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fiF gj 17 January 1997 AGE-NC Project No 95-0121 Page 2 of 5 2 2 GROUND WATER SAMPLE COLLECTION Monitoring wells MW-1 through MW-9 were allowed to recover for a minimum of one hour prior to sample collection Water samples were collected from wells MWA through MW-9 utilizing dedicated, disposable polyethylene bailers and new nylon rope Samples were collected in one-liter amber bottles and 40-m1 EPA vials containing hydrochloric acid as a preservative Care was taken to ensure that visible air bubbles were not present in the VOAs after filling and capping Ground water sample containers were labeled with the well designation, date, time, and the sampler's initials 23 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 of total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d), volatile aromatics (benzene, toluene, ethyl benzene and xylenes BTE&X) and methyl tert-butyl ether (MTBE) in accordance with appropriate EPA methods The laboratory report (CAL Laboratory No 952) 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 in wells MW-1 through MW-8 ranged between 21 42 and 22 46 feet below the top of each well casing Between August and November 1996, ground water depth increased an average of 0 11 feet at the site During ground water monitoring activities, the depth to ground water at MW-9 was recorded at 27 90 feet below the top of the well casing Due to the inconsistency of the ground water depth at MW-9 with respect to ground water depths from wells MW-1 through MW-8, we believe the ground water depth at MW-9 to be misread As a result, the ground water elevation data from MW-9 was omitted from Figure 3 -Relative Ground Water Elevation Map During the November 1996 sampling, ground water was between one and eleven feet above the top of the screened intervals in the each monitoring wells In November 1996, the gradient was calculated to be 0 0025 ft/ft or approximately 14 feet per mile, directed approximately N 04°E Between August and November 1996, ground water flow direction beneath the site rotated approximately 46° from east to northeast