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1 <br /> . 19 September 2002 <br /> AGE-NC Project No 98-0534 <br />' Page 3 of 4 <br />' 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> TPH-d was detected in the ground water samples collected from wells MW-4 and MW-6 at �- <br />' concentrations of 130 micrograms per liter(µg11)and 53 gg/l,respectively TPH-g was not detected <br /> in the ground water samples analyzed <br /> Toluene was the only BTEX compound detected in the ground water samples, at a maximum <br /> concentration of 1 1 gg/l in MW-4 <br />' MTBE was detected by EPA Method 8260 in the samples from wells MW-3,MW-4,MW-6,MW-7 <br /> and MW-8 at concentrations of 6 9 gg/l, 18 µg/1, 150 gg/l, 0 62 gg/l and 5 3 pg/l, respectively <br /> ETBE was detected in sample MW-6 at 4 2 gg/1 and TBA was detected in sample MW-4 at 21 gg/l <br />' No other fuel oxygenates were detected in the samples analyzed <br /> The current and historical groundwater analytical results are summarized on Table 2 The laboratory <br />' report (MAI laboratory ID No 0206274-1 to-7), chain-of-custody form and the laboratory QA/QC <br /> report are included in Appendix B <br /> 4.0. SUMMARY AND CONCLUSIONS <br /> The implications from the June 2002 ground water monitoring event are as follows <br /> • Ground water flow direction was indeterminate at the former UST area,but formed a water- <br /> table depression north of the UST area <br /> r <br /> • The ground water elevations at the site were within the screened intervals of the wells, which <br /> should yield samples fully representative of shallow ground water conditions <br /> • MTBE was detected in three ground water samples by EPA 8260,the MTBE concentrations <br /> in samples MW-4(18 gg/1) and MW-6 (150 gg/1)were above the DHS' pnmary Maximum <br /> Contaminant Level of 13 gg/I in drinking water <br /> • MTBE in shallow ground water has been delineated to the north and west, low MTBE <br /> concentrations are still present in easternmost and southernmost wells <br /> 5.0 RECOMMENDATIONS <br /> Based upon the results of the first quarter 2002 investigation, AGE recommends <br /> • Continued quarterly ground water monitoring utilizing wells MW-1 and MW-3 through <br /> Advanced GeoEnVLronmental,Inc <br />�3 <br />