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3.3 LABORATORY ANALYSIS AND RESULTS Fourteen groundwater samples were submitted for analyses to Pace Analytical of Petaluma, California, a State of California certified hazardous waste analytical laboratory 1 The samples were analyzed for the following 0 EPA 8015 modified -Total Petroleum Hydrocarbons as Gasoline (TPH-G), I0 EPA 8015 modified -Total Petroleum Hydrocarbons as Diesel (TPH-D), 0 EPA 8020 — Benzene, Toluene, Ethylbenzene, Total Xylenes (BTEX), and Methyl Tertiary Butyl Ether (MTBE), 0 EPA 8260 --Volatile Organic Compounds (VOCs) including MTBE, A summary of the laboratory results for groundwater samples is presented in Table 1 A copy of the laboratory reports and chain of custody records are presented in Appendix B The following are the results of the groundwater sampling o TPH-D concentrations were not detected in any of the groundwater samples collected this sampling event 0 TPH-G concentrations were detected in samples from wells MW-6 (1,700 pg/1), VW-1 (500 pg/1), and VW-2 (8,400 pgll) 0 Benzene concentrations were reported in samples from wells MW-2 (0 9 pg/i), MW- 3 (0 8 pgll), MW-6 (2 4 pg/1), MW-8 (2 0 pg/1), VW-1 (43 pg/1), and VW-2 (1 ,800 pg/1) The concentrations have generally remained unchanged since the previous quarters sampling event Charts presenting benzene concentration over time for wells MW-6 and VW-2 are included as Figures 3 and 4 0 MTBE concentrations were reported in samples from wells MW-2 (0 8 pg/1), MW-6 (11 pg/1), VW-1 (1 8pg11), and VW-2 (75 pg/1) A confirmation sample from VW-2 reported a lower concentration of 37 47 pgll by EPA Method 8260 0 1,2-Dichloroethane (1 ,2-DCA) was detected in monitoring wells MW-6 (52 5 ug/1) and MW-11 (9 44 ugh) Styrene was detected in monitoring well VW-2 (10 9 ug/1) All other VOC compounds other than BTEX and MTBE were not detected in the groundwater samples collected 3 F TransfedReportSCALTRANS1Calty0971710175STOCKTON1gm398Tin