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I 24 September 2004 • AGE-NC Project No 97-0301 ' Page 3 of 6 • Benzene, toluene, ethylbenzene and xylene (BTEX), methyl tertiary-butyl ether (MTBE) ' 1,2-Dichloroethane(1,2-DCA),ethylene dibromide(EBD),di-isopropyl ether(DIPE),ethyl tert butyl ether(ETBE),tert amyl methyl ether(TAME)and tertiary butanol(TBA)by EPA Method 8260B I � i3.0. FINDINGS f� Ground water elevation,flow direction and gradient were determined from field data collected on ' March 2004 The contaminant impact to ground water was quantified by laboratory analysis of the ground water samples collected on 31 March 2004 3 1 GROUND WATER ELEVATION AND GRADIENT wells MW-1 throw MW-12 vaned between 31 lect ' The dept�i to ground water measurements at e s through (MW-9B') and 33 05 feet (MW-8C) below the top of well casings, ground water elevations were calculated to be between 19 16 feet (MW-8A) and 20 26 feet (MW-11D) below mean sea level - (MSL) Generally, ground water elevation at the site increased an average 2 49 feet between the November 2003 and the March 2004 ground water monitoring events ' Ground water elevation data collected on 30 March 2004 from wells MW-8(A-C),MW-9(A-D)and MW-12(A-D) Is depicted on cross section D-D'(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, moderately steep to steep downward vertical gradients were observed between the Second, Third and Fourth Water ' Zones,nearly flat to very slight upward vertical gradient was observed between the First Water Zone and the Second Water Zone (Figure 3) , The ground water elevation at wells MW-1 through MW-12 were calculated by subtracting the measured depth to ground water from the survey casing elevation The March 2004 ground water ' elevation data collected from wells MW-1 thro gh MW-7 were plotted for the First Water Zone (Figure 4) as defined in AGE's CPT Site Investigation - Third Quarter 2001 (dated 25 October 200 1) Generally,the net ground water flow direction was towards the northeast at an approximate ' hydraulic gradient of 0 003 ft/ft or less (16 feet per mile) Advanced GeoEnvironmental,Inc 1 I