ACAT FOIA Repository 27

US Army Corpsof EngineersDecision DocumentGAMBELL FORMERLY USED DEFENSE SITEF10AK0696St. Lawrence Island, AlaskaJune 2005Prepared by:U.S. Army Corps of EngineersAlaska DistrictP.O. Box 6898Elmendorf AFB, AK 99506-6898F10AK069601_05.09_0500_a200-1eF10AK069601_05.09_0001_aF10AK069603_05.09_0500_aF10AK069603_05.09_0001_a200-1eDecision DocumentGambell SiteSt. Lawrence Island, Alaska[Page Intentionally Blank]Declaration StatementforDecision DocumentGambell Site F10AK0696St. Lawrence Island, AlaskaSite Name and LocationThe Gambell Formerly Used Defense Site (FUDS), project numbers F10AK069601 andF10AK069603, is located on St. Lawrence Island in the western portion of the Bering Sea,approximately 200 air miles southwest of Nome, Alaska. The Alaska Department ofEnvironmental Conservation (ADEC) contaminated sites record key (reckey) number for theoverall Gambell site is 198532X917919, individual areas of concern are also tracked withseparate reckeys (198532X917920-32 and 198532X117901-13). One area of concern, Site 5Tramway (reckey #198532X917923) will be addressed under a future decision document. TheEnvironmental Protection Agency (EPA) identification number is AKD981765894. TheGambell site is not listed on the National Priorities List (NPL).Statement of Basis and PurposeThis decision document presents the selected remedy for the Gambell site on St. LawrenceIsland, Alaska, which was chosen in accordance with the Comprehensive EnvironmentalResponse, Compensation, and Liability Act (CERCLA) of 1980, as amended by the SuperfundAmendments and Reauthorization Act (SARA) of 1986, 42 United States Code §9601 et seq.,and to the extent practicable, the National Oil and Hazardous Substances Pollution ContingencyPlan (NCP), 40 Code of Federal Regulations Part 300 et seq. The State of Alaska, through theDepartment of Environmental Conservation (ADEC) concurs with the selected remedy.This decision is based on the results of a phased remedial investigation and subsequent removalaction activities which were conducted from 1994 to 2003. The accompanying decisiondocument summarizes these activities. Detailed information supporting the selected remedialaction is also contained in the Administrative Record for this site, located at the U.S. ArmyCorps of Engineers (USACE) Alaska District Office on Elmendorf Air Force Base, AK, and theInformation Repositories located at the Alaska Resource Library and Information Services(ARLIS) in Anchorage, the Sivuqaq Lodge in Gambell, the Savoonga IRA Building inSavoonga, and the University of Alaska Fairbanks Northwest Campus Library in Nome.Assessment of SiteThe Gambell site was used by the military from 1948 until the late 1950’s. Various facilitieswere constructed near the village of Gambell to provide housing and operations, aircraft radar,communications, and other functions. Two discrete areas of contaminated soil are present atSites 7 and 12. The identified contaminants of concern (COCs) are arsenic, chromium and lead.The response action selected in this Decision Document is necessary to protect the public healthor welfare or the environment from actual or threatened releases of hazardous substances,pollutants or contaminants, which may present an imminent and substantial endangerment. Theresponse action will also address the physical hazards posed by one area containing inherentlyhazardous military debris, which poses a clear danger, likely to cause death or serious injury toPage 3 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskapersons exercising ordinary and reasonable care. These unsafe conditions include exposed metalMarston matting debris adjacent to the local airstrip at Site 8A.The Marston matting was abandoned in place when the military demobilized from the area in thelate 1950s. The exposed Marston matting debris is located in an area heavily traveled by localresidents using all terrain vehicles and snowmobiles. The debris poses a clear danger to localresidents due to the sharp and jagged edges which protrude above the ground surface and largepiles which create a navigation hazard during the winter when partially covered by snow.Description of Selected RemedyThe selected remedy was chosen from many alternatives as the best method of addressing thearsenic contaminated soil at Site 7 and the lead and chromium-contaminated soil at Site 12. Itaddresses the risks to health and the environment caused by the current or future exposure of aresident to contaminated soils. The selected remedy addresses this risk by reducing soilcontamination to below risk-based cleanup levels established for these sites. The selectedremedy at Site 7 is excavation and off-Island disposal of an estimated 4 tons of soil containinggreater than the cleanup level of 11 mg/kg arsenic. The selected remedy at Site 12 is excavationand off-Island disposal of an estimated 4 tons of soil containing greater than the cleanup levels of400 mg/kg lead and 26 mg/kg chromium. Inherently hazardous debris will also be removed fromSite 8A. The specific components of the selected remedy consist of the following:Approximately 4 tons of soil at Site 7 with arsenic concentrations in excess of 11 ppm will beexcavated and shipped off-Island to a permitted disposal facility;Approximately 4 tons of soil at Site 12 with lead concentrations in excess of 400 ppm andchromium concentrations greater than 26 mg/kg will be excavated and shipped off-Island to apermitted disposal facility;Confirmation soil sampling will be conducted to ensure cleanup goals are met;Approximately 50 tons of exposed metallic debris (i.e., Marston matting) at Site 8A will begathered and shipped off-Island to a permitted disposal or recycling facility;Sites 1A, 1B, 1C, 2, 3, 4A, 4B, 4C, 4D, 4E, 6, 8B, 8C, 8D, 9, 10, 11, 13, 14, 15, 16, 17, 18,19, 20, 21, 22, 23, 24, 25A, 25B, 26, 27, and 28 were investigated and previous responseactions removed debris and/or contaminated soils. Under the FUDS Program, no furtheraction is planned.Statutory DeterminationsThe selected remedy is protective of human health and the environment, complies with federaland state requirements that are legally applicable or relevant and appropriate to remedial actions,and is cost-effective. This remedy utilizes permanent solutions and alternative treatmenttechnologies to the maximum extent practicable. However, because treatment of thecontaminants at the site was not found to be practicable, alternative treatment technologies werenot selected. Because the selected remedy will not result in hazardous substances, pollutants, orcontaminants remaining on-site above levels that allow for unlimited use and unrestrictedexposure, a five-year review will not be required.In accordance with CERCLA and the Defense Environmental Restoration Program for FormerlyUsed Defense Sites (DERP-FUDS), the U.S. Army Corps of Engineers, Alaska District, hasPage 4 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaTABLE OF CONTENTSDeclaration Statement..................................................................................................................... 3Site Name and Location.............................................................................................................. 3Statement of Basis and Purpose.................................................................................................. 3Assessment of Site ...................................................................................................................... 3Description of Selected Remedy................................................................................................. 4Statutory Determinations ............................................................................................................ 4Authorizing Signatures ............................................................................................................... 5Glossary of Terms and Acronyms .................................................................................................. 81. Decision Summary................................................................................................................ 101.1Site Name, Location, and Brief Description................................................................. 101.2Site History ................................................................................................................... 131.3Community Participation .............................................................................................. 151.4Scope and Role of Response Action............................................................................. 171.5Site Characteristics........................................................................................................ 181.5.1Geographical and topographic information .......................................................... 181.5.2Hydrology and Groundwater Use ......................................................................... 181.5.3Ecological and Biological Resources.................................................................... 191.5.4Current and Potential Future Land Uses............................................................... 191.6Summary of Site Contamination................................................................................... 201.6.1Site 1A – North Beach, Army Landing Area........................................................ 201.6.2Site 1B – North Beach, Air Force Landing Area.................................................. 211.6.3Site 1C – North Beach .......................................................................................... 221.6.4Site 2 – Former Military Housing/Operations Burial Site .................................... 221.6.5Site 3 – Former Communications Facility Burial Area ........................................ 251.6.6Site 4A – Former Quonset Huts near USAF Radar Station.................................. 261.6.7Site 4B – Former USAF Radar Station................................................................. 271.6.8Site 4C – Sevuokuk Mountain .............................................................................. 291.6.9Site 4D – Sevuokuk Mountain.............................................................................. 291.6.10Site 4E – Western Face of Sevuokuk Mountain ................................................... 291.6.11 Site 6 – Military Landfill ...................................................................................... 301.6.12Site 7 – Former Military Power Facility ............................................................... 311.6.13 Sites 8A, 8B, 8C, 8D – West Beach Area............................................................. 351.6.14 Site 9 – Asphalt Barrel Cache............................................................................... 361.6.15 Site 10 – Sevuokuk Mountain Trail ...................................................................... 371.6.16 Site 11 – Communications Cable Route ............................................................... 371.6.17 Site 12 – North Nayvaghat Lakes Disposal Site................................................... 371.6.18Site 13 – Former Radar Power Station ................................................................. 391.6.19 Site 14 – Navy Plane Crash Site ........................................................................... 401.6.20Site 15 – Troutman Lake Disposal Site ................................................................ 401.6.21Site 16 – Gambell Municipal Building Site.......................................................... 411.6.22 Site 17 – Army Landfills....................................................................................... 411.6.23 Site 18 – Former Main Camp................................................................................ 421.6.24Site 19 – Diatomaceous Earth............................................................................... 431.6.25Site 20 – Schoolyard ............................................................................................. 431.6.26 Site 21 – Toe of Sevuokuk Mountain ................................................................... 43Page 6 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaska1.6.27Site 22 – Former CAA Housing............................................................................ 431.6.28Site 23 – Debris from High School Construction ................................................. 441.6.29Site 24 – South of Municipal Building ................................................................. 441.6.30Site 25A – Village of Gambell South Housing Units ........................................... 441.6.31Site 25B – Low Drainage Area Southwest of Armory ......................................... 451.6.32Site 26 – Possible Debris Burial Site .................................................................... 451.6.33Site 27 – Drum Storage Area ................................................................................ 451.6.34Site 28 – Disturbed Ground .................................................................................. 461.7Summary of Site Risks.................................................................................................. 471.8Remedial Action Objectives ......................................................................................... 491.9Description of Alternatives ........................................................................................... 521.10 Comparative Analysis of Alternatives .......................................................................... 531.10.1Threshold Criteria ................................................................................................. 531.10.2Balancing Criteria ................................................................................................. 531.10.3Modifying Criteria ................................................................................................ 571.11 Principal Threat Waste.................................................................................................. 591.12 Selected Remedy........................................................................................................... 601.13 Statutory Determinations .............................................................................................. 631.13.1Protective of Human Health and the Environment ............................................... 631.13.2 Applicable or Relevant and Appropriate Requirements ....................................... 631.13.3Cost Effectiveness................................................................................................. 641.13.4Utilization of Permanent Solutions and Alternative Treatment Technologies to theMaximum Extent Practicable................................................................................................ 641.13.5Preference for Treatment as a Principal Element ................................................. 641.13.6Five-Year Review Requirement ........................................................................... 641.14 Documentation of Significant Changes ........................................................................ 652. Responsiveness Summary..................................................................................................... 66Appendix A – Responsiveness SummaryPage 7 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaGlossary of Terms and AcronymsAACAlaska Administrative CodeADECAlaska Department of Environmental ConservationARARsApplicable or Relevant and Appropriate RequirementsBNAsBase, neutral, and acid compounds (includes PAHs)BTEXBenzene, toluene, ethylbenzene, and xyleneBGSBelow ground surfaceCERCLAComprehensive Environmental Response, Compensation, and Liability ActCFRCode of Federal RegulationsCOCContaminant of concernDODDepartment of DefenseDRODiesel-range organicsEPAUnited States Environmental Protection AgencyFSFeasibility StudyFUDSFormerly Used Defense SiteGROGasoline-range organicsICInstitutional Controlsmg/kgmilligram per kilogrammg/Lmilligram per literMWHMontgomery Watson HarzaNALEMPNative American Land Environmental Mitigation ProgramNCPNational Contingency PlanNFANo Further ActionOSCIOil Spill Consultants, Inc.pg/gpicogram per gramPOLPetroleum, oil, and lubricantsppmParts per millionPAHsPolyaromatic (or Polycyclic) HydrocarbonsPCBsPolychlorinated biphenylsPriorityPollutantMetalsAntimony, arsenic, barium, beryllium, cadmium, chromium, copper, lead, mercury, nickel,selenium, silver, thallium, and zinc.RCRAResource, Conservation and Recovery ActRCRA metalsarsenic, barium, cadmium, chromium, lead, mercury, selenium, and silverRROResidual Range OrganicsRABRestoration Advisory BoardPage 8 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaRIRemedial InvestigationRARemoval/Remedial ActionsSVOCsSemi volatile organic compoundsTAL metalsTarget Analyte List metals, includes aluminum, antimony, arsenic, barium, beryllium, cadmium,calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, mercury, nickel,potassium, selenium, silver, sodium, thallium, vanadium, and zinc.TCLPToxicity characteristic leaching procedureTRPHTotal recoverable petroleum hydrocarbonsUSACEUnited States Army Corps of EngineersUCLUpper Confidence LevelVOCsVolatile organic compoundsPage 9 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaska1. Decision SummaryThis Decision Summary provides an overview of the contaminants at the Gambell Site. Itidentifies the areas evaluated for remedial response, describes the remedial alternativesconsidered, and analyzes those alternatives compared to the criteria set forth in the NationalContingency Plan (NCP). The Decision Summary explains the rationale for selecting theremedy, and how the remedy satisfies the statutory requirements of the ComprehensiveEnvironmental Response, Compensation, and Liability Act (CERCLA).1.1 Site Name, Location, and Brief DescriptionThe Gambell Site, FUDS project #s F10AK069601 and F10AK069603, is located on St.Lawrence Island, Alaska, about 200 air miles southwest of Nome in the Bering Sea (see Figure1). The State of Alaska, Department of Environmental Conservation (ADEC) tracks the entiresite with reckey # 198532X917919, and also lists individual areas of concern by separate reckeys(198532X917920-32 and 198532X117901-13). One area of concern, Site 5 Tramway (reckey#198532X917923) will be addressed under a future decision document. The EPA identificationnumber for Gambell is AKD981765894. The site is situated on a gravel spit at the northwestpoint of the island. Gambell is located at latitude 63° 46’ 49” North and longitude 171° 43’ 46”West. The military leased approximately 2,500 acres in Gambell. Thirty-eight (38) separatesites of concern were identified during the remedial investigation process (see Figure 2). Theselected remedy for each site, except Site 5, is listed in Table 1.Figure 1 – Site Vicinity MapPage 10 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaTable 1 – Remedial Responses by Site LocationSite1A North Beach1B Army Landing Area1C Air Force Landing Area2 Military Burial Site3 Communications Facility4A Air Force Radar Site4B Former Quonset Huts4C Discarded Drums4D Former Transformers4E Western Face of Sevuokuk Mtn6 Military Landfill7 Military Power Facility8A Marston Matting8B Buried Debris8C Navy Landfill8D Beach Ammunition9 Asphalt Drums10 Army/Air Force Trails11 Communication Cable Route12 Nayvaghat Lakes Disposal Site13 Radar Power Station14 Navy Plane Crash Site15 Troutman Lake Disposal Site16 Municipal Building Site17 Army Landfills18 Main Camp19 Diatomaceous Earth20 Schoolyard21 Toe of Sevuokuk Mountain22 Former CAA Housing23 Debris from High School24 South of Municipal Building25A Gambell South Housing Units25B Low Drainage Area26 Possible Debris Burial Site27 Drum Storage Area28 Disturbed GroundSelected Remedial ResponseNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionExcavation and off-site disposal of arsenic-contaminated soilRemoval and off-site recycling/disposal of exposed metal debrisNo Further ActionNo Further ActionNo Further Action under FUDS *No Further ActionNo Further ActionNo Further ActionExcavation and off-site disposal of lead-contaminated soilNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further ActionNo Further Action* Site 8D is planned for future debris removal under NALEMP, pending the availability of funding.Page 11 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaFigure 2 – Site Location Map238C1C22Sevuokuk Mountain1A1762772625B 25A 16 202624 188B19 2115Troutman Lake324E4A54D118AAirs trip4B1B910Bering Sea4C288D12±N13to14100001000Page 12 of 662000 FeetDecision DocumentGambell SiteSt. Lawrence Island, Alaska1.2 Site HistoryThe military established the Gambell site in the 1950’s as part of a surveillance and intelligencegathering network. Various units of the U.S. Army and U.S. Air Force utilized the area. The AirForce built a base camp in 1950 at the foot of Sevuokuk Mountain and a radar site directly aboveon the mountain top (both abandoned in 1956). The Army occupied several sites during the late1950s, with a main base camp located just north of Troutman Lake. The Navy also laidcommunications cables from the village of Gambell, up Sevuokuk Mountain, and south toBrunnell Cape.Environmental investigations and cleanup activities at Gambell began in the mid 1980’s. Thegoals of the investigations were to locate and identify areas of contamination and to gatherenough information to develop a cleanup plan. The first major environmental study, theremedial investigation, was performed at Gambell in 1994. The study divided the concernsamong 18 separate sites. The results of the remedial investigation showed that contaminantswere present at some but not all sites. Some sites were subdivided into sub sites and new siteswere also added in subsequent investigations.In 1996, the second phase of remedial investigation was performed. In this study, additional soiland groundwater samples were collected from Sites 1A, 1B, 2, 3, 4B, 4D, and 5. The studyobjectives were to further delineate the extent of contamination, estimate amounts of debris, andconduct a geophysical survey.In 1997, a USACE contractor, Montgomery Watson, removed visible surface debris fromvarious sites around Gambell. During the 1999 field season, Oil Spill Consultants, Inc. (OSCI)performed further cleanup activities in Gambell, including the removal of additional debrisexposed by frost jacking after the 1997 cleanup activity. OSCI removed a total of 26.8 tons ofhazardous and non-hazardous containerized wastes such as asphalt drums, paint, generators,batteries, empty drums, and transformer carcasses. OSCI also removed 71 tons of exposed metaldebris such as runway Martson matting, cable, fuel tanks and equipment parts; and excavated 72tons of contaminated soil. However, OSCI was unable to complete the removal of Martsonmatting adjacent to the runway due to safety concerns over its proximity to airstrip utilities.In 2000 and 2001, the Army Engineering and Support Center (Huntsville, AL) conductedextensive research and investigations to locate possible ordnance and explosives materials leftbehind by the military. During the field surveys, small amounts of ordnance waste were found,consisting primarily of highly weathered 30-caliber small arms ammunition at a beach burial pitsouthwest of Troutman Lake. An Engineering Evaluation/Cost Analysis (EECA) datedNovember 2002 recommended institutional controls as the appropriate response action formilitary munitions and explosives of concern (MEC) at the Gambell Site. An ActionMemorandum, dated June 2003, documented the selected response action of institutionalcontrols.The institutional controls were implemented during the summer of 2004 and consisted ofdistributing informational pamphlets and posters about ordnance risks to local residents andbusinesses and holding a community meeting. An initial review to evaluate the continuedeffectiveness and reliability of the ordnance response action will be conducted in 3 years. AfterPage 13 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskathe initial review has been conducted, recurring reviews will be performed at 5-year intervals.The need for recurring reviews will be coordinated with regulators and stakeholders and justifiedin each recurring review report.A supplemental remedial investigation was conducted by Montgomery Watson Harza during the2001 field season, to verify previously collected confirmation data and investigate the nature andextent of contamination at four newly identified sites. These sites were identified as potentialareas of concern based on community concerns and a review of a historical photographicanalysis completed by the USACE Topographic Engineering Center in September 2000. Thesummary report recommended no further action for most sites. Further action was recommendedat Sites 4A, 4B, 6, 7, and 12 based on a comparison to screening levels. The ADEC Ingestionpathway cleanup levels were later determined to be the applicable cleanup levels for Sites 4A,4B and 6. Since Sites 4A, 4B and 6 meet the specified regulatory cleanup levels, only Sites 7and 12 require further action.The Corps of Engineers completed a Feasibility Study (FS) in February 2004. A Proposed Planwas distributed to the public in July 2004 which summarized site conditions, investigationresults, and described the remedial alternatives evaluated in the FS. A public meeting to discussthe plan was held in Gambell on July 21, 2004. The supporting documents can be found in theAdministrative Record located at the USACE Office on Elmendorf Air Force Base or at theInformation Repositories located in Gambell, Savoonga, Nome, and Anchorage.Remedial investigation and removal work at Gambell was carried out under the DefenseEnvironmental Restoration Program (DERP) FUDS program. There have been no enforcementactivities or notices of violation pertaining to the Department of Defense activities at theGambell site.Page 14 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaska1.3 Community ParticipationPublic participation has been an important component of the CERCLA process at the GambellSite. A Community Relations Plan was developed for the project in March 1996 and updated inApril 2002. The Community Relations Plan describes the measures used to meet the communityrelations goal of keeping Gambell residents and other interested people informed about projectactivities. It provided a means for local residents to share their knowledge about the Gambellarea and its history with the project team. It further allowed the residents and other interestedpersons to provide their feedback and comments on project activities, and gave everyone anopportunity to become involved in the project. Activities aimed at informing and solicitingpublic input regarding the Gambell Site include:Restoration Advisory Board (RAB): A RAB comprised of community members andother interested parties was established in January 2000. RAB meetings are heldapproximately 3 times per year to keep the public informed of ongoing project activities.Many Gambell residents identified areas of concern on maps or photographs and relayedinformation on past activities or stories about certain areas from village elders.TAPP Advisor/Community Liaison: The RAB is served by a technical advisor, under theTechnical Assistance for Public Participation (TAPP) program, to provide technicalguidance on workplans, reports, proposed remedies, and potential environmental andhuman health impacts. In addition, a local resident was employed as a community liaisonduring the remedial investigation phase, to help community members access technicalinformation, distribute meeting notices, and assist with agency communication.Meeting Notices: Meeting notices were published in the Nome Nugget newspaper andposted in prominent locations around town such as the Sivuqaq Lodge, City Hall, PostOffice, and Washeteria. Radio announcements were broadcast on KNOM of Nome, AK.Informal Meetings and Site Visits: Informal meetings occurred whenever project staffvisited with Gambell residents and other interested or knowledgeable parties. The projectteam gathered information on potential hazardous waste or debris locations, and gatheredavailable documentation through interviews with village residents, Native Village ofGambell IRA Council members and staff, Sivuqaq Incorporated board members, andother interested parties. These persons contributed information regarding historical andcurrent conditions at the Gambell site.Fact Sheets: Information about the project was published periodically through FactSheets distributed to RAB members and placed at the Information Repositories.Information Repositories: Project documentation, reports, and other materials areavailable at 4 locations including the Sivuqaq Lodge in Gambell, the Savoonga IRABuilding in Savoonga, the University of Alaska Fairbanks Northwest Campus Library inNome (formerly at the National Park Service) , and the Alaska Resource Library andInformation Services in Anchorage.Mailing List: A mailing list was compiled and updated throughout the project.Proposed Plan: The Gambell Proposed Plan was distributed to the public in July 2004; apublic meeting was held July 21, 2004; and the public review period was from July 21 toAugust 30, 2004. Comments from the public are contained in the ResponsivenessSummary found in the Appendix of this document.Page 15 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaPublic Notices: Public notices have been issued prior to all significant decision pointsincluding RAB meetings. A public notice for the Proposed Plan and Public Meeting waspublished in the Nome Nugget newspaper on July 14, 2004.Responsiveness Summary: Public comments were received on the Gambell ProposedPlan. The USACE maintains a record of all comments and has published responses to thecomments in this Decision Document. A Responsiveness Summary binder was alsodeveloped for the project to document implementation of the Community Relations Plan.It contains responses to all comments/concerns raised by the public during the project andwill continue to be updated until the project is completed.Page 16 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaska1.4 Scope and Role of Response ActionThe CERCLA process is intended to identify solutions to contamination issues where they exist.The remedial action described in this Decision Document addresses threats to human health andthe environment posed by contamination at the Gambell Site. The RI/FS Reports defined thesethreats as soil contaminants. Soil with contaminants that pose a potential threat to the public willbe removed, transported, and disposed in an appropriate facility. In addition, exposed militarydebris which poses a clear danger, likely to cause death or serious injury to persons exercisingordinary and reasonable care will be removed and transported to a permitted landfill or approvedrecycling facility.Page 17 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaska1.5 Site CharacteristicsThis section provides an overview of the Gambell Site, including geographical information,hydrology, ecological resources, and land use. Site locations are shown on Figures 2 and 3.1.5.1 Geographical and topographic informationThe Native Village of Gambell is located on St. Lawrence Island, in the western portion of theBering Sea, approximately 200 air miles southwest of Nome, Alaska (see Figure 1). The villageis situated on a gravel spit that projects north and westward from the island. Gambell isrelatively flat, with an elevation range from sea level to approximately 30 feet above mean sealevel. Sevuokuk Mountain forms the eastern boundary of the gravel spit, and rises steeply to aheight of approximately 619 feet. The dominant soil lithologies underlying the Gambell area areunconsolidated, poorly to well-sorted gravels with sand and poorly to well-sorted sand withgravels. These soils are interpreted as washed beach gravels deposited on a wave cut platform.Sevuokuk Mountain is composed of Cretaceous quartz monzonite, a gray rock rich in quartz andfeldspars.The entire Gambell site encompasses approximately 2,500 acres. The majority of the areas ofconcern are located within or adjacent to the village of Gambell, a community of 649 persons(US Census 2000).1.5.2 Hydrology and Groundwater UseGroundwater was encountered at depths ranging from 2.5 feet below ground surface (bgs) southof Troutman Lake to 16.5 ft bgs along the North Beach area. The largest and most permanentsurface water features in the vicinity of Gambell are Troutman Lake and North NayvaghatLakes. Small ephemeral ponds and bogs are also present on the tundra east of Troutman andNorth Nayvaghat Lakes.Groundwater from the central gravel spit is not suitable as a source of drinking water.Groundwater in the gravels is often saline, difficult to recover in useable quantities, and locatedin an active lens over permafrost. A drinking water well in the old Village area was abandonedin the past because of poor water quality (salt water intrusion) or quantity. Groundwaterencountered at the site has been limited in quantity, and only intermittently detected. Permafrostin Gambell is commonly encountered at depths ranging from 3 to 15 feet below the groundsurface. The groundwater aquifer (10-14 ft depth) that currently supplies drinking water to thecommunity is located at the base of Sevuokuk Mountain, approximately 1,500-2,000 feet east ofthe village on the far eastern edge of the gravel spit. The predominant surface water feature,Troutman Lake, is considered slightly brackish due to influences from the Bering Sea.Continuous permafrost acts as a barrier for soil contaminant migration to a groundwater zone.However, migration of contaminants may occur with groundwater movement in the active lensabove the permafrost layer (suprapermafrost groundwater). Suprapermafrost groundwater occurssporadically within the village of Gambell (i.e., in the vicinity of Sites 6, 7, 16, 17, 18). Thedocumented groundwater flow direction in this area is to the north, towards the Bering Sea, adistance of about 1,200 feet.Page 18 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaAccording to a State of Alaska hydrogeological investigation report (Ireland, 1994), the Gambellaquifer is canoe-shaped, originating along the front of the steep bluff of Sevuokuk Mountain, andcontinuing down the hydrological gradient across a highly permeable gravel bar towards theocean. The aquifer appears to be a thaw bulb in the permafrost, and as the permafrost expands orrecedes, the aquifer dimensions vary. Warm recharge water originating on Sevuokuk Mountaineffectively melts the permafrost where the mountain front joins the gravel spit. Most of thewater entering the aquifer comes from two springs that flow from the steep bluffs of themountain into the gravel. Shallow groundwater across the gravel spit does not appear to becontinuous because of the presence of shallow permafrost (Munter and Williams, 1992).1.5.3 Ecological and Biological ResourcesSt. Lawrence Island supports habitats for the following endangered or threatened species: thespectacled eider (endangered), Steller’s eider (threatened), and Steller sea ion. Walrus and polarare protected under the Marine Mammal Protection Act. The investigation areas of concern donot support sensitive habitats, and are predominantly comprised of gravel and sand within thecity of Gambell, adjacent roads or the airport.1.5.4 Current and Potential Future Land UsesSt. Lawrence Island is owned jointly by the two village native corporations: Sivuqaq, Inc., inGambell, Alaska, and the Savoonga Native Corporation in Savoonga, Alaska. Non-Native landon St. Lawrence Island is limited to state land used for airstrips and related facilities in Gambelland Savoonga. A federally recognized tribe is located in the community -- the Native Village ofGambell. Gambell is inhabited primarily by Native St. Lawrence Island Yupik people, who leada subsistence-based lifestyle. The Gambell area supports habitat for a variety of seabirds,waterfowl, and mammals that either breed in or visit the area. The area surrounding the top ofSevuokuk Mountain, above the Village of Gambell, supports a large bird rookery. The birds andbird eggs are a subsistence food source for local inhabitants. The ocean surrounding the Gambellarea is used extensively for subsistence hunting of whales, walrus, seals, sea birds, and fish.Future land use is expected to remain residential with the surrounding area used for recreationand subsistence hunting or gathering.Page 19 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaska1.6 Summary of Site ContaminationThis section summarizes the sampling strategy for 37 of the 38 sites in Gambell, identifiescontaminants of concern, and affected media. Two areas, Sites 7 and 12, were identified for aresponse action based on the presence of contaminants at levels which may pose a risk to humanhealth and the environment. The basis of this analysis is the data collected during the RemedialInvestigation (RI), which identified the nature and extent of contamination in Gambell. Oneadditional area, Site 8A, was identified for a response action based on the presence of physicalhazards consisting of exposed metal debris.During the remedial investigation process, soil, sediment, and shallow-aquifer groundwater weresampled and analyzed for a wide range of organic and inorganic constituents. Contaminantsdetected in the soil and shallow-aquifer groundwater were primarily fuels and metals.1.6.1 Site 1A – North Beach, Army Landing AreaSite 1A is located in the central portion of the North Beach, where two well-established allterrain vehicle (ATV) trails intersect. The Army landing area was located east of an area that iscurrently used by local residents to land or launch whaling boats. The site consisted of exposedsurface debris including engine pieces, Marston matting, weasel tracks, steel cables, a partiallyburied 100-foot crane, and other buried metallic debris which are periodically exposed andreclaimed by shifting gravels along the beach area.In 1997, Montgomery Watson removed all visible surface debris from Site 1A (5,545 pounds)and the surrounding beach area (3,630 pounds), including corrugated roofing material, piping,Marston matting, weasel tracks, protruding parts of a buried crane, engines, cables, and othermiscellaneous debris. No dangerous surface debris remains at this site. Buried debris is noteligible for further action under FUDS.SoilSurface and subsurface soil samples were collected in 1994. One surface soil sample wascollected and analyzed for total recoverable petroleum hydrocarbons (TRPH), BNAs, PCBs, andpriority pollutant metals (antimony, arsenic, barium, beryllium, cadmium, chromium, copper,lead, mercury, nickel, selenium, silver, thallium, zinc). Subsurface soil samples were collectedfrom 5 borings and analyzed for petroleum hydrocarbons (DRO, GRO, TRPH), VOCs, PCBs,and priority pollutant metals. Arsenic concentrations in soil ranged from 1 to 9 mg/kg. Thecalculated 95% upper confidence level (95%UCL) of the mean concentration for arsenic at Site1A is 5.0 mg/kg, which does not exceed the ADEC Table B ingestion cleanup level of 5.5mg/kg. No other contaminants were detected in soil above screening levels based on the ADECTable B migration to groundwater pathway cleanup levels in 18 AAC 75.341.GroundwaterFive monitoring wells were installed during the 1994 Phase I remedial investigation.Groundwater samples from all 5 wells were analyzed for petroleum hydrocarbons (DRO, GRO,TRPH), VOCs, PCBs, and priority pollutant metals. No contaminants were detected ingroundwater above screening levels based on the ADEC Table C groundwater cleanup levels in18 AAC 75.345.Page 20 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaFigure 3 – Site Location Map, Northern AreaNorth Beach1CArmy Landing AreaBERING SEA23 Debris fromHigh School8C Navy LandfillWestBeach8BBuriedDebrisArmy LandfillsCAAHousing25BLowDrainageArea171BFormer MilitaryBurial Site26MilitaryLandfillDrum StorageArea27 Former7 PowerFacility2625A 16S. Housing20VillageWaterSupply5FormerBuried TramwayFormerDiatomaceous DebrisMain4D FormerEarthCampTransformersHighSchool181521CityHall Washeterians Cable Rout e11tiocaTroutman Lakeni9 AsphaltDrums10CommuAirstripFormer4A Quonset Huts2024198AMarstonMatting4B34ECableDebrisFormerAir ForceRadar SiteAir For ce TrailOld VillageAreaFormerCommunicationsFacility1AArmy Trai l22Air ForceLanding AreaN50005001000 Feet1.6.2 Site 1B – North Beach, Air Force Landing AreaSite 1B is located west of Sevuokuk Mountain, and approximately 1,900 feet east of the ArmyLanding Area on North Beach. The site contained exposed surface debris, rust-stained gravel,and a separate patch of tar-stained gravel (degraded asphalt). Additionally, buried debris may beperiodically exposed as the gravel beach deposits shift or frost jacking occurs. This area receivesa large amount of ATV traffic due to its proximity to the bird rookeries on Sevuokuk Mountainvisited by local residents and tourists.In 1997, Montgomery Watson removed all visible surface debris from Site 1B (105 pounds) andthe surrounding beach area (2,865 pounds), including Marston matting, empty drums, sheetmetal, steel cables, and other miscellaneous debris. All dangerous surface debris has beenremoved. Buried debris is not eligible for further action under FUDS.Page 21 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaSoilDuring the 1994 remedial investigation, subsurface soil samples were collected from threeborings and analyzed for petroleum hydrocarbons (GRO, DRO, TRPH), VOCs, PCBs, andpriority pollutant metals. One surface soil sample was collected from the rust-stained soil andanalyzed for TRPH, BNA, PCBs, and priority pollutant metals. Petroleum hydrocarbons andlead were detected in soil, but did not exceed screening levels based on ADEC Table Bmigration to groundwater pathway cleanup levels in 18 AAC 75.341. Arsenic was also detectedin soil at concentrations ranging from 2 to 7 mg/kg. The calculated 95% UCL of the meanconcentration for arsenic at Site 1B is 4.8 mg/kg, which does not exceed the ADEC Table Bingestion cleanup level of 5.5 mg/kg. No other chemicals were detected in soil above screeninglevels based on the ADEC Table B migration to groundwater cleanup levels in 18 AAC 75.341.GroundwaterIn 1994, three monitoring wells were installed at Site 1B, to a maximum depth of 20.5 feet.Groundwater was encountered between 10 and 14.5 feet below ground surface. Groundwatersamples were collected from the three wells and analyzed for petroleum hydrocarbons (GRO,DRO, TRPH), VOCs, PCBs, and priority pollutant metals. No contaminants were detected ingroundwater above screening levels based on the ADEC Table C groundwater cleanup levels in18 AAC 75.345.1.6.3 Site 1C – North BeachSite 1C covers the entire length of North Beach and consists of underwater metallic debrislocated just offshore. The majority of the debris is thought to be Marston matting used toconstruct the two military landing areas. North Beach is the primary area used by local residentsfor launching and landing boats.In 1997, Montgomery Watson removed all exposed surface debris (10,105 pounds) from theentire length of the North Beach, including corrugated roofing material, piping, Marston matting,empty drums, heavy machinery parts, metal cables, and other miscellaneous debris. Theremaining underwater debris does not pose a physical hazard and is not eligible for further actionunder FUDS.1.6.4 Site 2 – Former Military Housing/Operations Burial SiteSite 2 is located approximately 1,000 feet south of the former Air Force Landing Area on NorthBeach, and just west of the base of Sevuokuk Mountain. Facilities associated with militaryhousing/operations, and a power plant, were reportedly demolished and buried at this site.Ordnance was potentially buried here as well, but investigations have not confirmed thispossibility. Exposed debris was observed at the site, including remnants of a rock fireplace,partially buried concrete pad, burned wood, scattered metal debris/gear, and discolored gravel.In 1997, Montgomery Watson removed 100 pounds of miscellaneous debris from Site 2. Theyalso removed a large quantity (total of 1,740 pounds) of cable spools, wheel rims, corrugatedmetal, and Marston matting from the vicinity of Site 2 (between Sites 1A and 3). Oil SpillConsultants, Inc (OSCI) removed the remaining exposed debris in 1999, but attributed allPage 22 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskaquantities of debris removed to Site 3. OSCI also removed 24,982 pounds (12.5 cubic yards) ofpetroleum-stained soils from near Site 2. The stained soil was located adjacent to a large rock atthe base of Sevuokuk Mountain, approximately 450 feet south of the Bering Sea/North Beach.This location was identified by Montgomery Watson as between Site 1A and 3. The partiallyburied concrete pad is not eligible for further action under FUDS.SoilSurface and subsurface soil samples were collected during the 1994 remedial investigation. Ninesubsurface soil samples were collected from three borings and analyzed for VOCs, GRO, DRO,TRPH, priority pollutant metals, PCBs, and explosives. Two surface soil samples were alsocollected at the areas of discolored gravel and analyzed for TRPH, BNA’s, and priority pollutantmetals. Fuels were detected in the soil below screening levels. Elevated levels of metals werealso detected in one surface soil sample above screening levels. Sampling results aresummarized in Table 2. No asbestos was detected in the fibrous material.With the exception of arsenic, metals were detected above screening levels in only one sampleout of 13. This single sample had anomalous concentrations of both lead (749 mg/kg) andchromium (391 mg/kg); the other samples demonstrated a mostly sympathetic relationshipbetween lead and chromium suggesting where lead is low, chromium will also be low. The 12other soil samples contained low levels of chromium (ND to 21 mg/kg) and lead (1 to 70 mg/kg).Chromium was not considered a contaminant of concern following the 1994 investigationbecause it did not exceed the 1994 screening levels (chromium screening levels have sincechanged). Further investigation was conducted in 1996 to determine the extent of leadcontamination surrounding this particular sample, since the lead results were more highlyanomalous. Eight surface soil samples were collected and analyzed for lead only. The samplingresults indicated the lead concentrations (3.6 to 63 mg/kg) were well below screening levels (400mg/kg). The 95% UCL of the mean lead concentration at the site does not exceed the ADECcleanup levels. Since lead was not elevated during the 1996 investigation, it is logical to assumethat the chromium contamination was similarly below levels of concern. Any remainingchromium is likely isolated and present in de-minimus quantities. The detected arsenicconcentrations (3 to 11 mg/kg) do not exceed site background concentrations. Although thearsenic concentrations exceed the ADEC Table B ingestion pathway cleanup level (5.5 mg/kg),the levels are consistent across many sites in Gambell, and do not appear associated with pastmilitary activity.Page 23 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaTable 2. Sampling Results at Site 2ChemicalCleanupScreeningLevel aLevel(1994)Soil (mg/kg)DRO10,250100 bTRPHNA2,000 biArsenic116.7 cChromium300390-78,000 dLead400500-1,000 eWater (mg/L)TRPHNAsheen (0.5)Range ofResults(1994)Range ofResults(1996)ND - 28ND - 7103 – 113 – 3911 – 749----3.6-630.2 – 0.5--95% UCL ofthe mean6.5 f82 – 165 g206 hNotes: NA - not available, ND - not detected, mg/kg - milligrams per kilogram (parts per million),mg/L - milligrams per liter (parts per million)a18AAC75, Table B, Under 40 Inch Zone, Ingestion (May 26, 2004)bADEC Interim Guidance Level A soil cleanup targets (July 17, 1991)cUSGS Element Concentrations in Soil and Other Surficial Materials of Alaska (1988)dUS EPA Region 3 Risk-Based Concentration Table (July 11, 1994), Cr III and Cr VIeUS EPA Region 5 Interim Guidance on Establishing Soil Lead Cleanup Levels at Superfund Sites(September 7, 1989)fbased on the gamma distributiongrange of values based on non-parametric methodshcalculated using all results from 1994 and 1996isite backgroundIn 1999, OSCI collected a pre-excavation sample to characterize the stained soils for disposalpurposes; the sample contained gasoline and diesel range organics at 309 and 6,440 mg/kg,respectively. The concentration of petroleum hydrocarbons in the removed soils did not exceedADEC Table B Ingestion pathway cleanup levels (1,400 mg/kg GRO and 10,250 mg/kg DRO).PCBs, VOCs, SVOCs, pesticide/ herbicides, and leachable metals were not detected. AfterOCSI removed a large quantity of stained soils, the Corps of Engineers stopped furtherexcavation because the scope of the removal action was limited to stained soils associated withdrums and other debris. The contamination was more extensive than anticipated. Commentsfrom local workers revealed that the petroleum stain at this site probably resulted from oil thatwas drained from ATVs by Gambell residents. No post-excavation samples were collected,because the Corps decided the stained soil was outside the scope of work. The observedpetroleum contamination may be the result of more recent oil spills that are not related to formerDoD activities.GroundwaterThree monitoring wells were installed at the site during the 1994 investigation. Groundwatersamples were collected from the 3 wells and analyzed for VOCs, GRO, DRO, TRPH, prioritypollutant metals, and explosives. Low levels of total hydrocarbons were detected in onegroundwater sample (see Table 2), but did not exceed ADEC Table C cleanup levels in 18 AAC75.345. No other analytes were detected in the groundwater.Military MunitionsEarth Tech, Inc. conducted two geophysical surveys at Site 2 during July and September 2000, todetermine the presence or absence of buried ordnance. First, the field team visually surveyed thearea and removed metallic scrap and debris from the surface. Next, metal detectors were used tomap the location of subsurface metal within three site grids. Mapped metallic anomalies werePage 24 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskathen excavated to determine the source of the magnetic signature. No evidence of any ordnancewas found during the investigation.1.6.5 Site 3 – Former Communications Facility Burial AreaSite 3 is located approximately 700 feet south of the North Beach, near the base of SevuokukMountain. The preliminary assessment indicated the possible burial of Jamesway huts, powerplant generators, transformers, oils, batteries, and sulfuric acid. Exposed above-ground debrisincluded weasel tracks, Marston matting, pipe, empty drums, and anchors for guy wire.In 1997, Montgomery Watson removed 1,740 pounds of debris from the vicinity of Site 3,including cable spools, corrugated metal, Marston matting, and cable wires. In 1999, OSCIremoved an additional 3,030 pounds of surface debris, including weasel tracks, 3 empty fuelstorage tanks, Marston matting and drums. All dangerous surface debris has been removed. Theburied debris is not eligible for further action under FUDS.SoilSurface and subsurface soil samples were collected during the Phase I investigation. Ageophysical survey identified two discrete areas with suspected buried material. Subsurface soilsamples were collected from two borings at depths of 2.5 and 5 feet, and analyzed for petroleumhydrocarbons, VOCs, priority pollutant metals, PCBs, sulfate/sulfur, and pH. No VOCs or PCBswere detected. The only petroleum hydrocarbon detected was DRO, but at concentrations belowcleanup levels. Several metals were detected in the soil, including arsenic, beryllium, cadmium,mercury, selenium, and thallium. Beryllium and thallium exceeded initial screening levels, andfurther sampling was conducted during the 1996 Phase II investigation. Four surface soilsamples were collected; the results were all below detection limits. The thallium results from1994 were determined to be spatially limited. Table 3 summarizes the sampling results.GroundwaterTwo monitoring wells, MW09 and MW10, were installed during the 1994 investigation andencountered groundwater at depths of 8 to 9 feet below ground surface. Groundwater samplesfrom the two wells were analyzed for VOCs, GRO, DRO, TRPH, PCBs, priority pollutantmetals, and sulfates. Lead was detected in the groundwater from MW10 at a concentrationwhich exceeded the ADEC Table C groundwater cleanup value. However, a filtered samplefrom this well did not contain any dissolved lead. A second monitoring well, MW09, locatedimmediately downgradient of MW10 did not contain detectable levels of lead in thegroundwater. Both monitoring wells are located downgradient of the village drinking watersupply well, and the groundwater gradient in the vicinity flows north toward the Bering Sea.Lead was not identified as a contaminant of concern, and no further groundwater sampling wasperformed at Site 3 after the Phase I investigation.Page 25 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaTable 3. Sampling Results at Site 3ChemicalCleanup ScreeningLevelLevel(1994)Soil (mg/kg)DRO10,250 a100 ghArsenic116.7 faBeryllium2001.5 faCadmium10039 ebMercury1823 eaSelenium510390 edThallium5.57.0 eWater (mg/L)Lead0.015 c0.015Lead, dissolvedMaximumResult(1994)522667111315MaximumResult(1996)ND (2.52)ND (0.28)0.045ND (0.002)Notes: mg/kg – milligrams per kilogram (parts per million)mg/L – milligrams per liter (parts per million)a18AAC75, Table B, Under 40 Inch Zone, Ingestion (May 26, 2004)b18AAC75, Table B, Under 40 Inch Zone, Inhalation (May 26, 2004)c18AAC75, Table C (May 26, 2004)dUS EPA Region 3, Risk-Based Concentration Table (April 4, 2004)eUS EPA Region 3, Risk-Based Concentration Table (July 11, 1994)fUSGS Element Concentrations in Soil and Other Surficial Materials of Alaska (1988)gADEC Interim Guidance, Level A soil cleanup targets (July 17, 1991)hsite background1.6.6 Site 4A – Former Quonset Huts near USAF Radar StationSite 4A consisted of collapsed Quonset Huts frames and transformer casings located on the topof Sevuokuk Mountain. In 1997, Montgomery Watson removed three empty transformercarcasses. In 1999, OSCI removed 14,772 pounds (7.4 tons) of unsafe debris, including twocollapsed Quonset hut frames, metal siding, drums, and petroleum-stained soil (1,877 pounds)associated with the drums and debris.SoilDuring the remedial investigation, three surface soil samples were collected adjacent to the fallentransformers and analyzed for PCBs. Asbestos samples were also taken around the fallenQuonset huts. No PCBs or asbestos-containing material (ACM) were detected in the soils.OSCI collected four confirmation soil samples from within and outside of the two Quonset hutfootprints following the 1999 removal action. The samples were analyzed for petroleumhydrocarbons (DRO/RRO/GRO), VOCs, SVOCs, PCBs, pesticides, and Resource Conservationand Recovery Act (RCRA) metals.The 1999 confirmation samples contained concentrations of diesel range organics and metalswhich exceeded screening levels, including arsenic, chromium, and lead. A supplementalinvestigation was conducted in 2001 at Site 4A to verify the previous confirmation samplingresults. Four samples were collected based on field screening results and analyzed for petroleumhydrocarbons and RCRA metals. Two of the samples were also analyzed for hexavalentchromium. The 2001 sampling results indicated that all chemicals of concern were below theADEC Table B ingestion pathway cleanup levels (18 AAC 75.341) or site background. InPage 26 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskaaddition, hexavalent chromium was not detected in the soil samples. Table 4 summarizes theconfirmation soil sampling results from Site 4A. The chromium detected in 1999 does not posea potential risk to human health or the environment because further investigation demonstratedthat the chromium exists the less toxic form (Cr III), and is not present in a significant quantity.No significant volume of contaminated soil remains at the site. The area consists of largeboulders on top of bedrock with small amounts of soil. Site 4A has been cleaned up to the extentfeasible, as there is minimal soil above bedrock.Table 4. Confirmation Sampling Results at Site 4AChemicalCleanup ScreeningMaximumMaximumLevel bLevel aConcentration Concentration(1999)(1999)(2001)Soil (mg/kg)Arsenic11 c28.33.9Chromium3002642212.1Lead40040031144DRO10,2502501,310970Notes: mg/kg – milligrams per kilogram (parts per million)a18AAC75, Table B, Under 40 Inch Zone, Ingestion (May 26, 2004)b18AAC75, Table B, Under 40 Inch Zone, Migration to Groundwater (May 26, 2004)csite background1.6.7 Site 4B – Former USAF Radar StationSite 4B was a US Air Force (USAF) radar station, located on top of Sevuokuk Mountain. Thesite covered an area approximately 375 feet by 500 feet. The radar station consisted of buildingsthat burned and caused ordnance to explode and scatter debris. In 1999, OSCI excavated 52 tonsof contaminated soil to a depth of 24 inches. The excavation area was approximately 29 by 37feet and was partly covered by boulders. The removal included soil with localized heavystaining and an oily substance. OSCI also removed 1.4 tons of miscellaneous metal debris fromSite 4B.SoilDuring the 1994 Phase I investigation, five surface soil samples were collected and analyzed forpetroleum hydrocarbons (TRPH), PCBs, priority pollutant metals, BNAs, and dioxin/furans. Thesampling results identified elevated concentrations of metals and dioxins.During the 1996 Phase II investigation, four additional surface soil samples were collected fromthe edges of the stained soil area to delineate the extent of metals contamination. Samples wereanalyzed for antimony, arsenic, cadmium, copper, and lead. The results were significantly lowerthan those detected during the Phase I. See Table 5 for a comparison of results.One pre-excavation soil sample and six post-excavation confirmation samples were collectedduring the 1999 removal action. The samples were analyzed for DRO, RRO, GRO, VOCs,SVOCs, PCBs, pesticides, metals (antimony, arsenic, cadmium, copper and lead), anddioxin/furans. Sampling results are shown in Table 5. The concentration of dioxins decreasedsignificantly as a result of removing the soils. The USEPA and ADEC have not establishedcleanup levels for dioxins. The USEPA Region 9 has established a screening level of 3.9 ppt fordioxins in residential soil. The State of Alaska adjusts the EPA screening level by one order ofPage 27 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskamagnitude to derive a preliminary remediation goal for residential soil of 39 ppt dioxin. TheAgency for Toxic Substance and Disease Registry (ATSDR) uses a screening level of 50 ppt andan action level of 1,000 ppt for dioxins in soil.In 2001, supplemental RI fieldwork was done at Site 4B to verify the 1999 confirmationsampling results because the latitude and longitude coordinates were not documented. Four soilsamples were collected and analyzed for petroleum hydrocarbons (DRO/RRO/ GRO) and RCRAmetals. As shown in Table 5, these confirmation samples contained no analytes which exceededcleanup levels. Antimony and copper were not analyzed in 2001 because they are not part of thestandard set of 8 RCRA metals (arsenic, barium, cadmium, chromium, lead, mercury, selenium,silver).Copper exceeded the ADEC Table B cleanup level of 4,060 mg/kg, based on the ingestionpathway, in 1 out of 6 samples collected in 1999. The highest concentration of copper in theremaining samples was 65.7 mg/kg. However, the maximum concentration of copper (6,940mg/kg) does not exceed the ADEC Table B cleanup level of 7,000 mg/kg based on the migrationto groundwater pathway. The 1999 sample with elevated copper also contained lead. Furthersampling in 2001 indicated lead at much lower levels, but copper was not included in theanalytical suite.Table 5. Comparison of Maximum Concentrations of Contaminants of Concern in Soil at Site 4BChemicalUnits199419961999 pre1999 post2001 postmaximummaximumexcavationexcavationexcavationresultsresultsresultmax resultsmax resultsAntimonymg/kg130ND (15)-3.3-Arsenicmg/kg3817-1.64.3Cleanuplevel aCadmiumCoppermg/kgmg/kg5226,60061,900---1.86,9400.4--Leadmg/kg3,24984039696TotalDioxins(TEQ)DRORROTRPHpg/g51.2--11.7 mg/L(TCLP)26241 a5.5 a11 e100 a4,060 b7,000 c400 a29--NA dmg/kgmg/kgmg/kg--690----4692,110--13,900984--10,000200--10,250 a10,000 aNANotes: ND – non detect, TEQ – total dioxin/furan equivalent, TCLP – toxicity characterization leaching procedure, NA – not available, -- notanalyzed for, mg/kg – milligrams per kilogram (parts per million), pg/g – picograms per gram (parts per trillion), mg/L – milligrams per litera18AAC75, Table B, Under 40 Inch Zone, ingestion pathway (May 26, 2004)bAdditional Cleanup Levels, ADEC Technical Memo 01-007 (November 24, 2003), ingestion pathway or c migration to groundwaterdThe ATSDR screening level for dioxin is 50 ppt, the ATSDR action level for dioxins is 1,000 ppt. USEPA Region 9, Preliminary RemediationGoal, residential soil (October 2004) for dioxin is 3.9 ppt. The State of Alaska uses a preliminary remediation goal of 39 ppt.esite backgroundNo contaminants of concern remain above ADEC Table B ingestion pathway soil cleanup levels,with the exception of copper. Site 4B is located at the top of Sevuokuk Mountain. The site isdominantly boulders and bedrock, and very little soil is present. It is unlikely that water fromSite 4B impacts the drinking water supply at Site 5 at the base of the mountain since Site 5 issignificantly south of Site 4B and the mountain slopes due west at Site 4B. Surface runoff wouldPage 28 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskalikely travel west off of the mountain or enter bedrock fractures. The steep open slope likelychannels many fractures to the west. At the base of Sevuokuk Mountain, west of Site 4B,groundwater in the gravel spit migrates slowly to the north, away from the drinking watersupply.The elevated copper at Site 4B is an isolated occurrence, confined to de-minimus quantities ofsoil. The contamination is an unlikely threat to the public drinking water supply locatedsouthwest of the Site at the base of Sevuokuk Mountain. It is impractical to remove additionalquantities of soil.1.6.8 Site 4C – Sevuokuk MountainSite 4C is located at the south end of Sevuokuk Mountain, and contained discarded drums alongan ATV trail. Scattered drums were collected from along ATV trails and the surrounding tundraat the southern end of Sevuokuk Mountain by OSCI during the 1999 field season. OSCIremoved a total of 12,516 pounds of drums and drum parts from the Army Trails (Site 10),which included the drums identified at Site 4C. All unsafe debris was removed during the 1999field season.SoilFive soil/sediment samples were collected and analyzed for PCBs during the Phase I remedialinvestigation. PCBs were not detected.1.6.9 Site 4D – Sevuokuk MountainSite 4D is located near the top of Sevuokuk Mountain. Three empty transformer casings andmiscellaneous debris were observed in the mountainside drainage above the pump house.In 1999, OSCI removed the three empty transformers from Site 4D. Wipe samples collectedfrom inside each transformer carcass did not contain any PCBs. All unsafe debris was removedduring the 1999 field season.Soil/Sediment/WaterDuring the 1994 investigation, one soil and four sediment samples were collected and analyzedfor PCBs. No PCBs were detected in the samples collected adjacent to the empty transformers.A background sample collected upgradient contained 0.194 mg/kg PCBs, which is well belowthe ADEC Table B Ingestion pathway cleanup level of 1 mg/kg. In 1996, groundwater from aformer infiltration gallery just downslope of Site 4D was also sampled and analyzed for BTEXand PCBs. No contaminants were detected in the groundwater.1.6.10 Site 4E – Western Face of Sevuokuk MountainVarious types of cable and wire are present on the ground surface along the sloped western faceof Sevuokuk Mountain. The Native Village of Gambell identified this area as an impacted siteduring preparation of a strategic project implementation plan for the Native American LandsPage 29 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaEnvironmental Mitigation Program (NALEMP). The debris is not eligible for further actionunder FUDS.1.6.11 Site 6 – Military LandfillSite 6 is located north of the Gambell High School and east of the new housing area. Thislandfill was used to dispose of building materials, vehicles, machinery, drums of latrine waste,and miscellaneous debris. A geophysical survey to delineate the extent of buried debris wascompleted in 1994.In 1999, OSCI removed exposed drums (7,897 pounds) and other metal debris (1,748 pounds).In 2003, NALEMP funded a removal action at Site 6. Montgomery Watson Harza (MWH)excavated and removed buried debris at the site, including empty 55-gallon drums used tocontainerize latrine waste, engine parts, vehicle parts, Marston matting, metal spikes, piping, tincans, miscellaneous household garbage, and used oil filters. MWH removed approximately1,000 drums and other debris, and excavated 2.5 tons of fuel-contaminated soils. There was nonotable evidence of fuel contamination associated with the buried debris.SoilOne soil sample was collected after removing surface debris from the site in 1999. OSCIcollected the confirmation soil sample from beneath the removed drum stockpile. The soilcontained no metals (except arsenic), fuels, solvents, PCBs, or pesticides above ADEC Table Bcleanup levels based on the migration to groundwater pathway in 18 AAC 75.341.In 2001, a supplemental investigation was conducted to verify the OSCI sampling results and tofurther define the nature and extent of soil and groundwater contamination. Two surface soilsamples were collected from the approximate location of the 1999 confirmation sample, andanalyzed for GRO, DRO, RRO, and RCRA metals. As shown in Table 6, no analytes exceededcleanup levels or site background.Five soil borings were also advanced to frozen soil during the 2001 field effort. Groundwaterwas not encountered in any of the soil borings. Soil samples were collected and analyzed forGRO, DRO, RRO, VOCs, and target analyte list (TAL) metals. Sampling results aresummarized in Table 6. The detected arsenic concentrations exceeded the ADEC Table Bingestion cleanup level of 5.5 mg/kg. The calculated 95% UCL of the mean concentration forarsenic at Site 6 is 7.2 mg/kg. The observed arsenic concentrations in soil are consistent withsite background levels, are not associated with a point source of contamination, and do notappear associated with past military activity. No other analytes were detected in the soil samplesat concentrations exceeding the ADEC Table B soil cleanup levels based on the ingestionpathway.Page 30 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaTable 6. Sampling Results at Site 6ChemicalCleanup Screening ConfirmationLevel aLevel bSample(1999)Soil (mg/kg)Arsenic11c25.3Antimony413.6Chromium300261.33Nickel2,00087DRO10,250250ND(9.35)Range of ResultsConfirmation Samples(2001)Range of ResultsSoil Borings(2001)6 – 7.73.7 – 13.2ND(0.2) – 7.31.1 – 591.3 – 120ND(5) – 1,2003 – 6.3ND(5) – 21Notes: ND - non detect, mg/kg – milligrams per kilogram (parts per million)a18 AAC 75, Table B, Under 40 Inch Zone, Ingestion (May 26, 2004)b18 AAC 75, Table B, Under 40 Inch Zone, Migration to Groundwater (May 26, 2004)csite backgroundGroundwaterGroundwater was evaluated during the initial remedial investigation of 1994. Five borings weredrilled at Site 6. No water was found in three of the borings, but two borings encountered meltedporewater which was sampled through the auger. The groundwater samples were analyzed forpetroleum hydrocarbons (DRO, GRO, TRPH), VOCs, metals, sulfate, biological oxygen demand(BOD), coliform, and total suspended solids/total dissolved solids (TSS/TDS). Low levels ofdiesel range organics and several metals were detected in the samples. Table 7 summarizes thesampling results. Although several metal concentrations did exceed screening levels, the metalswere primarily detected in unfiltered water samples. Exceedances were attributed to soilparticles suspended in the water column. Groundwater has not always been present at Site 6 andthe suprapermafrost groundwater is not considered a likely source of drinking water. The majorsource of potential contamination has been removed from the site and no significant residualcontamination was found in the soil or groundwater.Table 7. Sampling Results at Site 6ChemicalRange of Results(1994)Groundwater (mg/L)DRO0.46 – 0.75Arsenic0.03 – 0.05Beryllium0.007Cadmium0.007 – 0.008Chromium0.107 – 0.364Chromium, dissolved0.006Lead0.12 – 0.172Lead, dissolved0.008Nickel0.08 – 0.153ScreeningLevel a1.50.050.0040.0050.10.0150.1Notes: mg/L – milligrams per liter (parts per million)a18 AAC 75, Table C (May 26, 2004)1.6.12 Site 7 – Former Military Power FacilitySite 7 is located north of the Gambell Municipal Building, and west of the Gambell School. Amilitary power facility was reportedly demolished and buried in this location. A military motorpool building was also believed to be located in this vicinity. The site contained a concrete padPage 31 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskaand surface debris. A geophysical survey to locate buried debris was completed in 1994. Thesurvey revealed no major anomalies indicative of large amounts of buried metal. MontgomeryWatson removed all exposed surface debris in 1996. In 1999, OCSI verified that no measurablequantities of surface debris remained at the site.During 2003, MWH removed the concrete pad, underlying support timbers, a buried 55-gallondrum, and 1 cubic yard of incidental contaminated soils under NALEMP.SoilDuring the 1994 investigation, five soil borings were drilled to permafrost (6.5 to 15.0 feet belowground surface) and four were completed as monitoring wells. Two surface soil samples and 17subsurface soil samples were collected and analyzed for VOCs, GRO, DRO, TRPH, and prioritypollutant metals. The subsurface soil samples were also analyzed for PCBs.The investigation results indicated DRO and TRPH were present in surface and subsurface soil.The DRO concentrations did not exceed the ADEC Table B soil cleanup levels based on theIngestion pathway. There are no ADEC cleanup levels for TRPH. Table 8 summarizes theresults. No other analytes were present at concentrations exceeding the ADEC cleanup levels.Additional soil borings were drilled in 2001 to further investigate the potential for soilcontamination, and to address continuing community concerns regarding Site 7. Three soilborings (SB7-18, SB7-19, SB7-20) were drilled to permafrost (6.2, 7.2 and 10.0 feet bgs). The2001 investigation results showed DRO in one soil sample at a maximum concentration of 710mg/kg, which does not exceed the ADEC Table B ingestion cleanup level of 10,200 mg/kg.Arsenic was detected at concentrations ranging from 4.5 to 10.2 mg/kg, with a calculated 95%UCL of the mean concentration of 7.8 mg/kg at Site 7. Six of the eleven arsenic results exceededthe ADEC Table B ingestion cleanup level of 5.5 mg/kg arsenic. However, the observed arsenicconcentrations in soil are consistent with site background levels, are not associated with a pointsource of contamination, and do not appear associated with past military activity. PCBs were notdetected in any Site 7 samples. No other analytes were detected in the soil samples atconcentrations exceeding the cleanup levels.After the 2003 removal action, MWH collected five confirmation soil samples from the edges ofthe concrete pad excavation and one sample from beneath the excavated drum (see Figure 4).The soil samples were analyzed for DRO, RRO, PCBs, and TAL metals. One sample containedDRO at 570 mg/kg, which does not exceed the ADEC Table B ingestion cleanup level of 10,200mg/kg. This detection may correspond to leakage from a community fuel pipeline present at theedge of the pad. The five samples near the concrete pad contained arsenic levels ranging from4.2 to 34.9 mg/kg, which exceeds the ADEC Table B ingestion cleanup level of 5.5 mg/kg, andmay correspond to leached preservative from the treated timbers used as a form surrounding theconcrete pad. The arsenic concentrations are also significantly higher than site backgroundconcentrations and may pose a risk to human health and the environment.Page 32 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaTable 8. Sampling Results at Site 7 during 1994 investigationSS40,SB17MW24MW25SoilSS41(mg/kg)Arsenic3.0 – 4.02.0 – 5.42.0 – 4.01.0 – 2.0DRO1,950–ND20–94120–2712,090GRONDNDNDNDTRPH1,800–ND–4713–180400–1,3004,300BenzeneND(0.005) ND(0.005) ND(0.005) ND(0.005)MW26MW272.0 – 5.4NDCleanupLevel11 d10,250 aScreeningLevel2.0 b100 c2.018–1,840ND115–13,000ND(0.005)NDND–1621,400 aNA100 c2,000 cND(0.005)150 a0.5 cScreeningLevel b2.0Notes: NA - not available, ND - not detected. mg/kg – milligrams per kilogram (parts per million)a18 AAC 75 Table B, Under 40 Inch Zone, Ingestion (May 26, 2004)b18 AAC 75 Table B, Under 40 Inch Zone, Migration to Groundwater (May 26, 2004)cADEC Interim Guidance, Level A soil cleanup targets (July 17, 1991)dsite backgroundTable 9. Sampling Results at Site 7 (2001 and 2003)SB118SB119SB120 SL001 SL002Soil(mg/kg)Arsenic6.3 –4.5 – 10.24.9 –34.99.67.39.8DROND45 - 67160 570100710GRONDNDNDNDNDRROND120 - 310ND1,300480BenzeneNDNDNDNDND(0.005)(0.008)(0.005) (0.02)(0.02)SL003SL004SL0054.227.93.2CleanupLevel a11 c1209911 VJ10,250 a250ND370ND(0.02)ND430ND(0.02)ND38 VJND(0.02)1,400 a10,000 a150 a30011,0000.2Notes: ND - not detected, mg/kg – milligrams per kilogram (parts per million), VJ – analyte positively identified, estimated value.a18 AAC 75 Table B, Under 40 Inch Zone, Ingestion (May 26, 2004)b18 AAC 75 Table B, Under 40 Inch Zone, Migration to Groundwater (May 26, 2004)csite backgroundGroundwaterDuring the 1994 investigation, four monitoring wells were installed at Site 7 (see Figure 4).Three monitoring wells (MW24, MW25, MW27) encountered perched groundwater, but theywere essentially dry wells. The monitoring wells were installed by drilling down into the ice tocreate a reservoir which would collect melted groundwater. A fourth well (MW26) wasabandoned without collecting a groundwater sample due to lack of water. Suprapermafrostgroundwater was collected from the three wells, but the lack of water in these wells preventedstandard well development. The groundwater samples were analyzed for VOCs, GRO, DRO,TRPH, priority pollutant metals, and PCBs. A sufficient quantity of water could not bewithdrawn from MW27, and the sample was only submitted for analysis of VOCs, DRO, andpriority pollutant metals. DRO, GRO and TRPH were detected in the groundwater. Benzene wasalso detected in monitoring well MW24. The DRO and benzene results exceed the ADEC TableC groundwater cleanup levels. Water sample turbidity ranged from 9.3 to 82.5 NephelometricTurbidity Units (NTUs). This suggests that the laboratory results included contributions fromsuspended solids. Table 10 summarizes the Site 7 groundwater results.Page 33 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaTable 10. Sampling Results at Site 7 during 1994 investigationChemicalMW24MW25MW26MW27Groundwater (mg/L)DRO18.4GRO0.844TRPH4.2Benzene0.019Turbidity (NTUs)82.519.4--ND (0.0005)50.1------ADECCleanup Level a1.180.1031.1ND (0.0005)9.31.51.3NA0.0055bNotes: NA - not available, ND - not detected, NTU - nephelometric turbidity units, -- not analyzed formg/L – milligrams per liter (parts per million)a18AAC75 Table C cleanup levels (May 26, 2004)bgeneral standard for well samplingAdditional borings were drilled in 2001 to further investigate the potential for suprapermafrostgroundwater contamination, and to address continuing community concerns regarding Site 7.Three borings were drilled to permafrost (6.2, 7.2 and 10.0 feet bgs); but groundwater was notencountered in any of the soil borings.The supplemental investigation demonstrated that the groundwater at Site 7 is ephemeral, andsoil contamination is below cleanup levels. The risk of contaminant migration east towards theaquifer located at the base of Sevuokuk Mountain is extremely low.Figure 4 – Sampling Locations at Site 7!<SB27-1HouseSB27-2!<!<SB27-3"Q" BuildingHouse!(SS41MW26!( SS40SB7-18!<A!<SB1707SL00107SL00207SL00307SL00407SL005!({0MW27!<SB7-19100FeetPage 34 of 66Former Concrete Pad(removed 2003)!( A!(!(!(A MW25A50FormerMW24!<Community fuel pipelineSB7-20Decision DocumentGambell SiteSt. Lawrence Island, Alaska1.6.13 Sites 8A, 8B, 8C, 8D – West Beach AreaSite 8 includes the area surrounding the airstrip from west beach (north of the airfield), east tothe western edge of Troutman Lake, and south to the northern shore of North Nayvaghat Lakes.Exposed Marston matting debris (8A) is located along the eastern side of the airstrip. Buriedmiscellaneous metallic debris (8B) has been reported south of the old village area, includingnumerous 55-gallon drums and a Jeep. A Navy Landfill (8C) is located northwest of the formerCivil Aeronautics Administration (CAA) housing area and south of the village landfill. TheNavy reportedly constructed this landfill during their utilization of the former CAA housing area.The Navy landfill may have asbestos-containing materials (ACM). An Army landfill was alsoreportedly located northwest of the Nayvaghat Lakes area. A geophysical survey to determinethe extent of buried debris at the reported Army landfill was conducted in 1994. The surveyresults indicated no significant anomalies, confirming the reported Army landfill was not present.AirstripSmall-arms ammunition debris including intact 0.30 caliber rounds is also located along thebeach (8D) southwest of Troutman Lake. The buried debris is not eligible for further actionunder FUDS. FUDS Program Policy (ER 200-3-1), Chapter 3 (3-2.4.5 Building Demolition andDebris Removal Projects.) states that “Inherently hazardous BD/DR must present a clear danger,likely to cause, or having already caused, death or serious injury to a person exercising ordinaryand reasonable care.” In the OE Response ActionMemorandum for the Gambell Site, signed 16 October2003, it states on page 1 “During the EE/CA fieldinvestigation, ordnance was found at only one of theGambell sites (Area D), comprised solely of small armsammunition. Small arms ammunition does not presenta hazard to human safety, the environment, or publicinterest unless intentionally subjected to intense heat orother energetic activities.” Intentionally subjectingthese small rounds to intense heat is not exercisingSite8Aordinary and reasonable care.The Marston matting at Site 8A was abandoned inplace when the military demobilized from the area inthe late 1950s. The exposed Marston matting debris islocated in an area heavily traveled by local residentsusing all terrain vehicles and snowmobiles. The debrisposes a clear danger to local residents who frequentlytraverse the area on ATVs and snowmachines due tothe sharp and jagged edges which protrude above theground surface and large piles which create anavigation hazard during the winter when partiallycovered by snow.In 1999, OSCI removed surface debris from Site 8A,including scattered metal, small quantities of wood andconcrete, and an exposed layer of Marston mattingTroutmanLakeATVTrailSite 12North AreaSite 8D±0500 1,000FeetNorthNayvaghatLakesFigure 5 – Site 8 vicinity mapPage 35 of 66Site 12South AreaDecision DocumentGambell SiteSt. Lawrence Island, Alaskaapproximately 30 feet wide and 4,500 feet long along the eastern side of the airstrip. OSCI didnot complete the planned removal of the Marston matting because buried electrical linesprevented safe implementation of the field activities. Approximately 1,820 feet of exposed metalMarston landing mat remains at Site 8A.Earth Tech, Inc. recovered approximately 800 small arms ammunition rounds from Site 8D inJuly 2000, and shipped the material off-site to a facility in Colfax, Louisiana for disposal.Soil/GroundwaterA remedial investigation was completed in 1994 and included collection of limited soil andgroundwater samples at the reported Army landfill area located northwest of the NayvaghatLakes area. No samples were collected from other sub-areas of Site 8. The investigation resultsindicated that all detected analytes in soil/groundwater were below ADEC Table B cleanuplevels, based on the migration to groundwater pathway.Military MunitionsIn 2000, Earth Tech, Inc. surveyed Site 8D using metal detectors to locate possible ordnance andexplosive materials. Highly weathered small arms rounds were documented in a beach burial pitsouthwest of Troutman Lake. Approximately 800 small arms ammunition rounds wererecovered from the surface of Site 8D and shipped off-site to a facility in Colfax, Louisiana fordisposal. An OE Response Action Memorandum dated August 2003 documented the selectedordnance and explosives response actions for the Gambell site. Institutional controls wereapproved to manage any existing ordnance-related hazards and residual risks. The institutionalcontrols were implemented during the summer of 2004 and consisted of distributinginformational pamphlets and posters about ordnance risks to local residents and businesses andholding a community meeting. An initial review to evaluate the continued effectiveness andreliability of the ordnance response action will be conducted in 3 years. After the initial reviewhas been conducted, recurring reviews will be performed at 5-year intervals. The need forrecurring reviews will be coordinated with regulators and stakeholders and justified in eachrecurring review report.1.6.14 Site 9 – Asphalt Barrel CacheSite 9 is located on the east side of the local airport runway. Drums of leaking tar were observedin two areas. A debris inventory prepared by Montgomery Watson in 1997 indicated drumscontaining asphalt (6,200 estimated pounds) and empty drums (900 pounds) were located withinSite 8, which includes the area referred to as Site 9.OSCI overpacked and removed nine drums of asphalt (4,458 pounds) and associated stained soils(4,790 pounds) from east of the runway during the 1999 removal action. All empty drums werealso removed. All unsafe debris and contaminated soil have been removed from the site.SoilOSCI collected one confirmation soil sample after removing the asphalt drums and stained soil.The sample was analyzed for petroleum hydrocarbons (DRO, GRO, RRO), VOCs, SVOCs,Page 36 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaPCBs, pesticides, and metals. The results indicated that all analytes were either not detected orbelow the ADEC Table B cleanup levels based on the migration to groundwater pathway.In 2001, two additional soil samples were collected to verify the 1999 results. The samples wereanalyzed for petroleum hydrocarbons (DRO, GRO, RRO), and RCRA metals. Arsenic wasdetected at concentrations of 5.3 and 6.8 mg/kg, which exceeds the ADEC Table B ingestioncleanup level of 5.5 mg/kg. However, the levels are consistent with site background levels anddo not appear associated with past military activity. All other analytes were either below thecleanup levels or not detected.1.6.15 Site 10 – Sevuokuk Mountain TrailSite 10 consists of a trail system that originates at the southeast end of Troutman Lake andseparates into individual trails to the north, south, and east. Two trails lead to the top ofSevuokuk Mountain. Empty 55-gallon drums located approximately 250 feet apart marked thetrails. Other debris at the site included Marston matting and weasel tracks. No staining orstressed vegetation was observed during the initial remedial investigation and the drums wereeither empty or contained gravel.In 1999, OSCI removed all the scattered drums (12,516 pounds), miscellaneous metallic debris(1,388 pounds), and a small amount (540 pounds) of stained soils from beneath the drums. Allunsafe debris has been removed from the site.1.6.16 Site 11 – Communications Cable RouteSite 11 contained a sonar cable going up Sevuokuk Mountain, abandoned cable spools, and aremnant of braided metal cable on top of the mountain. The only evidence of sonar cables weresome cable spools observed near Site 4D during the 1994 remedial investigation. OSCI removedthe debris at Site 4D during the 1999 removal action. The remaining debris is not eligible forfurther action under FUDS.1.6.17 Site 12 – North Nayvaghat Lakes Disposal SiteSite 12 is located north of Nayvaghat Lakes on the southwest side of an all-terrain vehicle (ATV)trail. The site is divided into a north and a south area. The north area contained approximately120 drums, battery remnants, and miscellaneous metal debris. The south area containedapproximately 50 drums. The area south of Troutman Lake is within the City of Gambellboundary. The area is currently used primarily for recreation, subsistence food gathering, and asa gravel borrow source. However, this site has the potential to be developed for residential usein the future, given the flat topography and close proximity to a new drinking water source.In 1999, OSCI removed contaminated soil and debris from the site including drums, dried paint,and batteries from large vehicles consistent with former military use. OSCI removed 798 poundsof miscellaneous metal debris; 7,104 pounds of drums; 1,598 pounds of RCRA hazardousmaterials (lead contaminated soil, lead acid batteries, and lead paint); and 7,237 pounds ofpetroleum-stained soil associated with the drums.Page 37 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaSoilA remedial investigation was conducted in 1994; soil confirmation samples were collectedfollowing the 1999 removal action. Additional investigation was performed in 2001.Three surface and two subsurface soil samples were collected in 1994. The soil samples wereanalyzed for VOCs, GRO, DRO, TRPH, priority pollutant metals, and PCBs. Except for arsenic,the concentrations of metals detected in the soil samples were below screening levels. Arsenicconcentrations ranged from 4 to 10 mg/kg, consistent with site background levels. No otheranalytes were detected in the soil samples. Three confirmation surface soil samples were alsocollected after completing the 1999 removal action. Arsenic, cadmium, lead, and DRO weredetected in soil at concentrations exceeding screening levels based on the ADEC Table Bcleanup levels, migration to groundwater pathway.In 2001, supplemental RI fieldwork was completed at Site 12 to verify the previous confirmationsampling results. Five surface soil samples were collected and analyzed for petroleumhydrocarbons (GRO, DRO, RRO), and RCRA metals. Chromium and lead exceeded the ADECcleanup levels. DRO and cadmium were not detected at concentrations exceeding the cleanuplevels. The arsenic levels at Site 12 are consistent with site background levels and do not appearassociated with past military activity. The sampling results are summarized in Table 11. Noother analytes were detected at concentrations exceeding the ADEC cleanup levels.Table 11. Confirmation Sampling Results at Site 12ChemicalCleanupRange ofRange of ResultsLevelResults(2001)(1999)Soil (mg/kg)Arsenic11 c3–66 – 9.4Cadmium5a0.18 - 142ND(0.2) – 1.6Chromium26 a2.6 - 205.7 – 162Lead400 b12.4 - 5627 – 1,530DRO250 a463ND(5) – 46Notes: ND - non detect, mg/kg – milligrams per kilogram (parts per million)a18AAC75 Table B, Under 40 Inch Zone, migration to groundwater pathway(May 26, 2004)b18AAC75 Table B, Under 40 Inch Zone, ingestion pathway (May 26, 2004)csite backgroundWaterDuring the 1994 remedial investigation, one surface water sample was collected from NorthNayvaghat Lake, and two groundwater monitoring wells were installed. The three water sampleswere analyzed for VOCs, GRO, DRO, TRPH, PCBs, and priority pollutant metals. DRO andmetals were detected at low levels in surface water and groundwater, but did not exceed theADEC Table C cleanup levels.Page 38 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaFigure 6 – Site 12 vicinity mapSerstripTrailtn.MW18ASS47kM10ATV10AikuvuoSepticareaSS46MW17((!!"$)+99GAM009SLA01GAM012SS150SW165#*01GAM0123SS151$"+)Lakes99GAM919SLvaghatSS48Nay{01GAM012SS152!(+$)"99GAM011SL050100Feet1.6.18 Site 13 – Former Radar Power StationSite 13 is located east of the pond between Troutman and North Nayvaghat Lakes. The radarpower station consisted of two wooden Quonset huts, one long wooden building, and several 150foot towers that were reportedly demolished and buried on-site. Stained soils and miscellaneoussurface debris such as steel wire, pipes, and Marston matting were observed at the site.A geophysical survey was conducted in 1994 to determine the extent of buried debris. Thesurvey revealed strong anomalies around two mounds and scattered surface debris which areprobably related to significant amounts of buried material. In 1999, OSCI removed 343 poundsof miscellaneous metal debris from surface areas at Site 13. The buried debris is not eligible forfurther action under FUDS.Page 39 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaSoilTwo surface and five subsurface soil samples were collected during the 1994 remedialinvestigation. The subsurface soil samples were analyzed for VOCs, petroleum hydrocarbons(GRO, DRO, TRPH), priority pollutant metals, and PCBs. Surface soil samples were analyzedfor TRPH, PCBs, and priority pollutant metals. No analytes, except arsenic, were detected atconcentrations exceeding ADEC Table B cleanup levels based on the migration to groundwaterpathway. Arsenic concentrations ranged from 2 to 6 mg/kg, with a calculated 95% UCL of themean concentration at Site 13 of 4.5 mg/kg, compared to the ADEC Table B ingestion cleanuplevel of 5.5 mg/kg.WaterThree monitoring wells were installed during the 1994 remedial investigation. Groundwater wasencountered from 2 to 4 feet bgs and samples from all 3 wells were analyzed for VOCs, GRO,DRO, TRPH, PCBs, and priority pollutant metals. DRO (0.053 to 0.159 mg/L) and TRPH (0.2to 0.4 mg/L) were detected at low levels, but did not exceed ADEC Table C cleanup levels.1.6.19 Site 14 – Navy Plane Crash SiteSite 14 is located approximately 7 miles south of the Village of Gambell. A Navy P2V-5Neptune reconnaissance plane crash landed at this location in June 1955 after being attacked byRussian aircraft. The aircraft’s gasoline tank exploded and most of the fuels burned leaving noapparent stains or any stressed vegetation at the site. Debris remains on the tundra, in the areaimmediately surrounding the crash site.The plane crash location is outside the military property boundary identified for the Gambell site,and is therefore not eligible for action under the FUDS program. There is no reason to believehazardous materials are/were present.1.6.20 Site 15 – Troutman Lake Disposal SiteSite 15 was reported to contain submerged ordnance and other debris at the north end ofTroutman Lake. The underwater debris (miscellaneous metal debris) is not eligible for furtheraction under FUDS.Military MunitionsDuring 2000 and 2001, Troutman Lake was investigated using geophysical surveyingtechniques. The entire lake bottom was mapped along a series of transect lines, to detectunderwater anomalies representative of piles of steel ammunition boxes. Metallic anomaliesdetected by the equipment were then further investigated using ice augers, depth soundingequipment, poles, and an underwater video camera to determine the source of the metal signal.An open water investigation was also conducted to verify the anomaly source using dredginganchors, depth-sounding leads, and an underwater camera. Anomaly locations within 20 feet ofthe lakeshore were verified by visual inspection. The source of the magnetic anomalies rangedfrom runway matting and 55-gallon drums, to geologic features such as iron and fault features.No evidence of ordnance or large piles of ammunition boxes was discovered in Troutman Lake.Page 40 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaAdditional details regarding the ordnance investigation can be found in the report FinalEngineering Evaluation/Cost Analysis (Earth Tech Inc., 2002).1.6.21 Site 16 – Gambell Municipal Building SiteSite 16 consisted of a 35 by 55-foot area of stained gravel, located immediately west of theMunicipal Building. The origin of the stain is unknown, and staining is most visible after arainfall event. A geophysical survey was conducted in 1994. The survey results revealed foursmall anomalies which may be related to buried materials. The buried debris is not eligible forfurther action under FUDS.SoilSurface and subsurface soil samples were collected during the 1994 remedial investigation. Foursurface soil samples were analyzed for petroleum hydrocarbons (DRO, GRO, TRPH), andpriority pollutant metals. Three subsurface soil samples from one soil boring were analyzed forVOCs, GRO, DRO, TRPH, PCBs, and priority pollutant metals. Groundwater was notencountered in the soil boring. Arsenic results ranged from 2 to 7 mg/kg, with a calculated 95%UCL of the mean concentration at Site 16 of 5.4 mg/kg. Only 1 out of 7 samples exceeded theADEC Table B ingestion cleanup level of 5.5 mg/kg. No other contaminants were identified atSite 16 above the ADEC Table B migration to groundwater pathway soil cleanup levels.In 2001, four additional soil borings were drilled at the site based on community concerns. Thesoil samples were analyzed for petroleum hydrocarbons (DRO, GRO, RRO), VOCs or BTEX,and TAL metals. No analytes (except arsenic) were detected in any sample above ADEC TableB cleanup levels based on the migration to groundwater pathway. Arsenic concentrations rangedfrom 3.6 to 9.8 mg/kg. Only 1 sample exceeded the ADEC Table B ingestion cleanup level of5.5 mg/kg. The arsenic levels are consistent with site background levels and do not appearassociated with past military activity.1.6.22 Site 17 – Army LandfillsThe Army Landfills are located between the North Beach and Site 6 Military Landfill, which isnorth of the Gambell School and Municipal Building. The two landfills reportedly containedburied debris and/or trash, as well as exposed surface debris such as drums, Marston matting, andscrap metal. A geophysical survey of the area was conducted in 1994. The survey resultsindicated the potential for buried debris associated with the reported landfills. The remainingburied debris is not eligible for further action under FUDS.Exposed miscellaneous surface debris, including nodwell tracks, Marston matting, steel cableand scrap metal, was removed by OSCI during the 1999 removal action. The actual tonnage ofdebris removed was combined with Site 6 for a total of 1,748 pounds.SoilSoil samples were collected during the 1994 remedial investigation. Five soil borings werecompleted to permafrost (7.5 to 10.5 feet). Samples were analyzed for petroleum hydrocarbons(GRO, DRO, TRPH), VOCs, PCBs, and priority pollutant metals. Arsenic ranged from 2 to 6Page 41 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskamg/kg in soil, compared to the ADEC Table B ingestion cleanup level of 5.5 mg/kg. Only 1sample out of 13 exceeded the ADEC cleanup level. The arsenic levels are consistent with sitebackground levels and do not appear associated with past military activity. No other analyteswere detected in soil above ADEC Table B migration to groundwater cleanup levels.WaterMonitoring wells were not installed at the site because well completion was impractical. Meltedporewater samples were collected through the auger and submitted for analysis of VOCs, PCBs,petroleum hydrocarbons (GRO, DRO, TRPH), and priority pollutant metals. No groundwatercontaminants exceeded the ADEC Table C cleanup levels.1.6.23 Site 18 – Former Main CampSite 18 is located at the northeast end of Troutman Lake, between the current Municipal Buildingand the Gambell School. A geophysical survey was conducted in 1994 to determine the presenceof buried debris. The survey showed a linear anomaly in the center of the survey grid, betweenthe high school and the washeteria. This feature was thought to represent water delivery lines forthe existing Power Plant. The buried debris is not eligible for further action under FUDS.SoilSoil samples were collected during the 1994 remedial investigation. One soil boring was drilledsouth of the anomaly due to the reported burial of discarded underground storage tanks in thevicinity. Subsurface soil samples and melted porewater were collected and analyzed for VOCs,petroleum hydrocarbons (DRO, GRO, TRPH), priority pollutant metals, and PCBs. No analyteswere detected above screening levels based on the ADEC Table B migration to groundwaterpathway cleanup levels. Arsenic concentrations in soil ranged from 2 to 5 mg/kg, and did notexceed the ADEC Table B ingestion cleanup level.During the 2001 investigation, further sampling was conducted at Site 18 based on communityconcerns. One soil boring was placed adjacent to the north fence of the Municipal WaterTreatment/Washeteria Complex. The soil boring, 18A-1, was advanced to 17.5 feet belowground surface, and two soil samples were collected near the bottom of the boring at 12 and 14 ftbgs. The samples were analyzed for petroleum hydrocarbons (DRO, GRO, RRO), VOCs, andTAL metals. DRO was detected at concentrations ranging from 54 to 640 mg/kg in subsurfacesoil, which does not exceed the ADEC Table B ingestion cleanup level of 10,250 mg/kg.Arsenic was detected at concentrations ranging from 5.6 to 5.9 mg/kg, which slightly exceeds theADEC Table B ingestion cleanup level of 5.5 mg/kg. Arsenic levels are consistent with sitebackground levels and do not appear associated with past military activity. No other analyteswere detected above screening levels based on the ADEC Table B migration to groundwatercleanup levels.GroundwaterIn 2001, one well point was also installed at the location of soil boring 18A-1 and free productwas observed. The free product recovered from the well point appeared clear and clean, and hadthe strong odor of fresh fuel, features not typical of degraded fuels from previous militaryactivities. The free product was not sampled because the origin of the fuel was believed to bePage 42 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskanon-military. In 1997, the City of Gambell lost a reported 10,000 gallons of fuel while pumpingfuel from the north beach (via pipelines) to Site 18, the missing fuel was never located.Further investigation of the reported free product was conducted in July 2004. A well point wasinstalled in the same location as the previous well point. A groundwater sample was collectedand analyzed for total petroleum hydrocarbons (TPH) as diesel. A complete fuel characterizationanalysis (fingerprint) was not possible because enough free product could not be extracted fromthe water sample. The water sample had a sheen, but no obvious free product layer. The samplecontained 22 mg/L TPH, and the peak distribution was characteristic of a light diesel such asarctic diesel. The laboratory narrative report indicated the sample from Site 18 wascharacteristic of other fresh fuels dispensed in the United States and had experienced, at most,mild degradation from environmental exposure, based on interpretation of the chromatogram.1.6.24 Site 19 – Diatomaceous EarthSite 19 was identified as a separate area of concern by the Native Village of Gambell under theNALEMP program. This area coincides with the description of Site 18 presented above. Awhite powdery material was observed in a berm which borders Troutman Lake, and wasdetermined to be inert, diatomaceous earth previously used for water filtration by the military.Diatomaceous earth is an inert material which does not pose a chemical hazard, and thus cannotbe addressed further under the FUDS program.1.6.25 Site 20 – SchoolyardSite 20 is located north of the former Main Camp (Site 18) near the current Gambell School.The schoolyard contained two rubble piles that consisted primarily of concrete and rebar, plus apartially exposed concrete slab. The piles presented a physical hazard to local residents such aschildren attending school, ATV and snowmachine traffic. The rubble piles and concrete padwere removed in August 2003 under the NALEMP program.1.6.26 Site 21 – Toe of Sevuokuk MountainSite 21 is located at the base of Sevuokuk Mountain and southwest of Site 5, and is thought tocontain buried miscellaneous wire and metallic debris from military activities. The buried debrisis not eligible for further action under FUDS.1.6.27 Site 22 – Former CAA HousingFormer Civil Aeronautical Administration (CAA) Housing units are located near the northeastedge of the Old Gambell section of the village. The CAA housing area consists of six homes andone lodge originally built as a weather data collection facility to help guide Russian pilots duringWorld War II. The Navy and Army also reportedly used the housing area in the Cold War eraduring their efforts to lay submarine detection cables off the coast of St. Lawrence Island. Thissite was identified as a concern under the NALEMP program due to the possibility that asbestoscontaining materials may be present in the structures.Page 43 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaThe buildings are presently occupied and/or owned by local residents, thus they do not qualifyfor further action under FUDS due to beneficial reuse.1.6.28 Site 23 – Debris from High School ConstructionSite 23 was identified by local residents as a concern in the Strategic Project ImplementationPlan (SPIP) produced for the NALEMP program. The area is located due east of the Gambelllandfill and consists of metallic debris that was originally unearthed during the construction ofthe Gambell High School. The City of Gambell moved the excavated debris to the local landfillfor reburial.Removal actions undertaken by current landowners are not eligible for reimbursement or furtheraction under FUDS. The buried debris is not eligible for further action under FUDS.1.6.29 Site 24 – South of Municipal BuildingSite 24 is located south of the Municipal Building along the northern shore of Troutman Lake. Ageophysical survey of the site was conducted in 2000, and subsurface anomalies consistent withmetallic debris were found. The buried debris is not eligible for further action under FUDS.SoilDuring the 2001 supplemental remedial investigation, one soil boring was drilled to frozen soil.Two soil samples were collected and analyzed for petroleum hydrocarbons (DRO, GRO, RRO),VOCs, and TAL metals. The soil samples contained arsenic at concentrations of 5.7 and 6.3mg/kg. The arsenic levels are consistent with site background levels and do not appearassociated with past military activity. Fuels were not detected in the soil samples. No otheranalytes were detected at concentrations exceeding the ADEC Table B migration to groundwatercleanup levels.1.6.30 Site 25A – Village of Gambell South Housing UnitsLocal residents identified the south housing units, Site 25A, during the 2001 investigation as anarea that may be contaminated by fuel-related products of military origin. During constructionwork performed in 1997 by Alaska Village Safe Water, oily soils were encountered at thepermafrost interface. Residents are concerned that the military may have dumped barrels of oildirectly on the ground in this area.SoilDuring the 2001 supplemental investigation, six soil borings were drilled to permafrost. Soilborings were selected based on the location of depressions and trenches identified on historicalaerial photographs, and disturbed ground identified by local residents. The field crew carefullyavoided buried utility corridors.Eighteen subsurface soil samples were collected and analyzed for petroleum hydrocarbons(DRO, GRO, RRO), and BTEX. A subset of five samples was also analyzed for VOCs and TALmetals. The results were compared to the ADEC Table B cleanup levels based on the migrationPage 44 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskato groundwater pathway. Fuels, BTEX and VOCs were not detected above ADEC Table Bmigration to groundwater cleanup levels in any sample. Arsenic was detected at concentrationsfrom 2.2 to 19.2 mg/kg. Three of the five samples exceeded the ADEC Table B ingestioncleanup level of 5.5 mg/kg. The arsenic levels are consistent with site background levels, are notassociated with a point source of contamination, and do not appear associated with past militaryactivity.1.6.31 Site 25B – Low Drainage Area Southwest of ArmoryLocal residents identified Site 25B during the 2001 supplemental investigation as an area wherecontaminants may migrate and accumulate. The site is located west of the Sivuqaq Lodge,southeast of the Gambell store and fuel storage tanks, and near a local church and Army Guardbuilding.SoilTwo soil borings were drilled to frozen soil (depth of 11 and 12 feet) to identify potentialcontamination. Six subsurface soil samples were collected and analyzed for petroleumhydrocarbons (DRO, GRO, RRO) and BTEX. One sample was also analyzed for PCBs. Thesoil sampling results were compared with the ADEC Table B cleanup levels, based on themigration to groundwater pathway. No analytes were detected at concentrations exceeding theTable B cleanup levels.1.6.32 Site 26 – Possible Debris Burial SiteSite 26 was identified from a 1953 aerial photograph as a possible debris burial feature. The siteis located east of the Gambell School near the Former Main Camp (Site 18). Local residentsreported finding metal debris, machinery, oily debris, and transformers in this vicinity.SoilDuring the 2001 supplemental remedial investigation, two soil borings were drilled to frozensoil. Four subsurface soil samples were collected and analyzed for petroleum hydrocarbons(DRO, GRO, RRO), VOCs, and TAL metals. Arsenic was detected at concentrations rangingfrom 3.6 to 7.7 mg/kg in surface and subsurface soils. One out of four samples exceeded theADEC Table B ingestion cleanup level of 5.5 mg/kg. The arsenic levels are consistent with sitebackground levels and do not appear associated with past military activity. No other analyteswere detected above the ADEC Table B migration to groundwater cleanup levels.1.6.33 Site 27 – Drum Storage AreaAnalysis of an aerial photograph from 1955 indicated this location was a historical drum storagearea. The community was also concerned about an area of rust-stained soil at this site. The siteis located north of the former military power facility (Site 7), within the new housing area. Thedrums stored at this site have been removed.Page 45 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaSoilDuring the 2001 supplemental remedial investigation, four soil borings were drilled to frozen soilto determine if contamination was present. Eight subsurface soil samples were collected andanalyzed for petroleum hydrocarbons (DRO, GRO, RRO), VOCs, PCBs, and TAL metals. Thesoil sampling results were compared with the ADEC Table B cleanup levels, based on themigration to groundwater pathway. Arsenic concentrations ranged from 5.4 to 16.9 mg/kg. Theobserved arsenic concentrations are consistent with site background levels, are not associatedwith a point source of contamination, and do not appear associated with past military activity.No other analytes were detected in the soil samples at concentrations above the ADEC Table Bcleanup levels based on the migration to groundwater pathway.1.6.34 Site 28 – Disturbed GroundSite 28 was identified from a 1972 aerial photograph as a disturbed area. This site is locatedsouth of Troutman Lake and west of an unnamed pond. The U.S. Army leased this area fromJanuary 1955 to May 1958 and utilized the area for communications.SoilDuring the 2001 supplemental investigation, two soil borings were advanced to frozen soil todetermine if contamination was present. Six subsurface soil samples were collected andanalyzed for petroleum hydrocarbons (DRO, GRO, RRO), VOCs, and TAL metalsThe sampling results were compared with the ADEC Table B cleanup levels, based on themigration to groundwater pathway. Arsenic concentrations ranged from 5.5 to 10 mg/kg. Thearsenic levels are consistent with site background levels and do not appear associated with pastmilitary activity. No other analytes in the soil samples exceeded the ADEC Table B migration togroundwater pathway levels.Page 46 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaska1.7 Summary of Site RisksContaminants of concern were identified during the Remedial Investigation by comparison torisk-based screening levels and cleanup criteria. Screening levels were based on the moststringent Alaska Department of Environmental Conservation (ADEC) soil and groundwatercleanup levels promulgated in 18 Alaska Administrative Code (AAC) 75.341 and 345. TheADEC regulates cleanup of contaminated sites in Alaska. The cleanup levels established by theADEC are based on an estimate of the reasonable maximum exposure expected to occur undercurrent and future site conditions and are designed to be protective of human health and theenvironment. The cleanup level from Table B1 or B2 that applies at a site depends on theapplicable exposure pathway based on ingestion, inhalation, or the migration to groundwaterpathway.The soil cleanup standards regulations in Tables B1 and B2 of 18 AAC 75.341 set out threedifferent sets of soil cleanup standards based on climate variations ("zones") throughout the state.These zones were developed based on a sensitivity analysis of the factors affecting the migrationof contaminants through the soil into groundwater. The resulting three climate zones were:"Arctic" (continuous permafrost), "Under 40 Inch Zone" (that area of the state receiving less than40 inches of annual precipitation), and "Over 40 Inch Zone" (that area of the state receiving morethan 40 inches of annual precipitation). The Gambell Site is located in area which receives lessthan 40 inches of rainfall per year.Each zone was also assigned a conservative estimate of the reasonable exposure frequency tocontaminated soil for an individual within that geographic area. This analysis looked attemperature, snowfall, and ADEC's past risk assessment data within each zone. This analysisshowed that average temperature and snowfall uniquely affect potential exposure in Alaska. Theresulting exposure frequency values used to develop the soil cleanup standards for the Under 40Inch Zone was 270 days (90 days non-exposure time). Standardized default exposure parametersdeveloped by the United States Environmental Protection Agency were used except for exposurefrequency as outlined above. The target hazard quotient for non-carcinogenic compounds wasset a 1, and the target cancer risk was set at 1 x 10-5 for carcinogens. Cleanup levels werecalculated based on a 30-year exposure duration consisting of 6-years as a child and 24-years asan adult.The ADEC regulations consider three scenarios – ingestion (potential pathway of exposure tohazardous substances in soil through direct consumption of the soil), inhalation (potentialpathway of exposure to volatile organic hazardous substances in the soil through volatilization),or migration to groundwater (potential exposure to hazardous substances in soil through directingestion of groundwater contaminated with concentrations of hazardous substances at levelslisted in Table C at 18 AAC 75.345(b)(1) as a result of movement of hazardous substancesthrough soil to the groundwater). In general, the most stringent pathway is selected as thecleanup level, however, if a particular pathway is not applicable to a site, then the selectedcleanup level is based on the remaining exposure pathways contained in Table B.The selected soil cleanup levels for all sites in Gambell, with the exception of Site 12, are basedon the Table B, Under 40 Inch Zone, Ingestion soil cleanup levels. Site 12 is located in closePage 47 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskaproximity to the local aquifer, and the Table B, Under 40 Inch Zone, Migration to GroundwaterPathway soil cleanup levels are applicable at these sites. The groundwater cleanup levelspromulgated by the State of Alaska in 18 AAC 75.345 Table C are based on drinking watercriteria, and utilize standard US EPA exposure assumptions (70 kg body weight, 30 yearsaveraging time – noncarcinogen, 70 years averaging time – carcinogen, 2 liters/day ingestionrate, 350 days/year exposure frequency, 30 years exposure duration, target hazard quotient of 1,and target cancer risk of 1x10-5).A comparison of the concentrations of contaminants of concern was presented in Section 1.6.The only sites with contamination remaining above soil cleanup levels are Site 7 and Site 12.Based upon the relatively small size of the contaminated source areas in comparison to thehabitats of ecological receptors, there is little potential for significant exposure of wildlife to thecontaminants. The potential for significant ecological impacts appears small. No threatened orendangered species commonly occur at the Gambell Sites.Page 48 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaska1.8 Remedial Action ObjectivesSpecific remediation alternatives were developed and evaluated for contaminants of concern(COCs) at the Gambell site. The remedial action objectives are:At Site 7, protect human health and the environment by reducing the risk from potentialexposure to arsenic. Eliminate exposure via incidental ingestion of soils by removingsoils which exceed the site background level of 11 mg/kg arsenic.At Site 12, protect human health and the environment by reducing the risk from potentialexposure to chromium and lead. Eliminate exposure via incidental ingestion of soils ormigration to groundwater by removing soils which exceed the cleanup levels of 400mg/kg lead and 26 mg/kg chromium;Restore contaminated soils for future residential land use; andRemove exposed military debris which poses a clear danger, likely to cause death orserious injury to persons exercising ordinary and reasonable care.As part of the remedial investigation process, contaminants of concern were identified through acomparison of contaminant levels to risk-based screening levels and applicable regulatorycleanup levels. The primary COCs for soil at Gambell are arsenic at Site 7 and lead andchromium at Site 12. Contaminants at the other Gambell sites either do not exceed establishedcleanup levels, or exist in de-minimus quantities. The risks are below the target threshold of 1 x10-5 and result in no further action decisions for the remaining sites. These sites are available forunrestricted use.The Alaska Department of Environmental Conservation (ADEC) regulates cleanup ofcontaminated sites, and has established soil and groundwater cleanup levels in 18 AlaskaAdministrative Code (AAC) 75.340 and 345. Cleanup levels established following ADECregulations are based on an estimate of the reasonable maximum exposure expected to occurunder current and future site conditions. The cleanup levels are based on the most relevantexposure pathways at each site. The ADEC regulations consider three scenarios – migration togroundwater, ingestion, and inhalation. In general, the most stringent pathway is selected as thecleanup level, however, if a particular pathway is not applicable to a site, then the selectedcleanup level is based on the remaining cleanup levels contained in Table B. The selected soiland groundwater cleanup levels for all sites are risk-based and designed to be protective ofhuman health and the environment.The soil cleanup goals for Site 7 (Table 12) are based on the ADEC Table B2 ingestion pathwaysoil cleanup levels. The migration to groundwater pathway is not applicable at Site 7 due to thepresence of continuous permafrost which acts as a barrier to contaminant migration, and thesporadic presence of suprapermafrost groundwater at this site. The arsenic cleanup level of 11mg/kg represents the site background concentration.Page 49 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaTable 12Site 7 Soil Cleanup LevelsArsenic a11 mg/kgDRO b10,250 mg/kgRRO b10,000 mg/kgSources:asite backgroundb18 AAC 75, Table B, Under 40 Inch Zone,Ingestion Pathway (May 26, 2004)The soil cleanup goals for Site 12 (Table 13) are based on the ADEC Table B1 and B2 migrationto groundwater and ingestion pathway soil cleanup levels. Site 12 is located due south ofTroutman Lake, and the groundwater table is in close connection to surface waters.Table 13Site 12 Soil Cleanup LevelsArsenic a11 mg/kgCadmium b5 mg/kgChromium b26 mg/kgLead b400 mg/kgDRO b250 mg/kgRRO c10,000 mg/kgSources:asite backgroundb18 AAC 75, Table B, Under 40 Inch Zone,Migration to Groundwater Pathway (May 26, 2004)c18 AAC 75, Table B, Under 40 Inch Zone,Ingestion Pathway (May 26, 2004)The soil cleanup levels for Sites requiring No Further Action (Table 14) are based on the on theADEC Table B ingestion pathway soil cleanup levels. The migration to groundwater pathwaywas determined to be not applicable due to the presence of continuous permafrost which acts as abarrier to contaminant migration, and the sporadic presence of suprapermafrost groundwateracross the Gambell sites.Table 14Soil Cleanup Levels for Sites Requiring NFADRO b10,250 mg/kg Chromium b300bRRO10,000 mg/kg Copper b4,060Antimony b41 mg/kg Lead b400aArsenic11 mg/kg Mercury b18Beryllium b200 mg/kg Nickel b2,000Cadmium b100 mg/kg Selenium b510mg/kgmg/kgmg/kgmg/kgmg/kgmg/kgSources: a site backgroundb18 AAC 75, Table B, Under 40 Inch Zone, Ingestion Pathway (May 26, 2004)The site background concentration for arsenic was determined based on an analysis of area-widearsenic concentrations, established background levels at other sites on St. Lawrence Island, andstate-wide arsenic background levels. Of all the samples collected in Gambell with detections ofarsenic, 96.6% of the results were below 11 mg/kg, the established background concentration ofarsenic at Northeast Cape on St. Lawrence Island for gravel soils is 11 mg/kg, and the averagearsenic concentration in Alaska ranges from 6.7 to 9.6 mg/kg (USGS 1988). At Site 12,Page 50 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskapreviously detected arsenic concentrations ranged from 3 to 10 mg/kg. At Site 7, previouslydetected arsenic concentrations ranged from 1 to 10.2 mg/kg, with the exception of the 2 datapoints identified as highly anomalous in the 2003 confirmation sampling results.The soil cleanup levels for all other sites in Gambell are based on the ADEC Table B cleanuplevels, under 40 inch zone, ingestion pathway, as promulgated in 18 AAC 75.341. These sitesrequire no further remedial action, based on an evaluation of current site conditions and samplingdata results, as presented in Section 2.7. In general, continuous permafrost acts as a barrier forsoil contaminant migration. However, migration of contaminants can occur as groundwatertravels in the active lens above the permafrost layer (suprapermafrost groundwater).Suprapermafrost groundwater occurs sporadically within the village of Gambell (i.e. in thevicinity of Sites 6, 7, 16, 17, 18). The groundwater flow direction from these areas is to thenorth, towards the Bering Sea. The groundwater aquifer that supplies drinking water to thecommunity is located at the base of Sevuokuk Mountain, approximately 1,500-2,000 feet east ofthe village.Sites 4A and 4B, located at the top of Sevuokuk Mountain, are beyond the likely recharge areafor the village water supply. These sites are situated on bedrock. Very little soil is found at thetop of Sevuokuk Mountain and groundwater is expected to run off the side of the mountain orenter bedrock fractures. It is unlikely that groundwater from Sites 4A and 4B could impact thedrinking water aquifer at the base of the mountain.Page 51 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaska1.9 Description of AlternativesThe Corps of Engineers considered the following remedial alternatives for each site:No Further Action. No further action (NFA) is a response action selected when no additionalremedial actions are necessary to protect human health and the environment, based onestablished cleanup levels and regulatory standards. NFA is also used as a baseline to compareother responses.Institutional Controls. Institutional controls make use of restrictions to minimize exposure tocontaminants at a site. The restrictions can be physical, such as erecting a fence, or take the formof land management practices, such as requiring special building permits or not allowinginstallation of new wells in a particular area.Site-specific Actions. A feasibility study (FS) evaluated alternatives for Sites 4A, 4B, 6, 7, 8,and 12. These sites were recommended for potential remedial action based on the remedialinvestigation completed in 2002 which identified areas with petroleum and/or metalscontaminated soils. An evaluation of the site-specific exposure pathways indicated that ingestionof soils was the most relevant exposure pathway for Sites 4A, 4B, 6, 7, and 8. The level ofpetroleum contamination in soils at these sites do not exceed ADEC Table B cleanup levelsbased on the ingestion pathway. Therefore, the FS provided a detailed analysis of fouralternatives for the two remaining areas of concern, Sites 8 and 12.In 2003, a concrete pad was removed from Site 7. Confirmation samples collected fromunderneath the removed concrete pad indicated residual levels of arsenic which weresignificantly higher than site background and exceeded the ADEC risk-based cleanup level. TheFS was not updated to evaluate remedial alternatives for the arsenic-contaminated soil at Site 7.The No Further Action alternative was rejected for Site 7 because the chemical risk posed tohuman health and the environment would not be addressed since no actions would be taken toreduce the volume of arsenic contaminated soil. The alternative that is protective of humanhealth and the environment, complies with ARARs, and is cost effective, is excavation and offsite disposal in a permitted landfill, based on the small estimated quantity of contaminated soils.Alternative 1 - No ActionAlternative 2 - Debris Removal at Site 8Alternative 3 - Debris Removal at Site 8 and Soil Removal at Sites 7 and 12Alternative 4 - Debris Removal at Site 8, Soil Removal at Site 7, and In-situ Treatment ofContaminated Soil at Site 12Page 52 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaska1.10 Comparative Analysis of AlternativesThe Corps of Engineers evaluated the remedial alternatives based on the nine evaluation criteriaestablished under CERCLA. The comparative analysis describes how each of the alternativesmeets the CERCLA evaluation criteria relative to each other.1.10.1 Threshold CriteriaThe remedial alternatives were first evaluated by comparison with the threshold criteria: overallprotection of human health and the environment and compliance with ARARs. The thresholdcriteria must be fully satisfied by candidate alternatives before the alternatives can be givenfurther consideration in the remedy selection process.Protection of Human Health and the EnvironmentAlternative 1 is protective of human health and the environment and complies with ARARs forSites 1A, 1B, 1C, 2, 3, 4A, 4B, 4C, 4D, 4E, 6, 8B, 8C, 8D, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19,20, 21, 22, 23, 24, 25A, 25B, 26, 27, and 28.Alternatives 1 and 2 would not reduce the chemical risk posed to human health and theenvironment since no actions would be taken to address the lead and chromium contaminatedsoil at Site 12 or the arsenic contaminated soil at Site 7. Alternative 3 would be protectivebecause the lead and chromium contaminated soil at Site 12 and the arsenic contaminated soil atSite 7 would be permanently removed and disposed off-site. Alternative 4 would be protective,because the lead contamination would be chemically bound with a reagent to reduce theleachability of the lead.Compliance With ARARsThis criterion addresses whether each alternative will meet all of the applicable or relevant andappropriate requirements of other Federal and State environmental statutes or provides a basisfor invoking a waiver. All alternatives, except the no action alternative, had common ARARsassociated with the excavation of contaminated soil. The applicable requirements include thosecleanup standards promulgated by the State of Alaska in 18 Alaska Administrative Code 75.341and 345.Alternatives 1 and 2 would not reduce or remove lead and chromium in soil at Site 12, would notreduce or remove arsenic in soil at Site 7, would not meet state cleanup levels, and wouldtherefore not meet ARARs. Alternative 3 would comply with ARARs since the lead andchromium contaminated soil at Site 12 and the arsenic contaminated soil at Site 7 would beremoved and disposed off-island. Alternative 4 would also comply with ARARs, but additionaltests would have to be performed on the solidified soil following treatment to document thereduced leachability of the lead. Institutional controls would also be needed to verify theintegrity of the solidified material over time, and to control future landuse in the immediatevicinity.1.10.2 Balancing CriteriaFor those alternatives satisfying the threshold criteria, five primary balancing criteria are used toevaluate other aspects of the potential remedies. No single alternative will necessarily receivePage 53 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskathe highest evaluation for every balancing criterion. This phase of the comparative analysis isuseful in refining the relative merits of candidate alternatives for site clean up. The five primarybalancing criteria are: long-term effectiveness and permanence; reduction of toxicity, mobility,or volume through treatment; short-term effectiveness; implementability; and cost.Long-Term EffectivenessThis criterion addressed the results of each alternative with respect to the risk remaining at thesite after the conclusion of the remedial action. Evaluation of this criterion includes anassessment of the magnitude of the residual risk from untreated waste or treatment residuals. Italso includes an assessment of the adequacy, reliability, and useful life of any controls that are tobe used to manage hazardous substances that remain on site after the remediation.Alternative 3 has the greatest long-term effectiveness because this alternative has the highestpotential to permanently remove the lead and chromium contaminated soil at Site 12 and thearsenic contaminated soil at Site 7. Alternatives 1 and 2 provide the least long-termeffectiveness since neither includes action to reduce the amount of lead and chromiumcontaminated soil or the arsenic contaminated soil. Alternative 4 is less effective thanAlternative 3 over the long-term because it leaves the treated soil on-site. The solidified materialhas the potential to degrade over time in the harsh arctic climate due to continuous freeze thawcycles. Alternative 4 has a long-term effectiveness that is greater than Alternatives 1 and 2,because Alternative 4 treats the lead contaminated soil in-situ and reduces its leachability.Reduction of Toxicity, Mobility, and Volume Through TreatmentEvaluation of this criterion included: an assessment of the treatment processes to be employed byeach remedial action and the types of wastes they would treat; the amount of waste that would bedestroyed or treated; and the projected amount of reduction in toxicity, mobility, or volume.Also considered in this assessment is whether the alternative would satisfy the expressedpreference of the Superfund Amendments and Reauthorization Act (SARA), Section 121, forremedial actions that reduce toxicity, mobility, or volume of hazardous waste.Alternatives 1 and 2 do not reduce the toxicity, mobility, or volume of the lead and chromiumcontaminated soil or the arsenic contaminated soil. Alternative 3 reduces the volume ofcontaminants left on site through removal. Alternative 4 reduces the mobility and toxicity of thelead through chemical treatment.Short-Term EffectivenessThe potential health effects and environmental impacts of each alternative action duringconstruction and implementation were evaluated by this criterion. The factors assessed in thisevaluation include the protection of the community and site workers during implementation andconstruction, environmental impacts during implementation, and the estimated time required tomeet cleanup standards. None of the alternatives represent an unacceptable risk to thecommunity, workers or the environment during implementation and can be effectively managedby following a health and safety plan and using appropriate personal protective equipment tominimize exposure of site workers to contaminants. Additional measures such as use of safetyfencing/flagging would be taken to prevent residents from entering the areas duringimplementation of the alternative. Excavation of the contaminated soil at Sites 7 and 12 underAlternative 3 would involve about 4 days of field work. Under Alternative 4, treatment of thePage 54 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskacontaminated soils at Site 12 would require about 5 days of field work, plus 2 days to excavatesoil at Site 7.ImplementabilityAll of the alternatives can be implemented using commercially available services. Alternative 1and 2 could be easily implemented and few technical challenges would be expected. Alternative3 is more challenging. This alternative includes excavation and off-Island disposal of the metalscontaminated soil, and coordinating remote site logistics. Alternative 4 would be the mostchallenging to implement. Alternative 4 would require the application and mixing of a reagentwith the lead contaminated soil, utilization of additional equipment, additional laboratory testing,and increased time in the field. Alternative 4 would also require long term monitoring to ensurethe solidified material remains intact into the future and institutional controls which limit futuredevelopment at the site.Disposal sites are not available within Alaska but are available outside of Alaska in the lower 48United States. However, alternatives involving off-Island disposal could be implemented in onefield season. The in-situ treatment alternative cannot be effectively implemented at this site.CostsAlternative 1 has the lowest cost ($46,400) and Alternative 2 has the second lowest cost($460,900). Alternative 4 has the highest costs ($555,600) and Alternative 3 has the secondhighest cost ($538,200). Overall, the additional cost to remove and dispose of the lead andchromium contaminated soil is not significantly higher than Alternative 2 (Remove of ExposedDebris Only) and is less than Alternative 4 (Treat Contaminated Soil In-situ).The costs shown in Table 15 are based on the best available information regarding theanticipated scope of the remedial alternatives. The cost estimates were prepared to guide projectevaluation and implementation. Changes in the cost elements are likely to occur as a result ofnew information and data collected during the engineering design of the remedial alternative.This is an order-of-magnitude engineering cost estimate that is expected to be within +50 to –30percent of the actual project costs.Page 55 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaCriteriaOverallProtectivenessCompliance withARARsShort-termeffectivenessTable 15. Comparative Analysis of AlternativesAlternative 1Alternative 2Alternative 3Remove Exposed Debris(Site 8A), RemoveRemove Exposed Debris Arsenic-ContaminatedNo ActionOnlySoil (Site 7), Remove(Site 8A)Lead and ChromiumContaminated Soil(Site 12)No risk reduction.Reduces human healthNo risk reduction Reduces physical hazardrisk posed byposed by debris.contaminated soil.NoNot applicableLong-termeffectivenessNoneReduction ofToxicity,Mobility, orVolumeNoneImplementabilityNo technical oradministrativeissuesCost$46,400NoYesYesManageable with healthand safety workplan.Reduces leachability oflead and eliminates humanDoes not eliminateEliminates human health health risks due to arsenic.human health risk posedrisks posed byIncreased potential forby contaminated soil.contaminated soil.degradation of thesolidified material giventhe harsh arctic climate.No treatment ofcontaminated soils, butReduces mobility of leadNone.volume left on-site isin contaminated soil area.reduced by landfilldisposal.More complex toimplement soil treatment ata remote site with noreadily available servicesNo technical issues,No technical issues, someor equipment. Treatmentsome coordination with coordination with Dept.technique requiresDept. of Transportationof Transportationmonitoring, institutionalrequired for debrisrequired for debriscontrols, and additionalremoval near runway.removal near runway.trips to the site, thusincreasing cost and risk ofalternative not meeting riskreduction objectives.$460,900$538,200$555,600No short-term risks.Page 56 of 66Manageable with healthand safety workplan.Alternative 4Remove Exposed Debris(Site 8A), Remove ArsenicContaminated Soil (Site 7),and In-Situ Treatment ofLead and ChromiumContaminated Soil (Site12)Reduces human health riskposed by contaminatedsoil.Decision DocumentGambell SiteSt. Lawrence Island, Alaska1.10.3 Modifying CriteriaState AcceptanceThe State of Alaska, through the Department of Environmental Conservation, concurs with theselected remedial responses of soil excavation at Sites 7 and 12, debris removal at Site 8A, and adetermination of no further action at the remaining sites. However, the ADEC has requested theremaining small arms ammunition debris at Site 8D be removed. The decision may be reviewedand modified in the future if new information becomes available that indicates the presence ofpreviously undiscovered contamination or exposures that may cause unacceptable risk to humanhealth or the environment.Community AcceptanceBased on written and oral comments received from RAB members, local residents, local Nativecorporation representatives, nonprofit environmental groups, and the RAB’s technical advisorduring the public comment period on the Proposed Plan, there appears to be support from the localcommunity for the Preferred Alternative at Sites 7, 8A, and 12. However, there is somedisagreement with the selected alternative of no further action for all remaining sites, due toconcerns that inadequate site characterization was conducted at the Gambell site, inadequate sitespecific background metal concentrations were defined, and a desire for additional assurances thatsites won’t pose a threat in the future due to changing climate conditions, melting of permafrost,undetected contaminants, and contaminant migration. The community also requested additionalyearly groundwater monitoring events into the future at Site 5 and throughout the Gambell area,for a broader list of analytes. The Corps of Engineers will conduct additional investigation of thegroundwater quality at Site 5, to demonstrate compliance with ADEC groundwater cleanup criteriain 18 AAC 75.345 Table C or establish a concentration trend for petroleum hydrocarbons. A finaldecision on any appropriate remedial action at Site 5 will be made in the future. The community isalso concerned that buried military debris may become exposed in the future through erosion, frostheaving, or changing permafrost conditions and impact construction activities or resident’s safety.The FUDS program cannot address these concerns directly, since the buried debris has not beenassociated with soil contamination or migration. The debris impacts are documented in the NativeAmerican Environmental Tracking System (NAETS) database and will be addressed by the NativeAmerican Lands Environmental Mitigation Program (NALEMP), subject to eligibility and fundingconstraints. The Gambell NALEMP project is scoped to address surface/subsurface debrisremoval at the following sites: 1A, 1B, 1C, 2, 3A, 4E, 6, 8B, 8C, 13, 15, 17, 18, 19, 21, 23, and 24.In addition, USACE will develop a map for use by the community during construction activitieswhich depicts the general location of known buried military debris based on historic geophysicalsurveys and soil sampling results which exceed the Table B migration to groundwater pathwaycleanup levels.Detailed responses to each comment submitted on the Proposed Plan are contained in theResponsiveness Summary in the Appendix. The remedial alternatives were presented to thepublic at a Public Meeting held on July 21, 2004. The preferred alternatives presented at thepublic meeting were:Page 57 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskaexcavation and removal of arsenic contaminated soil at Site 7,excavation and removal of lead and chromium contaminated soil at Site 12,one groundwater monitoring event at Site 5,removal of exposed debris at Sites 8A and 8D, andno further action for the remaining sites.Page 58 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaska1.11 Principal Threat WastePrincipal threat wastes are those sources materials considered to be highly toxic or highly mobilewhich generally cannot be contained in a reliable manner or would present a significant risk tohuman health or the environment should exposure occur. The primary contaminant source areasat the Gambell site (e.g., military debris, contaminated soil) have already been removed throughprevious removal actions. The remaining wastes do not constitute principal threat wastes basedon the relatively low toxicity and mobility of the contaminants in the surface soils.Page 59 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaska1.12 Selected RemedyThe selected remedy is the final remedial action for 37 areas of concern at the Gambell FUDSsite. One area of concern will be considered under a future decision document. The remedyconsists of: no further action at 34 locations, removal of inherently hazardous military debris atone location, and excavation of contaminated soils at two locations. All debris and contaminatedsoils will be shipped off-Island for recycling or disposal at a permitted landfill. The selectedremedial alternatives for the 37 sites are:No Further Action at Sites 1A, 1B, 1C, 2, 3, 4A, 4B, 4C, 4D, 4E, 6, 8B, 8C, 8D, 9, 10,11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25A, 25B, 26, 27, 28Excavate and off-Island disposal of approximately 4 tons of arsenic-contaminated soilwhich exceeds 11 mg/kg at Site 7Removal and off-Island disposal of approximately 50 tons of exposed Marston matting atSite 8AExcavate and off-Island disposal of approximately 4 tons of lead and chromiumcontaminated soil which exceeds 400 mg/kg and 26 mg/kg, respectively at Site 12No Further Action SitesThe selected remedy of no further action for Sites 1A, 1B, 1C, 2, 3, 4A, 4B, 4C, 4D, 4E, 6, 8B,8C, 8D, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25A, 25B, 26, 27, 28 is protectiveof human health and the environment and satisfies all applicable or relevant and appropriaterequirements.Site 7Excavate approximately 4 tons of arsenic-contaminated soil, which exceeds the cleanup level of11 mg/kg, from around the edges of the former concrete pad location. Dispose of soil at an offsite landfill. Collect confirmation samples and analyze for arsenic. This alternative is protectiveof human health and the environment because it permanently reduces the risk posed by the soilcontaining elevated arsenic. The no further action alternative was rejected because it would notmeet established regulatory criteria, or reduce the toxicity, mobility, or volume of contaminatedsoil. Implementation of institutional controls or access restrictions is infeasible for the sitebecause it is located in a high-traffic, residential area of town.Site 8ARemove approximately 50 tons of exposed Marston matting along the east side of the runway.Transport the debris to an off-site landfill or recycling facility. This alternative will involvepicking up and consolidating the Marston matting. The Alaska District will coordinate with theAlaska Department of Transportation and Public Facilities and/or the Federal AviationAdministration during removal of the exposed debris to ensure airport operations are notdisrupted. This alternative effectively reduces the long-term physical hazard posed by the debris.Other alternatives were considered and rejected during the feasibility study phase. The exposeddebris would continue to pose a physical hazard to local residents if no further action is taken.Site controls such as installation of fencing near the runway at Site 8A would requirecoordination with and approval from the landowner, the Alaska Department of TransportationPage 60 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaskaand Public Facilities and/or the Federal Aviation Administration. Construction of fencing mayadversely affect maintenance of airport lighting/navigation aids or snow removal activities.Access restrictions were not retained for further evaluation.Site 12Excavate approximately 4 tons of lead and chromium contaminated soil, which exceeds thecleanup level of 400 mg/kg for lead and 26 mg/kg for chromium, and transport it off-site fordisposal at a permitted landfill. Collect confirmation samples and analyze for arsenic, lead,cadmium, chromium, DRO, and RRO. Excavation and off-site disposal of soil will permanentlyreduce the potential risk posed by contaminated soils at Site 12.The no further action alternative was rejected because it would not reduce the risk associatedwith the lead-contaminated soil. There would be no reduction in the toxicity, mobility, orvolume of contaminated soil. This alternative would not meet established regulatory criteria.Implementation of institutional controls or access restrictions was determined to be infeasible forthe site. In-situ treatment of the contaminated soils was also considered, but ultimately rejecteddue to challenges in implementation at a remote site and additional testing requirements.Cost Estimate for the Selected RemedyThe information in the cost estimate summary table is based on the best available informationregarding the anticipated scope of the remedial alternative. Changes in the cost elements arelikely to occur as a result of new information and data collected during the engineering design ofthe remedial alternative. Major changes may be documented in the form of a memorandum inthe Administrative Record. This is an order-of magnitude engineering cost estimate that isexpected to be within +50 to –30 percent of the actual project cost. The costs shown in thissummary table have been updated to include supervision and administration costs.Page 61 of 66Decision DocumentGambell SiteSt. Lawrence Island, AlaskaTable 16. Cost Estimate Summary for the Selected RemedyRemedial ActionDescriptionWorkplansMobilizationField WorkDemobilizationLaboratory SamplesProject ReportingProject ManagementSUB TOTALSupervision and Administration (13%)TOTALCost$38,200$127,100$98,400$220,300$10,700$27,700$15,800$538,200$70,000$608,200Page 62 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaska1.13 Statutory DeterminationsThe selected remedy satisfies the requirements under Section 121 of CERCLA and the NCP.The following section discusses how the selected remedy meets these requirements.The selected remedy is protective of human health and the environment, complies withapplicable or relevant and appropriate requirements and is cost-effective. The remedy utilizespermanent solutions and alternative treatment technologies to the maximum extent practicable.1.13.1 Protective of Human Health and the EnvironmentThe selected remedy is protective of human health and the environment. The current and futureexposure pathways are incidental ingestion of contaminated soil by local residents. The selectedremedy, by excavation and off-site disposal of soil, will eliminate the risk posed by thecontaminants of concern and achieve the risk-based cleanup levels promulgated by the State ofAlaska. Based on previous sampling results, the groundwater pathway does not pose a currentrisk to human health or the environment.1.13.2 Applicable or Relevant and Appropriate RequirementsThe action-specific, chemical-specific, and location-specific applicable or relevant andappropriate requirements (ARARs) for the selected remedies are regulations promulgated by theState of Alaska in Alaska Administrative Code (AAC), Title 18, Chapter 75, Sections 340 and341, as updated through May 26, 2004.The chemical-specific requirements for Site 7 are cleanup of contaminated soils to:10,250 mg/kg Diesel Range Organics10,000 mg/kg Residual Range Organicso Source: 18 AAC 75.341, Table B211 mg/kg Arsenico Source: 18AAC 75.340 (h)(1), site backgroundThe chemical-specific requirements for Site 12 are cleanup of contaminated soils to:5 mg/kg Cadmium26 mg/kg Chromium400 mg/kg Lead250 mg/kg Diesel Range Organics10,000 mg/kg Residual Range Organicso Source: 18 AAC 75.341, Tables B1 and B211 mg/kg Arsenico Source: 18AAC 75.340 (h)(1), site backgroundPage 63 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaska1.13.3 Cost EffectivenessThe selected remedy represents the most cost-effective of the alternatives in comparison to theiroverall effectiveness proportional to their costs. The selected remedy provides the best longterm permanence and risk protection by removing contaminated soil which poses a risk to localresidents.Disposal sites are not available in Alaska but are available outside of Alaska in the lower 48Unites States. Debris removal activities could be completed in one field season, reducing theneed for additional site visits and mobilization costs. The in-situ treatment alternative cannot beeffectively implemented at this site given the complex remote site logistics.1.13.4 Utilization of Permanent Solutions and Alternative Treatment Technologies to theMaximum Extent PracticableThe USACE and the State of Alaska have determined that the selected remedy represents themaximum extent to which permanent solutions and treatment technologies can be used in a costeffective manner at the Gambell site. The on-site treatment alternative would be the mostchallenging to execute given the remote site conditions and requires additional testing,landowners’ consent, and implementation of institutional controls.1.13.5 Preference for Treatment as a Principal ElementAlthough the selected alternative for the contaminated soil relies upon off-site disposal instead ofon-site treatment; the USACE and the State of Alaska have determined that this remedyrepresents the maximum extent to which permanent solutions and treatment technologies can beused in a cost effective manner at the Gambell site.1.13.6 Five-Year Review RequirementThe selected remedy will not result in hazardous substances, pollutants, or contaminantsremaining on-site above levels that allow for unlimited use and unrestricted exposure.Therefore, a five-year review is not required.Page 64 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaska1.14 Documentation of Significant ChangesThere were no significant changes between the Preferred Alternative that was submitted forpublic comment in the Proposed Plan and the Selected Remedy. The Corps of Engineers willconduct additional investigation of the groundwater quality at Site 5, to demonstrate compliancewith ADEC groundwater cleanup criteria in 18 AAC 75.345 Table C or establish a concentrationtrend for petroleum hydrocarbons. A final decision on any appropriate remedial actions at Site 5will be made after evaluating the investigation results.The proposed removal of small arms ammunition at Site 8D has been determined ineligible forthe FUDS program under the BDDR category, because the material does not meet the definitionof inherently hazardous debris, which presents a clear danger, likely to cause or having alreadycaused, death or serious injury to a person exercising ordinary and reasonable care. An ordnanceand explosives response decision, approved in August 2003, documented the appropriateresponse to be institutional controls focusing on providing community awareness and education,including ordnance information pamphlets and posters. The Corps of Engineers will recommendthat the Native American Lands Environmental Mitigation Program (NALEMP) provide fundingto remove the remaining small arms ammunition at Site 8D to fully address the remainingcommunity and state concerns regarding the beach burial pit. The impacts at Site 8D areidentified in the Native Village of Gambell’s Strategic Project Implementation Plan (SPIP),updated February 2005.Page 65 of 66Decision DocumentGambell SiteSt. Lawrence Island, Alaska2. Responsiveness SummaryThe primary avenues of public input have been through the Proposed Plan and public commentperiod. The Proposed Plan for Gambell was issued to the pubic on July 21, 2004. The publiccomment period was from July 21 through August 30, 2004. To encourage public comment, theUSACE inserted a pre-addressed form in distributed copies of the Proposed Plan. The commentforms were also distributed at the public meeting, held at City Hall in Gambell. The publicmeeting was attended by 14 people, including representatives from the Restoration AdvisoryBoard (RAB), the ADEC, and local residents. Oral comments were received at the meeting.Prior to the conclusion of the public comment period, 4 individuals submitted written comments.All comments received are documented in the administrative record file for the site. Detailedmeeting minutes from the public meeting are available to the public at the 4 informationrepositories. The repositories are located at the Sivuqaq Lodge in Gambell, the Savoonga IRABuilding in Savoonga, the University of Alaska Fairbanks Northwest Campus Library in Nome,and the Alaska Resource Library and Information Services (ARLIS) in Anchorage. A completeresponse to public comments is contained in Appendix A.Page 66 of 66Appendix AResponsiveness SummaryAppendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, AlaskaProposed Plan for Remedial Action, Gambell FUDS, St. Lawrence Island, AlaskaJuly 2004Responses to Public Comments1) Comment (P. Miller):I remain concerned that residents of St. Lawrence Island (SLI) have not had sufficientopportunity or time to review and formally comment on this document. It is especiallycritical that people of SLI be given ample opportunity to comment, as this is a criticalphase of the CERCLA process. I suggest that the Corps of Engineers provide time at theSeptember 9 RAB meeting for additional public comments from RAB members and otherresidents on the proposed plan.Response:The comment period was initially extended from August 23, 2004 to August 30, 2004.During a Restoration Advisory Board meeting in Savoonga, AK on September 9, 2004,the Corps Project Manager stated that additional comments were always welcome, andmay be included in the Responsiveness Summary if received by the week of September20, 2004.2) Comment (P. Miller):The proposed plan for remedial action does not sufficiently respond to communityconcerns and some suggested courses of action. Particularly, the proposed plan does notprovide measures to ensure proper monitoring and protection of the community drinkingwater source. At least once yearly, water from monitoring wells in and around thevicinity of the community drinking water source should be sampled and analyzed forheavy metals, VOCs, pesticides, and PCBs.Response:The Corps will conduct additional investigation of the groundwater quality at Site 5. Aminimum of two monitoring events should provide the necessary information to assurethat the village water supply is not being affected by contaminants left by the military. Ifsignificant fuel contamination is found, further action may be warranted. A final decisionon Site 5 will not be made until after the additional groundwater monitoring is completed.The State of Alaska typically requires three or four sampling events to establish aconcentration trend. The FUDS program is not authorized to conduct prospectivegroundwater monitoring into the indefinite future. Long-term monitoring is typicallyconducted as part of a natural attenuation scenario whereby known contaminants are leftin place to degrade over time.3) Comment (P. Miller):During the public meeting, a Gambell resident raised a significant point about thevulnerability of the drinking water source because of the permeability of the gravelsubstrate and susceptibility to contamination from storm surges and flooding.Contamination can readily migrate in this environment. The sites cannot be viewed asAppendix APage 2 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, Alaskaisolated from one another because the potential for cross contamination is high given thepermeability of the substrate.Response:We agree that the gravel substrate in Gambell is highly porous and the groundwatergradient is low. The predominant flow direction, however, is north towards the BeringSea. Salt-water intrusion is another likely impact from storm surge events, when flowdirections are periodically reversed. However, these events are rare and occur over shortperiods of time. There is no evidence of cross-contamination impacting the villagedrinking water supply.4) Comment (P. Miller):The proposed plan does not include adequate data to justify no further actiondeterminations for all but 4 of the 38 sites. Many of the sites warrant further investigationand cleanup.Response:The State of Alaska Department of Environmental Conservation (ADEC) providedregulatory oversight during the remedial investigation and all subsequent phases of thecleanup activities. The ADEC concurs that additional investigation is not warranted atthese sites. Also, the Department of Defense’s NALEMP Program has included 25 ofthese sites for buried debris removal.5) Comment (P. Miller):The document must identify sources of contamination, including thallium, beryllium,arsenic, lead, chromium, VOCs, benzene, fuels, and PCBs. Pesticides should be includedamong the potential contaminants of concern (including DDT metabolites, mirex,endosulfan, lindane, and other pesticides known to be used during the time of the militaryoccupation) especially since we have reason to assume that DDT and possibly otherpesticides were used at the site.Response:The contamination identified in the Proposed Plan is primarily fuels and metals. Fuelswould have been used throughout the military installation, as a source of power forgenerators, heating, and vehicles. Metals such as lead and chromium are commonconstituents of batteries. Other metals are common components of alloys used inbuilding materials or equipment parts. PCBs are a known component of some oldlubricating and transformer oils but have not been documented at significantconcentrations in Gambell. Metals are also natural elements found in the earth’s crustand rock formations. Through the remedial investigation process, pesticides have notbeen identified as a potential contaminant of concern and would not be reasonablyexpected at the Gambell site.6) Comment (P. Miller):Analysis of historical records and interviews with former military personnel should bethoroughly conducted to determine other possible sources of contamination andcontaminants of concern.Appendix APage 3 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, AlaskaResponse:The initial site inventory and planning phase of the project consisted of backgroundresearch, site reconnaissance, and interviews with local residents. In addition, aHistorical Time Sequence Aerial Photograph Analysis was conducted by the TopographicEngineering Center, this study included archival search of military records. As part ofthe ordnance investigation, an Archive Records Search was also conducted.7) Comment (P. Miller):The perception of most community members is that the Corps of Engineers has notadequately investigated reports of buried hazardous materials, including reports ofmunitions (including grenades and larger caliber UXO). Contamination may pose ahazard to health and safety, yet the concerns of the community have been too easilydismissed.Response: The Corps of Engineers has strived to be responsive to community concernsregarding buried hazardous materials or munitions. We have performed geophysicalsurveys and used heavy equipment to find such buried items, even re-checking areas.The Corps has also assigned QARs (Quality Assurance Representatives) to be on handduring removal actions to assure that a thorough debris removal job was accomplished.The Corps is greatly concerned about the public’s perception of our cleanup activities.We disagree that community members’ claims have been unreasonably dismissed, andwe continuously request input and feedback on site activities. We also have hired ageologist as a TAPP (Technical Assistance for Public Participation) advisor who canprovide additional technical assistance and interpretations to the community. We haveoffered suggestions on how to bring items to our attention, and we remain open to newevidence of buried debris or ordnance. We understand the community frustration that themilitary abandoned or buried its waste instead of removing it, and we diligently workthrough the FUDS program to evaluate the many leads we receive related to site cleanup.This includes investigating potential threats to human health and safety and theenvironment. In some areas, such as Troutman Lake, the potential for health or safetyhazards resulting from “undiscovered” ordnance remains so small that furtherinvestigations are just not warranted.8) Comment (P. Miller):In addition, although the Corps states that buried debris is not subject to remedial actionunder the FUDS program, the proposed plan must make provisions to remediate debrisand other hazardous material should it surface through erosion or frost heaving.Response:Program policy guidance for the FUDS program (ER 200-3-1) states that for eligibleBDDR projects, the conditions must have been hazardous as a result of prior DoD useand must have been inherently hazardous when the property was transferred or disposedof by GSA before 17 October 1986. The Proposed Plan cannot contain provisions for“what if” scenarios. In the future, if new evidence of military debris or hazardousmaterials becomes available, the data will be reviewed by the FUDS program todetermine if additional actions are necessary.Appendix APage 4 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, Alaska9) Comment (P. Miller):The proposed plan for remedial action must include provisions for sampling of indoor airfor volatile organics in the Gambell High School, other community buildings, and homesin the vicinity of the landfill and power facility sites (including sites 6, 7, and 17).Response:Volatile organic compounds have not been detected above cleanup levels in groundwateror soil samples collected at Sites 6, 7, and 17. There is no evidence to support indoor airsampling. The detected concentrations of volatile compounds in Gambell could notresult in significant indoor air pollution.10) Comment (P. Miller):Throughout the document, arsenic levels are considered “attributable to background” andnot of military source. In some cases, arsenic levels are averaged and no further action isjustified based on an average concentration. This is inappropriate and unjustified. Truebackground levels are not provided. Often arsenic levels exceed ADEC cleanupstandards. These sites should be remediated so that arsenic levels are below ADECcleanup standards.Response:It is appropriate to use average concentrations of arsenic on a site-specific basis. TheU.S. Environmental Protection Agency (US EPA) recommends calculating a reasonablemaximum exposure (RME) for residential scenarios. Thus, the RME for chronicexposure on a site-specific basis is estimated using an average concentration of achemical of concern. Average concentrations are typically derived by statistical methodsby calculating the 95% Upper Confidence Level on the arithmetic mean of a dataset.U.S. EPA’s Soil Screening Guidance Fact Sheet (July 1996) states that “For data sets oflesser quality, the 95% upper confidence level on the arithmetic mean of contaminant soilconcentrations can be compared directly to the SSLs [soil screening levels]. The TBD[Soil Screening Guidance: Technical Background Document (U.S. EPA 1996)] discussesstrengths and weaknesses of different calculations of the mean and when they areappropriate for making screening decisions.”Furthermore, according to Risk Assessment Handbook, Volume 1 Human HealthEvaluation, U.S. Army Corps of Engineers, Engineer Manual EM 200-1-4 (January1999), background values should be expressed as the 95% upper confidence level on themean.Arsenic has been documented at levels above ADEC cleanup standards throughout thestate of Alaska. The ADEC recognizes that in some areas, naturally occurring levels ofarsenic are higher than the most stringent ADEC cleanup levels. The ADEC hasconcurred that arsenic below 10-15 ppm is not a concern. According to the USGS Report“Element Concentrations in Soil and Other Surficial Materials of Alaska (1988), theaverage arsenic concentrations in the state ranged from 6.7 to 9.6 mg/kg (geometric andarithmetic mean). The calculated ambient concentration of arsenic at Northeast Cape onSt. Lawrence Island is 7.8 to 11 mg/kg (tundra and gravel soil).Appendix APage 5 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, AlaskaA statistical evaluation of the entire dataset (232 data points) of arsenic concentrations(excluding all non-detects) in Gambell demonstrates that 96.6% of the data falls below10.6 ppm and 97.4% of the data fall below 13.1 ppm. This dataset includes locationswhich have been subsequently removed during remedial actions at the site (e.g., thesample result of 38 ppm at Site 4B from 1994), or are planned for removal (e.g.,confirmation sampling results from Site 7 in 2003 of 27.9 and 34.9 ppm). A histogram ofthe data distribution is shown below, with the number of samples in each evenly spaced“bin” (i.e., an equally spaced interval) shown. The average arsenic concentration is 5.0mg/kg, with a standard deviation of 4.2, and a 95% upper confidence level of 6.2 mg/kg(Chebyshev, non-parametric method).Histogram of Arsenic Concentrations9080 8180Frequency70605150Frequency403020100111211100100110.6 3.1 5.6 8.1 10.6 13.1 15.6 18.1 20.5 23.0 25.5 28.0 30.5 33.0 35.5 >36Results (mg/kg)11) Comment (P. Miller):The document should cite screening levels for all contaminants of concern. Further, it isincorrect to make the assumption that certain data points are simply outliers. Forexample, the Site 2 sampling in 1994 indicated that levels for lead and chromiumexceeded screening levels. 1996 samples were tested for lead only and do not provide abasis for assuming that levels for other contaminants are below the ADEC cleanupthreshold. Site 2 requires further investigation and cleanup. The NFA determination isunjustified.Response:Screening levels are provided throughout the document. In some cases, sampling resultsare compared to proposed cleanup levels only and the screening step is not shown.Environmental data is inherently variable and an assessment of data distribution is areasonable rationale for identifying certain constituents as anomalous (i.e., outliers). AtSite 2 in 1994, only one sample out of 13 contained metals, besides arsenic, aboveAppendix APage 6 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, Alaskascreening levels. This single sample had anomalous concentrations of both lead andchromium; other samples demonstrated a mostly sympathetic relationship between leadand chromium suggesting that where lead is low, chromium will be low. Furtherinvestigation was conducted to determine the extent of lead contamination surroundingthis particular sample, since lead was more highly anomalous. The sampling resultsindicated lead was well below screening levels. Since lead was not elevated during the1996 investigation, it is logical to assume that the chromium contamination was similarlybelow levels of concern. Any remaining chromium is likely isolated and present in deminimus quantities. A surface debris cleanup was also completed at this location in1999. No further sampling is recommended for Site 2, and the ADEC concurs with theNFA determination.12) Comment (P. Miller):Site 3, p 12. Thallium and beryllium exceeded screening levels and other metals(including mercury and others) have been detected. Results cannot be dismissed asanomalies. This site warrants further investigation and cleanup.Response:The additional investigation performed in 1996 confirmed that thallium and berylliumwere not present above method detection limits. The ADEC concurs with the NFAdetermination for Site 3.13) Comment (P. Miller):Site 4 A, p 14. Although the document states that no significant volume of contaminatedsoil remains at the site, elevated levels of contaminants are present. Remedial actionshould include complete removal of all contaminated soil and coverage/reclamation ofthe area with clean soils and re-vegetation.Response:This area is a rocky outcropping of bedrock at the top of Sevuokuk Mountain.Vegetation is not present and reclamation with clean soils and re-vegetation is neitherpractical nor in harmony with the natural landscape.14) Comment (P. Miller):Site 4 B, p 14. The document states that “The concentration of dioxins decreasedsignificantly as a result of removing the soils.” However, dioxins and additionalcontaminants remain at levels of concern. Further removal actions are warranted herebecause of the potential for downgradient contamination. Dioxin contamination warrantsspecial remedial actions due to the extreme health hazards posed by even lowconcentrations.Response:The USEPA and ADEC have not established cleanup levels for dioxins. The USEPARegion 9 has established a screening level of 3.9 pg/g (parts per trillion, ppt) for dioxinsin residential soil. The State of Alaska adjusts the EPA screening level by one order ofmagnitude to derive a preliminary remediation goal for residential soil of 39 ppt dioxin.Appendix APage 7 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, AlaskaThe Agency for Toxic Substance and Disease Registry (ATSDR) uses a screening levelof 50 ppt and an action level of 1,000 ppt for dioxins in soil. The residual dioxincontamination of 29 pg/g does not exceed the ADEC’s preliminary remediation goal of39 ppt. Furthermore, the dioxin contaminated soil has been removed to the maximumextent practicable. Dioxins are generally not very mobile except through the air;downgradient movement is unlikely given the setting. The ADEC concurs with the NFAdetermination for Site 4B.15) Comment (P. Miller):Site 5, p 18. Further action to identify and remove the source of DRO contamination mustbe taken. Monitoring of water for PAHs, DRO, solvents/VOCs, and PCBs from a closeseries of monitoring wells in the vicinity of the drinking water source is mandatory.Response:Further actions were completed in 1996, 1997, and 1998. The ADEC does not requireadditional groundwater monitoring. However, since several years have elapsed since theinitial groundwater sampling was conducted, additional groundwater monitoring will beconducted to determine the groundwater quality in the vicinity of Site 5. There is noreason to suspect PCBs, PAHs, solvents, or VOCs are present. Earlier sampling eventstested for DRO/RRO/GRO, BTEX, PAHs, PCBs, and/or VOCs. The only detectedcontaminant was fuel. The additional round of groundwater sampling will includesampling for DRO/RRO/GRO only.Should significant fuel contamination bediscovered, additional actions will be considered. A final decision on any necessaryremedial actions at Site 5 will be made after evaluating the additional groundwater datacollected.16) Comment (P. Miller):Site 7, p 21. Benzene sources and other contamination must be remediated at this site,and not just arsenic.Response:Debris removals have already occurred at this site. The detected benzene concentration isnot representative of groundwater across the site, and the groundwater is not considered adrinking water source. Benzene was not detected (DL 0.005 mg/kg) in the soil samplescollected from Site 7 during the initial phase of remedial investigation (1994). During asubsequent phase of investigation (2001), three soil borings were advanced to permafrostand soil samples were analyzed for BTEX, DRO/RRO/GRO, VOCs, PCBs, and metals.Benzene was not detected (DL 0.003 – 0.007 mg/kg). The only analytes detected abovethe ADEC Table B migration to groundwater cleanup levels were arsenic and DRO.Arsenic concentrations ranged from 4.5 to 10.2 mg/kg. DRO concentrations ranged fromND(5) to 710 mg/kg. The DRO concentrations do not exceed the ingestion pathwayADEC cleanup level of 10,250 mg/kg.Appendix APage 8 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, Alaska17) Comment (P. Miller):Site 12, p 26. I support the proposed alternative to remove sources of heavy metalcontamination. Additional sampling should be done to delineate the full extent ofcontamination.Response:Confirmation samples will be collected after the soil is excavated, to verify thecontamination was adequately removed.18) Comment (P. Miller):Site 14, p 28. Further investigation is necessary to determine whether the plane wascarrying hazardous and/or radioactive material.Response:According to E&E (1992), a Navy reconnaissance plane crash landed south of Gambell,the belly gasoline tank exploded and most of the fuels burned leaving no apparent stainsor any stressed vegetation surrounding the crash site.According to Navy documentation, on June 22, 1955, a P2V-5 Neptune of VP-9, whileon patrol, was attacked by two MiG-15s, which set fire to the starboard engine and forcedthe Neptune to crash on St. Lawrence Island, near Gambell. There were no fatalities.The plane burned almost completely.The plane crash location is outside the military property boundary identified for theGambell site. This is not a FUDS site, and is not eligible for action under the FUDSprogram. Furthermore, there is no reason to believe hazardous and/or radioactivematerials are/were present.19) Comment (V. Waghiyi):Pg. 5, Table 1. Soil and Groundwater Cleanup Levels for All Sites and Sites 5 & 12: Whyare the Cleanup Levels different for DRO, RRO, Arsenic, Cadmium and Chromiumdifferent as noted in Table 1 for All Sites and Sites 5 & 12?Response:According to ADEC regulations (18 AAC 75), cleanup levels are based upon an estimateof the reasonable maximum exposure expected to occur under current and future siteconditions. The cleanup levels are based on the most relevant exposure pathways at eachsite. The regulations promulgated by the State of Alaska consider three scenarios –migration to groundwater, ingestion, and inhalation. In general, the most stringentpathway is selected as the cleanup level, however if a particular pathway is not applicableto a site, then the selected cleanup level is based on the remaining cleanup levelscontained in Table B of 18 Alaska Administrative Code (AAC) 75.345. The migration togroundwater pathway is not relevant for sites on the main gravel spit because continuouspermafrost acts as a barrier for soil contaminant migration to a groundwater zone. Theflow direction of the groundwater above the permafrost is typically north, towards theBering Sea, whereas the groundwater aquifer that supplies drinking water is locatedAppendix APage 9 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, Alaskaapproximately 1,500 to 2,000 feet east of the village. South of Troutman Lake near Site12, the groundwater may be in close connection with surface waters, and the moreconservative migration to groundwater pathway cleanup levels were selected.20) Comment (V. Waghiyi):Pg. 9, Site 1A-North Beach, Army Land Area, Investigation Summary: It does notdisclose how many soil and groundwater samples were collected in 1994. The onesurface soil sample does not seem enough, the geophysical survey boundaries for thelandfill are not noted, does this one surface soil sample denotes that is sufficient for theArmy landfill?Response:Site 1A refers to a beach area where Air Force landing activities occurred, i.e., theloading and unloading of barges bringing supplies to the installation. The geophysicalsurvey was conducted to determine the extent of possible buried debris and covered agrid measuring 400 by 200 feet. A cluster of anomalous areas was present in the easternhalf of the surveyed area. Two significant anomalous locations represented both surfacematerials and ferrous material at shallow depths. The predominant debris visible at thesurface included Marston matting, metal, and asphalt. The one surface soil samplecollected was sufficient to characterize the nature of the stained soils. The survey did notindicate a large landfill was present. The single surface soil sample was collected at arust-stained soil patch approximately four feet south of degraded asphalt along an ATVtrail. Three monitoring wells (MW6, MW7, and MW8) were also installed at Site 1B in1994. Three subsurface soil samples were collected for chemical analysis from the 2.5,5.0, and 10.0-foot depths in all three borings (a total of 9 samples). The only detection ofpetroleum hydrocarbons at Site 1B was 3.3 mg/kg of DRO at MW7 and 20 mg/kg ofTRPH in MW7 at 5 foot depth. Lead was detected at concentrations of 35 mg/kg in thesurface soil sample and at 117 mg/kg in MW8 at 15 feet depth. These concentrations aresignificantly below cleanup levels.21) Comment (V. Waghiyi):Pg. 9, Site 1B-North Beach, Air Force Landing Area: Do empty drums/barrels have to betested to see what they contained?Response:No. Empty drums are considered debris and are typically crushed for metal recycling orlandfill disposal.22) Comment (V. Waghiyi):Pg. 10, Former Military Housing/Operations Burial Site: The discolored gravel, was itsampled?Response:Yes. According to the site description, exposed debris observed during the 1994investigation included remnants of an apparent fireplace, concrete pad, pieces of burnedwood, scattered metal debris and two locations of discolored gravel. Two surface soilAppendix APage 10 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, Alaskasamples were collected from these gravel areas, at 50 feet west and 30 feet east of theconcrete slab at Site 2. The physical description of the samples (SS27 and SS28) states“fine gravel, coarse sand, silt/stained red”. The samples were analyzed for fuels (TRPH),BNA (base/neutral/acid compound), and priority pollutant metals. The figure showingthe sample locations also labels nearby debris as “red brick and concrete buildingremains”. Laboratory results showed high concentrations of metals in one of the twosurface soil samples for chromium (391 mg/kg), and lead (749 mg/kg). The detectedmetals were most likely caused by the debris contained in the area. The debris wasremoved during the 1999 removal action. See also the discussion under Response toComment #11.23) Comment (V. Waghiyi):Pg. 11, Former Military Housing/Operations Burial Site: Investigation Summary: 2ndparagraph, the sample from 1994 that exceeded the screening levels for chromium andlead. Which form of chromium is it? Form VI is a dangerous form of chromium and isvery mobile in groundwater and is almost always the result of human releases.Response:The sample was analyzed for total chromium. Speciation of chromium is not typicallyconducted during initial rounds of environmental sampling. However, during the 2001supplemental remediation investigation at Gambell, in a different site location (Site 4A),due to concerns over previously detected high levels of total chromium, two soil sampleswere collected and analyzed for both total chromium and hexavalent chromium (Cr+6/CrVI). Hexavalent chromium was not detected. Chromium is a very reactive element, andtypically gets reduced to the Cr+3 (III) form when it reacts with soil. In general,chromium is rarely found in the +6 (VI) form in soil.24) Comment (V. Waghiyi):The arsenic levels that exceed the ADEC cleanup level, and that are determined“consistent across sites in Gambell, and do not appear associated w/past military activity”The many sites that are referred to, the “consistent across sites in Gambell”, are theymilitary sites in question? And has samples of arsenic ever been taken for backgroundlevels outside of the boundaries of the military bases in Gambell?Response:The sites referred to include all areas sampled under the various investigations. Since ourinvestigations are confined to the FUDS property, all sampling could be consideredmilitary sites. Only a few “outside” or “background” samples have been collected.Nonetheless, the statistical evaluation of arsenic, as described in the Response toComment #10 above, has been considered appropriate in Gambell.25) Comment (V. Waghiyi):Pg. 12, Preferred Alternative: Chromium VI is dangerous, the single chromiumexceedance that is considered an outlier, what form is it and have background levels ofchromium been sampled outside of military boundaries to determine if the singlechromium exceedance is an outlier indeed?Appendix APage 11 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, AlaskaResponse:The sample was analyzed for total chromium, therefore, the valence state of thechromium is not known. However, as discussed in the Response to Comment 23 above,hexavalent chromium is rare in soils, and has not been detected in Gambell.26) Comment (V. Waghiyi):Pg. 12, Preferred Alternative: NFA, The village drinking water source is down gradientof site 2 & 3, warrants further sampling and monitoring.Response:According to groundwater level measurements taken at different times of the year, thevillage drinking water supply well is up gradient of Sites 2 and 3. Local residents didraise the issue of storm surges that might temporarily overwhelm the predominant waterflow directions during high water events. The short duration of these events would not beexpected to impact the drinking water aquifer.27) Comment (V. Waghiyi):Pg. 12, Investigation Summary, 3rd paragraph: Are beryllium and thallium (site 3 levels)dangerous?Response:The level of beryllium documented at Site 3 (6 mg/kg) is significantly less than the mostconservative ADEC cleanup level, which is 42 mg/kg, based on the migration togroundwater pathway, as well as the ingestion cleanup level of 200 mg/kg. Theberyllium concentration is also well below the risk-based screening levels of 150 and 160mg/kg for residential soil calculated by two U.S. EPA regional offices (Region 3’s riskbased concentrations and Region 9’s preliminary remediation goals). The U.S. EPA doesnot publish national soil cleanup levels, and other EPA regional offices have notcalculated screening levels. The level of thallium initially detected at Site 3 during the1994 investigation (15 mg/kg) did exceed screening levels published by U.S. EPARegions 3 and 9 (5.5 mg/kg). However, screening levels are meant to be conservativenumbers and are not equivalent to cleanup levels. Further investigation was conducted todetermine the full extent of potential contamination. The more detailed investigation in1996 documented that thallium was at non-detectable levels (less than 0.28 mg/kg) at Site3, which is well below the EPA screening levels of 5.2 and 5.5 mg/kg. It is thus veryunlikely that thallium poses a risk to local residents. The ADEC has not promulgated acleanup level for thallium.28) Comment (V. Waghiyi):Pg. 15 Site 4B-Former USAF Radar Station, Investigation Summary: 2nd Paragraph, DoEPA regions have different “risk-based concentrations”? Since we are in Region 10,does this US EPA, Region 3 risk-based concentration apply?Appendix APage 12 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, AlaskaResponse:Only two U.S. EPA regional offices have calculated risk-based concentrations, based onnational guidance documents. U.S. EPA Region 3 and Region 9 both have tables ofscreening values for use in site investigations. The values are typically quite similar.Region 10 does not publish its own list of risk-based concentrations, thus either tablewould apply.29) Comment (V. Waghiyi):Pg. 16, Site 4B-Former USAF Radar Station, Preferred Alternative: Were off militaryboundary background samples taken to see if the elevated copper is an isolatedoccurrence?Response:Two background surface soil samples were collected from north of the Radar Station(Site 4B), at the edge of the cliffs on the northern point of Sevuokuk Mountain. Copperwas analyzed for but not detected (detection limit of 2 mg/kg) in the two samples.Very little copper-impacted soil remains, and it is not practical to attempt removal.30) Comment (V. Waghiyi):Pg. 18, Site 5-Former Tramway Site, Investigation Summary: Since the only evidentactivity is from the military, and this site is by the Village water supply, the exceededlevel of DRO needs to be monitored and addressed.Response:The concentration of DRO detected in 1994 at MW16 was further investigated during asecond phase of study (1998) and could not be duplicated, therefore, the contaminationdiscovered at depth while drilling MW16 appears isolated (no large area of contaminationwas present). The 1998 replacement soil boring/monitoring well (MW32) was installedimmediately adjacent to the initial location of MW16 and the soil sampling resultsverified that the DRO contamination was not widespread. Four soil borings were alsocompleted at Site 5 during the 1998 investigation (SB33, SB34, SB35, and SB36) and nocontaminants of concern were detected. The DRO detected in groundwater frommonitoring well MW31 in 1998 remains a curiosity. Additional groundwater samplingwill be conducted to evaluate current site conditions. A final decision on any necessaryremedial actions at Site 5 will be made after evaluating the additional groundwater data.31) Comment (V. Waghiyi):Pg. 20, Site 6-Military Landfill, Investigation Summary: Have off military boundarybackground samples of metals been taken to determine that the levels of metals arenaturally occurring?Response:Two background samples were collected from a remote area in Gambell. Acomprehensive background study, with a statistically robust number of samples, has notbeen scoped because, with the exception of arsenic, elemental concentrations haveAppendix APage 13 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, Alaskalargely been below cleanup levels. Arsenic background levels have been computedstatistically as described above in Response to Comment #10.32) Comment (V. Waghiyi):Pg. 21, Site 7-Former Military Power Facility, Investigation Summary, 4th paragraph:Since this site is by the Gambell School and the DRO and benzene results exceed theADEC Table C groundwater cleanup levels, this site needs to be addressed. Benzene is along term contaminant in groundwater, it cannot readily evaporate underground and sincelittle microbial activity occurs in underground water, it is not degraded.Response:Groundwater has not been consistently detected at Site 7 and is not considered a likelysource of drinking water for the community. The monitoring wells were installed bydrilling down into the ice to create a reservoir that would collect groundwater.Furthermore, the samples from the monitoring wells were poor groundwater samples –the lack of water in these wells prevented standard well development, thus “dirty” watersamples were submitted. Water sample turbidity ranged from 82.5 NephelometricTurbidity Units (NTUs) at MW24, to 50.1 NTUs at MW25, to 9.3 NTUs at MW27.Ideally, turbidity should be less than 5 NTUs for well samples. This suggests that thelaboratory results included contributions from suspended solids (soil). Additionalinvestigation conducted in 2001 demonstrated that the suprapermafrost groundwater atSite 7 was not present. Soil sampling results from 2001 indicated that the maximumconcentration of DRO was 710 mg/kg, which does not exceed the ADEC ingestioncleanup levels of 10,200 mg/kg. Benzene was not detected in the soil samples (detectionlimit of 0.005 mg/kg). These contaminant levels do not pose a tangible threat to theschool (which is not in the immediate area) or the community.33) Comment (V. Waghiyi):Pg. 27, Site 12, North Nayvaghat Lakes Disposal Site, Investigation Summary, 2ndparagraph: The background levels for groundwater and surface water taken from MW-14located at the base of Sevoukuk Mt. are from Site 5, so therefore NOT BACKGROUND.Response:At the time of the Phase I Remedial Investigation in 1994, MW14 was designated abackground monitoring well. This site was selected because it was adjacent to the freshwater recharge area at the base of Sevuokuk Mountain and presumed to be upgradientfrom any potential contaminant sources, such as the Former Military Housing/OperationsSite (Site 2) and Former Communications Site (Site 3). No metals were detected in thegroundwater at this location; the comparison levels designated as background wereactually the method detection limits for this sample from the 1994 investigation.The only detectable analytes found in groundwater from 2 monitoring wells (MW17 andMW18) installed at Site 12 were the metals barium, lead and zinc. The concentrations ofthese elements were significantly below the ADEC Table C groundwater cleanup levels.Barium ranged from ND to 0.03 mg/L, compared to a cleanup level of 2.0 mg/L. LeadAppendix APage 14 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, Alaskaranged from ND to 0.004 mg/L, compared to a cleanup level of 0.015 mg/L. Zinc rangedfrom ND to 0.018 mg/L, compared to a cleanup level of 11.0 mg/L.One surface water sample (SW165) was also collected at a small pond situated in thenortheast corner of North Nayvaghat Lake. DRO was detected at a concentration of 0.06mg/L, compared to a cleanup level of 1.5 mg/L. Chromium and zinc were also detected,but at concentrations well below the ADEC Table C groundwater cleanup levels.Chromium ranged from ND to 0.007 mg/L, compared to a cleanup level of 0.1 mg/L.Zinc ranged from 0.048 to 0.049 mg/L, compared to a cleanup level of 11.0 mg/L.34) Comment (V. Waghiyi):Pg. 32, Site 22-Former CAA Housing, Preferred Alternative: Since the housing has thepossibility that asbestos-containing materials may be present in the structures, this siteneeds to be addressed to determine if the buildings do indeed pose a risk to the occupantsor local resident owners, they have a right to know!!Response:The FUDS program is not authorized to conduct remedial actions for structures that havebeen occupied and beneficially used since military use. Furthermore, FUDS programpolicy (ER 200-3-1) specifically states that the abatement of asbestos-containingmaterials (ACM) is an ineligible project, unless the abatement is incidental to completingan approved building demolition project.35) Comment (V. Waghiyi):Pg. 34, Site 26-Possible Debris Burial Site: Since this site is by the Gambell School, itwarrants cleanup since Local residents reported finding metal debris, machinery, oilydebris, and TRANSFORMERS in the vicinity, NFA is not an option due to the riskassociated with the site.Response:The 2001 remedial investigation demonstrated that soil contamination is not present atthis location. Therefore there is no risk from contaminants associated with this site. TheFUDS program is not authorized to excavate buried debris, unless hazardous constituentsare present and demonstrated to be migrating off-site.36) Comment (V. Waghiyi):Pg. 35, Site 28-Disturbed Ground, Site Description: The Army’s use of the land leasedJanuary 1955 to May 1958 needs to be determined, the community has a right to know ifit poses a risk!Response:According to the Findings and Determination of Eligibility (1985), 16.07 acres locatedimmediately south of Troutman Lake were obtained by Special Land Use Permit from theBureau of Land Management (BLM) for the Army in January 1955 and called “GambellArmy Site No. 2”, a defense site. This area was relinquished to BLM in February 1958.A small portion of this area, 0.23 acres, was obtained by notation of land records for theAppendix APage 15 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, AlaskaGambell National Guard in March 1962 and relinquished to BLM in February 1973.According to the Archives Search Report prepared by USACE (March 1998), the areasouth of Troutman Lake was used by the Army for communications.37) Comment (V. Waghiyi):Until credible samples of background arsenic levels are collected outside of the militaryboundaries in Gambell, Sites 1A, 1B, 2, 6, 7, 9, 12, 13, 16, 17, 18, 25A, 26 and 28 needto be taken off of “Preferred remedial alternatives NFA” proposed plans until if indeedthe arsenic levels are not associated w/past military activity.Response:A comprehensive study of background metals values has not been conducted in thevicinity of Gambell. Such study has not been scoped because, with the exception ofarsenic, elemental concentrations have largely been below cleanup levels. Arsenicbackground levels have been computed statistically as described above in Response toComment #10. Arsenic is a naturally occurring element that has been well documentedthroughout the state of Alaska at concentrations higher than the default ADEC cleanuplevels. Site 7 is the only site with a clear indication of elevated levels of arsenic. Thegravel soil at this site is proposed for excavation and removal in the Proposed Plan.38) Comment (V. Waghiyi):Are the following sites with buried debris scoped under NALEMP and will be removed?Sites 1A, 1B, 1C, 2, 3, 11, 13, 14, 15, 16, 17, 18, 21, 23 & 24.Response:The Native Village of Gambell (NVG) successfully removed debris at Site 18 during the2004 field season under a Fiscal Year (FY) 03 Cooperative Agreement with theDepartment of Defense. The NVG also planned to remove debris at Sites 17 and 19during the 2004 field season, but encountered more debris than anticipated at Site 18 andmay not have completed those sites. These sites would then be addressed during the2004 field season. The NVG was awarded a FY04 NALEMP Cooperative Agreement foradditional work to be performed during the 2005 field season. The FY04 CA anticipatescleanup at Sites 3A, 5, 1A, 6, 1B, 2, 8C, 8B, 4E, 13, 23, 15, and 1C. Sites 21 and 24 areincluded in the Strategic Project Implementation Plan (SPIP) prepared by the NativeVillage of Gambell, but have not yet been funded for cleanup by NALEMP. Sites 11 and14 are not identified as impacts by the Native Village of Gambell in their SPIP.39) Comment (V.Waghiyi):Sites 3, 4A, 4B, 5, and any other site that had samples that initially had elevated levelsand are a risk to human health and the environment, and after additional samples weretaken a year or years later, the results showed decreased levels, goes to show that thecommunities knowledge that the groundwater migrates and as a result the differences inthe contaminant levels needs to addressed and long term monitoring are warranted andmust remediate and cleanup the contaminants when concentration levels are above risk tohuman health and the environmentAppendix APage 16 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, AlaskaResponse:Sampling events are conducted over time and space to delineate the extent ofcontamination at a particular site. Sampling results that show a decrease incontamination can indicate several things. Natural attenuation for contaminants occursover time, or perhaps the samples just reflect inherent variation in contaminantconcentrations. Perhaps the subsequent sampling reached beyond the extent ofcontamination. In each of the areas mentioned, cleanup activities have already takenplace, and decreased levels of contamination can logically be attributed to these cleanupefforts. The latest sampling results suggest that neither further cleanup actions nor longterm monitoring is appropriate for these sites.40) Comment (R. Scrudato):One factor is clear from the data collected on the effects of the military occupancy is thatit is very difficult to effectively characterize and assess the environmental impacts withinthe Gambell area due to the complex hydrology and geology of the area. The highlypermeable and coarse grained nature of the cobble deposits are difficult to sample. Thepresence of permafrost, as well as the proximity of the impacted sites to the Bering Seaand the relative hydrologic influences of Troutman Lake, makes it difficult to effectivelycharacterize impacts to the various sites known to have been impacted by the release ofcontaminants during the time the military occupied the area.Response:We agree that site characterization has been challenging at the Gambell site.Nonetheless, investigations have been thorough enough to demonstrate that gross, largescale contamination is not a legacy of the Gambell FUDS. Whereas buried debris is acommonplace occurrence, contamination associated with that debris appears limited. TheADEC has concurred that site characterization is adequate to proceed with a remedialdecision.41) Comment (R. Scrudato):Additional complications are imposed by the difficulties in gaining an understanding ofthe relationships of the Gambell cobble deposits (the spit) to the bedrock especially thetransition at the base of the elevated mountainous area, including the interrelationship ofthe fractured bedrock, the talus and the on-lapping cobble deposits. This transition zoneis particularly important to the source of the Gambell water supply since the infiltrationgallery is charged by the groundwater deriving from this complex interrelationship. Thisinterrelationship is also subject to seasonal changes and further complicated by thepresence of contaminated cobble soils within the recharge gallery area. As I havementioned in earlier correspondence, the hydrology of the infiltration gallery andrelations to the contaminants identified in the sites located in proximity to the infiltrationgallery are less than well defined.Response:We acknowledge that the complex hydrologic relationships between the aquifer and itsrecharge area in the vicinity of Gambell are not fully understood. To date, we do notrecognize an imminent threat to the water supply and we remain cautiously optimisticAppendix APage 17 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, Alaskathat the status quo will be maintained. The cobble soils within the recharge gallery areahave been investigated during several phases of remedial investigation. A large source ofcontamination has not been identified which could impact the drinking water source. Inthe absence of water sampling results that indicate a definite problem, it is not an issuefor the FUDS Program.42) Comment (R. Scrudato):As I mentioned in my comments on the Gambell Feasability Report, it is important toprovide the Gambell residents with assurances that the environmental impacts derivingfrom the former military occupancy and release of contaminants at the various definedsites will not continue to affect their natural resources. The most effective way to providethis assurance is to establish a broad based monitoring program that will take intoconsideration the uncertainties inherent in effective site characterization due to thecomplex nature of the Gambell geology, hydrology, and relationship to permafrost,climatic changes and future land use to ensure that potential impacts will be identifiedand defined.Response:The purpose of site cleanups undertaken under FUDS is to remediate known sources ofmilitary contamination that pose a threat to human health or the environment. The Corpsused the most stringent level of protection under state guidelines (residential) whenconsidering the future land use in Gambell. It is not within the scope of the FUDScleanup to set up monitoring programs to safeguard against potential futureenvironmental concerns.Monitoring programs are established if recognizedcontaminants, above regulatory cleanup levels, are left in the ground and subject tonatural or induced remediation, or if institutional controls such as fencing or deedrestrictions are imposed. This does not appear to be the case in Gambell.43) Comment (R. Scrudato):I recommend a more comprehensive series of monitoring wells be established andmonitored throughout the Gambell area to ensure detection of contaminants will not goundetected. The Gambell residents should be provide a measure of confidence that futurepotential impacts will be detected and once detected effectively eliminated.Response:Monitoring for potential contaminants, indefinitely into the future, is not within the scopeof the FUDS Program. FUDS is a cleanup program, for known contamination.. If newinformation becomes available in the future regarding potential military impacts, theFUDS program will evaluate the data to determine the appropriate course of action.44) Comment (M. Apatiki):The overall concept of the Introduction and Description stated in this Documentregarding the Geophysical Surveys, Remedial Investigations and Feasibility Studies(RI/FS) that were conducted and the proposed Work Plans to perform the RemedialAction (Cleanup) by the Independent Contractor were excessively unexplicit for severalreasons stated in the following sections: The environmental impact on each of the SitesAppendix APage 18 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, Alaskado not seem to have a thorough examination and description regarding the analyticalsampling and previous cleanup actions. Specifically, the sites that were proposed for the“No Further Action”.Response:Please refer to the more detailed Remedial Investigation reports that are provided forpublic viewing at the Information Repository located at the Sivuqaq Lodge. The ADEChas provided regulatory oversight during the investigation and cleanup process for theGambell Site. The ADEC has concurred that site characterization is adequate to proceedwith a remedial decision.45) Comment (M. Apatiki):The analytical DATA Collections conducted by the Independent Contractor, that werestarted since the year of 1985 do not correspond with the other analytical comparisonresults conducted by the contractor that should have excessively exceeded the ADECCleanup Level Protocol.Response:The analytical data collected over time at the Gambell site has been verified for accuracyand usability. Data regarding analytical sampling should be expected to change overtime, especially if cleanup activities occur between sampling events. Scientific analysisof the data requires an objective interpretation to best understand the meaning of theresults.46) Comment (M. Apatiki):In accordance with the local eye-witness perspectives, regarding the sites that wereproposed for the cleanup removal were recommended as the unfinished projectperformance because of the content of the debris sites were partially been removed andthat still had the remains of the unidentified anomalies and contaminant that were stillintact on sites.Response:The proposed cleanup action includes removal of debris at the airstrip (Site 8A) whichwas originally slated for removal during the 1999 debris removal action. The initialremoval action encountered live electrical wires that prevented safe working conditionsnear this debris. A health and safety plan, and coordination with local airport officialswill be conducted to ensure the remaining surface debris is completely removed.47) Comment (M. Apatiki):The overall condition of the 28 Sites indicated in this document were positively stillremains on sites and some still needs to be addressed thoroughly on behalf of thecommunities of the St. Lawrence Island that were affected by the FUDS/HTRW.Response:Between the FUDS and NALEMP Programs, substantial cleanup activities are planned inthe Gambell area. It is certain that these activities will result in a cleaner community, andAppendix APage 19 of 20Appendix A - Responsiveness SummaryGambell SiteSt. Lawrence Island, Alaskaprovide opportunities for the local citizens to be involved, and for employment. TheADEC has provided regulatory oversight during the investigation and cleanup process atthe Gambell Site. The ADEC has concurred that site characterization is adequate toproceed with a remedial decision.Appendix APage 20 of 20Alaska District Corps of EngineersStaff I Action Sheet~ ""~IiiDivisionConcur1PM-C2j'M,CW~OC£$_311 VB~:JM 1/ KJ45/AU::?'ll'aIlAA_-j,DE-DIt/') I6DEs:Please intial concur or non & dateNonDateDate:Decision Document for HTRW and BD/DR Response theNative Village of Gambell, AK(F10AK 0696)12'1 J",-l'5"