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Geologccal UMA&cs Inc Page 4 <br /> ' Groundwater Monitoring Report <br /> Project No 425 2 <br /> December 5, 2002 <br /> 1.3 Laboratory Analyses <br /> ' Theg roundwater samples collected on September 11, 2002, were delivered to Sherwood <br /> Labs (Department of Health Services Certification No 1400), of Hilmar, California, for <br /> analysis <br /> The samples were analyzed using the following methods <br /> EPA method 8020/8015 — BTEX, MTBE <br /> e EPA method 5030/8015(m) - TPH-Gasoline <br /> 1 The detection limits for the above analyses are listed in Table 4 of Appendix A and the <br /> laboratory data are presented in Appendix B <br /> ' As required under AB2886 the laboratory data were submitted electronically to GeoTracker <br /> on September 25, 2002 - confirmation number 2515286087 The depth to water data was <br /> ' also submitted on the same date— confirmation number 3026905655 <br /> 20 FINDINGS AND DISCUSSION <br /> ' The laboratory analytical data generated during the event indicate that gasoline constituents <br /> TPH-G & BTEX have been detected in monitoring wells MW-1, MW-2, MW-4 and MW-5 <br /> The results of the September 11, 2002 event are comparable with the results from previous <br /> monitoring events The following observations are made <br /> O The horizontal groundwater gradient is currently towards the northeast <br /> o Vertical groundwater gradients were positive or upward in the shallow/intermediate and <br /> tntennediate/deep well pairs <br /> ' ® Groundwater levels are continuing to exhibit a trend of decreasing elevation <br /> o TPH-G concentrations in MW-1 continue to fluctuate within levels usually observed for <br /> the site Benzene concentrations are still decreasing and are lower then observed since <br /> late 1999 See Figure 6 for a graph of Benzene and TPH-G versus time and Figure 8 <br /> for the distribution of TPH-G <br /> O BTEX & TPH-G concentrations in MW-2 showed a slight increase for the first time <br /> ' since June of 2001 See Figure 7 for graph of Benzene and TPH-G versus time and <br /> Figure 8 for the distribution of TPH-G <br /> ® Contaminant concentrations in wells MW-4 and MW-5 fluctuate seasonally but exhibit <br /> ' an overall stable trend <br />