Laserfiche WebLink
California Regional Water Quality Control board <br /> Central Valley Region ' Y <br /> Karl E. Longley,SCD, PE, Chair ' <br /> Linda S.Adams Arnold <br /> S'ecruraayfw- Fresno Branch office Schwarzenegger <br /> Environmewal 1685 F.Street,Fresno,California 93706 Governor <br /> Prurecrrolr (559)415-5116■ Fax(559)445-5910 <br /> hIIp l/mvw.waterho-ards.ca.govlcen tralva II ey <br /> 8 May 2008 RECEIVE❑ <br /> MAY 12 2008 <br /> Chevron Efl i me*l Management Co. <br /> M. Scott Mansholt <br /> Chevron Environmental Management Company <br /> 6001 Bollinger Canyon Road <br /> Rm K2066 <br /> San Ramon, California 94583-2324 <br /> REVIEW — 2008 SEMI-ANNUAL GROUNDWATER SAMPLING AND MONITORING <br /> REPORT, US CAN-WELTY ROAD PROPERTY, VERNALIS, SAN JOAQUIN COUNTY <br /> Regional Water Board staff has reviewed the referenced document, dated 16 April 2008, <br /> describing field sampling activities for the US Can-Welty Road project monitoring wells. The <br /> report was submitted by Science Applications International Corporation (SAIC) on behalf of <br /> Chevron. <br /> According to SAIC's sampling and monitoring report: <br /> • Onsite monitoring wells MW-1 and 2 contain petroleum sheers and are not sampled; <br /> approximately 0.39 gallons of crude oil/water has been removed since 1999; new <br /> oleophilic (absorbent) socks were installed and annual inspection/replacement will <br /> continue; <br /> • Detectable total petroleum hydrocarbon as diesel (TPHd) of 1 ,600-pglL was reported in <br /> MW-3; detectable concentrations of three PAHs (polynuclear aromatic hydrocarbons) <br /> exceeding Environmental Screening Levels (ESLs) were reported; monitoring events <br /> from May 2006 to August 2007, reported insufficient water present for sampling MW-3; <br /> however, during the recent event, sufficient water was present and MW-3 was sampled; <br /> • TPHd and PAHs were non detect (ND) for MW-4; MW-5, on adjacent Western Farms <br /> Services property is not accessible for sampling; and, <br /> Depth to water, between 34 and 36 feet with an easterly gradient, is consistent with <br /> prior information. <br /> SAIC recommended that MW-4 and MW-5 should be properly destroyed in accordance with <br /> appropriate San Joaquin County well abandonment guidelines and MW-3 should be sampled <br /> an additional quarterly event provided sufficient water is available. <br /> California Environnaental Protection Agency <br /> V7 Recycled Paper <br />