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' 19 February 2001 <br /> • AGE-NC Project No 98-0465 <br /> ' Page 3 of 4 <br /> ' 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> Each sample was analyzed for TPH-g, TPH-d, BTEX, and for the suite of five oxygenated fuel <br /> ' additives TPH-g, TPH-d and BTEX were not detected at concentrations at or above the laboratory <br /> reporting limits in any of the ground water samples <br /> tMTBE was detected in the ground water samples collected from MW1, MW3, and MW4 at <br /> concentrations of 6 7 jLg/l, 72 4g/1 and 17 Ag/l, respectively MTBE detections were confirmed in <br /> the samples by EPA Method 8260 at concentrations of 6 5 µg/1, 73 ,ug/1 and 16 ,ug/l, respectively <br /> ' TBA was detected in the ground water sample collected from MW-3 at a concentration of 25 µg/1 <br /> No other fuel oxygenated compounds were detected in the ground water analyses <br /> ' Analytical results of water samples collected during October 2000 are summarized on Table 2, The <br /> laboratory report (MAI Lab No 58312 through 58315), QA/QC report and chain-of-custody form <br /> ' are included in Appendix B <br /> ' 4.0. SUMMARY AND CONCLUSIONS <br /> The following conclusions were drawn from the results of this Investigation <br /> 1 C The ground water elevations ranged from 7 48 to 7 61 feet below MSL Ground water is <br /> flowing toward the northwest under an average gradient of 0 0018 feet/feet The relative <br /> ' ground water elevation at the site increased an average 1 12 feet between the October 2000 <br /> and January 2001 monitoring events <br /> G Concentrations of dissolved MTBE have decreased significantly in monitoring wells MW3 <br /> and MW4 since the monitoring event in October 2000 MTBE levels have remained <br /> relatively constant in MW-1 <br /> ' G The lateral extent of petroleum hydrocarbon-impacted ground water has not been delineated, <br /> but does not appear to be significant <br /> ' G The lateral extent of MTBE-impacted ground water has been defined to the northeast of the <br /> former UST area,but not toward the east, south or west to northwest <br /> 1 <br /> 5.0. RECOMMENDATIONS <br /> Based on the findings of this investigation, AGE recommends contmued quarterly monitoring of the <br /> . ground water monitoring wells The next monitoring event should be performed In April 2001 <br /> ' Advanced GcoEnvlronment2L1,Inc <br />