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' 19 January 2004 iAGE-NC Project No 95-0130 ' Page 2 of 6 ' were subsequently repotted as `dry' The ground water elevation at wells MW-1 through MW-7, 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 I Ground water elevations were plotted and contoured on a scaled site map (Figure 3) After water levels were measured, approximately 1/2 to 18 gallons of ground water (a minimum of three casing-water volumes per well) were purged from wells MW-1 through MW-7, VW-1C, VW-2A and VW-3A by lower ing and raising a 3/8-inch outer diameter,length-discrete polyethylene hose equipped with a ball-valve water tip through the specific water-charged screened section A Watera-Hyde o-Lr ft II pump equipped with a mechanical arm was utilized to surge the polyethylene hose Temperatui c, 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 I Multi-level well purged ground water was transferred to 55-gallon drums and stored on-site in an area lacking general public access 22 GROUND WATER SAMPLING � . Ground water samples were collected from purged wells utilizing 3/8-inch diameter polyethylene tubing Giound water 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 Iensure that visible air bubbles were not present to 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 watct sample was logged on a ch at n-of-custody form,placed in a chilled container and transported to a California Department of Health Services (DHS)-certified laboratory for analysis Ifor • Total petroleum hydrocarbons quantified as gasoline (TPH-g) by EPA Methods 5030/8015 Modified, • Benzene,toluene,ethylberizerie and xylene(BTEX)and methyl-tet tiary butyl ether(MTBE), 1,2-Dichloroethane (1,2-DCA), ethylene dibromide (EBD), tertiary butanol (TBA), di- isopropyl ether (DIPE), ethyl cert butyl ether (ETBE), tert amyl methyl ether (TAME) and MTBE by EPA Method 8260B I Advanced CeoEnvironmentai,Inc I