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05 September 2003 AGE-NC Project No 97-0333 ' Page 8of10 ' PCE and/or TCE were detected in 42 of 47 water samples collected from monitoring wells MW-1 through MW-13 at concentrations as high as 1,500 µg/l(MW-4) Iso cone entration.maps displaying the estimated extent of dissolved PCE in First Zone and Second Zone aquifer are depicted in Figures 10 and 11 No other constituents of concern were detected above laboratory reporting limits in the water ' samples collected during the first quarter 2003 sampling event Analytical results of ground water monitoring well samples are summarized in Tables 3 and 4 The laboratory reports (Cal Tech Environmental Laboratories Identification No 0303-185 and 0304-006)and chain-of-custody forms are presented In Appendix E ' 4.0. SUMMARY AND CONCLUSIONS Previous soil characteristics data obtained by a CPT investigation enabled AGE to define four informal hydrologic units(CPT Site Investigation -Fourth Quarter 2000,dated 07 February 2001) The informal hydrogeologic units were defined as First Zone(15-47 feet bsg), Second Zone(58-92 ' feet bsg, Third Zone (102-120 feet bsg) and Primary Aquifer Zone(128-150 feet bsg) The results of pump and treat ground water remediation between 12 December and 27 March 2003 are as follows • Approximately 183,191 gallons of hydrocarbon-impacted ground water were extracted from well EW-1,which was completed in the First Zone aquifer A total volume of approximately t1,117,295 gallons of hydrocarbon-impacted ground water has been treated at the site since the start-up period in January 2002 (Table 5) ' • Dissolved MTBE was detected from grab samples collected at the influent-end of the treatment system at concentrations between 1,700 µg11 and 6,700 µg/l, laboratory analysis of grab water samples collected at the effluent-end of the pump and treat system did not ' detect any constituents of concern (Table 1) • Between 12 December 2002 and 27 March 2003, an estimated 8 36 pounds of MTBE was ' extracted from ground water(Table 5,Appendix B),a total mass of 197 67 pounds of MTBE has been removed since initiation of the pump and treat system on 21 January 2002 A plot of cumulative ground water pump and treat mass removal versus time and a plot of influent ' ground water MTBE concentrations versus time are included in Appendix C, although a moderate increase was reported in February 2003, the overall general trend of decreasing MTBE concentrations is evident ' Advanced Ge0$nVWOnmental,Inc