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' 18 September 2003 <br /> AGE-NC Project No 95-0111 <br />' Page 3 of <br />' 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> TPH-g was not detected at or above laboratory reporting]units in the ground water samples TPH-d <br /> t was detected in the ground water samples collected from wells MW-4 and MW-5 at concentrations <br /> of 990µg/1 and 110µg/1,respectively BTEX compounds were not detected in the samples analyzed <br /> MTBE was detected utilizing EPA method 8260 in the ground water samples collected from MW-1, <br /> MW-2 and MW-5 through MW-8 at concentrations of between 6 9 µg/1 (MW-1) and 380 gg/l <br /> (MW-5) No other fuel additives were detected at or above laboratory reporting limits in the ground <br /> water samples analyzed <br /> Analytical results of the ground water samples are summarized in Tables 2 and 3 The laboratory <br /> report(MAI Work Order 0307004),quality assurance and qualitycontrol report and chain-of-custody <br /> forms are included in Appendix B <br />' 4.0. SUMMARY AND CONCLUSIONS <br /> Based on the findings from this investigation, AGE concludes <br /> b The northerly ground water flow direction inferred from data collected during this <br />' monitoring event is consistent with ground water flow directions determined during past <br /> monitoring events at the site <br />' • TPH-d was detected in the ground water samples collected from wells MW-4 and MW-5 at <br /> concentrations of 990 µg/1 and 110 µg/1, respectively TPH-g was not detected at or above <br /> laboratory reporting limits in the ground water samples <br />' • BTEX compounds were not detected above laboratory reporting limits in the ground water <br /> samples collected during the second quarter 2003 monitoring event <br />' • MTBE was detected by EPA Method 8260 in the samples collected from MW-1,MW-2 and <br /> MW-5 through MW-8 The reported MTBE concentrations in off-site samples MW-5,MW-6 <br /> and MW-8 exceeded the DHS' Primary MCL in drinking water <br /> • MTBE concentrations in off-site well MW-6 had been below 3 0 gg/1 since ground water <br /> monitoring was initiated in January 1998, and,had decreased to non-detectable levels by <br />' September 1999(Table 3), MTBE had not been detected in well MW-8 prior to September <br /> 2001 However,since September 2001,MTBE was detected in well MW-8 in seven of eight <br /> monitoring events, with the highest concentrations detected in the more recent monitoring <br />' events of September 2002 and March 2003 In addition, MTBE has been detected again in <br /> well MW-6 The data strongly suggests an additional, off-site source of MTBE east of the <br /> • Grant Line Gas and Food site <br /> Advanced GeoEnvironmental Inc <br /> r <br />