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I 31 October 2003 AGE-NC Project No 01-0839 IPage 6 of 7 MTBE was detected In the water samples collected from wells MW3 and MW4 at a maximum concentration of 77 micrograms per liter (µg/1), in the sample from MW4 1,2-DCA was detected In water samples collected from MW3 and MW4 at a maximum concentration of 4 1 [ig/l (MW3) No other hydrocarbons or fuel additives were detected at or above laboratory detection limits In the ground water samples analyzed The previous and current analytical results of water samples collected in August 2003 are summarized on Table 2 The laboratory report(CTEL Lab Project No CT214-0308014), QA/QC report and chain-of-custody form are included in Appendix F 4.0. SUMMARY AND CONCLUSIONS ' The following conclusions were drawn from the results of this investigation • Ground water elevations at the site ranged 37 11 feet below mean sea level (MSL) to 37 10 • feet above MSL indicating that the ground water table is flat O Ground water on-site is impacted by TPH-g, BTE&X and MTBE In the area of the former and existing USTs The lateral extent of impacted ground water has not been defined to the Isoutheast of the USTs The highest concentrations of dissolved hydrocarbons detected in the ground water I monaitonng wells occurred in monitoring wells MW3 and MW4 at concentrations of 43 ug/l and 77 ug/l,respectively Both concentrations exceed the California Maximum Contaminant Level (MCL) of 13 ug/l for MTBE Isoconcentration maps depicting the approximate distribution of dissolved MTBE are presented in Figure 4 I5.0. RECOMMENDATIONS I Based on the findings of this investigation, AGE recommends • Continuation of the quarterly ground water monitonng program I0 Preparation of a work plan to define the lateral extent of Impacted ground water south- southeast of the USTs I IAdvanced GeoEnvironmental,Inc