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a Table 3. Chevron Stockton Laboratory Analysis of Soils - April and May 1991. Results • presented in mg/kg (ppm). SwTrfPL ID =VjWS TQLVENS OWL- xylmm TING " 71 A-MV .% 4/29-5/1/91 MWlfi53' ND 0 023 ND ISTD ND ND MWIfi3.5' ND 0 015 ND ND ND ND MwMU, ND 0 016 ND ND ND ND I Detection Lemets 00050 00050 00050 00050 10 10 Nous BM a Analyses by EPA method 8015/8020 TPHG =Total Petroleum Hydrocarbons as Gasoline TPHD Total Petroleum Hydrocarbons ss Diesel (1) @ Analyse by Modified EPA method 8015 (2) a Analysis by Modified EPA method 8015 ND Compounds Not Detected above Method Detection Lamets 7.0 LABORATORY ANALYSIS - GROUNDWATER To accurately determine groundwater quality beneath the site, groundwater samples were collected from each monitoring well on May 7, June 21, and August 22, 1991. During each '-• sampling round, groundwater samples were collected after purging approximately 3 to 5 well volumes of water from each well After adequate purging, groundwater samples were collected from each monitoring well using a new disposable Teflon bailer. Stabilization of EC, pH, and temperature was checked prior to sample collection to ensure samples collected were representative of formation water. All samples were sent to state-certified Sequoia Analytical j laboratories and analyzed for BTEX using EPA methods 8015, and TPHG and TPHD using modified EPA method 8015. Laboratory results from the May 7, 1991 sampling round detected low levels of benzene, toluene, ethylbenzene, xylenes, and TPHG in monitoring well MWI. Low levels of benzene, I xylene, TPHG and TPHD were also detected in monitoring well MW2. No dissolved petroleum ' hydrocarbon constituents were detected in well MW3. No constituents were present above E Maximum Contaminant Levels (MCLs) established by the State Department of Health Services. E i 't Cbnm U.S.&W.-X7 C SRMI 6 I I