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• 0 ,6 <br /> California Regional Water Quality Control Board ; ;v <br /> Central Valley Region , <br /> Alan C.Lloyd,Ph.D. Robert Schneider,Chair pp5 NpV -2 PM 109' <br /> Secretaryfor Arnold <br /> Fresno Branch Office <br /> Environmental 1685 E Street,Fresno,Califomia 93706 S A iL COU" TY Schwarzenegger <br /> Protection (559)445-5116-Fax(559)445-5910 ENVIRONMENTAL Governor <br /> http://www.wataboards.ca.gov/cmtmlvalley HEALTH DEPAP,TMENT <br /> 1 November 2005 <br /> M. Scott Mansholt <br /> Chevron Environmental Management Company <br /> Property Management <br /> 6001 Bollinger Canyon Road <br /> P. O. Box 6012 <br /> San Ramon, CA 94583-0712 <br /> SECOND SEMIANNUAL AND 2005 ANNUAL GROUNDWATER MONITORING REPORT, <br /> ALDEN PARK,TRACY, SAN JOAQUIN COUNTY <br /> We have reviewed the Second Semiannual and 2005 Annual Groundwater Monitoring Report, Alden <br /> Park, Tracy, San Joaquin County(report), dated 24 October 2005, prepared for Chevron Environmental <br /> Management Company by Science Applications International Corporation(SAIC). The monitoring was <br /> conducted in accordance with Monitoring and Reporting Program R5-2003-0801. The report provides <br /> the February and August 2005 groundwater monitoring analytical results and an annual summary for the <br /> former Old Valley Pipeline fuel oil reservoir site now occupied by Alden Park in Tracy, CA. In <br /> addition, the report presents a proposal for abandonment of five wells that are no longer necessary for <br /> monitoring. <br /> There are 21 monitoring wells associated with this project; twelve of the wells were purged and sampled, <br /> nine wells contained free product. Concentrations of total petroleum hydrocarbons as diesel (TPH-d) at <br /> 610 and 460 µg/L were reported in MW-7 during February and August, respectively for the year. Low <br /> concentrations ofTPH-d at 75 and 200 µg/L were reported in MW-2 and MW-11, respectively, during <br /> the February event. With the exception of the results noted above, TPH-d was not detected in the <br /> remaining monitoring wells. Low concentrations of polynuclear aromatic hydrocarbon compounds <br /> (PAHs)were detected at or slightly above the method detection limits (MDLs) during both semi-annual <br /> sampling events. <br /> During this event, floating product thickness ranged from a sheen in several wells to a maximum of 5.07 <br /> feet in MW-16. Since product removal was initiated in April 1997, over 400 gallons have been removed <br /> from the monitoring wells containing product. Absorbent socks have been placed in MW-5 and 21 for <br /> removal of the sheen present on groundwater in these wells. <br /> SAIC proposed five wells for destruction(MWs 1, 2, 13, 14, and 17)that are described as being <br /> redundant and not necessary for monitoring purposes. Review of historical results indicates these wells <br /> have been consistently non-detect or contain very low PAHs and TPH-d, and/or is less than water quality <br /> objectives since sampling commenced in 1997. Upgradient well MW-2 has been dry on different <br /> California Environmental Protection Agency <br /> iia' Recycled Paper <br />