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' 30 October 2003 AGE-NC Project No 96-0232 ' Page 11 of 15 ' 3 4 2 Laboratory Results of Ground Water Samples During the September 2003 sampling event, TPH-d was detected in the samples collected from ' MW-1 I and MW-12A at concentrations of 59 µg/1 and 320 µg/1, respectively The laboratory reports noted that the TPH-d sample chromatogram had no recognizable patterns ' ' MTBE (utilizing EPA Method 8260M) was detected in water samples collected from monitoring wells MW-4, MW-8A, MW-9A, MW-11B, MW-11D, MW-13A and MW-15 through MW-18 at concentrations as high as 420µg/1(MW-8A),isoconcentration maps displaying the estimated extent ' of dissolved MTBE in First Zone and Second Zone aquifer are depicted in Figures 8, 9 and 10 In addition, MTBE was detected in water samples collected from extraction wells EW-2 and EW-4 through EW-9 at concentrations as high as 24 µg/1 (EW-5 and EW-8) ' No other constituents of concern were detected above laboratory reporting limits in the water samples collected during the third quarter 2003 sampling event Analytical results of ground water ' monitoring well samples are summarized in Tables 5 and 6 The laboratory reports (McCampbell Analytical Inc work order nos 0309279, 0309287, 0309310, 0309314 and 0309340) and chain-of- custody forms are presented in Appendix H 4.0. SUMMARY OF FINDINGS FROM QUARTERLY ACTIVITIES Previous soil characteristics data obtained by a CPT investigation enabled AGE to define five ' informal hydrogeologic units (Final Remediation Plan, dated 31 August 2000) The informal hydrogeologic units were defined as First Zone (10-35 feet bsg), Second Zone (40-60 feet bsg), Rocky's Upper Zone (65-75 feet bsg), Secondary Aquifer Zone (85-105 feet bsg), and Primary Aquifer Zone (130-150 feet bsg) The Rocky's Upper Zone was the shallowest ground water zone screened in the destroyed Rocky's domestic drinking water well ' The results of pump and treat ground water remediation between 25 June 2003 and 15 September 2003 is as follows O Approximately 83 5,840 gallons of MTBE-impacted groundwater were extracted from wells EW-4, EW-5, EW-7 and EW-8, which were completed in the First Zone aquifer (Appendix A, Table 8) A total volume of approximately 22,425,645 gallons of MTBE- impacted water has been treated at the site since the start-up period in November 2000 (Table 8) • Steady, but low MTBE concentrations were detected from water samples collected at the influent end of the treatment system at concentrations of 19 µg/1, 18 µg/1 and 18 µg/1 Advanced GeoEnvironmental,Inc I