FORMER ADAK NAVAL COMPLEX, DECLARATION OF THE RECORD OF DECISION, OPERABLE UNIT A
Adak Naval Complex, Adak Island, Alaska

STATEMENT OF BASIS AND PURPOSE

Naval Air Facility Adak was placed on the National Priorities List (NPL) in 1994. Adak was divided into two operable units (OUs), OU A and OU B.

This Record of Decision (ROD) presents the selected remedial actions for OU A at the former Adak Naval Complex on Adak Island, Alaska. OU A comprises 58 Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) sites and 128 petroleum sites covered by the State-Adak Environmental Restoration Agreement (SAERA). Issues regarding ordnance explosives will be addressed in a separate ROD, which will be for OU B.

The 58 OU A CERCLA sites are separated into the following categories:

• No-further-action sites
• Institutional-control-only sites
• Industrial sites
• Landfills

Also included under the CERCLA discussion are major OU A water bodies adjacent to or downgradient of the CERCLA terrestrial sites, as well as the downtown groundwater area.

The petroleum sites are separated into the following categories:

• No-further-action sites
• Free-product-removal sites
• Monitored natural attenuation sites
• Soil removal sites

This ROD was developed in accordance with the Comprehensive Environmental Response,Compensation, and Liability Act of 1980, as amended by the Superfund Amendments and Reauthorization Act of 1986 (SARA); 42 United States Code (USC) Section 9601 et seq.; and, to the extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). This decision is based on the Administrative Record for OU A.

The State of Alaska concurs with the selected remedies. The following information is included in Sections 6 through 10 of this Record of Decision. Additional information can be found in the Administrative Record file for this site.

• Chemicals of concern (COCs) and their respective concentrations
• Baseline risk represented by the COCs
• Cleanup levels established for COCs and the basis for the levels
• Current and future land and groundwater use assumptions used in the baseline risk assessment and ROD
• Land and groundwater use that will be available at the site as a result of the Selected Remedy
• Estimated capital, operation, and maintenance (O&M), and total present worth costs; discount rate; and the number of years over which the remedy cost estimates are projected
• Decisive factor(s) that led to selecting the remedy (i.e., describe how the Selected Remedy provides the best balance of tradeoffs with respect to the balancing and modifying criteria)

ASSESSMENT OF THE SITE

Actual or threatened releases of hazardous substances from the CERCLA and petroleum sites, if not addressed by implementing the response actions selected in this ROD, may present an imminent and substantial endangerment to public health and welfare or to the environment. Removal actions and interim remedial actions have already taken place at numerous CERCLA and all petroleum sites.

DESCRIPTION OF THE SELECTED REMEDIES

This OU is addressing numerous sources of contamination to soils, surface water, sediments, and groundwater. The selected remedies reduce risk through removal and treatment, or containment, and institutional controls.

The major components of the selected remedy for the CERCLA sites (including the OU A water bodies and downtown groundwater) include the following:

• Excavation and treatment by thermal desorption of contaminated sediments and soils
• Recycling of treated sediment and soils as daily cover material at the on-island Roberts Landfill
• Placement of a soil cover over SWMU 4
• Institutional controls to prohibit unacceptable exposure to hazardous substances left on site
• Monitoring of groundwater for benzene, toluene, ethylbenzene, xylenes, diesel-range organics (DRO), gasoline-range organics (GRO), bis(2-ethylhexyl)phthalate, methylene chloride, tetrachloroethene, trichloroethene, lead, and natural recovery parameters
• Monitoring of aquatic biota for polychlorinated biphenyls (PCBs)

The major components of the selected remedy for the petroleum sites include the following:

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

STATUTORY DETERMINATION

Each selected remedy is protective of human health and the environment, complies with federal and state requirements that are legally applicable or relevant and appropriate to the remedial action, and are cost effective. Each remedy utilizes permanent solutions and alternative treatment technologies to the maximum extent practicable. The statutory preference for remedies that employ treatment that reduces toxicity, mobility, or volume as a principal element was not met for all sites. Treatment will be included as part of the remedy for SWMU 17, South Sweeper Creek, and the 12 soil removal petroleum sites.

Because these remedies will result in hazardous substances remaining at some source areas above health-based levels, a review will be conducted within 5 years after commencement of remedial action to ensure that the remedies continue to provide adequate protection of human health and the environment.

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