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CGeological Technics Inc Page 5 <br /> ' Groundwater Monitoring Report <br /> Project No 770 2 <br /> May 28,2003 <br /> ' 13 Laboratory Analyses <br /> ' The groundwater samples collected on March 19, 2003, were delivered to Sherwood Lab <br /> (Department of Health Services Certification No 1400), of Hilmar, California, for analysis <br /> Sherwood analyzed the seven monitoring well groundwater samples for <br /> • Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX) and Methyl Tertiary Butyl Ether <br /> ' (MTBE) by EPA method 8020 <br /> 0 Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 5030/8015(M) <br /> • TEPH- Diesel and Motor Oil by EPA method 3500/8100(M) [q. <br /> K �r`L.o4 <br /> 1 <br /> The detection limits for the above analyses are listed in Table 3 of Appendix A while the <br /> laboratory analytical results are presented in Appendix B <br /> As required under AB2886, the groundwater elevation and laboratory data were submitted <br /> electronically to GeoTracker on April 14, 2003 - confirmation numbers 6755665421 & <br /> ' 9403720259 <br /> 2.0 FINDINGS AND DISCUSSION <br /> The results of the groundwater sample analysis indicate the following <br /> r Diesel range petroleum hydrocarbons were detected in five of the site's eleven <br /> monitoring wells <br /> ' e Well MW-5 contained 5980 µg/l diesel and remains the most severely impacted well <br /> • Gasoline range petroleum hydrocarbons (TPH-G) were not detected in any of the wells <br /> for this event Several wells have had at least one event in which TPH-G was detected <br /> 0 Minor BTEX constituents are present at levels ranging from 0 6 — 1 2 µg/l to wells MW- <br /> 4, MW-5, MW-6 and MW-7 <br /> • Motor oil range petroleum hydrocarbons were not present in any of the groundwater <br />' samples at concentrations above the laboratory reporting limits <br /> • Deep wells MW-104, MW-105 and MW-106 did not contain contaminant <br />' concentrations above the laboratory reporting limits <br /> The samples were also analyzed for MTBE using EPA Method 8020 due to a <br /> communication error Wells MW-4 and MW-7 contained 1 8 and 5 5 ug/l MTBE, <br />' respectively, but these results may be false positives and have not been confirmed using <br /> EPA Method 8260 <br /> 0 The lateral extent of the diesel groundwater plume is currently undefined to the south <br />' 0 The vertical extent of the plume is intermittently defined by MW-104, 105, & 106 <br />