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i i27 February 2004 • AGE-NC Project No 95-0130 Page 2of6 `dry' The ground water elevation at wells MW-1 through MW-8, VW-1C, VW-2A and VW-3A were calculated by subtracting the measured depth to ground water from the surveyed casing elevation As-built monitoring well construction details are summarized in Table 1 Ground water elevations were plotted and contoured on scaled site maps depicting First Zone and Second iZone ground water elevations (Figures 3 and 4) After water levels were measured, approximately 1 to 18 gallons of ground water (a minimum of three casing-water volumes per well) were purged from wells MW-1 through MW-8, VW-1C, VW-2A and VW-3A by lowering and raising a 3/8 or 518-inch outer diameter, length-discrete ' polyethylene hose equipped with a ball-valve water tip through the specific water-charged screened section A Watera-Hydro-Lift H pump equipped with a mechanical arm was utilized to surge the polyethylene hose Temperature, pH and conductivity were measured for stabilization at regular ' purge-volume intervals from each well using the Oakton water analyzer Field data and logs are in Appendix B Multi-level well purged ground water was transferred to 55-gallon drums and stored on-site in an area lacking general public access 2 2 GROUND WATER SAMPLING ' Ground water samples were collected from wells MW-1 through MW-8, VW-1C, VW-2A and VW-3A utilizing 318-inch diameter polyethylene tubing Groundwater samples were transferred into ' 40-m1 EPA-approved volatile organic analysis(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 ' Each ground water sample was logged on a chain-of-custody form,placed in a chilled container and transported to a California Department of Health Services (DHS)-certified laboratory for analysis for ' • Total petroleum hydrocarbons quantified as gasoline(TPH-g)by EPA Method 5030/8015M, • Benzene, toluene, ethylbenzene and xylene (BTEX), methyl-tertiary butyl ether (MTBE), ' 1,2-Di chloro ethane (1,2-DCA), ethylene dibromide (EBD), tertiary butanol (TBA), di- isopropyl ether (DIPE), ethyl tert butyl ether (ETBE), tert amyl methyl ether (TAME) and MTBE by EPA Method 8260B 1 Advanced GeoEnviFOIL I11CF1 W,IIIc 1