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1 25 February 2005 AGE-NC Project No 96-0229 ' Page 2 of 6 ' After water levels were measured, approximately 2 5 to 9 5 gallons of ground water(a minimum of three casing-water volumes per well) were evacuated (purged) from wells MW-3 through MW-12 utilizing disposable bailers Approximately 6 0 gallons and 2 0 gallons were removed from wells I MW-1 and MW-2,respectively before the wells were purged dry Temperature,pH,and conductivity were measured for stabilization at regular purge-volume intervals from each well using an Oakton water analyzer Field data and logs are included in Appendix A Purged ground water was ' containerized in 55-gallon drums and stored on-site in an area lacking general public access Approximately 0 15 to 3 0 gallons of ground water(a minimum of three casing-water volumes per ' well) were purged from multi-level wells MW-13 (A-D), MW-14 (A-D), MW-15 (A-D), MW-16 (A-E),MW-17(A-C),MW-18(B-E),and MW-19(A-C) Approximately 0 04 gallons were removed from well MW-18A before the well was purged dry Each well was purged by lowering and raising ' a 3/8-inch outer diameter, length-discrete polyethylene hose equipped with a ball-valve water tip through the top chambers into the specific water-charged screened section A Waterra Hydro-Lift R pump equipped with a mechanical arm was utilized to surge each well with a polyethylene hose Temperature,pH,and conductivity were measured for stabilization at regular purge-volume intervals from each well,with the exception of MW-I 8A, using an Oakton water analyzer Field data and logs • are included in Appendix A Purged ground water was containerized in 55-gallon drums and stored on-site in an area lacking general public access 2 1 1 Ground Water Sampling Following well purging,the ground water level from each well was allowed to achieve a minimum of 80%recharge prior to sample collection Ground water samples were transferred into 40-milliliter (ml)EPA-approved volatile organic analysis(VOA)vials containing 0 5 ml 18%hydrochloric acid solution 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 2 1 2 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 SW5030/8015M, • Benzene, toluene, ethylbenzene, and xylenes (BTEX) by EPA Method 8260B, and ■ Advanced GeoEnvironmental,Inc I