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20 January 2003 AGE-NC Project No 95-0109 Page 6of8 One or more BTEX compounds were detected in samples from the same HU1 wells at concentrations as high as 38µg/l benzene(MW-14),3 1 µg11 toluene(MW-14),25 µg/l ethylbenzene (MW-9) and 130 µg11 total xylenes (MW-8) In addition, ethylbenzene and xylenes were detected in HU3 well MW-18 at concentrations of 0 76 µg11 and 13 µg11, respectively BTEX compounds were not detected in HU2 samples TBA and 1,2-DCA were the only fuel additives detected in the analyzed samples TBA was detected in the water samples collected from HU1 wells MW-9 and MW-14 at concentrations of 29 µg/l and 19 µg/l, respectively 1,2-DCA was detected in samples collected from HU1 wells MW-I, MW-3, MW-4, MW-5, MW-7, MW-9, MW-11, MW-13, MW-14, MW-16 and EW-1 at concentrations ranging from 0 56 µg/l (MW-13) to 54 µg/1 (MW-1) and HU2 well MW-15 at a concentration of 1 I µg11 Fuel additives were not detected in HU3 samples Eight additional analytes were detected by EPA Method 8260 Carbon disulfide was detected in HU1 sample MW-5, and n-butyl benzene, isopropylbenzene, naphthalene, 1,2,4 trimethylbenzene, sec- butyl benzene, n-propyl benzene and 1,3,5 trimethylberizene was detected in HU1 samples MW-8 and MW-9 • The analytical results for the December 2002 monitoring event are presented on Table 2 Historical analytical results are summarized on Table 3 The approximate extent of dissolved TPH-g,benzene and 1,2-DCA are depicted on Figures 4, 5 and 6 The laboratory reports (MAI Laboratory I D Nos 0212409-001 through 0212409-015 and 0212473-001 through 0212473-005)and chain-of-custody forms are included in Appendix D 4.0. DISCUSSION AND CONCLUSIONS Based upon data collected from the site, AGE finds • Saturated, poorly graded fine to medium sand was encountered from 70 feet to 79 feet and saturated silty sand was encountered from 79 feet 80 feet bsg in boring MW-15 The lithologic data corresponded with the results from the December 2001 CPT investigation • Ground water elevation increased an average of 0 52 feet between the September 2002 and December 2002 sampling events The ground water flow direction was inferred to be towards the south-southwest on-site and toward the south-southeast, south of the site Ground water elevations at the site have decreased an average of 142 feet between the December 2001 and December 2002 sampling events • TPH-g was detected in groundwater samples from HU1 wells MW-1,MW-4,MW-8,MW-9 and MW-14 and HU3 well MW-18 at concentrations as high as 3,300 µg/l(MW-8) TPH-g was detected at 100 µg11 in HU3 sample MW-18,screened from 112 feet to 117 feet bsg,but Advanced GeoEnvironmental,Inc