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7 <br /> 20 July 1998 <br /> AGE-NC Project No 98-0448 <br />' Page 3 of 4 <br /> r , <br /> f <br />' ground water measurements or changes in discharge/recharge of the local ground water could greatly <br /> modify ground water flow direction <br /> 3 2 LABORATORY RESULTS OF GROUND WATER SAMPLES <br /> Utilizing EPA method 8015M, TPH-g was detected in ground water samples collected from MW-1 <br /> and MW-2 at concentrations ranging up to 61,000 parts per billion(ppb, reported as micrograms per <br /> liter) ' <br />' <br /> Utilizing EPA method 8020, BTE&X compounds were detected in ground water samples collected <br /> from wells MW-1 and MW-2 at concentrations ranging up to 12,000 ppb (toluene, MW-2),benzene <br />' was detected from MW-1 and MW-2 at concentrations ranging up to 7,300 ppb Utilizing EPA <br /> method 8020,MTBE was not detected above laboratory reporting limits in ground water samples <br /> Utilizing EPA method 8260, MTBE was detected in the sample collected from MW-2 at a <br /> concentration of 320 ppb, DIPS, ETBE, TAME and TBA were not detected in the laboratory <br /> analysis of any ground water samples <br /> The laboratory report (McCampbell Analytical Inc Lab I D 90582 to 90584) and cham-of-custody <br /> form are presented in Appendix B, the results of the analysis are contained in Table 2 <br /> r <br /> 4.0. DISCUSSION AND CONCLUSIONS <br /> } <br />' Based upon data,collected during the June 1998 monitoring, AGE concludes the following <br /> • Ground water was inferred to be flowing toward the southeast at a calculated gradient of <br />' 0 006 ft/ft, or approximately 31 feet per mile (Figure 3) Due to the low gradient at the site, <br /> slight vanations in ground water measurements or changes of recharge/discharge of the local <br /> ground water could greatly modify ground water flow direction <br /> f • The ground water surface elevation at the site is above the slotted screen intervals in wells <br /> MW-1 through MW-3,therefore the analytical results of samples collected from these wells <br /> may not be completely representative of concentrations of dissolved petroleum hydrocarbon <br /> in shallow ground water on the site <br /> • From April-1997 to June 1998, concentrations of dissolved petroleum hydrocarbon in <br /> samples collected from MW-2 decreased substantially (Appendix C), BTE&X constituents <br /> previously detected in ground water samples collected from MW-3 were not detected during <br /> the June 1998 quarterly event The decrease in hydrocaibon concentrations reported from <br /> Advanced GeoEnvironmental,Inc <br /> " r <br />