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` California Regional 'Water Quality Control Board <br /> Central Valley Region <br /> Linda (` <br /> ' S.Adams Robert Schneider,Chair °``~^�"=�'' <br /> Secretary for Arnold <br /> Environmental Fresno Branch Office Schwarzenegger <br /> Protection <br /> 1685 L Street,Fresno,California 93706 _ Governor <br /> (554)445-5116•Fax(559)445-5910 <br /> htip://tNN�7v.waterboards,.ca.gov/ceritrdivalley <br /> 20 September 2006 SEP 2 2 2006 <br /> M. Scott Mansholt <br /> Chevron Environmental Management Company -- --- <br /> 6001 Bollinger Canyon Road, Room K2066 <br /> San Ramon, CA 94583-2324 <br /> REVIEW- SOIL AND GROUNDWATER INVESTIGATION REPORT — VERNALIS PUMP <br /> STATION, 35500 WELTY ROAD, VERNALIS, SAN JOAQUIN AND STANISLAUS <br /> COUNTIES <br /> Regional Water Board staff have reviewed the referenced report, dated 29 August 2006 for <br /> the Chevron Old Valley Pipeline (OVP) project site, near Vernalis, CA. The report was <br /> prepared for Chevron by Science Applications International Corporation (SAIC). The site <br /> consists of two separate properties: Bellini (formerly Roberts) and Arcos. Bellini, the northern <br /> triangular portion, is undeveloped and generally vacant. Arcos, adjacent to the south, contains <br /> a residence and office used as a storage facility for miscellaneous materials and equipment. <br /> The Vernalis sites are located in a rural and light-industrial area, generally surrounded by <br /> residences and agricultural land. <br /> The purpose of the investigation was to characterize the extent of impacted groundwater <br /> ' downgradient of the site, east of Highway 33 and upgradient (onsite) west of existing <br /> monitoring wells and historical borings. Monitoring wells were installed downgradient of the <br /> site and additional groundwater monitoring and sampling conducted. Additionally, a search of <br /> public records was conducted to obtain information on water supply wells within a 2,000-foot <br /> radius of the Vernalis sites. <br /> Shallow soil samples, collected at one and five feet for health risk assessment data and <br /> samples near the maximum depth at each boring (33 to 68 feet), were obtained and submitted <br /> for analysis. Two one-foot samples reported total petroleum hydrocarbons (TPH) as crude oil <br /> ' (TPHc) at 330 and 380 mg/kg; based on the analysis for the one-foot samples (330 and 380 <br /> mg/kg) and five-foot soil samples (ND) results, the report suggests that the shallow results <br /> ' may be attributed to surface spills by former site operations or other unknown sources <br /> unrelated to the pipeline that was buried several feet below ground. <br /> Low concentrations (0.001 to 0.0008 mg/kg) of polynuclear aromatic hydrocarbons (PAHs), at <br /> or slightly over their respective method detection limits, were present in the one-foot samples. <br /> The PAH concentrations were less than the U. S. EPA Preliminary Remediation Goals (PRGs) <br /> for those compounds. The other one-foot samples, the five-foot samples, and the remaining <br /> deeper samples were non detect (ND) for TPH compounds. <br /> California Environmental Protection Agency <br />' (a Recycled Paper <br />