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' Geo(n zca(TecFrnus Zn e Page 3 <br /> g <br /> Groundwater Monaonng Report <br /> Project No 662 2 <br /> .lune 12,2001 <br /> ' All water purged from each monitoring well and not used as a sample, was placed in a 55 <br /> gallon DOT approved container, properly labeled and stored on site until its proper <br /> ' disposition can be arranged <br /> Groundwater monitoring field logs are included in Appendix C <br /> ' 1.3 Laboratory Analyses <br /> The groundwater samples collected on April 27, 2001 were delivered to Sherwood Labs <br /> (Department of Health Services Certification No 1400), of Hilmar, California, for analysis <br /> ' Sherwood analyzed the three monitoring well groundwater samples for <br /> • Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX) by EPA method 602 <br /> ' • Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 503018015(M) <br /> Additional samples were sent to Entech Analytical Labs (Department of Health Services <br /> ' Certification No 2346) from Sherwood Labs for the analysis of <br /> • MTBE, D1PE, ETBE, TAME and TBA by EPA method 8260 <br /> The detection limits for the above analyses are listed in Table 2 of Appendix A while the lab <br /> analytical results are presented in Appendix B <br /> 2.0 FINDINGS AND DISCUSSION <br /> ' The results of the groundwater sample analysis show the following <br /> • The laboratory results indicate stable MTBE concentrations present in wells MW-1 & <br /> ' MW-3 <br /> • MW-2, which is upgradient of the former USTs, remained free of detectable <br /> contamination for the sixth consecutive event <br /> ' • Neither BTEX nor TPH-G was present in any of the groundwater samples above the <br /> laboratory reporting limits <br /> ' 0 Oxidation-Reduction Potential measurements (Table 3) show that the three wells at this <br /> site are not significantly impacted by biodegradation of a BTEXITPH-G plume The <br /> values are still positive, suggesting that there is a limited amount of biodegradation of <br /> ' the contaminant plume occurring This is to be expected, since the primary contaminant <br /> is MTBE, which is very resistant to biodegiadation <br /> The release of petroleum fuels from this site appears to be minor with MTBE surviving <br /> ' biodegradation The MTBE plume appears to be limited in extent as will be further <br /> discussed in the site characterization report submitted on June 12, 2001 <br /> 1 <br />