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i <br /> Ciro gkaI Techgks I= Page 4 <br /> 3rd Quarter 2004 Groundwater Monitoring Report <br /> Project No 507 2 <br /> November 4,2004 <br /> 1 <br /> Groundwater monitoring field logs are included in Appendix C <br /> ' 1.3 Laboratory Analyses <br /> i The groundwater samples collected on August 25, 2004, were delivered to Sherwood Labs <br /> Corporation, Department of Health Services Certification No 1400, of Hilmar, California, <br /> for analysis <br /> Sherwood Labs analyzed the groundwater samples for <br /> A Benzene, Toluene,Ethyl Benzene, and Xylene (BTEX) by EPA method 8020 <br /> i ® Total Petroleum Hydrocarbons as Gasoline (TPH-G)by EPA method 5030/8015 <br /> A MTBE by EPA Method 8020 <br /> iThe 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 /> iAs required under AB2886, the laboratory and groundwater elevation data were submitted <br /> electronically to GeoTracker on October 15 & 29, 2004 - confirmation numbers 2362063288 <br /> & 8678527653 <br /> i2.0 FINDINGS AND DISCUSSION <br /> The results of the groundwater sample analyses indicate the following <br />' ® 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 and/or BTEX contamination However, the <br />' concentrations of BTEX and TPH-g have increased slightly since the last (6/4/04) <br /> monitoring event in both monitoring wells <br /> e Water table well MW-7 did not contain BTEX or TPH-G concentrations above the <br /> laboratory reporting limits but it did contain 3 7 pg/1 MTBE The well has intermittently <br /> contained MTBE since its installation in May 2001 The source of this contamination <br />' may be surface infiltration from unpaved areas and from the open storm water drainage <br /> ditch traversing the front of the parcel <br /> ® Water table well MW-10 did not contain contaminant concentrations above the laboratory <br />' reporting limas since February 2002 The well has previously contained xylene at levels <br /> just above the laboratory reporting limit of 0 3 µg/1 <br /> e Deep well MW-109 did not contain contaminants above the laboratory reporting limits <br /> for the fifth consecutive event The reduction in contaminant concentrations from the <br /> first sampling event on June 1, 2001 is noted and sufficient monitoring has been <br /> 1 <br />