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13 April 2001 AGE-NC Project No 96-0232 Page 10 of 14 ' MW-11B and MW-12A at concentrations as high as 270 gg/l, however the laboratory indicated that the diesel range compounds in the MW-10A, MW-11B and MW-12A sample chromatograms were significant, but did not have recognizable diesel patterns, the laboratory indicated the sample chromatogram from MW-6A contained significant oil range compounds ' BTEX compounds were not detected in any samples during the March 2001 laboratory analysis MTBE (utilizing EPA Method 8260)was detected in water samples collected from morntoring wells ' MW-1, MW-6B, MW-7, MW-9A, MW-9C, MW-11A, MW-11B, MW-11D, MW-12A and MW-13A at concentrations as high as 680 ,ug/l (MW-9A), isoconcentration maps displaying the estimated extent of dissolved MTBE in First Zone and Second Zone aquifer are depicted in Figures ' 7 and 8 MTBE was detected in water samples collected from extraction wells EW-2, EW-4, EW-5, EW-6, EW-7, EW-8, EW-9 and EW-10 at concentrations as high as 540 /.cg/l (EW-4), an isoconcentration map displaying the estimated extent of dissolved MTBE in ground water extraction ' wells is depicted in Figure 9 MTBE was detected in a grab sample collected from the Rocky's Restaurant domestic water well (RDW-1) at a concentration of 8 3 /.Zg/1 10 No other constituents of concern were detected above laboratory reporting limits from the water samples collected during the first quarter 2001 sampling event Site investigation and the current first quarter 2001 analytical results of ground water monitoring well samples are summarized in Tables ' 5 and 6 The laboratory reports(McCampbell Analytical Inc I D Nos 62013 through 62033, 62468 through 62485 and 63386 through 63390) and chain-of-custody forms are presented in Appendix 1 ' 4.0. SUMMARY OF FINDINGS FROM QUARTERLY ACTIVITIES Previous soil characteristics data obtained by a CPT investigation enabled AGE to define five tentative hydrologic units (Final Remediation Plan, dated 31 August 2000) The informal ' hydrogeologic units are defined as First Zone(5-35 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 is the shallowest ground water zone screened in the Rocky's domestic drinking water well The results of pump and treat ground water remediation between 01 January and 31 March 2001 are Ias follows • Approximately 2,474,726 gallons of MTBE-impacted ground water were selectively extracted from wells EW-2, EW-4, EW-5, EW-6, EW-7, EW-8, EW-9 and EW-10, which are completed in the First Zone aquifer • Laboratory analysis of three grab water samples collected at the effluent-end of the pump and Advanced GeuEnvsronmental,[no