RECORD OF DECISION for 3,3. OPERABLE UNIT 2 FORT WAESfWRIGHT FAIRBANKS, ALASKA

January 1997 DECLARATION STATEMENT for RECORD OF DECISION FORT WAINWRIGHT FAIRBANKS, ALASKA OPERABLE UNIT 2 JANUARY 1997

SOURCE AREA NAME AND LOCATION

Operable Unit 2 Fort Wainwright Fairbanks, Alaska

STATEMENT OF BASIS AND PURPOSE

This Record of Decision (ROD) presents the selected remedial actions for Operable Unit 2 (OU-2) at Fort Wainwright in Fairbanks, Alaska. OU-2 originally consisted of eight source areas: the Defense Reutilization and Marketing Office (DRMO) Yard, the Building 1168 Leach Well, the North Post Site, the 801 Drum Burial Site, the Engineers Park Drum Site, the Drum Site South of the Landfill, Building 3477, and the 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 and 42 United States Code 9601 et seq., and, to the extent practicable, the National and Hazardous Substances Pollution Contingency Plan and 40 Code of Federal Regulations 300 et seq. This decision is based on the Administrative Record for this OU.

The United States Army, the United States Environmental Protection Agency, and the State of Alaska, through the Alaska Department of Environmental Conservation, have agreed to the selected remedies.

ASSESSMENT OF THE SITE

Actual or threatened releases of hazardous substances from the DRMO Yard and Building 1168 Leach Well source areas, if not addressed by implementing the response actions selected in this ROD, may present a substantial endangerment to public health, welfare, or the environment. Specific hazardous substances in the soil and groundwater at the DRMO Yard and Building 1168 Leach Well include benzene, tetrachloroethene, trichloroethene, and by-products.

DESCRIPTION OF THE SELECTED REMEDIES

This is the third OU to reach a final-action ROD at this National Priorities List site. This ROD addresses soil and groundwater contamination at OU-2.

The 801 Drum Burial Site, Engineers Park Drum Site, and Drum Site South of the Landfill were assigned to the Fort Wainwright OU-1 investigation and will be addressed through the OU-1 decision process. No further action is selected for Building 3477 and the Tar Sites. The contaminated soils at the North Post Site were addressed adequately through an Army removal action; it is anticipated that this will constitute final action for the North Post Site. Therefore, no analysis of remedial alternatives was conducted for these source areas. The documents recommending these actions are included in Appendix A.

The remedial action objectives for the DRMO Yard and Building 1168 Leach Well are designed to:

• Restore ground water to drinking water quality;

• Prevent further leaching of contaminants into groundwater;

• Reduce or prevent further off-site migration of contaminated groundwater; and

• Prevent use of groundwater above federal Safe Drinking Water Act and State of Alaska Drinking Water Standards (18 Alaska Administrative Code 80) maximum contaminant levels (MCLs).

The major components of the remedies at both source areas are:

• In situ soil vapor extraction and air sparging of the groundwater to reduce volatile organic compounds to a level that meets state and federal MCLs;

• Institutional controls that would include restrictions on ground- water well installations, site access restrictions, and maintenance of fencing at the DRMO Yard until state and federal MCLs are met;

• Additional institutional controls, including a limitation on refilling the DRMO Yard fire suppression water tank from the existing potable water supply well, until state and federal MCLs are met (except in emergency situations); and

• Natural attenuation to attain Alaska Water Quality Stan