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California �egional Water Quality Control Board <br /> Central Valley Region <br /> Katherine Hart, Chair „. <br /> Linda S.Adams 1685 E Street, Fresno, California 93706 <br /> (559)445-5116 • Fax(559)445-5910 Edmund G.Brown Jr. <br /> Acting Secretary for http://www.waterboards.ca.gov/centraIvaIley Governor <br /> Environmental Protection <br /> To: Shelton R. Gray FROM: C. Dean Hubbard <br /> Senior Engineering Geo ogist Enginee;pirrg , eologist <br /> DATE: 25 January 2011 SIGNATURE: <br /> SUBJECT: REVIEW— HUMAN HEALTH SCREENING EVALUATION, CATELLUS <br /> PROPERTY, TRACY, SAN JOAQUIN COUNTY <br /> Chevron Environmental Management Company (Chevron) submitted a Human Health <br /> Screening Evaluation report (Report, HHSE) for the Catellus Property. The Report, dated 20 <br /> October 2010, was prepared for Chevron by Science Applications International Corporation — <br /> Benham Companies, LLC (SAIC). The Catellus Property (Site) is along W. Byron Road, <br /> between West Grant Line Road and Van Sosten Road, immediately northwest of Tracy and <br /> near California Interstate 205. 1 have reviewed the referenced Report and related 2006 — <br /> 2008 documents in our project files and my comments are provided below. <br /> The Site includes part of the highway alignment, the Union Pacific Railroad (UPRR) right-of- <br /> way (ROW), and several private properties on either side of W. Byron Road. ROWs <br /> associated with the historical Old Valley Pipeline (OVP) are present along the south side of the <br /> highway and the historical Tidewater Associated Oil Company (TAOC) crude oil pipelines are <br /> located within the UPRR ROW. The historical TAOC/OVP pipelines were owned/operated by <br /> Chevron predecessors. Two active petroleum hydrocarbon product pipelines are also present <br /> within the UPRR easement ROW. <br /> Based on the findings, Central Valley Regional Water Quality Control Board (Central Valley <br /> Water Board) staff concurred in a 17 December 2008 letter to Chevron, that crude oil affected <br /> soil and groundwater had been delineated. There are four areas of affected soil (from <br /> approximately 125 feet across up to about 200 feet by 750 in length) at the Site, primarily <br /> within/beneath and parallel to W. Byron Road. Since it was established that adequate data <br /> had been collected, a Screening Evaluation could be prepared. <br /> Onsite soil and groundwater has been affected by total petroleum hydrocarbons as crude oil <br /> (TPHc), low concentrations of certain polynuclear aromatic hydrocarbon (PAH) compounds, <br /> and benzene, toluene, ethylbenzene, and xylenes (BTEX). Previous fuel fingerprint evaluation <br /> determined that the petroleum hydrocarbons present are consistent with weathered San <br /> Joaquin Valley crude oil. <br /> According to SAIC's HHSE: <br /> • Chemicals of potential concern (COPCs) are analytes detected in at least one soil <br /> sample between depths of 0 and 10 feet below ground surface (bgs). Low <br /> concentrations of BTEX and certain PAHs are considered Site COPCs and were <br /> evaluated quantitatively for the HHSE. All analytes detected in at least one sample <br /> California Environmental Protection Agency <br /> Recycled Paper <br />