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03,September 2004 <br /> AGE-NC Project No 98-0448 <br />' Page 9 of 13 <br />' 4.0. QUARTERLY GROUND WATER MONITORING AND SAMPLING <br /> A quarterly ground water monitoring event was performed at the site on wells MW-1,MW-2,MW-4 <br />' and MW-6 on 02 July 2004 Ground water monitoring procedures were outlined in the AGE- <br /> prepared Remediallnvestigation/Feasibility Study Work Plan, dated 02 March 1999 and approved <br /> by the San Joaquin County Environmental Health Department (SJCEHD) by letter dated 07 April <br />' 1999 As-built monitoring well construction details are summarized in Table 2 <br /> I41 WELL MONITORING PROCEDURES <br /> On 02 July 2004, depth to ground water was measured in monitoring wells MW-1, MW-2, MW-4 <br />' (A and B)and MW-6 from the top of the well casing to the nearest 0 01-foot utilizing a Solinst water <br /> level meter The ground water elevation in each well was calculated by subtracting the measured <br /> depth to ground water from the surveyed casing elevation(Table 1) Ground water elevations were <br /> plotted and contoured on a scaled site map (Figure 6) <br /> After water levels were measured, approximately 5 to 13 gallons of ground water (a minimum of <br /> three casing-water volumes per well)were evacuated(purged)from wells MW-1,MW-2,MW-4(A <br /> and B)and MW-6 utilizing a polyethylene disposable bailer Temperature,pH and conductivity were <br /> measured for stabilization at regular purge-volume intervals from each well using an Oakton water <br /> analyzer Field data and logs are provided in Appendix J Purged ground water was containerized <br /> in properly labeled Department of Transportation (DOT)-approved 55-gallon drums and stored <br /> Ion-site in an area lacking general public access <br /> I42 GROUND WATER SAMPLING PROCEDURES <br /> Following well purging, the ground water level in each of the purged wells was allowed to achieve <br /> a minimum of 80%recharge prior to sample collection Ground water samples were collected from <br /> the purged wells utilizing new, disposable polyethylene bailers and transferred into 40-m1 EPA- <br /> approved volatile organic analysis(VOA)vials containing 0 5-ml 18%hydrochloric acid as a sample <br /> preservative Care was taken to ensure that visible air bubbles were not present in the vials after <br /> filling and capping Ground water sample containers were labeled with the well designation, date, <br /> time, and sampler's initials <br /> I <br /> Advanced GeoEnviron mental,Inc <br /> I , t <br />