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GealcgxaI Teckua Inc Page 4 <br /> ' Yd Quarter 2001 Groundwater Monitoring Report <br /> Project No 507 2 <br /> � November 6,2001 <br /> 1 <br /> Groundwater monitoring field logs are included in Appendix C <br /> 1.3 Laboratory Analyses <br /> ses <br /> The groundwater samples collected on September 17, 2001, were delivered to California <br /> Laboratory Services (CLS), Department of Health Services Certification No 1233, of <br /> ' Rancho Cordova, California, for analysis <br /> CLS analyzed the eleven-groundwater samples <br /> ' • Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX) by EPA method 602 <br /> • Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 5030/8015 <br /> • MTBE, DIPS, ETBE, TAME, TBA, EDB and 1,2 DCA by EPA method 8260 <br /> ' • Methanol and Ethanol by GC-FID <br /> The results and detection limits for the above analyses are listed in Table 3 of Appendix A <br /> while the lab analytical results are presented in Appendix B <br /> 2.0 FINDINGS AND DISCUSSION <br />' The results of the groundwater sample analyses indicate the following <br /> O Wells MW-1, MW-2 and MW-3 remain free of detectable contamination <br />' ® MW-4, MW-5 and MW-9 have significant BTEX and TPH-G contamination <br /> • MW-6 and MW-8 have minor TPH-G or BTEX contamination <br /> • New water table well MW-7 contained 13 ug/l MTBE This is the second event <br /> completed since the well was installed in May 2001 <br /> • Cross gradient well MW-10 contained 1 8 ug/1 xylenes This is the second event <br />' completed since the well was installed in May 2001 and the well had previously been <br /> non-detect for contaminants on June 1, 2001 <br /> • New deep well MW-109 contained minor BTEX, TPH-G and MTBE contamination for <br />' the second consecutive event A reduction in contaminant concentrations was noted, <br /> however additional monitoring is needed to conclude that it is a dulling artifact <br /> • Figures 4 and 6 indicate a previously inverse relationship between groundwater <br /> elevation and contaminant concentrations in wells MW-9 and MW-6 These two <br /> parameters have demonstrated parallel slopes for the past two events In Figure 5, the <br />' inverse trend was consistent for well MW-5 for the first four monitoring events, but <br /> since the January 2001 event the relationship has been parallel <br />