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GeologicalTuhxics/ac. Page 4 Groundwater Monitoring Report Project No.750.2 December 10,2002 j A chain of custody document, listing all samples collected accompanied the samples from P p field to laboratory, thereby providing a means to track their movement and ensure their integrity. Thep urge water was placed in a properly labeled 55 gallon DOT approved container and stored on site until its proper disposition can be arranged. Groundwater monitoring field logs are:included in Appendix C. 1.3 Laboratory Analyses The groundwater samples collected on September 23, 2002, were delivered to Sherwood Labs of Hilmar, California (Department of Health Services Certification No. 1400), for analysis. The groundwater samples were analyzed for: • Benzene, Toluene, Ethyl Benzene,',and Xylene (BTEX)by EPA method 8020/8015 C • Total Petroleum Hydrocarbons as Gasoline TPH-G by EPA method 5030/8015(M) Additional samples were sent to Entech Analytical Labs, Inc. from Sherwood Labs for the analysis of. • Fuel oxygenated compounds (MTBE, DIPE, ETBE, TAME & TBA) by EPA method 8260 L The detection limits for the above analyses are listed in Table 2 of Appendix A and the lab data are presented in Appendix B. As required under AB2886, the laboratory data was submitted electronically to GeoTracker on December 6, 2002, with confirmation number 1479858458. Li 2.0 FINDINGS AND RECOMMENDATIONS The results of the groundwater sample;analyses show the following: • Well MW-1 has consistently contained low concentrations of gasoline range petroleum hydrocarbons (TPH-G, BTEX). However, during this event, the well only showed trace concentrations of Xylene. Figure 4 illustratesgroundwater elevation and TPH-G concentrations in MW-1 versus time. r • The remaining wells were found to be free of contaminants, which is consistent with L+ other events. i r