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07 November 2005 . AGE-NC Project No 98-0448 ' Page 2 of 9 ' letter dated 07 April 1999 As-built monitoring well construction details also are summarized in Table 1 ' 2 1 WELL MONITORING AND EVACUATION ' During the September 2005 monitoring event, depth to ground water measurements were collected in monitoring wells MW-1,MW-2 and MW-4 through MW-8 from the top of the well casing to the nearest 0 01-foot utilizing a Solmst water level meter Well MW-3 was inaccessible and was not ' monitored The ground water elevation in each well was calculated by subtracting the measured depth to ground water from the surveyed casing elevation(Table 1) Ground water elevations were plotted and contoured on a scaled site map (Figure 3) ' After water levels were measured, approximately 4 5 to 9 5 gallons of ground water(a minimum of three casing-water volumes per well)were evacuated(purged) from wells MW-1, MW-2,MW-4A Iand MW-6 utilizing polyethylene disposable bailers Approximately 14 gallons of ground water was purged from well MW-4B by lowering and raising a 5/s-inch outer diameter, polyethylene hose equipped with a ball-valve water tip through the screened section A Waterra Hydro-Lift II pump equipped with a mechanical arm was utilized to surge the polyethylene hose 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 provided in Appendix A Purged ground water was containerized in properly labeled Department of Transportation (DOT)-approved 55-gallon drums and was stored on-site in an area lacking general public access 2 2 GROUND WATER SAMPLING IFollowing well purging,the ground water level in each of the purged wells was allowed to achieve a minimum of 80%recharge prior to sample collection Ground water samples were collected from the purged wells utilizing new, disposable polyethylene bailers and 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 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 23 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 Cal Tech Environmental Laboratory (CTEL), a California Department of Health Advanced GeoEnvironmental,Inc I