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1 ' 27 October 2003 AGE-NC Project No 98-0450 ' Page 14 of 17 ' pump and approximately 125 to 8 25 gallons of water were purged from the remaining wells with dedicated,disposal bailers An Oakton water analyzers was utilized to monitor temperature,pH and conductivity of purged water at regular purge-volume intervals Stabilization data and field logs are ' included in Appendix D Purged ground water was containerized in 55-gallon drums and stored on- site 5 3 1 Ground Water Sample Collection The ground water levels in all six wells were allowed to recharged to a minimum of 80% of the initial well volume prior to sample collection, except well MW-4 which only recharged a small quantity of the original volume Subsequently,ground water samples were collected from each well t using a new disposable plastic bailer Each water sample was then transferred into three 40-m1 volatile orgamc analysis(VOA)vials containing 0 5 ml 18%HCl as a sample preservative and a one- liter amber bottle without preservative,except well MW-4 which would not yield enough water for ' liter of water The samples were then labeled and placed in a chilled container for transport under chain-of-custody to McCampbell Analytical,Inc (MAI)of Pacheco,California,a State of California - Department of Health Service (DHS)-certified laboratory The samples were analyzed for the '. following • Total petroleum hydrocarbons quantified as gasoline (TPH-g) and total petroleum ' hydrocarbons quantified as diesel(TPH-d)in accordance with EPA Method 8015 Modified for gasoline and diesel, respectively, ' Benzene, toluene, ethyl benzene and xylene(BTEX)and methyl tert-butyl ether(MTBE)in accordance with EPA Method 8020, • The fuel additives di-isopropyl ether (DIPE), ethyl tertiary-butyl ether (ETBE), methyl ' tertiary-butyl ether(MTBE),tertiary-amyl methyl ether(TAME) and tertiarvbutanol(TBA) ethyl-dibromide(EDB)and 1,2-dichloroethane(1,2-DCA)in accordance with EPA Method 8260 Modified, respectively ' S 3 2 Relative Ground Water Elevation and Gradient The depths to ground water from the tops of the monitoring well casings were measured at 51 80 to 50 87 feet below surface grade (bsg) The corresponding ground water elevations ranged from 6 69 feet below mean sea level (MSL)in well BMW-4 to 7 18 feet below MSL in MW-5 (Table 7) The ground water elevation data for the well network during the latest ground water monitoring ' event is depicted in Figure 3 The ground water flow direction was inferred to be south to southwestwards at a hydraulic gradient of approximately 0 0048 t/ft Based on a southerly flow Advanced GeoEnvironmental,Inc