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cie0bgkiITecknus Inc Page 5 Groundwater Monitonng Report Project No 770 2 March 31,2004 ' 1,3 Laboratory Analyses ' ' The groundwater samples collected on December 16, 2003, were delivered to Sherwood Lab (Department of Health Services Certification No 1400), of Hilmar, California, for analysis ' Sherwood analyzed the seven monitoring g well groundwater samples for • Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX)by EPA method 8020 • Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 5030/8015(M) • TEPH- Diesel and Motor Oil by EPA method 3500/8100(M) The detection limits for the above analyses are listed in Table,3' of Appendix A while the laboratory analytical results are presented in Appendix B As required under AB2886, the groundwater elevation and laboratory data were submitted electronically to GeoTracker on January 29 and March 30 - confirmation numbers 2307700276 & 2984745621. 2.0 FINDINGS AND DISCUSSION e The results of the groundwater sample analysis indicate the following • The reversal of groundwater direction by 180° in the deeper aquifer for the April and May 2003 sounding events is anomalous to the historical data The deeper aquifer has ' been monitored by three wells (MW-104, MW-105 and MW-106) since June 2002 and the other events all displayed an easterly trend to groundwater direction It is noted that the gradients for these two events were higher than normal suggesting that off site ' production is influencing the aquifer A well receptor survey was completed for the site in January 2001 and two agricultural wells were identified approximately 1600 feet west of the site (see Map 1, Table 1 — Appendix D) If these wells were operated during the ' months in question, it is possible that the Marci site was within the cone of depression created by the well pumping The shallow aquifer did not reverse during this period and this may be due to the domestic wells to the southeast of the site that may be screened ' shalIower than the agricultural wells and exert a primary influence on the water table that is easterly • Diesel range petroleum hydrocarbons were detected in five of the site's eleven monitoring wells • Well MW-5 contained 4,820 Fig/1 diesel and remains the most severely impacted well ' The reversal in groundwater direction discussed above may be the reason that the core plume is displaced from the location of the former UST