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CaliforniVegional Water Quality Co*l Board ° <br /> Central Valley Region <br /> Linda S.Adams Karl E. Longley,ScD, P.E., Chair ' <br /> k - <br /> Secretaryfor 1685 E Street,Fresno,California 93706 Arnold <br /> Environmental (559)445-5116• Fax(559)445-5910 Schwarzenegger <br /> Protection http://www.waterboards.ca.gov/centralvalley Governor <br /> 8 September 2008 R E C E���� <br /> SEP 0 9 X008 <br /> M. Scott Mansholt <br /> Chevron Environmental Management Company ENVIRONMENT HEWN <br /> 6111 Bollinger Canyon Road PERMITISERVI <br /> Room 3432 <br /> San Ramon, CA 94583 <br /> REVIEW— EXCAVATION WORKPLAN, 990 BEECHNUT PROPERTY, TRACY, SAN <br /> JOAQUIN COUNTY <br /> Regional Water Board staff reviewed the referenced workplan, dated 14 August 2008, for the <br /> Chevron Environmental Management Company (Chevron) 990 Beechnut project site (Site) in <br /> central Tracy. AMEC Geomatrix, Inc. (AMEC) prepared the report for Chevron. <br /> The Site was part of the former Tidewater Associated Oil Company (TAOC) Tracy Pump <br /> Station and pipeline system that stored and transported heated crude oil from Kern County oil <br /> fields to Richmond area refineries until the late 1960's. The larger portion of the former TAOC <br /> Tracy Pump Station site (880 Beechnut) is just east of the Site, across Forest Hills Drive. <br /> Pipelines connecting both sites to another former petroleum storage facility (Alden Park) <br /> reportedly crossed the north and south portions of the Site. <br /> Regional Water Board staff reviewed 1989 to 2004 investigation reports and health risk <br /> assessments for both sites and Alden Park. According to the reports, the lateral extent of total <br /> petroleum hydrocarbon (TPH) affected soil had been adequately defined on the Site, including <br /> high levels of polynuclear aromatic hydrocarbons (PAHs) identified in boring GMX-09. A soil <br /> sample from this boring at a depth of 5 feet below ground surface, contained elevated <br /> concentrations of benzo(a)pyrene (BaP) (among other PAHs), at 5.8 milligrams per kilogram <br /> (mg/kg). Following review of the recent reports, Regional Water Board staff requested a <br /> workplan for the excavation of TPH/PAH-affected soil in the vicinity of GMX-09. <br /> Based on the prior reports, future Site use was designated as a commercial/industrial worker <br /> scenario as was addressed in an earlier risk assessment screening evaluation. The City of <br /> Tracy General Plan map shows the Site is zoned medium density residential, which allows <br /> uses other than residential development. However, AMEC decided to use environmental <br /> screening levels' (ESLs) to establish remediation goals for removal of affected soil that are <br /> consistent with the commercial/industrial worker scenario. <br /> Remediation Goals from: Environmental Screening Levels, California Regional Water Quality Control Board, San <br /> Francisco Bay Region, May 2008, Screening for Environmental Concerns at Sites with Contaminated Soil and <br /> Groundwater, Interim Final. <br /> California Environmental Protection Agency <br /> �a Recycled Paper <br />