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lie 25 February 2005 AGE-NC Project No 96-0229 ' Page 3 of 6 ' Ethylene dibromide (EDB), 1,2--dichloroethane (1,2-DCA), tert-butyl alcohol (TBA), di- isopropyl ether(DIPS), ethyl tert-butyl ether(ETBE),tert-amyl methyl ether(TAME), and methyl tert-buyl ether(MTBE)by EPA Method 8260B ' 3.0. FINDINGS Ground water monitoring field data was utilized to determine ground water flow direction and ' gradient, petroleum hydrocarbon-impact to ground water was quantified by laboratory analysis of samples ' 3 1 GROUND WATER ELEVATION AND GRADIENT ' The depth to ground water measurements on 29 September 2004 ranged between 33 44 feet(MW-5) and 36 62 feet(MW-12)below the tops of the well casings, the water level decreased an average of . 3 70 feet between the June 2004 and the September 2004 ground water monitoring events ' Ground water elevations were calculated by subtracting the measured depth to ground water from the surveyed casing elevations The ground water elevations averaged 22 59 feet below mean sea level (MSL) at the site,with a range of between 20 90 feet(MW-4) and 23 66 feet(MW-12)below MSL Ground water elevation data collected from wells MW-1, MW-2, MW-3, MW-13 (A-D), MW-14 (A-D), and MW-16 (A-E) on 29 September 2004 is depicted on cross section B-B' (Figure 3) By determining the difference between ground water elevations (dh) and dividing by the difference of the screen interval midpoints (dl), the vertical gradient between adjacent screen intervals was calculated Generally,slightly downward or nearly flat vertical gradients were observed between the Second Water Zone,Second Confining Unit and Third Water Zone screen intervals of all the above wells (Figure 3), however, moderate downward vertical gradients were generally observed in the First Confining Unit (;rrmnd urnter elarratinng tx/PYP ninttari rm crµlerl qiVe "La"o fnr the infnrn�ai 17vv�i W f 7--- (between 15 and 45 feet, Figure 4) and Second Water Zone (between 70 and 95 feet, Figure 5) 3 1 1 First Water Zone Ground water elevation data collected in the First Water Zone(15 to 45 feet bsg) at the site inferred a net ground water flow towards the northeast at a hydraulic gradient of approximately 0 005 ft/ft IAdvanced GeoEnvironmental,Inc