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12 January 2005 AGE-NC Project No 97-0326 ' Page 10 of 11 HU6 TPH-g and BTEX compounds were detected in samples MW-8D and MW-9D,the maximum concentrations were detected in sample MW-9D at 1,300 µg/l TPH-g, 80 }tg/l benzene, 13 µg11 toluene, 8 7 �tg/l ethylbenzene and 25 µg11 xylenes ' No additional analytes were detected at or above the laboratory reporting limits in the samples analyzed The laboratory report (CTEL Project No 214-0404061) and cham-of-custody forms are presented in Appendix H Analytical results are summarized in Table 3 Documents confirming the upload of laboratory electronic deliverable format (EDF) files and depth to water measurements to GeoTracker are included to Appendix l 4.0. SUMMARY AND CONCLUSIONS ' The following conclusions were drawn from the results of this investigation • In general, the site stratigraphy consisted of laterally discontinuous lenses of fine to coarse sand at depths between 19 and 24 feet bsg and at approximately 34 feet bsg and laterally- continuous sand layers at depths between 70 and 80 feet bsg, 110 and 120 feet bsg and • 135 and 150 feet bsg, fine-grained soil consisting of silt, clayey silt and clay characterizes the remaining subsurface sediment • AGE identified seven hydrogeologic units (HUs) at the site The second, fourth and sixth ' HUs are sandy and potentially high permeability flow units with significant lateral continuity The first and third HUs are predominantly silt and clayey silt intervals, which are possibly leaky confining layers through which the contaminates of concern can apparently migrate iThe fifth and seventh HUs appear to be clay layers or consist of a significant amount of clay • Petroleum hydrocarbons were detected in soil samples collected from all HUs The highest ' contaminant concentrations were centered in HU1 beneath the tank-pit area, and in the vadose zone at well MW-3(Figure 5),however,the latter maybe a due to a dispenser-related leak TPH-g in soil does not extend below HU1,although BTEX compounds,including low ' benzene concentrations, extend vertically to as deep as HU4, and low concentrations of xylenes were detected in HU5 and HU6 • The ground water elevations in HU1 wells (water table) on 07 April 2004 ranged from 20 89 feet to 2105 feet below MSL, the net ground water flow was inferred to be flowing south-southeast at a gradient of approximately 0 007 ft/ft ' W TPH-g and BTEX compounds were detected in ground water samples collected from all HUs, but the fuel additives MTBE and 1,2-DCA were detected only in HU1 Laterally, the highest concentrations of contaminants in HU1 were centered around the tank-pit and dispenser areas (Figures 7 and 8), vertically, TPH-g and BTEX compounds exhibited decreasing concentrations with increasing depth ' Advanced GeaEnvironmental,Inc