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i 13 August 1997 AGE-NC Project No 95-0130 IPage 2 of 5 I2 2 GROUND WATER SAMPLING The ground water levels in monitoring wells MW-1 through MW-5, VW-1C, VW-2A and VW-3A, I were allowed to recover for a minimum of one hour prior to sample collection Ground water samples were collected utilizing disposable polyethylene bailers and new nylon rope Sufficient ground water sample was collected from each well to fill three 40-m1 EPA-approved VOA vials containing 0 5 ml I 18% hydrochloric acrd as a preservative for the samples Care was taken to ensure that visible air bubbles were not pr(sent in the VOA vials after filling and capping Ground water sample containers were labeled with the well designation, date, time, and sampler's initials I 2 3 LABORATORY ANALYSIS OF GROUND WATER SAMPLES Each ground water sample was logged on a chain-of-custody form, placed in a chilled container and transported to a California state-certified laboratory for analysis in accordance with EPA method 8015M for total petroleum hydrocarbons quantified as gasoline (TAH-g), and in accoidance with EPA method 8020 for volatile aromatics (benzene, toluene, ethyl benzene and xylene BTE&X) with methyl-tertiary butyl ether(MTBE) The laboratory report (Castle Analytical Laboratories Reference No 1145) and chain-of-custody forms are presented in Appendix B 3 0. FINDINGS 3 1 RELATIVE GROUND WATER ELEVATION AND GRADIENT The depths to ground water from wells MW-1 through MW-5, VW-1C, VW-2A and VW-3A were measured between 45 27 and 46 34 feet below the top of well casings Between March 1997 and June 1997, ground watei depth decreased at an a\,erage of 1 08 feet at the site The ground water elevation data for MW-1 though 5 is depicted in Figure 3 - Relative Gi ound Water Flevalron Map During the June 1997 quarterly ground water event, ground water was between 4 40 and 14 73 feet above the screened intervals in monitoring wells MW-1 through MW-5 Therefore, the wells are "drowned", and may not be fully representative of ground water conditions near the top of the saturated zone, where fuel hydrocarbons would be expected to have the greatest impact In June 1997, the gradient was calculated at 0 005 ft/ft (approximately 28 feet per mile) with a ground water flow direction generally toward the southeast From January 1995 until the current monitoring period, the ground water flow direction at the site has remained relatively constant Ed>anted GeoEn%ironinental,Inc