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3.0 LABORATORY ANALYSIS <br /> The groundwater samples were transported to Severn Trent Laboratories, Inc. (STL), a state-certified <br /> laboratory, located in Pleasanton, California. The groundwater samples were analyzed in accordance <br /> ' with San Joaquin County Environmental Health Department's March 2004 letter as follows: <br /> ■ Wells MW-1R, MW-9 and MW-10 were analyzed for the presence of MTBE by EPA Method <br /> 8260B; <br /> ■ Wells MW-2 and MW-5 were analyzed for the presence of MTBE, TAME, and TBA by Method <br /> 826013; <br /> ■ Well MW-4 was analyzed for TPH-G(by Method 8015B), BTEX(Method 8021B)as well as for <br /> MTBE(by Methods 8015M-8021B); <br /> Copies of the laboratory analytical report and chain of custody record are provided in Appendix C. y <br /> 4.0 SUMMARY OF RESULTS <br /> Based on groundwater elevation data for August 24, 2005 the groundwater flow direction in wells in both <br /> the upper and lower screened intervals was towards the southeast at gradients of approximately 0.002 <br /> feet per foot (ft/ft) and 0.003 ft/ft, respectively (Figures 3 and 4). Because groundwater elevation is <br /> consistent wells screened in both the upper and lower zone, we infer the zones are hydraulically <br /> connected. The groundwater flow directions and gradients noted during this sampling event are <br /> consistent with historical trends. <br /> Results of Con ventional Sampling: <br /> TPH-G was analyzed only in MW-4 which samples the lower aquifer; with a concentration level of 56 <br /> pg/L which is not significantly different from the previous quarterly sampling concentration of 50 µg/L. <br /> BTEX compounds were sampled in MW-4; only toluene was found above the detection limits <br /> (concentration of 28 pg/L). Toluene concentration has fluctuated since it appeared in MW-4 in 2003. <br /> The concentration this quarter is higher than last quarter, but is lower than first quarter 2005. <br /> Oxygenates: MtBE was reported in groundwater samples collected from upper zone well MW-5 at a <br /> t concentration of 200 µg/[.,. ' MtBE was also reported in lower zone wells MW-1R and MW-2 at <br /> concentrations of 2.8 pg/L, 21 pg/L, respectively. MtBE was reported below detection levels in MW-4, <br /> MW-9 and MW-10. TBA was present in MW-5 at a concentration of 90 pg/L. <br /> Results ofMicro purge Sampling: <br /> LJ' TPH-G was analyzed only in MW-4 which samples the lower zone; with a concentration level of less <br /> than 50 pg/L(the detection limit). <br /> BTEX compounds were sampled in MW-4; only toluene was found above the .detection limits <br /> M (concentration of 30 gg/L). <br /> Quarterly GW Monitoring Report-3rd Qtr 2005 <br /> Quik Stop No. 132 <br /> (MATC Qulk Stop Markets,Inc, <br /> ATC Project No.75.62503.3206 <br /> September 30,2005 <br /> Page 2 of 4 <br />