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12 April 2006 . AGE-NC Project No. 97-0301 ' Page 2 of 7 2.1. WELL MONITORING AND PURGING On 20 December 2005, depth to ground water was measured in wells MWA, MW-2 and MW-4 through MW-12 from the top of the well casing to the nearest 0.01-foot utilizing a Solinst water level meter. I ' On 20 December 2005, single-completion monitoring wells MWA,MW-2, MW-4 acid MW-7 and multi-level monitoring wells MW-8 through MW-12 were purged by lowering and raising a.length- discrete polyethylene hose ( 3/8-inch on CMT and %-inch in 2-inch wells), equipped with a ball- valve water tip through the top chambers into the specific water-charged screened section.A Waterra Hydro-Lift 11 pump equipped with a mechanical arm was utilized to surge each well with 3/a-inch diameter polyethylene hose.Approximately 2.25 to 27 gallons of ground water(a minimum of three t casing-water volumes per well)were purged from single-completion wells MW-1, MW-2,MW-4, MW-5, MW-6 and MW-7 and approximately 0.30 to 3 gallons were purged from multi-level wells MW-8 through MW-12. 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. All purged ground water ,was transferred to Department of Transportation (DOT)-approved model 17H 55-gallon drums and stored on-site in an area Iacking ' . general public access. J 2.2. GROUND WATER SAMPLING After each well was purged, ground water levels were re-measured to verify the amount of ground I ' water recharge. Upon achieving at least 80% ground water recharge, samples were collected from wells MW-1,MW-2 and MW-4 through MW-12,utilizing the techniques described above in purging ' each well. Ground water samples from each well were transferred into three 40 milliliter(ml)EPA- approved volatile organic analysis (VOA) vials containing 0.5 ml 18%hydrochloric acid solution as a sample preservative and one i-liter amber bottle without 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. 2.3. LABORATORY ANALYSIS OF GROUND WATER SAMPLES ' Following collection and labeling,each ground water sample was logged on a chain of custody form, placed in a chilled container, and transported to Cal Tech Environmental Laboratories (CTEL), a California Department of Health Services (DHS)-certified laboratory, for analysis for: ' Advanced GeoEnvironmental,Inc. I