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' 16 December 2005 • AGE-NC Project No. 04-1214 Page 5 of 8 1 ; two-inch diameter PVC casing with 0.020-inch slotted screen installed from approximately 20 feet ' to 40 feet bsg with blank casing extended to the surface. The filter pack(No. 3 Lonestar sand).was installed from approximately 18 feet to 40 feet bsg. An approximate 3-foot bentonite chip plug was installed above the filter pack and hydrated.The wells were grouted to near the surface with portland cement. Water-tight, traffic-rated well boxes were installed over the wells. As-built well diagrams are depicted on the boring logs in Appendix A. 3.1.4. Monitoring Well Development ' On 17 October 2005, a Solinst water level meter was used to measure the depth to groundwater in monitoring wells MW-101 through MW-104 relative to the tops ofthe well casings,prior to any well purging. The ground water elevations and gradient were determined from these data,(Table 1). Monitoring wells MW-101 through MW-104 were developed utilizing a stainless steel hand bailer ' and an inertia pump. Ground water was purged from each monitoring well until ground water was visually sediment free. Twenty-four to thirty gallons of water were removed from wells MW-101, MW-103 and MW-104,representing ten volumes of the typical well water column purged from the ' . wells, suggesting adequate recharge in these wells. Ten gallons were purged from MW-102 before the well was pumped dry,representing approximately four volumes of the water column,indicating low recharge rates in this well. Ground water temperature, pH and conductivity were measured at regular intervals during purging using an Oakton water analyzer. Field sheets and data are included In Appendix B. Purged water was stored on-site in properly labeled, 55-gallon Department .of Transportation (DOT)-approved drums. ' 3.2. COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES Ground water samples were collected from the purged wells using new disposable plastic bailers ' after allowing the wells to achieve a minimum 80% recovery of the pre-purge water volume. Each sample was transferred into three 40-milliliter(ml)EPA-approved volatile organic analysis(VOA) vials and three 1-liter amber bottles. Samples were properly labeled,stored in a chilled container and transported udder chain of custody to Cal Tech Environmental Laboratories (CTEL), a California Department of Health Services(DHS)-certified laboratory, for analysis. Each sample was analyzed for: Volatile organic compounds(VOCs)or(benzene, toluene,ethylbenzene,and total xylenes) and fuel oxygenates methyl tertiary-butyl ether (MTBE), tertiary-butyl alcohol (TBA), di- isopropyl ether (DIPS), ethyl tertiary-butyl ether (ETBE), tertiary-amyl methyl ether . (TAME), 1,2-dibromoethane(EDB),and 1,2-dichloroethane(1,2-DCA)in accordance with ' Advanced GeoEnvironmental,Inc.