SITE INFORMATION AND CORRESPONDENCE

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Draft Final Investigation Report - 2 - OWS 2 - OWS 12, 410A & 508 NCTS, Stockton Building 410A OWS The Building 410A OWS site is located adjacent to Building 410A and was used for steam cleaning machinery and vehicles. The principal elements of the OWS system include a wash pad drain grate, an OWS, a 500-gallon waste oil tank, and connected piping. The OWS system was installed in 1983, ceased operation on October 23, 1998 and has remained inactive through the present. Contents of the OWS and waste oil tank were removed and the components were cleaned. Following the cleaning procedures, the integrity of the system was examined by NCTS environmental personnel who recommended the site be secured and its use discontinued. Investigations in September and October of 1999 included soil and grab groundwater sampling for TEH as diesel, TEH as motor oil, TVH as gasoline, BTEX, gas oxygenates, VOCs, SVOCs, PCBs, and CAM 17 metals. Soil samples show an insignificant amount of motor oil at 6 feet in sample B41 OA-7 at 21 mg/kg. Unfortunately, sampling occurred at the end of the dry season in late September. Minimum amounts of grab groundwater samples were analyzed for TVH as gasoline, BTEX, gas oxygenates, and VOCs from four of the seven sampling points. The other three locations did not produce a sufficient amount of groundwater to sample. We do not concur with the Navy's recommendation that no further action is warranted at his site. Because an insufficient amount of groundwater was available for sampling, the Navy should propose additional groundwater sampling. Additional samples should be near the same locations to ensure that each component of the OWS has been completely investigated. We recommend that sampling be completed during or soon after the rainy season between November and May. Building 508 OWS Building 508 is located adjacent to the shoreline of the Stockton Deep Water Channel on the north side of the island. The principal elements of the OWS system include a wash pad drain grate (i.e., silt basin), an OWS, a 500-gallon waste oil tank, and connected piping. The OWS system was installed in May 1986 and ceased operation in September 1999. The system was used to contain wastewater from the cleaning of vehicles and other machinery by NAVSEA. The contents of the OWS system were removed and system components were steam cleaned. The site was secured by NCTS environmental personnel on September 28, 1999. Investigations in September and October of 1999 included soil and grab groundwater sampling for TEH as diesel, TEH as motor oil, TVH as gasoline, BTEX, gas oxygenates, VOCs, SVOCs, PCBs, and CAM 17 metals. Several sampling locations yielded an insufficient amount of groundwater to run a full suite of constituents. Nevertheless, other samples showed extensive contamination in soil and groundwater. We concur with the Navy's recommendation to conduct a site investigation to further characterize the lateral extent of the soil and groundwater contamination at the OWS site at Building 508. Three monitoring wells are proposed to be installed in the suspect source area and up and down-gradient of the source area. Monitoring and groundwater chemical data collected from the wells would be utilized to establish groundwater flow direction and hydraulic gradient and evaluate representative groundwater quality. In this regard, the Navy should submit a work plan which should, not only include details of the investigation (i.e., sampling and analysis plan, quality assurance/quality control plan), but should also include a time schedule for initiating the