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J 30 July 2004 i AGE-NC Project No 96-0232 Page I1 of 16 3 5 2 Laboratory Results of Ground Water Samples During the June 2004 sampling event,TPH-g was detected in the water sample collected from well _ MW-19A at a concentration of 63 µg11, however,the laboratory reported one to a few isolated`non- target'peaks present in the sample chromatogram TPH-d was detected in the water sample collected from well MW-12A at a concentration of 330 pgll, the laboratory report noted that the TPH-d sample chromatogram had significant diesel range compounds MTBE was detected in water samples collected from monitoring wells MW-8A,MW-9A,MW-11B and MW-14 through MW-19B at concentrations as high as 4,800 pg/1(MW-I 9A), 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-4, EW-5 and EW-7 through EW-10 at concentrations as high as 79 4g/1 (EW-7) No other constituents of concern were detected above laboratory reporting limits in the water samples collected during the second quarter 2004 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 0406242 and 0406263)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 16 March 2004 and 15 June 2004 is as follows Approximately 1,212,292 gallons of MTBE-impacted ground water were continuously extracted from wells EW-4,EW-5,EW-8 and EW-10,which are completed in the First Zone aquifer (Appendix A) After 28 April 2004, well EW-7 was also utilized to continuously extract ground water simultaneously with wells EW-4, EW-5, EW-8 and EW-10 A total volume of approximately 26,200,733 of MTBE-impacted water has been treated at the site since the start-up period in November 2000 (Table 8) Advanced GeoEnvironmentid,Inc