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lie 20 December 2001 AGE-NC Project No 95-0144 ' Page 4 of 7 ' 3 1 WELL MONITORING AND EVACUATION A Soloist water Ievel meter was used to measure the depth to ground water in 14 monitoring wells at the subject site relative to the tops of the well casings The ground water elevation, flow direction and hydraulic gradient were determined from these data(Table 1) ' After depth to water measurements were recorded, the yells to be sampled were purged using new, disposable bailers Approximately three casing-water volumes of water,(approxi nately 4 to 17 5 gallons) were removed from each of the purged wells Temperature, pH and conductivity of purged ' water were measured at regular purge-volume intervals using a Hydac water analyzer The recorded field data and logs are included in Appendix A All purged water was stored in 55-gallon. DOT- approved drums on-site ' 32 COLLECTION OF GROUND WATER SAMPLES ,The depth to water was remeasured immediately following purging each well to gauge the recharge ' rate and to assure a minimum of 80 percent recharge prior to sampling although three wells (MW-19A,MW-20B and MW-2 I B)were bailed dry and were sampled prior to 80 percent recharge Water samples were collected from,each purged well using new disposable bailers Samples were ' transferred into 40-m1 EPA-approved VOA vials containing 0 5 ml 18% hydrochloric acid as a sample preservative and into 1-liter amber bottles without preservative The samples were labeled, stored on ice and transported under chain-of-custody to McCampbell Analytical, Inc (MAI), a ' California Department of Health ,Services (DHS)-certified analytical laboratory Each sample was analyzed for ' • Total petroleum hydrocarbons quantified as gasoline(TPH-g),total petroleum hydrocarbons quantified as diesel (TPH-d) and total petroleum hydrocarbons quantified as motor oil (TPH-mo) in accordance with EPA Methods 5030/8015 and 3550/8015, respectively, • Benzene, toluene, ethylbenzene and total Xylenes (BTEX) and methyl tertiary-butyl ether (MTBE) m accordance with EPA Method 80201602, and ' • Fuel oxygenated compounds - tertiary butanol(TBA), di--isopropyl ether (DIPS), ethyl tert butyl ether (ETBE), tert amyl methyl ether (TAME) and MTBE by EPA Method 8260M 33 WASTE DISPOSAL ' On 16l 200 gallons of non-hazardous purge water was pumped from s November 200 1, approximately on-site 55-gallon drums The purge water was generated durmg previous ground water monitoring Advanced GeoEnvraninental,Inc