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IM <br /> MQOMCVR115�._ - <br /> '� <br /> S" <br /> Q4 <br /> CHAPTER 4 <br /> FIELD AND ANALYTICAL RESULTS <br /> � in order to satisfy San Joaquin County (County) requirements, <br /> groundwater and soil samples were collected to determine the current <br /> extent of contamination at the site. The sampling requirements were <br /> discussed during the April 17, 1987, meeting between Brown and <br /> Caldwell (BC) , the California Regional Water Quality Control Board, <br /> Central Valley Region (Regional Board) , and County personnel. Depth <br /> �. to groundwater at the site is approximately 11 to 13 feet below <br /> ground surface, based on May 11, 1987, measurements of the 11 <br /> existing groundwater monitoring wells. <br /> Groundwater Samplin2 <br /> On May 11 and 12, 1987, BC personnel collected groundwater <br /> samples from the existing monitoring wells installed by EMCON in 1984 <br /> (see Figure 1-3) . The groundwater samples were submitted to BC's <br /> California Department of Health Services state-certified laboratory <br /> in Emeryville, California. The samples were analyzed for ' total <br /> petroleum fuel hydrocarbons (U.S. Environmental Protection Agency <br /> (EPA) Method 8015, modified) , benzene, toluene, and xylene (BTX) (EPA <br /> 602 for water, EPA 8020 for soil) , and total lead. The results of <br /> these analyses are summarized in Table 4-1. The complete laboratory <br /> report is included in Appendix F. <br /> Photoionization detector (PID) readings for Wells F.-7 and E-10, <br /> indicated no accumulation of product vapors in these wells, whereas <br /> readings for Wells E-2, E-3, E-4, E-5, E--6, E-8, E-9, E-11, and 8-12 <br /> indicated product vapor accumulation. The PID measurements are shown <br /> in Table 4-2. The readings are qualitative because the wells were <br /> open to air. <br /> Water Su2ply Well Sampling <br /> On May 15, 1987, BC personnel collected water samples from three <br /> water supply wells located within 1/2-mile of the site. Wells 2OM2 <br /> r and 20F1 are located northeast of the site on Swenson Golf Course, <br /> and are owned by the City of Stockton Municipal Utility District <br /> (City) . Flood control Well 20L1 is located approximately 1/2-mile <br /> southeast of the site on Belmont Place and owned by the San Joaquin <br /> County Maintenance District (District) . These water samples were <br /> submitted to BC's Emeryville laboratory and analyzed for EPA 8015, <br /> EPA 602, and total lead. The results of these analyses are <br /> summarized in Table 4-3. The complete laboratory report is included <br /> in Appendix F. For sampling purposes, the three wells were labeled <br /> by their informal designations of #10 for Well 20M2, #2 for well <br /> i 20F1, and #5 for Well 20L1. <br /> f� <br /> =j <br /> ! <br /> 11 <br />