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v <br />California Regional Water Quality <br />Central Valley Region <br />Winston H. Hickox <br />Secretaryfor <br />Environmental <br />Protection <br />13 July 2001 <br />Mr. Bob Cochran <br />Chevron Products Co. <br />PO Box 6004 <br />San Ramon, CA 94583 <br />Control Board <br />Robert Schneider, Chair <br />Sacramento Main Office <br />Internet Address: http://www.swrcb.ca.gov/rwgcb5 <br />3443 Routier Road, Suite A, Sacramento, California 95827-3003 <br />Phone (916) 255-3000 • FAX (916) 255-3015 <br />Ivern and Roger Baffoni <br />1175 Orangewood Drive <br />Lodi, CA 95240 <br />C_ <br />tom— Gray Davis <br />Governor <br />J <br />REMEWPROBLEMASSESSMENT REPORT AND FINAL REMEDIATIONPLANADDENDUM, <br />FORMER CHEVRON STATION #9-5775,301 WEST KETTLEMANLANE, LODI, CLEANUP AND <br />ABATEMENT (C&A) ORDER NO. 5-00-704 <br />Staff reviewed the 5 June 2001 Problem Assessment Report /Final Remediation Plan Addendum <br />(Addendum Report) and the 30 March 2001 Aquifer Test Report both submitted by Secor International <br />Incorporated (Secor) for the subject site. The Addendum Report provides a summary of site soil and <br />groundwater investigation activities and results, and an evaluation of remedial alternatives to address soil <br />and groundwater contamination. The Aquifer Test Report presents aquifer test data needed to evaluate <br />groundwater extraction as a remedial alternative. <br />The Addendum Report did not include a groundwater flow diagram or a monitoring well detail table as <br />requested in our 22 September 2000 Notice of Violation letter. Due to the various groundwater flow <br />directions identified early in the investigation, the groundwater flow diagram was requested to document <br />historic flow directions and magnitude. In addition, due to the number of vapor extraction, monitoring, <br />and groundwater extraction wells completed at this site, a comprehensive table to list all monitoring well <br />details was requested. This table or tables should include the well number, date installed, casing <br />diameter, casing material, slot size, surveyed elevation, top and bottom of screen, top and bottom of filter <br />pack, depth to water, groundwater elevation, and aquifer zone. This information is still required, and we <br />request that you submit the diagram and table as part of your next quarterly progress report. <br />Between October 2000 and February 2001, Secor completed seven borings, installed nine monitoring <br />wells, and one groundwater extraction well as part of the additional investigation activities. Soil <br />sampling results from boring B5 (converted to MW -19C) at the former underground storage tanks (USTs) <br />showed TPHg, benzene, and MtBE constituents at 58 and 62.5 feet, which is below the existing water <br />table. A previous soil sample collected from SB -1 in the same area as B5 showed benzene and MtBE <br />contamination to 72 feet below the former USTs. A soil sample collected from B5 at 82 feet was non - <br />detect for all constituents. This additional work defines the vertical extent of soil contamination to - <br />approximately 72 feet. <br />Groundwater contamination has been defined in the A (45 to 66 feet) and B (76 to 90 feet) aquifer zones, <br />but has not been fully defined in the C (105 to 112 feet) aquifer zone south of the site. MtBE was <br />California Environmental Protection Agency <br />00 Recycled Paper <br />The energy challenge facing California is real. Every Californian needs to take immediate action to reduce energy consumption. <br />For a list of simple ways you can reduce demand and cut your energy costs, see our Web -site at http://www.swrcb.ca.gov/rwgcb5 <br />