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Chevron Products Company Former Chevron Service Station #9-5775, 301 West Kettleman Lane, Lodi, California April 15, 2002 0 1.0 INTRODUCTION SECOR International Incorporated (SECOR), on behalf of Chevron Products Company (Chevron), presents 1st quarter 2002 groundwater monitoring results, and operating 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 (Attachment A), and covers the period of December 26, 2001 through March 27, 2002. 2.0 GROUNDWATER MONITORING AND SAMPLING Between January 16 and 17, 2002, SECOR conducted 1st quarter 2002 groundwater monitoring and sampling. Wells were gauged on January 16, 2002, and sampled from January 16 through January 17, 2002. Field and laboratory procedures are presented in Attachment B. Certified laboratory analytical reports and chain -of -custody documentation and monitoring and sampling field data sheets are included in Attachments C and D, respectively. A brief description is presented below. 2.2 Monitoring Well Gauge Data During the 1st quarter, monitoring well gauge data indicates the approximate depth to groundwater in A, B, and C -zones ranges from 56 to 60 feet below ground surface (bgs). Gauge data is presented as Table 1. Groundwater flows measured in the A -zone were calculated to flow to the southeast under an approximate gradient of 0.01 feet/foot. Groundwater near the site appears to flow radially toward extraction wells EX -1 and EX -3 (Figure 2). Groundwater in the B -zone flows to the southeast, with an approximate hydraulic gradient of 0.005 feet/foot (Figure 3). 2.1 Sample Analytical Results During the I" quarter sampling 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 (RIPE), ethyl tertiary butyl ether (EtBE), tertiary amyl methyl ether (TAME), ethanol, methanol, ethylene di -bromide (EDB), and 1,2-dicholoethane (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 contour map for MtBE is presented as Figure 4. lAChevron1957751Periodic Monitoring\Quarterly Progress Reports1200211st Quarter -2002 Progress Report.doc