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A view of Downtown Adak, overlooking Sweeper Cove

Since 1989, the Navy has removed hundreds of USTs, closed miles of fuel transfer pipelines, and conducted site assessments of the petroleum sites. During UST excavations, soil samples were collected and analyzed. Soils with petroleum concentrations above limits set forth in ADEC guidance were removed from the individual excavations. Soil samples were also collected at scores of locations along the former pipelines. Additional soil samples were collected at locations where petroleum concentrations exceeded ADEC cleanup levels.

During late 1996, remediation of the stockpiled soil began using thermal desorption. Thermal desorption is a treatment process that heats soils to temperatures sufficient to cause organic compounds to volatilize and physically separate (desorb) from the soil. Approximately 8,500 cubic yards of petroleum-contaminated soil has been treated and used as daily cover for on-island landfills.

Cleanup of the petroleum-contaminated sites has been conducted to comply with ADEC requirements, but follows a CERCLA decision-making process. A regional focused feasibility study (FFS) was prepared by the Navy in 1998 to evaluate the options for addressing petroleum contamination on Adak. The FFS included conceptual site models to help assess the risks to human health and the environment. An addendum to the FFS was prepared in June 1999, to present information supporting the final disposition of the 128 petroleum release sites pursuant to the newly promulgated ADEC cleanup regulations of 18 Alaska Administrative Code (AAC) 75. The Proposed Plan for cleanup of the petroleum sites was published in January 1998. The Record of Decision (ROD) for Operable Unit (OU) A includes decisions on petroleum sites as well as CERCLA sites.

A total of 128 petroleum-release sites were investigated under State Adak Environmental Restoration Agreement and included in the OU A ROD. The cleanup remedies for the petroleum sites are listed in OU A ROD. Major components of the remedies selected for the remaining petroleum-release sites are being implemented on a site-by-site basis. These include the following:

Free-product recovery to the maximum extent practicable as an interim remedial measure, followed by an evaluation of remedial alternatives to achieve final cleanup levels under 18 AAC 75 for groundwater (ongoing)
Removal and treatment of petroleum-contaminated soil to meet 18 AAC 75 requirements for soil
Recycling of treated soils as daily cover material at Roberts Landfill
Monitored natural attenuation of petroleum chemicals in groundwater (ongoing)
Institutional controls to minimize the potential for direct contact, to restrict groundwater use, and/or to restrict soil excavation until remedial action objectives have been met (ongoing)

A number of sites were determined to require no further action. At 15 of the 128 petroleum-release sites included in OU A, free product floating on groundwater has been detected at least once . Product recovery was the remedy selected in the OU A ROD for 14 of these sites – for the Arctic Acres Housing Area, free product has not been detected since 1993. Monitoring natural attenuation was selected in the ROD as the remedy for that site. Product recovery has been ongoing at many of these sites for several years.

Site-specific risk assessments were performed during 2003 for each of the 14 free-product recovery petroleum sites on Adak Island to determine if residual concentrations of petroleum-related chemicals in soil, groundwater, sediment, or surface water at a site pose a risk to human health or the environment above ADEC target health goals. Based on the results of these risk assessments, free-product recovery petroleum sites at the former Adak Naval Complex can be grouped into two categories:

Sites where concentrations of petroleum-related chemicals in soil, groundwater, sediment, and surface water pose no risk to human health or the environment above ADEC target health goals
Sites where concentrations of petroleum-related chemicals in soil, groundwater, sediment, or surface water pose a risk to human health or the environment above ADEC target health goals

Proposed plans were developed in 2003 for each site where the site-specific risk assessment determined that no risk was apparent to human health and the environment above the ADEC target health goals. Sites were divided dependent on whether or not groundwater was a potential drinking water source. Sites where groundwater is a potential drinking water source include:

GCI Compound;
SA 80, Steam Plant 4; and
Tanker Shed.

Sites where groundwater is not a potential drinking water source include:

NORPAC Hill Seep Area;
SA 78, Old Transportation Building;
SA 82, P-80/P-81 Buildings;
SA 88, P-70 Energy Generator;
SWMU 58 and SA 73, Heating Plant 6; and
Yakutat Hangar.

Potential remedies selected for these sites include 1) preventing exposure to petroleum-related chemicals in soil and groundwater at the site, and 2) over the long run, reducing concentrations of petroleum-related chemicals in groundwater to levels below Alaska DEC (ADEC) groundwater cleanup criteria. These plans are still under review by the Navy and regulatory bodies.

Site-specific focused feasibility studies are under development for each site where the site-specific risk assessment determined that a risk was apparent to human health and the environment above the ADEC target health goals. These sites include:

NMCB Building Area, T-1416 Expanded Area;
South of Runway 18/36;
SWMU 17, Power Plant 3; and
SWMU 62, New Housing Fuel Leak (Sandy Cove and Eagle Bay Housing).

When completed, remedial alternatives will be ranked as to their feasibility.

At 12 of the 128 petroleum-release sites included in OU A, limited soil removal was the remedy selected in the ROD. These sites include:

ASR-8 Facility,
Contractor's Camp Burn Pad,
Finger Bay Quonset Hut,
Girl Scout Camp,
Mount Moffett USTs,
Navy Exchange Building UST 30027-A,
Officer Hill/Amulet Housing UST 31047-A,
Officer Hill/Amulet Housing UST 31049-A,
Officer Hill/Amulet Housing UST 31052-A,
Quarters A,
SA 77 - Fuels Facility and Small Drum Storage, and
Yakutat Hangar USTs T-2039-B and C.

The limited soil removal activities were performed during the 1999 field season. In addition, a limited soil removal was performed at a 13^th site, Boy Scout Camp West Haven Lake, for which the remedy selected in the ROD was limited groundwater monitoring. The limited soil removal was performed at the site because the surface soil contained petroleum-related chemicals at concentrations above ADEC soil cleanup levels. The soil removed from all of these sites has been treated by thermal desorption and then used as daily cover at Roberts Landfill. At 2 of the 13 sites, limited soil removal activities were prevented by facility operations. These are SA 77, Fuels Facility Refueling Dock, Small Drum Storage site and ASR-8 Facility (UST 42007-B) site.

At 8 of the 128 petroleum-release sites included in OU A, limited groundwater monitoring was the remedy selected in the ROD. Upon completion of the limited soil removal, four sites transitioned into limited groundwater monitoring. These sites include:

Boy Scout Camp - West Haven Lake,
Finger Bay Quonset Hut,
MAUW Compound UST 24000-A,
NAVFAC Compound,
Navy Exchange Building UST 30027-A,
New Roberts Housing,
Officer Hill/Amulet Housing UST 31052-A,
ROICC Contractor's Area UST ROICC-7,
ROICC Warehouse UST ROICC-2,
ROICC Warehouse UST ROICC-3,
SA 79 - Main Road Pipeline,
Yakutat Hangar USTs T-2039-B and C.

Additional groundwater monitoring wells were installed at these sites during 1999 and 2000. Quarterly groundwater monitoring was performed at the four sites in 2000 to determine whether concentrations in local groundwater exceeded ADEC groundwater cleanup levels. This monitoring began in the third quarter of 1999. As of 2003, all limited groundwater monitoring sites have achieved their respective endpoint criteria except for ROICC Contractor's Area UST ROICC-7 and SA 79 - Main Road Pipeline, where groundwater monitoring is continuing.

At 22 of the 128 petroleum-release sites, monitored natural attenuation with institutional controls was the remedy selected in the ROD. Of these, wells at 14 sites are monitored for surface water protection. These sites include:

Antenna Field,
Former Power Plant,
GCI Compound,
Housing Area - Arctic Acres,
NMCB,
NORPAC Hill Seep,
ROICC Contractor's Area UST ROICC-8,
Runway 5-23 Avgas Valve Pit,
SA 73/SWMU 58 - Heating Plant 6,
SA 78 - Old Transportation Building,
SA 82 - P-80/P-81 Buildings,
SA 88 - P-70 Energy Generator,
South of Runway 18-36,
SWMU 14 - Old Pesticide Disposal Area,
SWMU 15 - Future Jobs/DRMO,
SWMU 17 - Power Plant 3,
SWMU 60 - Tank Farm A,
SWMU 61 - Tank Farm B,
SWMU 62 - New Housing Fuel Leak,
Tanker Shed, and
Yakutat Hangar UST T-2039-A.

Natural attenuation refers to physical, chemical, or biological processes acting without human intervention to reduce the mass, toxicity, mobility, volume, or concentration of contaminants in soil or groundwater. These sites will be monitored to verify the rate at which natural attenuation is occurring. Institutional controls will be used to protect human health by restricting the use of groundwater. In 1999, a total of 27 new monitoring wells were installed to monitor 17 CERCLA and petroleum sites. Additional new monitoring wells were installed in 2003.

Aesthetic remedies were initiated at locations where contamination did not exceed cleanup criteria but where remediation of visual impacts was appropriate. Placement of clean soil as a cover has been completed at the following petroleum sites: the SWMU 17 Power Plant 3 Area site, the SWMU 58/SA 73 Heating Plant 6 site, the SWMU 74 Old Batch Facility site, the airport canal near the Former Power Plant Building T-1451 site, and Yakutat Hangar.