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' 17 April 2006 • AGE-NC Project No 98-0432 ' Page 2 of 4 8 5 gallons of water)were removed from monitoring wells MW-1 through MW-8 Temperature,pH, ' and conductivity of the purged water were measured at regular purge-volume intervals using an Oakton water analyzer Monitoring well field logs are included in Appendix A Purge water ' generated from the monitoring wells was contained on-site in appropriately labeled 55-gallon drums ' 2 2 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES Ground water samples were collected from the monitoring wells using the disposable polyethylene ' bailers, these bailers are disposed of after one use and require no decontamination, thereby minimizing cross-contamination from sampling devices Each water sample was transferred into three 40-milliliter (ml) EPA-approved volatile organic analysis (VOA) vials containing 0 5 nil 18%hydrochloric acid solution as a sample preservative, and Into one 1-liter amber bottle without preservative After collection, the samples were labeled and placed in a chilled container for transportation under chain of custody to Cal Tech Environmental Laboratories(CTEL),a California Department of Health Services (DHS)-certified analytical laboratory located in Paramount, California Each sample was analyzed for ' • • Total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d, respectively) in accordance with EPA Method 8015 Modified, and ' • Benzene,toluene,ethylbenzene, and total xylenes(BTEX)and fuel additive compounds di- isopropyl ether (DIPE), ethyl tertiary-butyl ether (ETBE), methyl tertiary-butyl ether (MTBE), tertiary-amyl methyl ether (TAME), tertiary butanol (TBA), 1,2-dichloroethane (1,2-DCA), and 1,2-dibromoethane (EDB), in accordance with EPA Method 8260B ' 3.0. FINDINGS ' Ground water elevation, flow direction, and gradient were determined from field data collected in April,the contaminant impact to ground water was quantified by the ground water sample laboratory analytical data. 3 1 GROUND WATER ELEVATION, FLOW DIRECTION AND GRADIENT ' The depth to ground water measured in the monitoring wells ranged from 13 04 feet to 14 82 feet below the tops of the well casings (Table 1) The ground water elevation at the site ranged from ' 22 88 feet (MW-7) to 23 52 feet (MW-3 and MW-5) above mean sea level (MSL), the average • ground water elevation increased approximately 3 18 feet since the previous monitoring event in the 1 Advanced GeoEnvironmental,Inc,