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S E C O R Fourth Quarter 2002, Quarterly Progress Report January 14, 2003 Page 1 1.0 GROUNDWATER MONITORING AND SAMPLING 1.1 Introduction SECOR International, Incorporated (SECOR), on behalf of Chevron Environmental Management Company (Chevron), presents fourth quarter 2002 (4Q02) groundwater monitoring and sampling results, and operational data for the groundwater extraction (GWE) and soil vapor extraction (SVE) systems at 301 West Kettleman Lane, Lodi, California (Figure 1). This report was prepared in accordance with Cleanup and Abatement Order (CAO) No. 5-00-704, dated April 20, 2000 (Appendix A). 1.2 Groundwater Monitoring and Sampling On October 28 and 29, 2002, Gettler-Ryan Incorporated (G -R) conducted 4Q02 groundwater monitoring and sampling. Certified laboratory analytical reports and chain -of -custody documentation and monitoring and sampling field data sheets are included in Appendices B and C, respectively. A brief description is presented below. 1.3 Monitoring Well Gauge Data Monitoring well gauge data indicates the approximate depth to groundwater in A, B, and C -zones ranges from 60.65 to 68.56 feet below ground surface (bgs). Groundwater gauging data is presented as Table 1. Groundwater in the A -zone near the site appears to flow radially toward extraction well EX -3 (Figure 2). Groundwater in the B -zone flows to the south to southeast, with an approximate hydraulic gradient of 0.014 (feet per feet) ft/ft (Figure 3). " 1.4 Sample Analytical Results During the 4002 event groundwater samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethyl -benzene, and total xylenes (BTEX), methyl tertiary butyl ether (MtBE), tertiary butyl alcohol (TBA), di -isopropyl ether (DIPE), ethyl tertiary butyl ether (EtBE), tertiary amyl methyl ether (TAME), ethanol, methanol, ethylene di -bromide (EDB), and 1,2-dichloroethane (1,2 -DCA). Sample analytical results are presented as Table 2. Maximum concentrations of detected constituents for A. B, and C -zones are presented in the table below. An A -zone isoconcentration map for MtBE is presented as Figure 4.