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r <br /> California Vional Water Quality Cor -I Board 2 <br /> Central Valley Region 5 <br /> Katherine Hart, Chair w� <br /> 1685 E Street, Fresno,California 93706 <br /> Linda S.Adams (559)445-5116 - FAX(559)445-5910 Edmund G.Brown Jr. <br /> Acting Secretary for http://www,waterboards.ca.gov/centraIvaliey Governor <br /> Environmental Protection <br /> 14 February 2011 <br /> REC IV [D <br /> Lee Higgins FE <br /> Chevron Environmental Management Company <br /> 6001 Bollinger Canyon Road <br /> ENVIRONMENTAL[-IEAtTht <br /> P. O. Box 6012 PERJM/7`/SERV.IC,E8 <br /> San Ramon, CA 94583 <br /> REVIEW - SOIL DELINEATION AND PROFILING WORKPLAN, FORMER TRACY PUMP <br /> STATION, TRACY, SAN JOAQUIN COUNTY <br /> Chevron Environmental Management Company (Chevron) submitted a workplan dated <br /> 5 January 2011 for the Tidewater Associated Oil Company (TAOC) Pump Station property <br /> (Site) at 14821 West Grant Line Road. The Site is northwest of the intersection of Byron Road <br /> and West Grant Line Road, in a rural area northwest of Tracy, central-western San Joaquin <br /> County. The workplan was prepared by Science Applications International Corporation — <br /> Benham Companies, LLC (SAIC). <br /> Central Valley Regional Water Quality Control Board (Central Valley Water Board) staff <br /> reviewed the referenced workplan and related investigation reports in the project files. The <br /> Site is part of the historical Old Valley Pipeline (OVP) and the former Tracy Pump Station <br /> facility. These features were part of a conveyance pipeline system that transported crude oil <br /> from Kern County oil fields to Richmond area refineries until the late 1960s to early 1970s. <br /> Site investigations have been conducted since approximately 2002. A soil investigation <br /> included a boring (TS-04) completed within a former pond containment area. According to the <br /> laboratory results, elevated concentrations of polynuclear aromatic hydrocarbon (PAH) <br /> compounds were detected at concentrations that exceeded screening levels. The extent of <br /> the PAHs was not determined and additional characterization is needed. <br /> Chevron subsequently determined that additional investigation was warranted to delineate the <br /> extent of PAHs in soil near the former boring. Chevron also decided to conduct limited <br /> excavation near TS-04 to remove the shallow soil containing the elevated PAHs. Soil removal <br /> would result in more conservative land use conditions and be more protective of human health <br /> at the Site. The excavation confirmation sample results will be used as part of a future health <br /> risk screening evaluation for the Site. <br /> To minimize disturbance of the Site businesses and nearby residences, SAIC proposes pre- <br /> excavation soil borings. Samples will be collected for laboratory analysis to define the extent <br /> of shallow soil containing elevated PAHs. This process will expedite the excavation, removal <br /> of the affected soil, and backfilling when the removal is done. <br /> California Environmental Protection Agency <br /> (:Yecycled Paper <br />