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I30 September 2004 <br /> AGE-NC Project No 96-0254 <br /> Page 3 of 4 <br /> I3 2 LABORATORY RESULTS OF GROUND WATER SAMPLES <br /> TPH-g, TPH-d,BTEX constituents and the fuel additive MTBE were detected In the ground water <br /> samples collected from monitoring wells MW-1B and MW-4 TPH-g was detected at concentrations <br /> of 750 micrograms per liter(µg/1) from MW-1B and 480 gg/1 from MW-4 TPH-d was detected at <br /> concentrations of 110µg/1 from MW-1B and 82 µg/1 from MW-4 BTEX constituents were detected <br /> at maximum concentrations of 150 µg/1 benzene, 26 Vg/l toluene, 35 pLg/1 ethylbenzene and 27 µg/1 <br /> xylenes,In the groundwater sample collected from MW-1B MTBE was detected at concentrations <br /> of at 2 3 �tg/l from MW-1B and 3 4 µg/1 from MW-4 <br /> No other target analytes were detected In the ground water samples collected The analytical results <br /> are summarized In Tables 2 and 3 Copies of the laboratory report (MAI Work Order 0405315), <br /> quality assurance/quality control (QA/QC) reports and chain of custody forms are in Appendix C <br /> Confirmation pages confirming the submission of the laboratory electronic deliverable format(EDF) <br /> files and depth to water measurements to the GcoTracker database are Included In Appendix D <br /> 4.0. SUMMARY AND CONCLUSIONS <br /> Based on the data collected during this monitoring period, AGE concludes <br /> I • Ground water elevation at the site was between 28 93 feet and 30 06 feet above MSL, the <br /> flow direction was north-northeast at an average gradient of 0 005 fl/ft The ground water <br /> Iflow measurements were consistent with calculations from previous monitoring events <br /> • Petroleum hydrocarbon compounds were detected In ground water samples MW-1B and <br /> MW-4 The benzene concentrations detected this quarter exceed the DHS' maximum <br /> contaminant level for drinking water of 1 �tg/l <br /> 5.0. RECOMMENDATIONS <br /> I Based on the results of this Investigation, AGE recommends continued quarterly ground water <br /> monitoring at the site, with the next monitoring event performed In September 2004 The <br /> measurement of natural attenuation parameters was Initiated In the third quarter 2004 monitoring <br /> event <br /> • <br /> IAdvanced GeoEnvironmental,Inc <br /> I <br />