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I01 March 2004 a AGE-NC Project No 99-0645 Page 9 of 11 The ground water flow direction was estimated to flow toward the northwest,however,the well head Ielevation for MW-1R has not been resurveyed Figure 4 illustrates the contoured ground water elevations as measured on 06 October 2003 36 ANALYTICAL RESULTS OF WATER SAMPLES TPH-g, TPH-d, BTEX compounds, TBA, DIPE, ETBE, TAME, EDB, and 1,2 DCA were not detected in any of the water samples MTBE was detected in the sample collected from well MW-1 Iat a concentration of 120 gg/L Analytical results from the ground water samples are summarized in Tables 5 and 6 The laboratory report (MAI Lab ID Numbers 0310093-001 to-003),QA/QC and chain-of-custody are Included in Appendix G 4.0. SUMMARY AND CONCLUSIONS . Based on the data collected from the site, AGE concludes • The sand units occurred at depths of 15 to 30 feet bsg and 75 or 80 feet to 80 or 85 feet bsg I The deepest sand unit previously encountered may actually be two thinner units Ground water was encountered at approximately 96 feet bsg Ground water flow direction at the site was northwest The decrease of ground water elevation of approximately 4 feet between July ' 2002 and October 2003 may be due to seasonal fluctuation • TPH-g was detected in the soil boring sample collected north of the site (B6') Low ' concentrations of MTBE were detected in the soil sample to a depth of 55 feet bsg in the same boring Benzene concentrations were detected in the two deepest soil samples collected from the northern boring, Indicating the northern migration of only benzene,at a depth of 60 ' feet to 70 feet bsg or the presence of another source off the northern edge of the site With no detections of benzene in the upper 55 feet of boring B676,only low detections of benzene in the former UST soil boring B1, all less than 0 1 mg/Kg, and the lack of detectable ' hydrocarbons in the soil boring MW-1 R below 50 feet bsg,the source of the off-site benzene detected in the further most reach of boring B6' appears to be from another source than the UST release However, soil vapor extraction on the site will likely effectively mitigate the ' detections off-site • TPH-g was not detected In the soil boring sample collected at the west edge of the site ' (VW3) Only low concentrations of MTBE were detected at 30 and 40 feet bsg In boring VW3 TPH-g was not detected in the soil boring sample collected at the southern edge of the site (137) Only one detection of MTBE was In the soil, from 30 feet bsg in boring B7 ' Advanced GeoEnvironmental,Inc I