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1 <br />' 17 May 2002 <br /> . AGE-NC Project No 96-0263 <br />' Page 3 of 4 <br />' 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> TPH-g was detected in the water samples collected from monitoring wells MW2, MW4, MW5, <br />' MW7 and MW8 at concentrations ranging from 69 micrograms per liter (µg/1) in MW8 to <br /> 12,000 µg/1 in MW7 <br />' Benzene was detected in the water samples collected from monitoring wells MW2, MW4, MW5, <br /> MW7 and MW8 at concentrations ranging from 0 72 µg/l in MW8 to 1,700 µg/1 in MW7 Toluene, <br /> ethylbenzene and total xylenes were also detected in the same samples,with the exception of toluene <br />' and xylenes in MW8, at concentrations ranging from 0 59 µg/1 of ethylbenzene in MW8 to 1,700 <br /> µg/1 of toluene in MW7 <br />' MTBE was detected by EPA method 8021B in monitoring well samples MW2, MW4, MW5 and <br /> MW7 at concentrations ranging from 160 µg/1 in the sample from MW4 to 37,000 µg/1 in MW7 <br /> MTBE was confirmed by EPA method 8260m in the same samples at concentrations ranging from <br />' 180 µ.g/1 in MW4 to 41,000 µg/1 in MW7 and detected in the sample collected from MW8 at a <br /> concentration of 3 6 µg/1 No other fuel additives were detected in the ground water samples <br /> ie collected from the site <br /> l <br /> The current and past ground water sample analytical results are summarized on Table 2 Copies of <br />' the laboratory report (MAI Lab ID Nos 0203458-001 through 0203458-011), QA/QC report and <br /> chain-of-custody form 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 6 78 feet to 7 90 feet below the well casing tops The <br />' prevailing ground water flow direction in March 2002 was inferred to be towards the <br /> north-northwest at an average hydraulic gradient of 0 005 feet/feet <br /> • The dissolved hydrocarbon plume extends northward from the former UST and dispenser <br /> areas, but not beyond the two down-gradient monitoring wells (MW9 and MW10) The <br /> dissolved phase plume has been defined laterally in all directions Isoconcentration maps <br /> I illustrating the approximate extent of TPH-g-,benzene- and MTBE-impacted ground water <br /> are depicted on Figures 4, 5 and 6 <br /> • <br />