD OF DECISIONLORINO AIR FORCE BASE

iiiil|s|lllill:ilillllllll:llill

LF-2 SHALLOW BEDROCK GROUND WATER |< 200' bga

TatraohloroathanaVinyl Chloridaoia-1 ,2-DioNoroathana1 ,2.4-Triohlorooanzana2,6-Dinitrotoloanabia(2-Ethyihaxyl)phthalataAraamoBariumIronManganaaa

LF-2 DEEP BEDROCK QROUNDWATER O20O1 bga)

bia(2-Ethylhaxyl)phthalataAluminumArsanioBariumCadmiumChromiumronLaadManganaaaZinc

LF-2 OVERBURDEN QROUNDWATER OUTSIDE THE PERI

Vinyl Chloridabi«(2-Ethylhaxyl)phthalataiariumlAanganaaa

LF-2 OVERBURDEN QROUNDWATER INSIDE THE PERIME

,4-DichlorobanzanaBanzanaChlorobanzanaVinyl Chloridabia(2-Ethylhaxyl)phthalataDialdrinHaptaohloriarium

Manganaaa

iiii^^iiiiiiilliilPSililiiiHii

0.002O.OO0170.00070.0160.002O.O110.0040O.I 286.641.46

0.0040.05760.00170.0230.00420.0107

1.490.061

O.O4414.78

METER OF THE LANDFILL

0.000270.0030.05880.144

TER OF THE LANDFILL

0.0010.00050.002

O.OO0160.003

0.0000020.0000180.05880.144

iiiiiiiiiiiiisiiiis tiisit

0.004O.O01410.00070.0160.002O.O110.00460.1286.641.46

0.0222.14

0.00420.9160.03260.026

330.4950.3913

0.000270.0030.05880.144

0.0010.0020.013

0.000230.01

O.OOOOO2O.OOO0180.05880.144

PiiWI;ini ^;;lPl

0.001286O.OO0351O.OO0633O.OO6B71O.OO4571O.OO5857

O.OO460.1286.641.46

0.01250.713350.0024880.2761760.0168760.013625

16.470.1862630.174725

8.24

O.OO01 1 10.0060.05880.144

0.00060.000910.0033

0.0001080.0072

0.0000080.0000060.05880.144

ilillliiita

2 / 74 / 7

/ 6/ 7/ 7/ 7/ 1/ 1/ 1/ 1

4 / 43 / 43 / 44 / 44 / 43 / 44 / 44 / 44 / 44 / 4

1 / 41 / 41 / 11 / 1

1 / 63 / 52 / 52 / 63 / 51 / 61 / 51 / 11 / 1

NOTE: For Information on data aata (walla, analyaaa, and aampla dataa) uaad in tha RA, aaa Tabla 3-1 of tha Braft Final FS (ABB-ES, 1996a).

6-5

OU4-COC.XLS 6/13/96

SECTION 6

LF-2 Overburden Groundwater Inside the Perimeter of the Landfill. The totalcancer risks for the average and maximum scenario are 9x10^ and 2xlO"5, respectively.Only the maximum exposure risk exceeds the MEDEP cancer risk guidance value ofIxlO"5. Both the average and maximum risks are within the USEPA carcinogenic riskrange of IxlO"4 to IxlO"6. The noncancer risks are less than an HI of 1. The HI forthe average exposure is 0.4, and for the maximum exposure is 0.7.

6.1.3 Landfill 3/Coal Ash Pile

Risks from exposure to bedrock and overburden groundwater at LF-3/CAP wereevaluated separately. Because of distinct differences in the nature of contamination,overburden groundwater from within the landfill boundary was evaluated separatelyfrom overburden groundwater outside the landfill boundary. The contaminants ofconcern identified for each data set are presented on Table 6-3. Lead was detectedin the bedrock data set at a maximum concentration less than the USEPA ActionLevel of 15 /*g/L; therefore, no further evaluation of lead was performed forLF-3/CAP.

LF-3/CAP Bedrock Groundwater. The total cancer risks for the average andmaximum exposures are 8xlO"5 and 3x10 , respectively. These risks exceed theMEDEP cancer risk guidance value of IxlO'5, and the maximum exposure riskexceeds the USEPA carcinogenic risk range of IxlO"4 to IxlO"6. The primarycontributors to the carcinogenic risks are arsenic, vinyl chloride, and heptachlor. Thenoncancer risks equal or exceed an HI of 1. The HI for the average exposure is 1,and the HI for the maximum exposure is 6. The primary contributors to thenoncancer risks are iron and manganese.

LF-3/Cap Overburden Groundwater Outside the Perimeter of the Landfill. Thetotal cancer risk for both the average and maximum exposure is 4x10"*. This riskexceeds the MEDEP cancer risk guidance value of IxlO"5, and the USEPAcarcinogenic risk range of 1x10^ to IxlO"6. The only contributor to the carcinogenicrisk is arsenic. The noncancer risks exceed an HI of 1. The HI for both the averageand the maximum scenario is 7. The primary contributors to the noncancer risk areiron, arsenic, and manganese.

LF-3/CAP Overburden Groundwater Inside the Perimeter of the Landfill. The totalcancer risk for both the average and maximum exposure is 5x10 . This risk exceedsthe MEDEP cancer risk guidance value of IxlO"5, and the USEPA carcinogenic risk


W0039621.080 8741-166-6

TABLE 6-3CHEMICALS OF CONCERN FOR LANDFILL 3/COAL ASH PILE



p"*""" ** — — ^<— »•*LF-3/CAP BEDROCK QROUNDWATER

BenzeneVinyl Chloride

bis(2-Ethylhexyl)phthalateHeptachlorHeptachlor EpoxideAluminumArsenicCopperIronManganese

LF-3/CAP OVERBURDEN QROUNDWATER

ArsenicBariumIronManganese

illll liiSiiillmrnmmmm&mmmimi^iim!??*1^^ ^ ^ ^ ^BESs£nvniaM

0.0030.00050.001

0.0000720.000001

0.5330.00260.00480.09110.0077

OUTSIDE THE PERIMETER

0.0180.33723.22.46

mm«±mm*mjmm$iiji$i»%i*!$$$®®

0.0030.002460.007

0.0000720.000001

1.410.00620.12422.72.78

OF THE LANDFILL

0.0180.33723.22.46

iiiiiiii-mmmmM**s::m:mmmmm*^llll tMitl

0.0007270.000460.0051360.0000120.0000040.2833830.0021830.0130753.4305330.3241

0.0180.33723.22.46

LF-3/CAP OVERBURDEN QROUNDWATER INS.DE THE PEIUMETER OF THE LANDFILL

1,1-Dichloroethane1 ,4-Dichlorobenzene

|2-ButanoneBenzeneTetrachloroethene

TolueneTrichloroetheneVinyl Chloride

cis-1,2-Dichloroethene4-MethylphenolAcenaphtheneNaphthaleneArsenicIron

Manganese

0.003O f\f\O.uuo0.0170.011O.OO4

0.250.007

0.000840.0140.050.0020.0170.01823.22.46

0.0530.0427.5

0.011O.OO4

1 R1 .0

0.0660.00084

0.222

0.0020.0920.01823.22.46

0.0531670.0553333.51675

0.0525830.051417

0.6775830.056

0.0002030.0828330.7825

0.1324170.125250.01823.22.46

1 / 1136132529

/ 11/ 11/ 10/ 10/ 12/ 12/ 12/ 12

12 / 12

1 / 11 / 11 / 11 / 1

2 / 63 / 64 / 41 / 61 / 85 / 62 / 6

/ 62 / 6

3 /1 / 11 / 11 /

FS(AaMs.189e>1.

6-7

OU4-COC.XLS

6/13/96

SECTION 6

range of 1x10"* to IxlO"6. The primary to the carcinogenic risk are arsenic, vinylchloride, 1,4-dichlorobenzene, TCE, benzene, and PCE. The noncancer risks exceedan HI of 1. The HI for the average exposure is 16, and for the maximum exposureis 27. The primary contributors to the noncancer risk are 4-methylphenol, iron,benzene, arsenic, manganese, and cis-l,2-dichloroethene (DCE).

6.1.4 Chapman Pit Debris Area

Risks from exposure to bedrock and overburden groundwater at the CPDA wereevaluated separately. The contaminants of concern identified for each data set arepresented on Table 6-4.

Lead was detected in the bedrock data set at a maximum concentration less than theUSEPA Action Level of 15 /xg/L; therefore, no further evaluation of lead wasperformed for the CPDA.

CPDA Bedrock Groundwater. The total cancer risks for the average and maximumexposures are IxlO"6 and 2xlO"6, respectively. These risks are less than the MEDEPcancer risk guidance value of IxlO"5, and within the USEPA carcinogenic risk rangeof lxl(T* to IxlO"6. The noncancer risks are less than an HI of 1. The HI for theaverage exposure is 0.4, and the HI for the maximum exposure is 0.7.

CPDA Overburden Groundwater. The total cancer risks for the average andmaximum exposures are IxlO"6 and 3xlO"6, respectively. These risks are less than theMEDEP cancer risk guidance value of lxlO"s, and within the USEPA carcinogenicrisk range of IxlO4 to IxlO"6. The noncancer risks are less than an HI of 1. The HIfor the average scenario is 0.01, and the HI for the maximum exposure scenario is0.02.

6.2 UNCERTAINTY EVALUATION

Quantitative estimates of risk are based on numerous assumptions, most of which areintended to be protective of human health (i.e., conservative). A summary ofpotential sources of uncertainty, and the likely tendency of their effects (i.e., to over-or underestimate risks) is presented in the Final OU 4 FS (ABB-ES, 1996b).Although some uncertainties in the RA methodology might bias the evaluation in the


W0039621.080 8741-166-8

TABLE 6-4CHEMICALS OF CONCERN FOR CHAPMAN PIT DEBRIS AREA


OPERABLE UNIT 4 RECORD OF DECISIONLORINO AIR FORCE BASE

CSji-iiiiii&i ^.:-.\-.-.:\\:-:'-^

• :•:•:•• ••••••'•••1:x-x:::x-:;:;X-X;:;X-::;;X;:::;:;:;:;:::;:;;:;:;:;:X:::x-x:X:X'X:x:xox x:x:::::x:x:x-X'X:''X :

CPDA BEDROCK QROUNDWATER

bis(2-Ethylhexyl)phthalateAluminumIronManganeseNickel

CPDA OVERBURDEN QROUNDWATER

Methylene ChlorideDi-n-butylphthalatebis(2-Ethylhexyl)phthalate

|:;|:||:Mii!Bmtirfl;||*:::::::S:!:|||!J>e id:||!!i

ConoentrationiilP:<rir lilP?l

0.0021.12

0.4110.09680.0173

0.00310.000520.00094

i iiijMaxim iiinSSiH|||||| «|t|i(l|||: >:: : • C ono Hri ty flttonW^®$ffiJKp^®

0.0071.121.58

0.5130.0173

0.00790.00190.005

|||||;!|:Me«fl|;|i:||||:;Concentration

;|;:;:;::;g;;;:;::g:j iJi:S::as;sssss

0.00450.645250.99550.30490.01275

0.0045250.0023270.002723

IlliPpf

;*;*s:*ss:b«i

21221

446

Q«ier ;:S:::i;tS::;:;;g;:;;::S:::H::::;;;:::::: ::::::::^:M^i^m:M^M^ff-KA

^XiiiMiiiK

1 21 21 21 21 2

1 8/ 6/ 6

NOTE: For information on data »«ts (well*, analyses, and sample dates) used in the RA, see Table 3-1 of the Brafe-Final FS (ABB-ES, 1996a).

6-9

OU4-COC.XLS 6/13/96

SECTION 6

direction of an underestimation of risk, most assumptions will bias the evaluation inthe direction of overestimation of risk.

6.3 CONCLUSION

A summary of quantitative risks for each of the OU 4 sites is presented on Table 6-5.

Landfill 1 and Chapman Pit Disposal Area. The risk estimates for domestic use ofboth overburden and bedrock groundwater at LF-1 and the CPDA are belowMEDEP and USEPA carcinogenic and noncarcinogenic target risk levels, with theexception of bedrock groundwater at LF-1 which exceeds the MEDEP cancer riskguidance value. Although risks associated with groundwater at LF-1 are within theUSEPA risk range of IxlO"4 to IxlO"6, a soil cover system is being installed in 1996as required by the MEDEP Solid Waste Management Regulations. For thesereasons, the USAF has proposed NFA under CERCLA for LF-1 and the CPDA.

Landfill 2. At LF-2, the noncarcinogenic risk estimates for domestic use of bedrockgroundwater exceed an HI of 1.0. The maximum exposure carcinogenic risk forshallow bedrock groundwater exceeds the MEDEP and USEPA target risk levels.The average exposure for shallow bedrock exceeds the MEDEP cancer risk guidancevalue and equals the upper end of the USEPA target risk range. Both average andmaximum exposures for deep bedrock groundwater, exceed the MEDEP and USEPAtarget risk levels. Detections of lead in bedrock groundwater were qualitativelyevaluated using the IEUBK Model, which indicated that blood lead levels due toconsumption of lead at both average and maximum concentrations in drinking waterwould exceed the USEPA guidance blood lead level of 10 ^ig/dL. No remedialalternatives were evaluated in the FS for overburden groundwater, because risks donot exceed MEDEP and USEPA target levels, with the exception of overburdengroundwater inside the perimeter of the landfill where the maximum exposure riskslightly exceeds the MEDEP cancer risk guidance value. For bedrock groundwater,five remedial alternatives were developed and screened, and the No Action, MinimalAction, and Groundwater Collection/Treatment/Discharge alternatives were carriedthrough detailed analysis in the FS.

Landfill 3/Coal Ash Pile. At LF-3/CAP, both average and maximum exposure riskestimates for domestic use of overburden groundwater exceed MEDEP and USEPAcarcinogenic and noncarcinogenic target risk levels. The average and maximum


W0039621.080 8741-166-10

TABLE 6-6QUANTITATIVE RISK SUMMARY


LF-1 BEDROCK GROUNDWATER

LF-1 OVERBURDEN GROUNDWATER

LF-2 SHALLOW BEDROCK GROUNDWATER « 200' bgs)

LF-2 DEEP BEDROCK GROUNDWATER O2001 bgs)

LF-2 OVERBURDEN GROUNDWATER: OUTSIDE THE LANDFILL

LF-2 OVERBURDEN GROUNDWATER: INSIDE THE LANDFILL

LF-3/CAP BEDROCK GROUNDWATER

LF-3/CAP OVERBURDEN GROUNDWATER: OUTSIDE THE LANDFILL

LF-3/CAP OVERBURDEN GROUNDWATER: INSIDE THE LANDFILL

CPDA BEDROCK GROUNDWATER

CPDA OVERBURDEN GROUNDWATER

4E-05

7E07

IE-04

6E-05

6E-06

9E-06

8E-05

0.02

0.006

0.1

0.4

1E-04

1E-06

IE-04

1E-05

2E-05

0.06

0.009

0.1

0.7

1E-06

1E-06

0.4

0.01

2E-06

3E-06

0.7

0.02

NOTES:Shaded vilues exceed upper «nd of USEPA target risk rang* (10-6 to 10-4) or an HI of 1.0.

Total risks include ingestion, dermal, end inhalation exposure!,bgs = below ground surface

OU4SUM.XLS 4/26/96

SECTION 6

exposure risk estimates for bedrock groundwater exceed the MEDEP cancer riskguidance value. The maximum exposure risk estimate for bedrock groundwater alsoexceeds USEPA target risk levels. Remedial alternatives for both overburden andbedrock groundwater were evaluated in the FS due to elevated risks.

Actual or threatened releases of hazardous substances to groundwater from LF-2 andLF-3/CAP, if not addressed by implementing the response action selected in thisROD in conjunction with the response action selected in the OU 2 ROD, maypresent an imminent and substantial endangeraient to public health. The objectiveof the selected remedial action is to implement institutional controls and conductdowngradient groundwater monitoring, in conjunction with the low permeability coversystems being installed as source control under OU 2. Through this action, exposuresto the contaminants in groundwater at LF-2 and LF-3/CAP will be significantlyreduced.


W0039621.080 8741-166-12

SECTION 7

7.0 DEVELOPMENT AND SCREENING OF ALTERNATIVES

Three alternatives for LF-2 and LF-3/CAP were developed and screened in theOU 4 FS (ABB-ES, 1996b). This section describes the response objectives and thedevelopment and screening of alternatives.

The USAF has determined that NFA under CERCLA is necessary for groundwaterassociated with LF-1 and the CPDA, and therefore, no remedial alternatives weredeveloped for these sites.

7.1 STATUTORY REQUIREMENTS/RESPONSE OBJECTIVES

Under its legal authorities, the USAF's primary responsibility at NPL sites is toundertake remedial actions that are protective of human health and the environment.In addition, Section 121 of CERCLA establishes several other statutory requirementsand preferences, including: a requirement that the USAF's remedial action, whencomplete, must comply with all federal and more stringent state environmentalstandards, requirements, criteria or limitations, unless a waiver is granted; arequirement that the USAF select a remedial action that is cost-effective and thatutilizes permanent solutions and alternative treatment technologies or resourcerecovery technologies to the maximum extent practicable; and a preference forremedies in which treatment that permanently and significantly reduces the volume,toxicity or mobility of the hazardous substances is a principal element over remediesnot involving such treatment. Response alternatives were developed to be consistentwith these Congressional mandates.

Based on preliminary information relating to types of contaminants, environmentalmedia of concern, and potential exposure pathways, remedial action objectives weredeveloped to aid in the development and screening of alternatives. These remedialaction objectives were developed to mitigate existing and future potential threats topublic health and the environment. These response objectives for groundwater atLF-2 and LF-3/CAP are:

• to prevent human exposure to contaminated groundwater; and

• to protect downgradient groundwater from contamination.


7-1

SECTION 7

7.2 TECHNOLOGY AND ALTERNATIVE DEVELOPMENT AND SCREENING

CERCLA and the NCP have set forth the process by which remedial actions areevaluated and selected. In accordance with these requirements, a range ofalternatives were developed for LF-2 and LF-3/CAP.

With respect to groundwater response action, the FS developed a range ofalternatives considering the CERCLA statutory preference for a treatment thatreduces the toxicity, mobility, or volume of the hazardous substances. This rangeincluded an alternative that removes or destroys hazardous substances to themaximum extent feasible, eliminating or minimizing to the degree possible the needfor long-term management. This range also included alternatives that treat theprincipal threats posed by the site but vary in the degree of treatment employed andthe quantities and characteristics of the treatment residuals and untreated waste thatmust be managed; alternative(s) that involve little or no treatment but provideprotection through engineering or institutional controls; and a no action alternative.

Of the five groundwater remedial alternatives screened in Section 6 of the FS, threewere retained for detailed analysis. Tables 6-1 and 6-3 in the FS identify the threealternatives that were retained through the screening process, as well as those thatwere eliminated from further consideration.


W0039621.080 8741-167-2

SECTION 8

8.0 DESCRIPTION OF ALTERNATIVES

This section provides a narrative summary of each alternative evaluated in the FS.The alternatives developed for LF-2 include No Action and Minimal Action. Thealternatives developed for LF-3/CAP include No Action, Minimal Action, andGroundwater Collection/Treatment/Discharge. A detailed assessment of eachalternative can be found in Section 7.0 of the OU 4 FS (ABB-ES, 1996b).

The landfill cover systems at LF-2 and LF-3 under OU 2 are expected to result inmitigation of groundwater contamination by isolating a large volume of the wastefrom groundwater contact. All alternatives presented are evaluated, withconsideration given to the effects of the cover systems on contaminant concentrations.

8.1 No ACTION

The No Action alternative was evaluated for both LF-2 and LF-3/CAP (alternativesLF2-1 and LF3-1 in the FS), as required by the NCP, to provide a baseline againstwhich other alternatives could be compared during detailed analysis. This No Actionalternative differs from the "traditional" No Action alternative in that beneficialimpacts on groundwater quality are expected from remediation being done inaccordance with OU 2. Therefore, the No Action alternative does not assume thatcurrent conditions, as described in the OU 4 RI Report, would remain even if thisalternative were selected.

Implementation of this alternative would not limit exposure of contaminatedgroundwater to existing and future groundwater users outside of the area of landfilledwastes at LF-2 and LF-3 in the short term. Future residential exposure togroundwater would remain possible for both new users and existing users. There areno costs associated with this alternative.


W0039621.080 8741-168-1

SECTION 8

8.2 MINIMAL ACTION

The Minimal Action alternative was also evaluated for both LF-2 and LF-3/CAP(alternatives LF2-2 and LF-3-2 in the FS). The components of this alternative, inaddition to the OU 2 actions, are as follows:

• institutional controls• groundwater monitoring• five-year site reviews• contingency action, if necessary (see Subsection 10.2)

This alternative would include institutional controls to protect against humanexposure to contaminated groundwater. Monitoring wells downgradient of LF-2 andLF-3 would be used to monitor contaminant levels downgradient of the landfill.These monitoring locations would be used to verify and define the zone ofattainment for action levels, as well as serve as compliance points between existinggroundwater users and the landfills.

Five-year reviews would evaluate the monitoring system, including the frequency ofmonitoring, the zone of attainment, and the downgradient distribution ofcontaminants. If landfill-related contaminants are detected at the compliance pointat concentrations above the action levels, a contingency action will be implemented.The contingency action is discussed in Subsection 10.2.

Implementation of this alternative would limit exposure of existing and futuregroundwater users to contaminated groundwater outside of the area of landfilledwastes at LF-2 and LF-3.

Estimated Time of Operation: 30 Years

Estimated Capital Cost: $87,000

Estimated Operation and Maintenance (O&M) Costs (net present worth):$810,000

Estimated Total Cost (net present worth): $897,000


W0039621.080 8741-168-2

SECTION 8

8.3 GROUNDWATER COLLECTION/TREATMENT/DISCHARGE

The Groundwater Collection/Treatment/Discharge alternative was also evaluatedfor LF-3 (alternative LF3-4 in the FS). This alternative consists of components fromthe Minimal Action alternative, along with a groundwater collection and treatmentsystem designed to recover contaminated groundwater from the overburden andshallow bedrock aquifers downgradient of LF-3. Key components of this alternativeinclude:

• pre-design hydrogeologic studies• groundwater extraction system construction• groundwater treatment facility construction and operation• treated groundwater discharge• institutional controls• groundwater monitoring• five-year site reviews

Prior to design of this alternative, hydrogeologic studies are recommended tooptimize the design of the groundwater extraction system in controlling contaminantmigration from LF-3.

Because of the existence of a groundwater divide beneath LF-3, two extraction wellswith variable pumping rates of up to 25 gallons per minute (gpm) would be necessaryto prevent off-site migration of contaminated groundwater. One well would beplaced at the northwestern end of LF-3, the other at the southeastern end of thelandfill.

Extracted groundwater would be pumped to a centrally-located groundwatertreatment facility. The following treatment train was selected for this alternative,based on an evaluation of available treatment technologies: chemical oxidation/precipitation, filtration, air stripping, and carbon adsorption.

Discharge of the treated groundwater would be to the LAFB wastewater treatmentplant (WWTP) via a trenched forcemain.

Implementation of this alternative would limit exposure of contaminated groundwaterto existing and future groundwater users outside of the area of landfilled wastes atLF-3. It would provide added protection by preventing the migration of groundwater


8-3

SECTION 8

contaminants from beneath the landfill until the beneficial effects of the cover systemon groundwater quality are realized.

Estimated Time of Operation: 5 to 30 Years

Estimated Capital Cost: $2,257,000

Estimated O&M Costs (net present worth):

Range from $1,761,000 to $3,688,000

Estimated Total Cost (net present worth):

Range from $4,018,000 to $5,945,000


W0039621.080 8741-168-4

SECTION 9

9.0 SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES

Section 121(b)(l) of CERCLA presents several factors that, at a minimum, theUSAF is required to consider in its assessment of alternatives. Building upon thesespecific statutory mandates, the NCP articulates nine evaluation criteria to be usedin assessing the individual remedial alternatives.

9.1 EVALUATION CRITERIA USED FOR DETAILED ANALYSIS

A detailed analysis was performed on the alternatives using the nine evaluationcriteria in order to select an interim site remedy. Section 9.2 contains a summary ofthe comparison of each alternative's strengths and weaknesses with respect to thenine evaluation criteria. These criteria are summarized in Subsections 9.1.1 through9.1.3.

9.1.1 Threshold Criteria

The two threshold criteria described below must be met in order for the alternativesto be eligible for selection in accordance with the NCP.

• Overall protection of human health and the environment addresseswhether or not a remedy provides adequate protection and describeshow risks posed through each pathway are eliminated, reduced, orcontrolled through treatment, engineering controls, or institutionalcontrols.

• Compliance with applicable or relevant and appropriate requirements(ARARs) addresses whether or not a remedy will meet all of theARARs of other Federal and state environmental laws and/or providegrounds for invoking a waiver.

9.1.2 Primary Balancing Criteria

The following five criteria are utilized to compare and evaluate the elements of onealternative to another that meet the threshold criteria.


9-1

SECTION 9

• Long-term effectiveness and permanence addresses the criteria that areutilized to assess alternatives for the long-term effectiveness andpermanence they afford, along with the degree of certainty that theywill prove successful.

• Reduction of toxicity, mobility, or volume through treatment addressesthe degree to which alternatives employ recycling or treatment thatreduces toxicity, mobility, or volume, including how treatment is usedto address the principal threats posed by the site.

• Short-term effectiveness addresses the period of time needed toachieve protection and any adverse impacts on human health and theenvironment that may be posed during the construction andimplementation period, until cleanup goals are achieved.

• Implementability addresses the technical and administrative feasibilityof a remedy, including the availability of materials and services neededto implement a particular option.

• Cost includes estimated capital costs (indirect and direct) and annualO&M costs, as well as present-worth costs.

9.1.3 Modifying Criteria

The modifying criteria are used on the final evaluation of remedial alternativesgenerally after the USAF has received public comment on the RI/FS and ProposedPlan.

• State acceptance addresses the state's position and key concernsrelated to the preferred alternative and other alternatives, and thestate's comments on ARARs and to be considered (TBC) criteria orthe proposed use of waivers.

• Community acceptance addresses the public's general response to thealternatives described in the Proposed Plan and RI/FS report.


W0039621.080 8741-169-2

SECTION 9

9.2 SUMMARY OF COMPARATIVE ANALYSIS

During the detailed analysis of each individual alternative, a comparative analysis wasconducted, focusing on the relative performance of each alternative against the ninecriteria. The complete comparative analysis is presented in Section 7.0 of the OU 4FS (ABB-ES, 1996b). The following subsections present the nine criteria and a briefnarrative summary of the alternatives and their strengths and weaknesses accordingto the detailed and comparative analysis. A tabular assessment of each alternativeaccording to the criteria can be found in Table 9-1.

9.2.1 Overall Protection of Human Health and the Environment

The OU 2 cover system is expected to result in eventual attainment of remediationgoals at both LF-2 and LF-3. An increased level of protection to human health willbe provided in the interim by the Minimal Action alternative through theimplementation of institutional controls. The Groundwater Collection/Treatment/Discharge alternative would further increase protection by preventing migration ofgroundwater contaminants from beneath the landfill until the beneficial effects of thecover system on groundwater quality are realized.

9.2.2 Compliance with Applicable or Relevant and Appropriate Requirements

The No Action alternative would not trigger action- or location-specific ARARs, andthere would be eventual attainment of Maximum Contaminant Levels (MCLs) dueto the effects of the cover system. The Minimal Action alternative will not triggerlocation- or action-specific ARARs. Chemical-specific ARARs will be met by theeventual attainment of MCLs. The Groundwater Collection/Treatment/Dischargealternative would meet all ARARs during construction and operation, assumingmodifications are made to the WWTP discharge permits.

9.2.3 Long-term Effectiveness and Permanence

Because the cover systems currently being constructed at LF-2 and LF-3 are expectedto result in improved groundwater quality, all three alternatives would provide long-term effectiveness. Permanence of the alternatives is dependent upon propermaintenance and effectiveness of the cover system.

installation Restoration ProgramW0039621.080 8741-16

9-3

TABLE 9-1COMPARATIVE SUMMARY OF REMEDIAL ALTERNATIVES

OPERABLE UNIT 4 RECORD OF DECISIONLORING AIR FORCE BASE

ALTERNATIVELF2-1/LF3-1

No Action

LF2-2/LF3-2

MinimalAction

LF3-4

GroundwaterCollection/Treatment/Discharge

OVERALL PROTECTION

OU 2 cover systemexpected to result ineventual attainmentof action levels.Human health maynot be sufficientlyprotected duringinterim.OU 2 cover systemexpected to result ineventual attainmentof action levels.Human healthprotected duringinterim by institutionalcontrols.OU 2 cover systemexpected to result ineventual attainmentof action levels.Human healthprotected duringinterim byground waterextraction andinstitutional controls.

COMPLIANCE WITHARARs

Action- and location-specific ARARs nottriggered. Eventualattainment of MCLs.

Action- and location-specific ARARs nottriggered. Eventualattainment of MCLs.

Meets ARARs duringconstruction.Assuming permitmodification toWWTP, meetsARARs duringoperation.

LONG-TERMEFFECTIVENESS

Assuming propercover systemmaintenance, thisalternative provideslong-termeffectiveness andpermanence.



REDUCTION OF MOBILITY,TOXICITY, AND VOLUME

No reductions throughtreatment, butmobilizing influenceswould be mitigated bycover system.

No reductions throughtreatment, butmobilizing influenceswould be mitigated bycover system.

Contaminatedgroundwater treatedduring treatment facilityoperation. Mobilizationinfluences would bemitigated by coversystem.

SHORT-TERMEFFECTIVENESS

Not effectiveduring short- term.Domestic users ofdowngradientgroundwaterpotentiallyexposed tocontaminants.Effective duringshort term.Domestic users ofdowngradientgroundwaterprotected byinstitutionalcontrols.Effective duringshort term.Domestic users ofdowngradientgroundwaterprotected byinstitutionalcontrols andgroundwaterextraction.

IMPLEMENTABILITY

Easilyimplementable.Activitiesimplementedunder OU 2closure plan.

Easilyimplementable.Institutionalcontrols areassumed to beimplementable onand off LAFBproperty.Groundwaterextraction andtreatmentimplementable.Discharge toWWTP expectedto meet regulatoryapproval.

- Cost ";,:,;.:,

$0

$897,000

Variable costsdepending onlength ofoperation.

5 Years:$4,018,000

10 Years:$4,696,000

20 Years: -$5,524,000

30 Years:$5,945,000

Notes:

(1) Total Present Worth

1-16

SECTION 9

92A Reduction of Mobility, Toxicity, or Volume through Treatment

Since the No Action alternative and the Minimal Action alternative do notincorporate any treatment system, there would be no reduction due to treatment.However, the cover system may reduce infiltration and leachate generation. TheGroundwater Collection/Treatment/Discharge alternative would also use the coversystem to mitigate the mobilizing influences, but would provide further protection byusing groundwater collection and treatment to reduce contaminant concentrations toacceptable levels.

9.2.5 Short-term Effectiveness

The No Action alternative would provide protection only to potential receptorsengaged in activities in the immediate vicinity of the landfills. The Minimal Actionalternative would provide expanded protection with aggressive and widespread useof institutional controls and environmental monitoring, while providing contingencyplans in the event that drinking water supplies are affected by contaminatedgroundwater. The Groundwater Collection/Treatment/Discharge alternative wouldprovide a higher level of short-term protection for potential human receptors byintercepting currently contaminated water that would otherwise continue to affect theaquifer downgradient of LF-3.

9.2.6 Implementability

The No Action alternative does not include remedial actions. Installation ofmonitoring wells and well head treatment systems for Minimal Action involves easilyimplementable technologies. Implementation of institutional controls would requirecoordination with local governments. The technologies available for the constructionof a groundwater extraction and treatment system are more complex and wouldrequire significantly more time to construct.

9.2.7 Cost

The cost criterion includes both the capital costs of implementing an alternative andthe O&M costs. The No Action alternative has no associated costs. The MinimalAction alternative has an estimated cost of $897,000 for each landfill, includinginstallation and monitoring costs. The costs associated with the Groundwater


W0039621.080 8741-16

SECTION 9

Collection/Treatment/Discharge alternative range from $4,018,000 to $5,945,000depending on the length of operation of the treatment system.

9.2.8 State Acceptance

The MEDEP, as a party of the FFA, has provided comments on the FS andProposed Plan, and has documented its concurrence with the remedial action. Asstated in Section 13 of this ROD. A copy of the MEDEP's letter of concurrence ispresented in Appendix C of this ROD.

9.2.9 Community Acceptance

The Proposed Plan presents the preferred alternative for LF-2 and LF-3/CAP,Minimal Action, and the preferred alternative for LF-1 and the CPDA, NFA. FromMay 17, 1996 through June 15, 1996, the USAF held a public comment period toaccept public input. A public meeting was held on June 11, 1996 to discuss theProposed Plan and to accept any oral comments.

Community acceptance of the Proposed Plan was evaluated based on commentsreceived at the public meeting and during the public comment period. This isdocumented in the transcript of the Public Meeting in Appendix A, and in theResponsiveness Summary in Appendix B of this ROD.


W0039621.080 8741-169-6

SECTION 10

10.0 THE SELECTED REMEDY

The selected remedy for groundwater associated with LF-2 and LF-3/CAP isMinimal Action (Alternatives LF-2-2 and LF3-2 of the FS). In addition to the sourcecontrol remedy outlined in the OU 2 ROD (ABB-ES, 1994b), Minimal Action forLF-2 and LF-3/CAP will include institutional controls, downgradient groundwatermonitoring, and a contingency action, if necessary, to protect against human exposureto contaminated groundwater The remedial action is a final remedy for thegroundwater associated with LF-2 and LF-3/CAP.

10.1 ACTION LEVELS

In accordance with USEPA Risk Assessment Guidance for Superfund and the NCP,the USAF has established, with concurrence of the regulatory agencies, site-specificaction levels that will be protective of human health and the environment. Actionlevels have been established for LF-2 bedrock groundwater and LF-3/CAP bedrockand overburden groundwater, based on the Chemical-specific ARARs (i.e., DrinkingWater MCLs and Maximum Contaminant Level Goals (MCLGs) presented inTable 11-1 of this ROD, State MEGs, and Risk Assessment (i.e., IxlGr* excess cancerrisk level and hazard quotient equals one per compound). If a value described byany of the above methods was not capable of being detected with sufficient precisionand value, then the practical quantitation limit or background value was used asappropriate for the groundwater action level. Compounds for which action levelshave been established are listed in Tables 10-1 and 10-2 for LF-2 and LF-3/CAP,respectively.

Cumulative carcinogenic and noncarcinogenic risk posed by ingestion of groundwaterand inhalation of VOCs from domestic water usage has been calculated for thecontaminants of concern using the action level concentrations. Table 10-3summarizes the individual and cumulative carcinogenic and noncarcinogenic risks.


W0039621.080 8741-1610-1

TABLE 10-1LF-2 BEDROCK GROUNDWATER""

ACTION LEVELS


CHEMICAL OF CONCERNBis(2-ethylhexyl)phthalate

Tetrachloroethene

Vinyl Chloride

Cadmium

Iron

Lead

Zinc

MAXIMUMDETECTED

CONCENTRATION

22

4

1.41

32.6

33,000

495

13,000

PRACTICALQUANTITATION

LIMIT111

10

0.5

0.15

2

25

5

25

BACKGROUNDCONCENTRATION13

-

-

-

0.3

8,330

5.7

59.2

MCL(3)

6

5

2

5

300®

151"

5,000W

MEG141

25

3

0.15

5

-

20

-

RISK-BASEDCONCENTRATION""

4.7

0.71

0.019

14

8,400

80

8,400

ACTIONLEVELS'"

10

3

0.15

5

8,400

80

8,400

RATIONALE

PQL

MEG

MEG

MCL

Risk-Based

Risk-Based

Risk-Based

9N> Sources:

(1)(2)(3)(4)(5)

(6)

Notes:

(a)(b)(c)UnitsMEGMCLPQL

PACE, Inc., New England-ME Laboratory, Westbrook, MaineJanuary 1995 data from OU 12 bedrock wells sampled using conventional sampling proceduresDrinking Water Regulations and Health Advisories, U.S. Environmental Protection Agency, Office of Water, May 1995The source of these MEGs is the State of Maine Department of Human Services October 23, 1992 Letter Regarding Revised Maximum Exposure Guidelines.Calculated at a carcinogenic risk level of 10* or an HI of 1. Lead concentrations would not result in exceedance of USEPA Guidance Blood Lead Level of10 micrograms per liter (calculated using Integrated Exposure Uptake Biokinetic Model)Developed by comparison of maximum detected concentration to PQL, background concentration, MCL, MEG, and risk-based concentration.

Includes shallow bedrock (<200 feet bgs) and deep bedrock (>200 feet bgs) groundwaterSecondary Drinking Water Standard, suggested level, not an ARAR.Suggested action level at tap for water systems (SDWA; 40 CFR 141.80), not an MCL or ARAR.micrograms per literMaximum Exposure GuidelineMaximum Contaminant LevelPractical Quantitation LimitNo value

W0039621.T80/1 8741-16

TAB! J-2LF-3 BEDROCK AND OVERBURDEN GROUNDWATER

ACTION LEVELS


CHEMICAL OFCONCERN

BEDROCKVinyl Chloride

IronManganese

Overburden

1 ,4-Dichlorobenzene4-Methylphenol

Benzene

TetrachloroetheneTrichloroethene

Vinyl Chloride

IronManganese

MAXIMUMDETECTED

CONCENTRATION

2.46

22,700

2,780

42

2,000

11

4

66

0.84

23,200

2,460

PRACTICALQUANTtTATION

LIMIT111

0.15

25

5

0.5

10

0.5

0.5

0.5

0.15

25

5

BACKGROUNDCONCENTRATION121

-8,333

94

-

-

-

-

-

-

399

112

MCL131

2

3001"

501"

75

-

5

5

5

2

300W

501*

MEG141

0.15

-

200

27

-

5

3

5

0.15

-

200

RISK-BASEDCONCENTRATION161

0.019

8,400

1,300

1.5

140

1.3

0.71

3.4

0.019

8,400

1,300

ACTIONLEVELS'"

0.15

8,400

1,300

27

140

5

3

5

0.15

8,400

1,300

RATIONALE

MEG

Risk-Based

Risk-Based

MEG

Risk-Based

MCL

MEG

MCL

MEG

Risk-Based

Risk-BasedSources:

(1)(2)

(3)(4)(5)(6)

Notes:

(a)UnitsMEGMCLPQL

PACE, Inc., New England-ME Laboratory, Westbrook, MaineBedrock - January 1995 data from OU 12 bedrock wells sampled using conventional sampling procedures. Overburden - July 1995 data from OU 12 overburden wellssampled using low-flow sampling procedures.Drinking Water Regulations and Health Advisories, U.S. Environmental Protection Agency, Office of Water, May 1995The source of these MEGs is the State of Maine Department of Human Services October 23, 1992 Letter Regarding Revised Maximum Exposure Guidelines.Calculated at a carcinogenic risk level of 10* or an HI of 1.Developed by comparison of maximum detected concentration to PQL, background concentration, MCL, MEG, and risk-based concentration.

Secondary Drinking Water Standard, suggested level, not an ARAR.micrograms per liter (/ug/L)Maximum Exposure GuidelineMaximum Contaminant LevelPractical Quantitation LimitNo value

W0039621.T80/2 8741-16

TABLE 10-3GROUNDWATER ACTION LEVELS AND RISK SUMMARY


LF-2 Bedrock GroundwaterCARCINOGENIC CHEMICALOF CONCERNbis(2-ethylhexyl)phthalateTetracholoretheneVinyl Chloride

SUMMARY CANCER RISK

ACTION LEVELfc/G/U

10

3

0.15

BASIS

PQL

MEG

MEG

LEVEL OF RISK

2.1X10"6

4.2x1 0"6

7.7x1 0"6

1X10*

NONCARCINOGENICCHEMICAL OF CONCERNbis (2-ethyl hexyl) phthalateTetrachloroethene

CadmiumIron

Lead

Zinc

SUMMARY HAZARD INDEX

ACTION LEVELWU10

3

5

8,400

80

8,400

BASIS

PQLMEG

MCLRisk-Based

Risk-Based

Risk-Based

TARGET ENDPOINT OFTOXICITYLiverLiver

BloodLiver

Central Nervous System,BloodRespiratory System3

HAZARDQUOTIENT0.018

0.02

0.36

1.0

1.0

2 :

LF-3 Bedrock GroundwaterCARCINOGENIC CHEMICALOF CONCERNVinyl Chloride

SUMMARY CANCER RISK

ACTION LEVELfc/G/L)0.15

BASIS

MEG

LEVEL OF RISK

7.7x1 0"6

8X10*

NONCARCINOGENICCHEMICAL OF CONCERNIronManganese

Summary Hazard Index

ACTION LEVEL0/G/t)

8,400

1,300

BASIS

Risk-BasedRisk-Based

TARGET ENDPOINT OFTOXICITYLiver

Central Nervous System

HAZARDQUOTIENT1.0

0.99

2 - ' •

W0039621.T80/5

10-4

TABLE 10-3GROUNDWATER ACTION LEVELS AND RISK SUMMARY


LF-3 Overburden Groundwater

CARCINOGENIC CHEMICAL ACTION LEVELOF CONCERN fr/G/L)1 ,4-Dichlorobenzene 27Benzene 5

Tetrachoroethene 3Trichloroethene 5Vinyl Choloride 0.15

SUMMARY CANCER RISK

BASIS

MEG

MCL

MEG

MCL

MEG

LEVEL OF RISK

1.7X10"5

3.9x1 0"6

4.2x1 0"6

1.5X10"6

7.7x1 0"6

3X10*

NONCARCINOGENIC ACTION LEVELCHEMICAL OF CONCERN (pG/L)Benzene 5Tetrachloroethene 3Trichloroethene 5

4-Methylphenol 140

Iron 8,400

Manganese 1 ,300

SUMMARY HAZARD INDEX

Notes:

(a) based on zinc compoundsfjq/L micrograms per literMEG Maximum Exposure GuidelineMCL Maximum Contaminant LevelPQL Practical Quantrtation Limit

BASIS

MCL

MEG

MCL

Risk-Based

Risk-BasedRisk-Based

TARGET ENDPOINT OFTOXICITYBloodLiverLiver, Respiratory System,Heart, Central NervousSystem, KidneysCentral Nervous System,Respiratory SystemLiver

Central Nervous System

HAZARDQUOTIENT1.10.02

0.053

1.0

1.0

0.99

4

10-5W0039621.T80/6

SECTION 10

The action levels are consistent with ARARs criteria for groundwater and attainUSEPA's risk management goal for remedial actions. The determination of theeffectiveness of the remedy cannot be made until residual levels are known. Ifconcentrations above action levels are detected at the compliance point, a riskassessment will be performed on the residual groundwater contamination todetermine whether the remedial action is protective. This assessment andcontingency action are discussed in Subsection 10.2.

10.2 DESCRIPTION OF REMEDIAL COMPONENTS

The following paragraphs describe the remedial alternative developed by the USAFfor groundwater associated with LF-2 and LF-3/CAP: Minimal Action. In additionto the OU 2 low permeability cover systems, 30-year landfill post-closure monitoring,and deed restrictions, implementation of the selected alternative will include thefollowing activities:

• institutional controls;• groundwater monitoring;• five year site reviews; and• contingency action, if necessary.

The components are described in the following paragraphs.

Institutional Controls. The ROD for OU 2 (ABB-ES, 1994b) specifies the use ofproperty deed restrictions on the land in the vicinity of the landfills (i.e., limits of thecover systems) to limit subsurface development (excavation or drilling), use of theproperty, and excessive vehicular traffic (including off-road vehicles and dirt bikes).Consequently, installation of drinking water supply wells within the landfills will notbe possible. The OU 2 deed restrictions are intended to protect human health andthe environment from exposure to landfilled waste and to restrict activities that couldcompromise the integrity of the final cover system.

In addition to the restrictions for OU 2, institutional controls will be established forOU 4 to restrict the use of groundwater. The limits of institutional controls arepresented on Figure 10-1. These limits would restrict groundwater use from theperimeter of the landfills to the adjacent property lines or a minimum of 500 feet


W0039621.080 8741-1610-6

KETCH POND

| LANDHLL 3

LEGEND

COMPLIANCE BOUNDARY

BASE BOUNDARY

INSTITUTIONAL CONTROL BOUNDARY

FIGURE 10-1

COMPLIANCE ANDINSTITUTIONAL

CONTROL BOUNDARIES400 800 1600 FEET

LORING AIR FORCE BASELIMESTONE, MAINESCALE: 1=800'

10-7

SECTION 10

where possible, and would be inclusive of downgradient monitoring wells.Restrictions on property transferred from the USAF and located in the vicinity anddowngradient of the landfills would prohibit installation of drinking water wells andprohibit the use of underlying and downgradient groundwater.

Groundwater Monitoring. Groundwater monitoring at wells located upgradient,within, and immediately downgradient of the landfill, is incorporated into the OU 2ROD for the 30-year post-closure monitoring period. Monitoring wells will be usedfurther downgradient as part of the Minimal Action alternative, to monitorcontaminant levels downgradient of the landfill. These monitoring locations will beat the compliance boundary, shown on Figure 10-1, and will serve as compliancepoints between existing groundwater users and the landfills. One residential well(Hopkins Residence) downgradient of LF-2 on Nebraska Road adjacent to the baseproperty line will also be monitored. If concentrations of contaminants above actionlevels are detected at a compliance point, a contingency action will be implemented.

The downgradient zone beyond the compliance boundary will be covered bygroundwater use restrictions as a minimum requirement to protect human health.OU 2 groundwater monitoring performed in conjunction with OU 4 groundwatermonitoring will be used not only to assess contaminant migration and geochemicalattenuation, but also to measure the performance of the cover systems in reducingleachate generation and associated groundwater contamination.

The Post-Closure Plan for OUs 2 and 4 (ABB-ES, 1996d) proposes monitoring wellsfor OU 2 post-closure monitoring based on knowledge of local hydrogeologicconditions. At LF-2, the USAF has proposed a new upgradient bedrock andoverburden pair of wells southeast of, and adjacent to, the perimeter road; existingdowngradient bedrock wells JMW-0802 (Zone B) and JMW-0801 (Zone B); existingdowngradient overburden wells, JMW-0805 and JMW-0806; a new downgradientoverburden well to be installed next to JMW-0801; and existing overburden wellJMW-0882 located within the LF-2 waste boundaries. At LF-3/CAP, the USAF hasproposed existing upgradient bedrock wells JMW-0941 on the southwest, andJMW-0960 on the northeast; existing upgradient overburden well JMW-0961; a newupgradient overburden well to be installed next to JMW-0941; new overburden andbedrock well pair is proposed for the south downgradient wells; new overburden welland retrofitting bedrock well RFW-39 with a screen are proposed for northdowngradient wells; and overburden well JMW-0980 located within the LF-3 wasteboundaries.


W0039621.080 8741-1610-8

SECTION 10

The USAF proposes to use two bedrock and overburden well pairs furtherdowngradient of LF-2 and LF-3/CAP for OU 4 monitoring to augment the proposedOU 2 groundwater monitoring plan. New bedrock and overburden wells for LF-2will be located approximately 400 feet northwest (downgradient) of LF-2. Thedowngradient well pair for LF-3/CAP, JMW-0991 and JMW-0992, will be locatedapproximately 400 feet southeast (downgradient) of LF-3/CAP.

The monitoring locations selected will be at the compliance boundary and allow forsufficient time to modify the minimal action remedy, should downgradient impactsabove the action levels be identified in the monitoring program. Selected monitoringwell locations as currently proposed are shown on Figure 10-2. The final selectionof monitoring well locations will be presented in the Final Post-Closure Plan for OUs2 and 4.

OU 2 and OU 4 groundwater monitoring will be conducted on the same samplingand reporting schedule. Details on the monitoring program, including samplingfrequency will be presented in the Post-Closure Plan for OUs 2 and 4. The Hopkins(formally Gauvin) well downgradient of LF-2 on Nebraska Road adjacent to the baseproperty line will be sampled and analyzed annually. The analytical program for allwells will use the same analytical methods and quality control levels presented in thePost-Closure Plan for OUs 2 and 4 (ABB-ES, 1996d). Contaminants on Table 10-3will be charted and tracked. Analytical results from downgradient wells will beanalyzed every year using statistical trend analysis to identify statistically significantincreases or decreases over time. Details on the statistical trend test and reportingrequirements can be found in the Post-Closure Plan for OUs 2 and 4 (ABB-ES,1996d).

Contingency Action. Currently there are no exceedances of the action levels at thecompliance boundary. The Post-Closure Plan for OUs 2 and 4, discussed previouslyin Subsection 10.2 of this ROD, will locate monitoring wells for evaluating theeffectiveness of the LF-2 and LF-3 cover system on groundwater migration and fordetermining compliance. The Post-Closure Plan will also describe the manner inwhich the USAF will monitor these wells. The USAF will notify the USEPA andMEDEP immediately if concentrations above the action levels set forth in Tables 10-1 through 10-2 are detected in any compliance wells.

If concentrations above action levels are detected at any of these compliance wells,the USAF will also sample all potable water supplies downgradient of the landfills


10-9

SECTION 10

which might be affected by contamination originating from the landfills. In addition,the USAF will perform a risk assessment on the groundwater for OU 4 to determinewhether the remedial action adopted herein is protective. This risk assessment willcomply with the Loring Air Force Base Risk Assessment Methodology (HAZWRAP,1994).

If, after review of the risk assessment, the remedial action is determined not to beprotective by the USEPA and MEDEP, the remedial project managers (as definedin the FFA) shall decide what contingency action will be necessary. The contingencyaction will include an evaluation by the USAF of the effectiveness of the LF-2 andLF-3 cover systems to prevent groundwater migration, and may include either passiveor active remedial options. Passive components may include, but are not limited to,the hook-up of threatened or affected residences to public water supplies and theimplementation of institutional controls on the affected properties. Activecomponents may include, but are not limited to, plume control measures, theconstruction of a slurry wall, or a groundwater extraction and treatment system. Anyactive component which may be implemented shall be presented in a CERCLAdecision document (e.g., ROD Amendment, Explanation of Significant Differences[ESD], or a new ROD) pursuant to applicable USEPA guidance. If a future activecontingency measure is determined to be appropriate, groundwater ARARs will beevaluated and designated at the time of the new CERCLA decision document.

The USEPA, MEDEP, or the Air Force have the authority to implement the DisputeResolution process for any action conducted within the scope of the InstallationRestoration Program, pursuant to Section 14.2(2) of the Loring Federal FacilitiesAgreement (as amended).

Five-year Site Reviews. Results of groundwater monitoring for LF-2 and LF-3/CAPwill be included in an Annual Report to be submitted to the MEDEP as specifiedby the Post-Closure Plan for OUs 2 and 4 (ABB-ES, 1996d). In addition to theAnnual Report, the USAF will review the LF-2 and LF-3/CAP monitoring programat least once every five years in accordance with applicable USEPA guidance. Thefive-year site reviews are intended to evaluate whether the response action continuesto protect human health and the environment, assess site conditions, and proposefurther actions, if necessary.


W0039621.080 8741-1610-10

Ik10 400 800____1600 FEET

S—^™SCALE: 1"=800'

KETCH POND

LANDRLL 3

RGURE10-2$

EGEND

COMPLIANCE BOUNDARYBASE BOUNDARYINSTITUTIONAL CONTROL BOUNDARYINTERPRETED GROUNDWATERCONTOUROVERBURDEN MONITORING WELL LOCATIONBEDROCK MONITORINGWELL LOCATION

| LF3MW4| •£ NEW MONITORING WELL LOCATION

INTERPRETED DIRECTION OFGROUNDWATER MOVEMENTINTERPRETED GROUNDWATERDIVIDE

INTERPRETED WATER TABLECONTOURS AND GROUNDWATER

MONITORING WELLS

LORING AIR FORCE BASELIMESTONE, MAINE

10-11

SECTION 11

11.0 STATUTORY DETERMINATIONS

The remedial action selected for implementation at the OU 4 locations, LF-2 andLF-3/CAP, is consistent with CERCLA and, to the extent practicable, the NCP.Implementation of this remedy is intended to be in conjunction with the LF-2 andLF-3 cover systems constructed under OU 2. The selected remedy is protective ofhuman health and the environment, attains ARARs, and is cost- effective. Theremedy, applied in combination with the cover systems, uses permanent solutions tothe maximum extent practicable. The selected remedy does not satisfy the statutorypreference for remedies that employ treatment that reduces toxicity, mobility, orvolume as a principal element. However, the selected remedy, in combination withthe landfill cover systems, will most likely reduce toxicity through isolation of thewaste material from infiltrating rainwater, and reduce mobility of contaminantsthrough the containment features of the cover systems.

ll.l THE SELECTED REMEDY is PROTECTIVE OF HUMAN HEALTH AND THEENVIRONMENT

The selected remedy, in conjunction with the landfill cover systems, will meet theresponse objectives of preventing human exposure to contaminated groundwater andprotecting downgradient groundwater from contamination. Landfill capping willprevent a large volume of the pre-cap wastes above the water table from furtherleaching and cause a large reduction in the generation of leachate. Groundwatertable conditions under the landfills are not anticipated to change to any great extent,due to exclusion of recharge areas from capping. Therefore, the net effect of cappingwill be a reduction in groundwater contamination beneath and downgradient of LF-2and LF-3/CAP. Placement of the cover systems is expected to lead to the eventualattainment of remediation goals at LF-2 and LF-3, through the reduction ofgroundwater/waste interaction.

Elimination of human exposure to groundwater within and immediately downgradientof the landfills is incorporated in OU 2, and will be augmented in the selectedremedy by the use of additional institutional controls, enhanced groundwatermonitoring, and contingency actions, if necessary.


W0039621.080 8741-1611-1

SECTION 11

11.2 THE SELECTED REMEDY ATTAINS ARARs

The selected remedy will attain ARARs. The ARARs for this remedy and themanner in which they will be met are summarized in Table 11-1.

11.3 THE SELECTED REMEDIAL ACTION is COST-EFFECTIVE

In the USAF's judgment, the selected remedy is cost-effective (i.e., the remedyaffords overall effectiveness proportional to its costs). In selecting this remedy, oncethe USAF identified alternatives that were protective of human health and theenvironment and that attain ARARs, the USAF evaluated the overall effectivenessof each alternative by assessing the relevant three criteria - long term effectivenessand permanence; reduction in toxicity, mobility, or volume through treatment; andshort-term effectiveness - in combination. The relationship of the overalleffectiveness of this remedial alternative was determined to be proportional to itscosts. The costs of this remedial alternative for each landfill are:

Estimated Capital Cost: $87,000Estimated O&M Costs (net present worth): $810,000Estimated Total Cost (net present worth): $897,000

The selection of this alternative represents a reasonable value with regard to theother alternatives. Compared to the other alternative that provides overall protectionto human health and the environment and complies with ARARs, the selectedremedy is much less expensive. All costs of the landfill cover systems are incurredunder OU 2.


W0039621.080 8741-1611-2

m

TABLE 11-1CHEMICAL-SPECIFIC ARARs, CRITERIA, ADVISORIES, AND GUIDANCE

MINIMAL ACTION ALTERNATIVE


MEDIA REQUIREMENT STATUS REQUIREMENT SYNOPSISACTION TO BE TAKENTO ATTAIN ARAR

GROUNDWATER

Federal Safe Drinking WaterAct (SDWA) -MaximumContaminant Levels(MCLs) (40 CFR141.11 - 141.16)

SDWA - MaximumContaminant LevelGoals (MCLGs) (40CFR 141.50 -141.51)

Relevant and MCLs have been promulgated for severalAppropriate common organic and inorganic

contaminants. These levels regulate theconcentration of contaminants in publicdrinking water supplies, but may also beconsidered relevant and appropriate forgroundwater aquifers used for drinkingwater.

Relevant and MCLGs are health-based criteria to beAppropriate considered for drinking water sources.

MCLGs are available for several organicand inorganic contaminants. Non-zeroMCLGs are to be used as goals whenMCLs have not been established.

Use of the minimal actionremedy will result in attainmentof MCLs in the groundwater atthe compliance boundary.

Use of the minimal actionremedy will result in attainmentof non-zero MCLGs in thegroundwater at the complianceboundary.

Notes:

ARAR = Applicable or Relevant and Appropriate RequirementCFR = Code of Federal RegulationsMCL = Maximum Contaminant LevelMCLG = Maximum Contaminant Level GoalNCR = National Contingency PlanOU = Operable UnitSDWA = Safe Drinking Water Act

W0039621 .T80/5 8741-16

SECTION 11

11.4 THE SELECTED REMEDY UTILIZES PERMANENT SOLUTIONS AND ALTERNATIVETREATMENT OR RESOURCE RECOVERY TECHNOLOGIES TO THE MAXIMUMEXTENT PRACTICABLE

Once the USAF identified those alternatives that attain or, as appropriate, waiveARARs, and that are protective of human health and the environment, the USAFidentified that alternative which utilizes permanent solutions and alternativetreatment technologies or resource recovery technologies to the maximum extentpracticable. This determination was made by identifying the alternative that providesthe best balance of trade-offs among alternatives, in terms of: 1) long-termeffectiveness and permanence; 2) reduction of toxicity, mobility, or volume throughtreatment; 3) short-term effectiveness; 4) implementability; and 5) cost. Thebalancing test emphasized long-term effectiveness and permanence and the reductionof toxicity, mobility or volume through treatment; and considered the preference fortreatment as a principal element, the bias against off-site land disposal of untreatedwaste, and community and state acceptance.

The selected remedy, when implemented in conjunction with the OU 2 landfill coversystems, provides the best balance of trade-offs among the alternatives. The selectedremedy provides long-term protection of human health and the environment becauseonce cover construction is complete, future migration of contaminants will bereduced. Landfill capping will exclude a large volume of the pre-cap wastes abovethe water table from further leaching, having the potential to cause a large reductionin the generation rate of leachate. The net effect will be a reduction in groundwatercontamination beneath and downgradient of LF-2 and LF-3. Placement of the coversystems is expected to lead to the eventual attainment of action levels at LF-2 andLF-3 due to the reduction of groundwater/waste interaction.

The selected remedy will not reduce mobility, toxicity, or volume through treatmentof source area contaminants. However, the selected remedy, in combination with thelandfill cover systems, will most likely reduce toxicity through isolation of the wastematerial from infiltrating rainwater, and reduce mobility of contaminants through thecontainment features of the cover systems. Placement of the cover systems isexpected to lead to the eventual attainment of action levels at LF-2 and LF-3/CAP,due to the reduction of groundwater/waste interaction.

The selected remedy provides expanded protection with use of institutional controlsand environmental monitoring. Adverse effects on workers are not anticipated,


W0039621.080 8741-1611-4

SECTION 11

provided safe working practices are followed. Adverse effects on the community arenot expected as a result of implementing the selected remedy.

Installation of the selected remedy involves easily implementable, reliable, andavailable technologies.

The selected remedy is cost-effective in that it provides a reasonable value withregard to the other alternatives. It provides overall protection to human health andthe environment, complies with ARARs, meets the response objectives, and is theleast expensive.

11.5 THE SELECTED REMEDY DOES NOT SATISFY THE PREFERENCE FORTREATMENT WHICH PERMANENTLY AND SIGNIFICANTLY REDUCES THETOXICITY, MOBILITY OR VOLUME OF THE HAZARDOUS SUBSTANCES AS APRINCIPAL ELEMENT

The selected remedy will not reduce mobility, toxicity, or volume through treatmentof source area contaminants as a principal element. However, the selected remedy,in combination with the landfill cover systems, will most Likely reduce toxicity throughisolation of the waste material from infiltrating rainwater, and reduce mobility ofcontaminants through the containment features of the cover systems. Placement ofthe cover systems is expected to lead to the eventual attainment of action levels atLF-2 and LF-3/CAP through the reduction of groundwater/waste interaction.


W0039621.080 8741-1611-5

SECTION 12

12.0 DOCUMENTATION OF NO SIGNIFICANT CHANGES

The USAF presented a Proposed Plan (ABB-ES, 1996c) outlining the proposedalternative of Minimal Action for groundwater associated with LF-2 and LF-3/CAP,and NFA for groundwater associated with LF-1, the CAP, and the CPDA. TheProposed Plan was presented to the public, and public comments have beenconsidered prior to the selection of the preferred alternative.

No significant changes have been made to the preferred alternative described in theProposed Plan.


W0039621.080 8741-1612-1

SECTION 13

13.0 STATE ROLE

The MEDEP, as a party of the FFA, has reviewed the various alternatives. TheMEDEP has also reviewed the Remedial Investigation, Risk Assessment andFeasibility Study to determine if the selected remedy is in compliance with applicableor relevant and appropriate state environmental laws and regulations.

The MEDEP concurs with the selected remedy for OU 4. A copy of the letter ofconcurrence is presented in Appendix C of this ROD.


13-1


ABB-ESACCAFCEEARAR

BEHPbgs

CADACAPCERCLA

CFRCOCCPCCPDACRP

DCADCEDBADHS

ESD

FFAFS

gpm

HAZWRAPHI

IEUBKIRP

LAFBLaw

ABB Environmental Services, Inc.Air Combat CommandAir Force Center for Environmental ExcellenceApplicable or Relevant and Appropriate Requirement

bis(2-ethylhexyl)phthalatebelow ground, surf ace

Coal Ash Disposal AreaCoal Ash PileComprehensive Environmental Response, Compensation, andLiability ActCode of Federal Regulationschemical of concernchemical of potential concernChapman Pit Disposal AreaCommunity Relations Plan

dichloroethanedichloroetheneDrum Disposal AreaDepartment of Human Services

Explanation of Significant Differences

Federal Facilities AgreementFeasibility Study

gallons per minute

Hazardous Waste Remedial Actions ProgramHazard Index

Integrated Exposure Uptake BiokineticInstallation Restoration Program

Loring Air Force BaseLaw Environmental, Inc.


W0039621.080 8741-16


LF LandfillLFS low-flow sampling

MCL Maximum Contaminant LevelMCLG Maximum Contaminant Level GoalMEDEP Maine Department of Environmental ProtectionMEG Maximum Exposure Guidelinemg/L milligrams per liter

NCP National Contingency PlanNFA No Further ActionNPL National Priorities List

O&M operation and maintenanceOU operable unit

PA Preliminary AssessmentPAH polynuclear aromatic hydrocarbonsPCB polychlorinated biphenylPCDA Paint Can Disposal AreaPCE tetrachloroethenePQL Practical Quantitation Limit

RA risk assessmentRAB Restoration Advisory BoardRCRA Resource Conservation and Recovery ActRI remedial investigationRME reasonable maximum exposureROD Record of Decision

SAC Strategic Air CommandSARA Superfund Amendments and Reauthorization ActSDWA Safe Drinking Water ActSI site investigationSVOC semivolatile organic compound

TBC to be consideredTCE trichloroethene

W0039621.080


8741-16


TPH

USAFUSEPA/xg/Dl

VOC

WWTP

total petroleum hydrocarbon

U.S. Air ForceU.S. Environmental Protection Agencymicrograms per decilitermicrograms per liter

volatile organic compound

Waste Water Treatment Plant

W0039621.080


8741-16

REFERENCES

ABB Environmental Services, Inc. (ABB-ES), 1994a. OU 2 Remedial Investigation/Focused Feasibility Study; Final; Installation Restoration Program; Loring AirForce Base; prepared for HAZWRAP; Portland, Maine; August 1993, revisedJuly 1994.

ABB Environmental Services, Inc. (ABB-ES), 1994b. OU 2 Record of Decision; FinalInstallation Restoration Program; Loring Air Force Base; prepared forHAZWRAP; Portland, Maine; November 1994.

ABB Environmental Services, Inc. (ABB-ES), 1995. OU 4 Remedial InvestigationReport; Final; Installation Restoration Program; Loring Air Force Base;prepared for HAZWRAP; Portland, Maine; November 1995.

ABB Environmental Services, Inc. (ABB-ES), 1996a. Operable Unit 2A (OU 2A)Record of Decision; Final; Installation Restoration program; Loring Air ForceBase; prepared for HAZWRAP; Portland, Maine; March 1996.

ABB Environmental Services, Inc. (ABB-ES), 1996b. OU 4 Feasibility Study; Final;Installation Restoration Program; Loring Air Force Base; prepared forHAZWRAP; Portland, Maine; May 1996.

ABB Environmental Services, Inc. (ABB-ES), 1996c. Proposed Plan, No FurtherCERCLA Action and Minimal Action for Operable Unit 4; InstallationRestoration Program; Loring Air Force Base; prepared for HAZWRAP;Portland, Maine; May 1996.

ABB Environmental Services, Inc. (ABB-ES), 1996d. Post-Closure Plan for OUs 2and 4; Draft Final; Installation Restoration Program; Loring Air Force Base;prepared for HAZWRAP; Portland, Maine; May 1996.

Advanced Sciences, Inc. (ASI), 1994. Draft Final RI Report for OU 24, Loring AirForce Base; prepared for HAZWRAP; Oak Ridge, Tennessee; December1994.

Air Force Center for Environmental Excellence (AFCEE), 1995. Remedial ActionReport/Project Closure Report, OU 2, OU 2A, OU 6, OU 7, and Other Sites;Loring Air Force Base; January 1995.


W0039621.080 8741-16

REFERENCES

CH2M Hill, 1984. Records Search Report; Installation Restoration Program; LoringAir Force Base; prepared for HAZWRAP; Limestone, Maine; January 1984.

Federal Facility Agreement (FFA) Under CERCLA Section 120, The Matter ofLoring Air Force Base by U.S. Environmental Protection Agency Region I,State of Maine, and the U.S. Department of the Air Force, January 30, 1991.

Hazardous Waste Remedial Actions Program (HAZWRAP), 1994. Loring Air ForceBase Risk Assessment Methodology; Final; Environmental Restoration andWaste Management Programs, Oak Ridge, TN; August, 1994.

Law Environmental, Inc. (Law), 1996. Final RI/ASI Technical Report for DebrisDisposal Areas - Operable Unit 3; Loring Air Force Base; March, 1996.

Loring Air Force Base (LAFB), 1995. "Consensus Statement: InorganicContaminants in Overburden Groundwater"; prepared for Loring Air ForceBase, the U.S. Environmental Protection Agency, Region I, and the MaineDepartment of Environmental Protection; August 1995.

Patterson, James W., 1985. Industrial Wastewater Treatment Technology:Butterworth Publishers; Stoneham, Massachusetts.

Maine Department of Environmental Protection and Department of Human Services(MEDEP/DHS), 1994. Guidance Manual for Human Health Risk Assessmentsat Hazardous Substance Sites; June 1994.

RKG Associates, 1995. "Executive Summary - Loring Redevelopment Plan;Financial, Marketing and Implementation Strategy"; Prepared for LoringDevelopment Authority of Maine; Durham, New Hampshire; March 1995.

Tseng, W. P., Chu, H. M., How, S. W., Fong, J. M., Lin, C. S., and Yen, S., 1968."Prevalence of Skin Cancer in an Endemic Area of Chronic Arsenicism inTaiwan"; J. Natl. Cancer Inst. 40: 453-463.


W0039621.080 8741-16

REFERENCES

U.S. Environmental Protection Agency (USEPA), 1982. "Letter from Robert M.Perry, Associate Administrator, Office of General Counsel to Rita Lavelle,Assistant Administrator for Office of Solid Waste and Emergency Response";September 1, 1982.

U.S. Environmental Protection Agency (USEPA), 1988a. Guidance for ConductingRemedial Investigations and Feasibility Studies Under CERCLA; Office of SolidWaste and Emergency Response; OSWER Directive 9335.01; Washington,DC; March 1988.

U.S. Environmental Protection Agency (USEPA), 1989a. Risk Assessment Guidancefor Superjund: Human Health Evaluation Manual (Part A); Volume 1; InterimFinal; USEPA 540/1-89/002; Washington, DC; December 1989.

U.S. Environmental Protection Agency (USEPA), 1989b. Exposure FactorsHandbook; Exposure Assessment Group; Office of Health and EnvironmentalAssessment; USEPA/600/8-89/043.

U.S. Environmental Protection Agency (USEPA), 1989c. Ecological Assessment ofHazardous Waste Sites: A Field and Laboratory Reference; EnvironmentalResearch Laboratory; U.S. Environmental Protection Agency; Corvallis,Oregon; EPA 600/3-89/013.

U.S. Environmental Protection Agency (USEPA), 1989d. Supplemental RiskAssessment Guidance for Superjund Program; USEPA Region I RiskAssessment Work Group; USEPA 901/5-89-001.

U.S. Environmental Protection Agency (USEPA), 1990a. National Oil andHazardous Substances Pollution Contingency Plan (National ContingencyPlan); Code of Federal Regulations, Title 40, Part 300; Federal Register,Volume 55, Number 46, pp. 8666 et seq.; March 8, 1990.

U.S. Environmental Protection Agency (USEPA), 199 la. Risk Assessment Guidancefor Superjund. Volume I: Human Health Evaluation Manual, Part A,Supplemental Guidance, "Standard Default Exposure Factors," Interim Final;Office of Solid Waste and Emergency Response 9285.6-03; March 25, 1991.


W0039621.080 8741-16

REFERENCES

U.S. Environmental Protection Agency (USEPA), 199Ib. Loring RI Report/RiskAssessment Approach Meeting between representatives of EPA Region I,Maine Department of Environmental Protection, U.S. Fish and WildlifeService, Loring AFB, HAZWRAP, ABB Environmental Services;December 6, 1991.

U.S. Environmental Protection Agency (USEPA), 1995b. Health Effects AssessmentSummary Tables (HEAST), Annual FY 1995, EPA 540/R-95/O36.PB95-921199. USEPA, Office of Solid Waste and Emergency Response. May,1995.


W0039621.080 8741-16

APPENDIX A

TRANSCRIPT OF THE PUBLIC MEETING (JUNE 11,1996)


W0039621.080 8741-16A-l

STATE OF MAINE AROOSTOOK, ss

OPERABLE UNITS 4, 9 & 11

PUBLIC HEARING

JUNE 11, 1996

CARIBOU CITY COUNCIL CHAMBER

CARIBOU, MAINE

7:26 P.M.

BENNETT LEGAL TRANSCRIPT SERVICESP. 0. Box 947

Caribou, ME 04736-0947(207)498-2729

T A B L E O F C - - O N T E N T S

1 PETER FORBES

2

3

4 E X H I B I T S

5 NONE

6

7

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

1

2

3 June 11, 1996

4

5 PETER FORBES: Good

6 evening. -Welcome to the public hearing to receive

7 comments on the proposed plans for Operable Units

g 4 and 9 and 11 at Loring Air Force Base. Today's

g date is June llth, 1996. My name is Peter

10 Forbes, the Remedial Project Manager for the

n Installation Restoration Program at Loring.

12 Seated with me are Michael Nalipinski, Remedial

13 Project Manager for the U.S. Environmental

14 Protection Agency, and Naji Akladiss, Remedial

15 Project Manager for the Maine Department of

16 Environmental Protection, and they will assist me

17 in receiving your comments.

is This hearing is being held in accordance with

19 the provisions of the Comprehensive Environmental

20 Response Compensation and Liability Act or CERCLA

21 as amended in 1986, also known as Superfund. The

22 ; act requires federal facilities on the National

23 Priorities List to present clean up proposals to

24 the local community for comment and consideration

25 before the final clean up decisions are made. The

4

1 purpose of this hearing is to receive comments on

2 the Proposed Plans for Operable Units 4 and 9 and

3 11.

4 Mr. Philip Bennett from Aroostook Legal

5 Reporters will serve as the court reporter

6 tonight, preparing a verbatim record of the

7 proceedings. The verbatim record will become a

8 part of the final clean up plan. The court

g reporter will be able to make a complete record

10 only if he is able to hear and understand what you

n say. With that in mind, please follow these

12 ground rules. Speak only after I recognize you

13 and please address your remarks to me. State your

14 name and the organization you represent and

15 present your statement. Do not begin speaking

16 until you have reached the microphone and speak

i? slowly and clearly into the microphone. If you

18 have prepared your statement beforehand, you may

19 read it aloud or you may paraphrase it and place

20 it on the table.

21 Are there individuals wishing to make a

22 comment or statement at this time?

23 Ladies and gentlemen, it is 7:30 p.m., June

24 11, 1996 and I declare the public hearing to

25 receive comments on the Proposed Plans for

5

Operable Units 4 and 9 and 11 at Loring Air Force

2 Base closed. Thank you all for coming.

3

4

6

7

8 ' C E R T I F I C A T I O N

9

10

n I HEREBY CERTIFY THAT the foregoing is a true and

12 correct transcript of my stenographic notes taken

13 at the Operable Units 4 & 9, 11 Public Hearing

14 held on June 11, 1996.

15

16

17

18P19 Philip R. Bennett, Jr.,

20 Court Reporter

21

22

23

24

25 STATE OF MAINE AROOSTOOK, ss.

APPENDIX B

RESPONSIVENESS SUMMARY


W0039621.080 8741-16B-l

APPENDIX BOU 4 RESPONSrVENESS SUMMARY

The Air Force held a 30-day comment period from May 17, 1996 to June 15, 1996,to provide an opportunity for the public to comment on the Proposed Plan and otherdocuments developed for Operable Unit (OU 4) at Loring Air Force Base, Maine.The Proposed Plan is the document that identifies remedial action objectives,evaluates remedial alternatives, and recommends the alternative that best meets theevaluation criteria for OU 4..

The Air Force made a recommendation of its preferred alternative for No FurtherAction for Landfill (LF) 1 and Chapman Pit Disposal Area, and Minimal Action forgroundwater associated with LF-2 and LF-3/Coal Ash Pile (CAP) in the OU 4Proposed Plan. The Proposed Plan was issued on May 17, 1996, before the start ofthe comment period. All documents on which the preferred alternative is based wereplaced in the Administrative Record for review. The Administrative Record is acollection of the documents considered by the Air Force when choosing the remedialaction for OU 4 groundwater.

The Air Force received no verbal or written comments on the OU 4 Proposed Planat a public hearing held on June 11, 1996, or during the 30 day public commentperiod.

The Air Force will select the Minimal Action alternative for groundwater associatedwith LF-2 and LF-3/CAP, which includes institutional controls, groundwatermonitoring, five-year site reviews, and contingency action if necessary. Institutionalcontrols will be established to restrict groundwater use, and groundwater monitoringwill be integrated with OU 2 into a comprehensive monitoring program. Five-yearsite reviews will be conducted to ensure that the remedial action continues to beprotective of human health and the environment. If landfill-related contaminants aredetected at the compliance point at concentrations above the action levels, acontingency action will be implemented. The contingency action is discussed inSubsection 10.2 of the OU 4 ROD.


W0039621.080 8741-16B-l

APPENDIX C

LETTER OF CONCURRENCE


W0039621.080 8741-16C-l

STATE OF MAINE

DEPARTMENT OF ENVIRONMENTAL PROTECTIONANGUS S. KING, JR. EDWARD O. SULLIVANGOVERNOR COMMISSIONER

September 25, 1996

Mr. Alan K. OlsenAFBCA/DR1700 N. Moore Street, Suite 2300Arlington, VA 22209-2802

Re: Loring Air Force Base Superfund Site, Maine

Dear Mr. Olsen:

The Maine Department of Environmental Protection (MEDEP) has reviewed the DraftFinal Record of Decision (ROD) regarding Operable Unit 4 (OU4) for the Loring Air Force baseSuperfund Site located in Limestone, Maine.

Based on the Draft Final ROD, the MEDEP concurs with the Air Force's recommendations, inSection 10.0 which is summarized as follows:

The selected remedy for groundwater associated with LF-2 and LF-3/CAP is Minimal<* Action (Alternatives LF-2-2 and LF3-2 of the FS). In addition to the source control

remedy outlined in the OU2 ROD (ABB-ES, 1994b), Minimal Action for LF-2 and LF-3/CAP will include institutional controls, downgradient groundwater monitoring, and acontingency plan for providing additional remedial measures. The Minimal Action is afinal remedy for the groundwater associated with LF-2 and LF-3/CAP.

Clean Up Levels

The USAF has established, in conjunction with the regulatory agencies, site-specificaction levels protective of human health and the environment. These action levels havebeen established for LF-2 bedrock groundwater and LF-3/CAP bedrock and overburdengroundwater, based on background concentration, analytical detection limits, MCL's,MEG's or risk calculations. Tables 10-1 and 10-2 in the Final ROD, list the compoundsand elements for which action levels have been set, as well as summaries of riskassociated with the sites included in this operable unit. The State concurs with the actionlevels listed in the tables above.

The State's concurrence with the selected remedy, as described above, should not beconstrued as the State's concurrence with any conclusion of law or finding of fact whichmay be set forth in the Record of Decision (for OU4). The State reserves any and allrights to challenge any such finding of fact or conclusion of law in any other context.

* Serving Maine People & Protecting Their EnvironmentAUGUSTA PORTLAND BANGOR PRESQUE ISLE17 STATE HOUSE STATION 312 CANCO ROAD 106 HOGAN ROAD 1235 CENTRAL DRIVE, SKYWAY PARKAUGUSTA, MAINE 04333-0017 PORTLAND, ME 04103 BANGOR, ME 04401 PHESQUE ISLE, ME 04769(207) 287-7688 FAX: (207) 287-7826 (207) 822-6300 FAX: (207) 822-6303 (207) 941-4570 FAX: (207) 941-4584 (207) 764-0477 FAX: (207) 764-1507OFFICE LOCATED AT: RAY BUILDING, HOSPITAL STREET

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- 2 -

This concurrence is based upon the State's understanding that the MEDEP will continueto participate in the Federal Facilities Agreement and in the review and approval ofoperation, design and monitoring plans. This concurrence is also based upon theunderstandings set forth in the attached Letter of Understanding dated September1996.

The MEDEP looks forward to working with the Department of the Air Force and theUSEPA to resolve the environmental problems posed by this site. If you need additionalinformation, do not hesitate to contact myself or Mark Hyland.

Sincerely,

/^Edward O. Sullivan[ Department of Environmental Protection

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subj: loring air force base - record -q-f decision v ,. .. . … of decisions summary - sept....

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