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' Geofn8 xa1Tecfunws Inc Page 3 <br /> Groundwater Monitoring Report <br /> t Project No 724 2 <br /> April 17,2000 <br />' The sampling technician while collecting all samples wore disposable gloves <br />' 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 /> The groundwater samples collected on March 8, 2000, were delivered to Sherwood Labs of <br /> Hilmar, California (certification 41400) for analysis of <br /> Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX)by method EPA method 602 <br /> • Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 5030/8015(M) <br />' Additional samples were sent to Entech Analytical (certification #2346) from Sherwood Labs <br /> for the analysis of <br /> MTBE, D1PE, ETBE, TAME and TBA by EPA method 8260B <br /> 1 <br /> The detection limits for the above analyses are listed in Table 2 of Appendix A while the lab <br />'. analytical results are presented in Appendix B <br />' 2.0 FINDINGS AND DISCUSSION <br /> The results of the groundwater sample analysis show the following <br /> • MW-1, MW-3 and MW-5 have slight BTEX contamination <br /> • MW-2 and MW-4 have moderate to high benzene contamination and slight to low <br />' concentrations of the other BTEX analytes <br /> • MW-2 and MW-3 have moderate to low TPI -G contamination MW-4 has high TPH-G <br /> contamination <br />' • Contaminant concentrations are similar to those observed in the last monitoring event in <br /> all of the wells <br />' During field monitoring/well purging work, water quality parameters were measured, <br /> including Oxidation-Reduction Potential (ORP) The ORP results (reported on the <br /> groundwater monitoring field notes in Appendix C) show a direct correlation of negative <br />' values for wells in the contaminated zone MW-5 is both the only well that has a positive <br /> ORP value and, as expected, the only well that shows no contamination <br />' The contamination plume is defined laterally to the east by MW-5 It is not defined laterally <br /> in any other direction, nor is it defined vertically <br /> r <br />