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Georogica(Technics Inc. <br /> C&B Equipment Page 3 <br /> Groundwater Monitoring Report <br /> Project No.336.2 <br /> -, April 13, 1998 <br /> f j A chain of custody document, listing all samples collected and their intended analyses, <br /> accompanied the samples from field to the laboratory, thereby providing a means to track <br /> their movement and insure their integrity. <br /> 1.3 Laboratory Analyses <br /> F The groundwater samples collected on March 18, 1998 were delivered to Sherwood Lab <br /> (Department of Health Services Certification No. 1400), of Hilmar, California, for analysis. <br /> The samples were analyzed using the following methods: <br /> • method 602 - benzene,toluene, ethylbenzene,total xylene (BTEX) <br /> t_ e method 602 - methyl tertiary butyl ether(MTBE) <br /> • method m8015/LUFT-total petroleum hydrocarbons as gasoline (TPH-G). <br /> The detection limits and the results of the above analyses are listed in Table 2 of Appendix A <br /> and the lab data sheets are presented in Appendix B. <br /> 2.0 FINDINGS AND DISCUSSION <br /> The results are summarized as follows: <br /> } • MW-1 tested positive for low levels of benzene but was non-detect for all other analytes. <br /> The samples from this well were non-detect during the last monitoring event, October <br /> -� 1997. Figure 4 is a graph of benzene and TPH-G concentration versus time in MW-1. <br /> • MW-2 tested positive for low levels of BTEX and moderate levels of TPH-G. The <br /> samples from this well were also non-detect during the last monitoring event, October <br /> 1997. Figure 5 is a graph of benzene and TPH-G concentration versus time in MW-2. <br /> • MW-3 was non-detect for all analytes for the first time since December of 1996. <br /> • MW-4, 5, 6 & 7 were all non-detect. <br /> • MW-101 showed concentrations of BTEX and TPH-G that were about an order of <br /> magnitude lower then the first time it was sampled in October of 1997. <br /> • The domestic well was non-detect for all analytes. <br /> 3.0 CONCLUSIONS AND RECOMMENDATIONS <br /> Conclusions <br /> The following conclusions can be made from review of the data: <br /> 1. Concentrations in MW-1 have shown a significant decreasing trend over the history of <br /> the project. <br /> i <br /> i <br />