SWMU 17, Power Plant 3 CERCLA and Petroleum Site
Background
SWMU 17, Power Plant 3 Area, became operational in 1950 and currently serves as the main electrical generating source on Adak. SWMU 17 contains or contained a number of areas of concern, including the waste oil pond, the north pond, the bulk storage waste oil tank, two oil/water separators, two temporary drum accumulation areas, the power plant tank farm, the seepage area along the slope below the power plant, a Quonset hut used previously for transformer storage, and the dry cleaners.
Two of the five storage tanks were closed in place and one of five tanks was removed in 1998, while the two remaining tanks (31015 and 31016) contain JP 5 used to fuel the power plant. The waste oil pond was constructed in the mid-1960s to contain waste petroleum, oil, and lubricants (POL) generated at the plant. The Quonset hut has historically been used for electric line and transformer repairs and for auto repair. The dry-cleaning facility located south of the power plant began operation in 1968. The dry cleaners and the Quonset hut are not currently in use.
Seeps of free product were observed along the roadside ditches in 1995. The Navy installed coffer dams within the trench to act as oil/water separators. Approximately 5,000 gallons of water and product were recovered from the trench by January 1996. During the summer of 1996, a product recovery trench was constructed at the intersection of Amulet Way and Akutan Way. During the construction of the recovery trench, much of the stained surface soil in the ditches was excavated.
The results of the 1997 Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) investigation indicated that chemicals in freshwater sediment and surface water posed a risk to ecological receptors, and chemicals in groundwater and surface water posed a risk to human health. The 1999 OU A Record of Decision (ROD) specified sediment removal from the waste oil pond and retention pond, CERCLA-compliance monitoring, and institutional controls (ICs) as the remedy. In 1999, oil/water separators were removed and impacted soil in the waste oil pond and water retention pond was removed and treated.
As part of the State-Adak Environmental Restoration Agreement (SAERA) investigation for the site, petroleum concentrations were detected in soil in excess of state cleanup levels, and free product was detected in 7 of 18 wells. Free-product recovery has been conducted at the SWMU 17 Power Plant area intermittently from August 1996 through July 2002, when the free-product recovery system was shut down. The cleanup remedy in the 2006 SAERA Decision Document is monitored natural attenuation and ICs.
The final remedies to satisfy CERCLA and SAERA are in place.
Identified Contaminants
Petroleum hydrocarbons, semivolatile organic compounds (SVOCs), and volatile organic compounds (VOCs) in soil and groundwater; petroleum hydrocarbons and SVOCs in sediment
Current Actions
The Navy maintains and inspects ICs annually. On an annual basis, the Navy monitors groundwater for natural attenuation in eight wells, for CERCLA compliance in one well, and for product thickness in two wells.
CERCLA Institutional Controls
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Petroleum Institutional Controls
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Petroleum Engineering Controls
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SWMU 17 - Power Plant No. 3
Background
Power Plant No. 3 began operating in 1950. Five above ground storage tanks stored oil supplies for the plant. Free product was first seen in two monitoring wells at the plant in September 1994. Seeps and stained soil were observed in 1995. Later petroleum contaminated soil was noted in ditches along roads to the site. The most likely source of free product was from a 1994 release of 500 gallons of JP-5 from a cracked storage tank valve. Other possible sources were overfilling of the storage tanks and leaking pipes. The original product recovery system used skimmers and submersible pumps to recover free product. Modifications to the system were installed in June and July 1996, and in September 1997 to improve product extraction. To date, 1,157 gallons of petroleum have been recovered. The recovered quantity typically ranges between three and 85 gallons per month, with more petroleum recovered between August and October. Contaminated soils and sediments were excavated and replaced with clean fill materials in 1999. In addition, oily waste and discharges associated with the Power Plant have been eliminated (US Navy 1999b). SMWU 17 is approximately 12.72 acres.
The remaining remedial action objectives for SWMU 17 are to maintain the current commercial and industrial land due to elevated residential ICR of 4x10E-4 (the ICR for the current industrial use is 1x10E-6); maintain the operation of the petroleum remediation systems and minimize impacts through institutional controls; and conduct groundwater sampling. Groundwater sampling will be conducted and reported under the Comprehensive Monitoring Plan (US Navy 2000c).
Chemicals of Concern
The following COC's were identified; Aroclor 1254 in groundwater at a maximum concentration of 0.97 ug/L which results in a residential ICR of 2x10E-5; beryllium in groundwater at a maximum concentration of 10 ug/l, which results in a residential ICR of 5x10E-5; Aroclor 1260 in soils at a maximum concentration of 1.4 mg/kg, which results in a residential ICR of 4x10E-5 and exceeds ADEC residential soil cleanup level of 1.0; beryllium in soils at a maximum concentration of 10.8 mg/kg, which results in a residential ICR of 3x10E-5 and exceeds the ADEC residential soil cleanup level of 1.6 mg/kg.
As part of the SAERA investigation for the site, the petroleum issues were addressed. Free product was detected in 7 of 18 wells. The maximum DRO concentration in surface soil was 220,000 mg/kg, which exceeds the Alaska DEC supplemental screening criteria of 5,000 mg/kg for industrial sites. The maximum DRO concentration in subsurface soil was 71,000 mg/kg, which exceeds the Alaska DEC supplemental screening criteria of 12,500 mg/kg for industrial sites. SVOCs in groundwater from one location and xylene in surface water from one location exceeded their respective screening criteria.
Location
Legal Description in Alaska state plane coordinates: BEGINNING at U.S. Navy control point A-12 (NAD 83 - N=318,813.81 E=3,131,902.86), which is South 23°48'38" East 2,882.16 feet from U.S. Navy control point L-13. Thence North 63°04'59" East 549.92 feet; thence South 10°07'40" East 697.97 feet; thence South 50°33'01" West 521.70 feet; thence North 70°21'41" West 458.75 feet; thence North 00°42'45" East 282.25 feet; thence North 33°13'57" East 398.37 feet to the POINT OF BEGINNING. Containing 12.72 acres more or less.