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30 January 1998 AGE-NC Project No 95-0104 Page 2 of 4 bailers and new nylon rope Sufficient sample was collected from each well to till three 40-m1 EPA- approved VOA vials containing 0 5 ml 18%hydrochloric acid as a sample preservative Care was taken to ensure that visible air bubbles were not present in the vials after filling and capping Ground water sample containers were labeled with the well designation, date, time, and sampler's initials 23 LABORATORY ANALYSIS OF GROUND WATER SAMPLES Following collection, each sample was logged on a chain-of-custody form, placed in a chilled container and transported to Alpha Analytical Laboratories, a California state-certified laboratory for analysis by EPA Method 8015-m for total petroleum hydrocarbons quantified as gasoline (TPH- g), by EPA Method 8020 for volatile aromatics (benzene, toluene, ethylbenzene and xylenes BTE&X) with methyl-tertiary butyl ether (MTBE), and were transported to KIFF Analytical, a California state-certified laboratory for analysis by EPA Method 8260 for tertiary butanol (TBA), di-isopropyl ether(DIPE), ethyl tert butyl ether(ETBE) and tert amyl methyl ether (TAME), and to fconfirm and quantify any MTBE detected by EPA Method 8020 lie 3.0. FINDINGS 3 1 RELATIVE GROUND WATER ELEVATION AND GRADIENT The depths to ground water from wells MW-I through MW-6 and VW-1 were measured between 67 91 and 69 20 feet below the top of well casings Between September 1997 and December 1997, depth to ground water decreased an average 1 79 feet at the site The ground water elevation data for MW-1 through MW-6 during December's ground water monitoring event is depicted in Figure 3 During the December 1997 monitoring event, ground water was between 11 80 and 12 09 feet above the top of screened intervals from monitoring wells MW-2 through MW-4 As a result, the screened intervals from these wells are completely submerged, and may not yield water samples 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 December 1997, the adient was calculated to be 0 006 ft/ft or approximately 34 feet per mile � � PP Y (Figure 3) Ground water monitoring data collected in the area of MW-2,MW-4 and MW-6, suggests that the ground water flow direction was toward the northeast, ground water monitoring data collected in the area of MW-1, MW-3 and MW-5 suggests that the ground water flow direction was Itoward the southeast Advanced GeoEn\[ronmenial,Inc