SWMU 16, Former Firefighter Training Area CERCLA Site
Background
SWMU 16 was used for firefighter training from 1970 to 1989. It was included in the CERCLA investigations because petroleum, waste oil, and solvents were ignited on site during training exercises. The site was cleared of training materials in 1992. It encompasses an abandoned hardstand off of former Taxiway E, near the west end of Runway 5-23 and comprises an area of about 4 acres (US Navy 1996).
The remedial action objective is to maintain the commercial and industrial land use for SWMU 16 due to a historical detection of Aroclor 1260 that results in a residential ICR of 4x10E-5. The estimated risks for recreational and industrial use are below State of Alaska cumulative risk level of 1x10E-5.
Identified Contaminants
Analytical results of sediment, surface and subsurface soil, and groundwater were used to assess human health and ecological risk in the preliminary source evaluation report for the site (URSG 1996a).
The risk driver was Aroclor 1260. In 1997 the Navy conducted an interim removal of soil near the concrete apron, which contained PCBs in excess of 1 mg/kg. Another risk evaluation that was based on post-removal conditions (URS 1997a) indicates that the human health cancer risk is 4E-05 because of Aroclor 1260 in groundwater (based on a residential scenario). It was detected in 1 of 38 groundwater samples at a concentration of 0.8 ug/L, which results in an estimated residential ICR of 4x10E-5. It has not been detected in groundwater since 1990.
CERCLA Institutional Controls
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CERCLA Engineering Controls
Engineering controls encompass a variety of engineered remedies to contain or reduce contamination, or physical barriers intended to limit access to property. Engineering controls, as they relate to Adak Island, include fences, signs, caps or barriers, and treatment systems including monitoring wells. The engineering controls identified in the OU A ROD, petroleum cleanup sites, and those that will apply as interim measures to OU B are described below.
Under the OU A ROD signed in 2000, fishing advisory signs were posted for subsistence fishers because of low levels of PCBs detected in bottom fish (rock sole) and shellfish (blue mussels) of Sweeper Cove and Kuluk Bay. The OU A ROD Amendment removes the requirement for fish advisory signs. Instead, the Navy will provide an information pamphlet to the residents of the City of Adak, because they are the most likely people to eat locally caught fish and shellfish as part of a subsistence diet. Fish information pamphlets will be updated as new information is collected and trends are analyzed. Copies of the updated pamphlets will be put in residence mail boxes, and copies will be placed at the City of Adak and U.S. Fish and Wildlife offices. The consumption of rock sole or blue mussels by recreational fishers poses no unacceptable health risks.
Ordnance hazard signs are in place on fencing around the part of the perimeter of the access restricted area adjacent to Lake Andrew. As of the end of the 2002 field season, remediation has been completed on all areas outside the access-restricted area adjacent to Lake Andrew. For this reason, with the exception of the signs at the perimeter of the Lake Andrew area, these signs are no longer required and were removed in 2003. Fences and gates at the access-restricted areas adjacent to Lake Andrew will be retained and maintained until the OU B-2 ROD is executed. Thereafter, ICs and ECs will be subject to the terms of the OU B-2 ROD.
| Other Engineering Controls Other engineering controls/remedies listed in the Comprehensive Monitoring Plan, Revision 1 are listed below.
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