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Californi egional Water Quality Cool Board <br /> Central Valley Region <br /> Karl E. Longley, ScD, PE,Chair <br /> Linda S. Adams Arnold <br /> Secrelaryfor Fresno Branch Office Arnold <br /> Environmental 1685 E Street,Fresno,California 93706_ Governor <br /> Prosection <br /> (559)445-5116•Fax(559).445---5 <br /> g 1 f <br /> http:l/wwvv.Waterboards.ca. trl:ren ra � L � <br /> : :.>4L <br /> 18 July 2008 ENViR0M`Ei'�i I� <br /> pF �:!IT.13ERvlcFl <br /> M. Scott Mansholt <br /> Chevron Environmental Management Company <br /> 6111 Bollinger Canyon Road <br /> BR1 Y3432 <br /> San Ramon, CA 94583 <br /> REVIEW - GROUNDWATER SAMPLING, FISH WELL CONFIRMATION ANALYSIS, <br /> MOUNTAIN HOUSE SITE #3, MOUNTAIN HOUSE, SAN JOAQUIN COUNTY <br /> Regional Water Board staff has reviewed the referenced report, dated 9 July 2008 submitted <br /> by Science Applications International Corporation (SAIC) on behalf of Chevron Environmental <br /> Management Company (Chevron). The report provides the confirmation analytical results of <br /> the groundwater sample collected from a private domestic well designated as the Fish Well. <br /> During an earlier soil and groundwater investigation conducted at Mountain House Site #3 in <br /> October 2007, the Fish Well was sampled to determine if the well had been impacted by crude <br /> oil leaks from the nearby historical Tidewater Associated Oil Company (TAOC) and/or Old <br /> Valley Pipeline (OVP) pipelines. Total petroleum hydrocarbons as diesel (TPHd) was reported <br /> present at a concentration of 170 micrograms per liter (pg/L). However, there were quality <br /> control problems at the laboratory with a surrogate recovery, plus the vial containing the <br /> sample did not have the required pH of less than 2. Consequently, Chevron's laboratory <br /> report presented the Fish Well results as an estimate and a footnote that the sample was not <br /> correctly acidified. Regional Water Board staff provided comments to Chevron in a letter <br /> dated 16 April 2008, that included a request to resample the well due to the quality control <br /> problems. <br /> According to the recent confirmation sampling report, the TPHd results for the Fish Well was <br /> reported as non-detect (ND). In addition, the results were ND for polynuclear aromatic <br /> hydrocarbons (PAHs), benzene, toluene, ethylbenzene, and xylenes (BTEX) constituents. <br /> SAIC concluded that additional groundwater investigation for this area of the Mountain House <br /> Site #3 project is not needed. Regional Water Board staff concur with SAIC's conclusion. <br /> California Environmental Protection Agency <br /> �a Recycled Paper <br />