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' 07 March 2003 <br /> • AGE-NC Protect 99-0570 <br />' Page 3 of 4 <br />' 32 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br />' TPH-g was detected in samples MW-2 and MW-3 at concentrations of 450 micrograms per liter <br /> (µg/1) and 520 µg/l, respectively TPH-d was detected in these same samples at 510 µg/1 and 400 <br /> µg/1, respectively <br />' Benzene was detected in sample MW-2 at a concentration of 0 52 ug/1 while the remaining BTE&X <br /> compounds were detected up to 4 5 ug/1 of ethylbenzene BTE&X compounds were not detected in <br /> the remaining ground water samples <br /> MTBE was detected in samples MW-1, MW--2 and MW-3 at 6 1 µg/l, 12 g g/l and 150 µg/1, <br /> respectively TBA was detected in sample MW-1 at a concentration of 9 3 µg/1 No other fuel <br /> oxygenates were detected In any of the samples <br /> Laboratory results of water samples analyzed for petroleum hydrocarbons are summarized in <br /> Table 2 The laboratory reports for the quarterly monitoring event(MAI Laboratory ID No 0301367- <br /> 01 to 05) QA/QC reports and chain-of-custody form are included in Appendix B <br /> 4 0 SUMMARY AND CONCLUSIONS <br /> Based un the findings from this investigation, AGE draws the following conclusions <br /> g g <br /> I Ground water flow direction was towards the northwest from the former dispenser area at <br /> a hydraulic gradient of 0 02 feet/feet This flow direction and gradient are similar to previous <br /> monitoring events <br /> • MTBE was detected in three ground water samples,with the highest dissolved concentration <br /> occurring southeast of the dispenser area and the former UST excavation MTBE <br /> concentrations in samples MW-2 and MW-3 were above the DHS' Maximum Contaminant <br /> Level of 13 µg/1 in drinking water The up-gradient well, MW-3, has the highest MTBE <br /> concentration and has had increasing concentrations over the last four quarters <br /> • TPH-g, TPH-d were only detected in monitoring wells MW-2 and MW-3 during this <br /> sampling event In general, the TPH-g and TPH-d concentrations decreased in MW-2 and <br /> increased in MW-3 when compared to the last monitoring event results BTE&X <br /> concentrations dropped significantly In monitoring well MW-2 between this and the previous <br /> monitoring event <br /> Advanced GeoEnvironmental,Inc <br />