SA 76 - Old Line Shed Building CERCLA Site
Background
This Old Line Shed Building, approximately 2.53-acres, is rectangular open area with a concrete foundation pad surrounded by gravel. At the time of the investigation, the site was used to stockpile gravel. Historically, the site was used for office space, line crew living quarters, and storage space for a variety of materials. The structure was removed after it was damaged in a 1982 storm and rendered uninhabitable
(US Navy 1995b).
The remedial action objective for the Old Line Shed Building is to maintain the current commercial and industrial land due to the presence of arsenic and indeno(1,2,3-cd)pyrene at levels that result in an estimated residential ICR of 9x10E-5 (the estimated ICR for the current industrial use is 4x10E-6); and conduct groundwater sampling. Groundwater sampling will be conducted and reported under the Comprehensive Monitoring Plan
(US Navy 2000c).
Identified Contaminants
Arsenic and Indeno(1,2,3-cd)pyrene were identified as Chemicals of Concern (COC's)in the OU-A ROD. The maximum detected concentration for arsenic was 98.5 mg/kg, and an estimated residential ICR of 5x10E-5 and exceeds the ADEC soil cleanup level of 1.8 mg/kg. The maximum detected concentration for Indeno(1,2,3-cd)pyrene was 1.1 mg/kg and an estimated residential ICR of 3x10E-5.
CERCLA Institutional Controls
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Groundwater Restrictions
Domestic use of groundwater in the Downtown Area is restricted because of the potential presence of petroleum compounds and other chemicals in the groundwater. Domestic groundwater use is defined as that used by households or transients for human and animal consumption, cooking, bathing, showering, gardening, irrigation, or use on consumable food products, watering animals and any other domestic use. The excavation notification program at individual sites provides one barrier to drilling; enforcement of the prohibition will also occur through periodic visual inspections. The visual inspections will focus on unauthorized wells in the restricted area. Groundwater use restrictions are included in the equitable servitude.
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Land Use Restrictions
Outdoor recreational and commercial and industrial land uses for the CERCLA Downtown Area sites are allowable under the OU A ROD. Examples of recreational land uses include hiking, bird watching, hunting, nature watching or any other short-term, non-intrusive activity on the land. Examples of commercial and industrial uses include manufacturing, industrial research and development, utilities, commercial warehouse operations, retail gas stations, auto service stations, equipment repair and service stations, professional offices, financial institutions, publicly owned office buildings, retail business where the principal activity is the sale of food or merchandise, personal service establishments (health clubs, barber/beauty salons, mortuaries, photographic studios, etc.), churches providing worship services (excluding daycare services), and motels/hotels (excluding those that allow residences). The planned land use at the Downtown Area CERCLA sites (except landfills) is consistent with these land use restrictions.
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Soil Excavation Restrictions
Excavation Notifications are required for all the Downtown Area CERCLA sites as an IC. The excavation notifications will be required for all proposed excavations below 2 feet at each of the ICs sites. The notifications will be evaluated to determine whether a proposed project at an IC site is consistent with the land use restrictions. The notifications are an additional tool for the Navy to receive timely information (in the absence of local zoning requirements) to monitor land use restrictions. The primary purpose of the IC Excavation Notification is to apprise the Navy of any changes in land use. Information regarding the depth to contamination present is available in the information repository on the second floor of Bob Reeves High School. In the event of an emergency excavation for utility repairs, the requester shall notify the Navy within three working days after the emergency repair has been completed to provide the name, location, depth, and duration of the excavation.
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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.
Excavation and treatment by thermal desorption of contaminated sediments and soils and recycling of treated sediment and soils as cover material at Roberts Landfill;
Placement of a soil cover on one non-landfill site;
Recycling of treated soils from CERCLA sites as cover material at Roberts Landfill;
Monitoring groundwater at CERCLA sites for volatile compounds and semivolatile compounds;
Removal and treatment of petroleum-contaminated soils to meet State of Alaska cleanup requirements;
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 final remediation to achieve cleanup levels under State of Alaska requirements for soils and groundwater; and
Maintenance of an Munitions Awareness educational program for on-island residents and visitors.
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