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' C4014 1cal Technics lnc <br /> g Page 4 <br /> Groundwater Monitoring Report <br /> Project No 723 2 <br /> November 13,2003 <br /> ' A chain of custody document, listing all samples collected and their intended analyses, <br /> accompanied the samples from the field to the laboratory, thereby providing a means to <br /> ' track the movement of the samples and ensure their integrity <br /> 1.3 Laboratory Analyses <br /> ' The groundwater samples collected on September 12 20 <br /> p 03, were delivered to Sherwood <br /> Labs of Hilmar, California(certification#1400) for analyses of <br /> ' • Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX), MTBE, by EPA method 8020 <br /> • Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 5030/8015(M) <br /> Sherwood forwarded well MW-201 samples to Castle Analytical Laboratory (Department of <br /> Health Services Certification No 2480) of Atwater, California, for analysis of <br /> ' • Oxygenated Fuel Compounds (MTBE, DIPE, ETBE, TAME & TBA) by method 8260 <br /> The detection limits for the above analyses are listed in Table 2 of Appendix A, while the <br />' lab analytical results are presented in Appendix B <br /> As required under AB2886, groundwater elevation and laboratory data were submitted <br /> electronically to GeoTracker on September 25 and October 31, 2003 - confirmation <br /> numbers 5267616093 & 9667983 829 <br />' 2.0 FINDINGS AND DISCUSSION <br /> The results of the groundwater sample analysis show the following <br /> • Review of the historic groundwater elevations show that groundwater levels raised each <br />' season from the mid 1990s to spring 2000 and have been decreasing steadily with each <br /> seasonal cycle since spring 2000 <br /> • The concentrations of BTEX and TPH-G continue to fluctuate in individual monitoring <br /> wells from one sampling event to the next However, there is a general trend of <br /> concentrations tracking the groundwater elevations <br />' • Intermediate well MW-101 continues to contain BTEX & TPH-G, but concentrations <br /> continue to fluctuate from one sampling event to the next <br /> • Deep well MW-201 did not contain contaminant concentrations above the laboratory <br /> reporting limit for the first time since its installation The previously noted <br /> contamination is probably a drilling artifact created by the use of mud rotary drilling <br /> The contaminant concentration decline since the first monitoring event in December <br /> 2001 supports the conclusion that the initial high concentrations were from a drilling <br /> artifact <br />