Laserfiche WebLink
California Regional Water Quality Control Board <br /> Linda S.Adams Central Valley Region ° <br /> Karl E.Longley,ScD P.E. Chair Arnold <br /> Staryjor ' ' <br /> Environmental Protection Schwarzenegger11020 Sun Center Drive#200,Rancho Cordova,California 95670-6114 Governor <br /> Phone(916)464-3291•FAX(916)464-4645 <br /> http://www.waterboards.ca.gov/centmlvalley <br /> 25 November 2008 WE"CE� " E <br /> DD <br /> DEC 0 2 2008 <br /> DESJC, IVI.BENSON ENVIRONMENT HEALTH <br /> Defense Distribution Depot San Joaquin PERMIT/SERVICES <br /> P.O. Box 960001 <br /> Stockton, CA 95296 <br /> UNDERGROUND STORAGE TANK 25 SITE CLOSURE WORK PLAN, DEFENSE <br /> DISTRIBUTION DEPOT SAN JOAQUIN— TRACY, SAN JOAQUIN COUNTY <br /> California Regional Water Quality Control Board, Central Valley Region (Regional Water <br /> Board) staff has reviewed the September 2008 Underground Storage Tank 25 Site Closure <br /> Work Plan (Work Plan) received 29 September 2008. URS Group Inc. prepared the Work <br /> Plan on behalf of Defense Logistics Agency Enterprise Support San Joaquin, California <br /> (DESJC) for the Defense Distribution Depot Tracy Site (DDJC Site), located in Tracy, <br /> California. <br /> The Work Plan proposes to advance six cone penetrometer test (CPT) borings at the <br /> UST 25 site. Groundwater samples would be collected from five of the borings and soil <br /> samples from the sixth boring. All but one of the borings would be advanced at the locations <br /> of borings advanced in 2003. Laboratory chemical analyses results on the CPT boring <br /> samples would be compared to the results of the 2003 sampling event. A technical <br /> memorandum would present the results of the investigation and would recommend closure if <br /> the comparison of laboratory results are supportive. Regional Water Board staff does not <br /> concur with this strategy because the magnitude and trend of groundwater contamination <br /> have not been sufficiently characterized. <br /> Background <br /> Underground Storage Tank (UST) 25 was located in the south courtyard of Building 255 at <br /> the DDJC Site. A 500- gallon UST used for storage of Number 2 fuel oil was removed in <br /> 1988. Apparently, the UST was installed before 1982. The Work Plan reports that only one <br /> soil sample was collected, at an unspecified depth beneath the tank location, at the time it <br /> was removed. Laboratory chemical analysis on the sample detected total petroleum <br /> hydrocarbons (TPH) in the diesel range at a concentration of 26,000 milligrams per kilogram <br /> (mg/kg). Also, the laboratory reported concentrations of benzene, toluene, ethylbenzene, <br /> and total xylenes (BTEX) at 2, 1.6, 14, and 21 mg/kg, respectively. During removal of the <br /> UST, an unknown volume of soil was also removed. Groundwater was not sampled. <br /> California Environmental Protection Agency <br /> *Recycled Paper <br />