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California Regional Water Quality Control Board QW; An H. Hickox retaryfor zavironmental Protection Central Valley Region Robert Schneider, Chair Sacramento Main Office Internet Address: http://www.swrcb.ca.gov/rwgcb5 3443 Routier Road, Suite A, Sacramento, California 95$27-3003 Phone (916) 255-3000 • FAX (916) 255.3015 13 March 2002 MAR 15 2002 Mr. Bob Cochran lvern and Roger Baffoni Chevron Products Co. 1175 Orangewood Drive PO Box 6004 Lodi, CA 95240 San Ramon, CA 94583 REVIEW FOURTH QUARTER 2001 PROGRESS REPORT AND FINAL REMEDIATION PLAN ADDENDUM, FORMER CHEVRON STATION #9-5775,301 WEST KETTLEMAN LANE, LODI, CLEANUP AND ABATEMENT (C&A) ORDER NO. 5-00-704 Board staff reviewed the 11 January 2002 Quarterly Progress Report, Fourth Quarter 2001 (Q4-2001 Report) and the 9 January 2002 Final Remediation Plan Addendum (FRP Addendum) both submitted by Secor International Incorporated (Secor) for the subject site. The Q4-2001 Report documents decreasing trends of petroleum hydrocarbon and MtBE constituents in on-site monitoring and extraction wells due to continued remedial activities at the site. The FRP Addendum includes a proposal to defer off-site groundwater extraction as previously proposed by Secor in June 2001 and approved by this office in July 2001. Concentrations of petroleum hydrocarbons and MtBE have decreased significantly since the soil vapor extraction (SVE) and groundwater extraction and treatment (GET) systems began operation in July 2000. As of December 2001, 4.4 million gallons of contaminated groundwater from the former Chevron site has been extracted, treated with carbon, and discharged to the City of Lodi industrial sewer line. MtBE has decreased in on-site monitoring wells, and the GET system influent concentration has stabilized at approximately 130 micrograms per liter (µg/1). In combination, the SVE and GET remedial systems have reportedly removed 671 gallons of total petroleum hydrocarbons as gasoline (TPHg), 12 gallons of benzene, and 85 gallons of MtBE. The continued groundwater extraction appears to be effectively stabilizing the on-site groundwater plume, and reducing groundwater contaminants. Currently, only one off-site well (MW -9) shows a detection of MtBE at 1.0 (µg/1). During the Q4-2001 sampling event, MtBE was only detected in A -zone (45 to 66 feet) monitoring wells, and was not detected in monitoring wells completed in the B (76 to 90 feet) or C (105 to 112 feet) aquifer zones. Concentrations of MtBE in extraction well EX -1 have decreased from a maximum of 720,000 µg11 in March 2000 to 13,000 µg/1 in November 2001. The 13,000 µg/1 in extraction well EX -1 is currently the highest MtBE concentration at this site. Based on declining concentrations of groundwater contaminants both on-site and off-site, Secor proposes not to install and operate groundwater extraction wells on the property south of Kettleman Lane as proposed in Secor, s June 2001 addendum. to the Final Remediation Plan. Board staff met with Bob Cochran from Chevron and Secor personnel on 13 November 2001 to discuss these changes, and Board staff agreed that groundwater California Environmental Protection Agency Recycled Paper The energy challenge facing California is real. Every Californian needs to take immediate action to reduce energy consumption. For a list of simple ways you can reduce demand and cut your energy costs, see our Web -site at http:llwww.swrcb.ca.gov/rwgcb5