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18 September 2003 <br /> AGE-NC Project No 96-0263 <br /> IPage 3 of 4 <br />' 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> TPH-g was detected in water samples MW2,MW4,MW5,and MW7 at concentrations ranging from <br />' 1,400 micrograms per liter (µg/1) in MW4 to 43,000 µg/1 in MW7 <br /> Benzene was detected in water samples MW2, MW4, MW5 and MW7 at concentrations ranging <br />' from 9 0 gg/l(MW2)to 1,900 gg/l(MW7) Toluene was detected in sample MW7 at a concentration <br /> of 26 gg/l Ethylbenzene was detected in samples MW2 and MW7 at a concentrations of 2 6 µg/1 j <br /> and 32 2 6µg11,respectively Total xylenes were detected in samples MW2,MW4 MW5 and MW7 <br />' at concentrations ranging from 2 5 gg/l (MW5) to 113 gg/l (MW7), respectively <br /> i <br /> MTBE was detected in samples MW2, MW4, MW5, MW6, MW7 and MW8 at concentrations <br />' ranging from 6 6 gg/l (MW8) to 43,000 µg/1 (MW7) TAME was detected in sample MW7 at a <br /> concentration of 57 gg/l TBA was detected in sample MW7 at a concentration of 25 µg/1 No other <br />' fuel additives were detected in the ground water samples collected froze the site <br /> The current and past ground water sample analytical results are summarized on Table 2 Copies of <br /> I the laboratory report(CTEL Project No CT214-0307060),QA/QC report and chain-of custody form <br /> are in Appendix B <br />' 4.0. SUMMARY AND CONCLUSIONS <br />' Based on the results of this investigation, AGE concludes that <br /> • Depth to ground water ranged from 7 87 feet to 9 07 feet below the tops of the well casings <br />' Ground water elevations at the site ranged from 28 00 feet above mean sea level (MSL) in <br /> well MW9 to 28 66 feet above MSL in well MW11 The ground water at the site was <br /> inferred to be flowing to the northwest at an average gradient of 0 004 feet/feet <br />' 0 Contaminant concentrations increased moderately since the previous monitoring event <br /> MTBE was detected for the fust time in the past four sampling events in well MW6 and for <br />' first time in the past five sampling events in well MW8 <br /> The dissolved hydrocarbon plume extends northward from the former UST and dispenser <br />' areas, but not beyond the down-gradient monitoring wells (MW8,MW9 and MW10) The <br /> dissolved phase plume has been defined laterally in all directions Isoconcentration maps <br /> illustrating the approximate extent of TPH-g-,benzene-and MTBE-impacted ground water <br />' are depicted on Figures 4, 5 and 6 <br /> I <br />