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' 01 March 2000 <br /> • AGE-NC Project No 99-1828 <br /> Page 7 of 8 <br /> 44 RESULTS OF GROUND WATER SAMPLE ANALYSIS <br /> A total of six grab ground water samples were submitted to DHS-certified laboratories for analysis <br /> TPH-g was detected in ground water samples collected from B-1, B-6, B-7, and B-8 at <br /> concentrations as high as 2,200 micrograms per liter (µg/1) in the sample from B-1 TPH-d was <br />' detected in samples B-1, B-4, B-6, B-7, and B-8 at concentration as high as 1,900 µg/l (B-1) <br /> Utilizing EPA Method 8020, BTEX compounds were detected at concentrations as high as 67 µg11 <br />' in grab ground water samples collected from B-1, B-6, B-7, and B-8 MTBE was detected in grab <br /> ground water samples B-6 and B-7 at concentrations of 93 µg/1 and 11 ,ug/l, respectively <br /> Utilizing EPA Method 8260, MTBE was detected in grab ground water samples collected from all <br /> six samples at concentrations as high as 150 ,ug/l (B-6) The analytical results of water samples are <br /> summarized in Tables 3 and 4 The laboratory reports and chain-of-custody forms are included in <br /> Appendix C <br /> r• 5.0. SUMMARY AND CONCLUSIONS <br />' Based on data collected during the 29 October 1999 and 01 November 1999 soil probe borings and <br /> grab ground water sampling, AGE concludes <br />' Field observations, OVM readings, and laboratory analysis indicate that the most intense <br /> hydrocarbon impact in soil is in the area of borings B-1, B-2, and B-7 at 15 feet bsg <br /> • Laboratory analysis of the grab ground water samples indicate that the highest concentrations <br /> of TPH-g, TPH-d, BTEX, and MTBE is in the vicinity of former dispenser islands Based <br /> on the data collected, the dispenser islands appear to be the primary source of the <br />' hydrocarbon release <br />' 6.0. RECOMMENDATIONS <br /> Based upon data collected during October and November 1999, AGE recommends <br />' Installation of ground water wells to determine the ground water gradient and flow direction <br /> and chemical concentrations in the ground water at the site These well should be installed <br />' at the locations proposed in Figure 6 to further assess the lateral extent of petroleum <br /> ^hydrocarbon-impacted ground water <br />' Advanced GeoEnvironmental,Inc <br /> I <br />