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27 October 2000 <br /> AGE-NC Project No. 98-0497 <br /> Page 5 of 8 <br /> 3.6. MONITORING WELL PURGE PROCEDURES <br /> Ground water sampling of the on-site wells was conducted on 23 August 2000. For the sampling <br /> event, a Solinst water level meter was used to measure the depth to ground water in the three <br /> monitoring wells relative to the tops of the well casings. The ground water elevations and gradient <br /> were detemiined from these data (Table 1). <br /> After depth to ground water measurements, a minimum of 3 standing casing water volumes was <br /> purged from each well to be sampled using a PVC submersible two-stage pump. Eight gallons of <br /> water were removed from each well.Temperature,pH and conductivity of purged ground water were <br /> measured at 2-gallon intervals using a Hydac water analyzer. The field data and field sheets are <br /> included in Appendix B. Purged water was temporarily stored on-site in 55-gallon DOT-approved <br /> H-17 storage drums pending proper disposal. Following purging, the depth to ground water was <br /> measured to ensure that a minimum of 80% well-volume recharge had been achieved prior to <br /> sampling. <br /> 3.7. GROUND WATER SAMPLE COLLECTION <br /> A water sample was collected from each well using a new, clean, disposable plastic bailer. <br /> Immediately upon retrieval, samples were transferred into three 40-m1 EPA-approved VOA vials <br /> -- containing 0.5 ml 18% hydrochloric acid as a sample preservative and into one-liter amber bottles <br /> without the preservative. The samples were logged on a chain-of-custody form, stored in a chilled <br /> container and transported under chain-of custody to Castle Analytical Laboratory(CAL). Samples <br /> were also transported in a chilled container under chain-of-custody by CAL to MAI for EPA Method <br /> 8260 analysis. Both laboratories are California Department of Health Services (DHS)-certified. The <br /> ground water samples were analyzed in accordance with: <br /> • EPA Method 8015M modified for TPH-g; <br /> y • EPA Method 8015M for TPH-d; <br /> EPA Method 8020 for BTEX and MTBE; and <br /> EPA Method 8260M modified for DIPE, ETBE, MTBE, TBA, TAME, methanol, and <br /> ethanol, EDB and 1,2-DCA. <br /> Advanced Geo Environmental,Inc. <br />