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<40ate Californi�egional Water Quality CO of Board@�.,11Central Valley Region <br /> Karl E.Longley,ScD,PE,Chair <br /> Linda S.Adams Arnold <br /> Secretaryjor Fresno Branch Office Schwaaenegger <br /> Environmental 1685 E Street,Fresno,California 93706 Governor <br /> Protection (559)445-5116•Fax(559)445-5910 <br /> hup://www.waterboards.ca.gov/centralvalley nn (� <br /> 21 November 2007 W ECC 1°lpp <br /> E© <br /> M. Scott Mansholt NOV 2 7 1007 <br /> Chevron Environmental Management Company ENVIRONMENT HEALTH <br /> 6001 Bollinger Canyon Road PERMIT/SERVICES <br /> Rm K2066 <br /> San Ramon, California 94583-2324 <br /> REVIEW — 2007 ANNUAL GROUNDWATER MONITORING AND SAMPLING REPORT, <br /> FORMER LYOTH LOADING STATION, TRACY, SAN JOAQUIN COUNTY <br /> Regional Water Board staff has reviewed the referenced document, dated 24 October 2007, <br /> describing sampling and monitoring activities at the former Lyoth Loading Station project. The <br /> report was submitted by Science Applications International Corporation (SAIC) on behalf of <br /> Chevron. <br /> According to the October 2007 Annual sampling and monitoring report SAIC stated that: <br /> •. During this event, three of six monitoring wells (MWs) were sampled; two wells were <br /> inaccessible and MW-2 contains a sheen. Total petroleum hydrocarbons as diesel <br /> (TPHd) was non detect (ND) in MW-1 and MW-3 and 110 pg/L in MW-7; polynuclear <br /> aromatic hydrocarbons (PAHs) were ND and/or at or slightly above respective method <br /> detection limits (MDLs); <br /> • Onsite monitoring well MW-2 contains a petroleum sheen and was not sampled; since <br /> 1997, approximately 5:5-gallons of crude oil/water has been removed from this well. An <br /> absorbent sock, used to collect the crude oil sheen, was replaced during the August <br /> 2007 sampling event. When the petroleum sheen is removed, sampling of the well can <br /> resume; <br /> • A groundwater sample from MW-3 was submitted for general mineral analysis to <br /> evaluate water quality conditions at the site. The results reported boron 1.3 mg/L (0.6), <br /> chloride at 357 mg/L (250/106), nitrate/nitrogen at 30.7 mg/L (10), sodium - 230 mg/L <br /> (20), and sulfate 414 mg/L (250/10) exceeded applicable MCLs (Maximum <br /> Contaminant Levels; ;values in parentheses], California Department of Health Services, <br /> 2002) and/or WQOs* ; the remaining results did not exceed applicable MCLs and/or <br /> WQOs; and, <br /> *1 - The US EPA 'Suggested No Adverse Response Levels", 1980, describes 100 pg/L as the taste and odor water quality <br /> objective(WQO) threshold for diesel in groundwater. <br /> California Environmental Protection Agency <br /> p�a Recycled Paper <br />