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18 June 2001 <br /> AGE-NC Project No. 98-0433 <br /> Page 7of8 <br /> a reference point marked of the top of the PVC well casing. Before and after each use, the <br /> measurement device will be rinsed with water. <br /> 3.5.2. Well Purging <br /> Subsequent to measurement of depth to water and prior to sampling,the water in the well casing will <br /> be purged using a disposable bailer or pump to ensure that the sample is representative of the <br /> formation,rather than water standing in the well casing. The well will be purged until: 1) a minimum <br /> of three casing volumes is removed from the well; and/or 2) the field-measured ground water <br /> parameters have stabilized. If a well is purged dry prior to removal of three casing volumes,a ground <br /> water sample will be collected following 80 percent recovery of ground water level within the well <br /> or within 8-hours of purging the well. <br /> 3.5.3. Sample Collection <br /> Water samples will be collected from the monitoring well, following 80 percent recovery of ground <br /> water level within the well,using a disposable polyethylene bailer.These bailers are disposed of after <br /> one use and require no decontaminating, thereby minimizing cross contamination due to sampling <br /> devices. Samples will be drawn and collected in such a manner that agitation and exposure of the <br /> groundwater to the atmosphere is minimal. Sample containers will be filled using the appropriate <br /> disposable sampling attachment which allows controlled flow out of the bottom of the bailer by <br /> lifting up on the check valve. <br /> 3.5.4. Sample Preservation <br /> Ground water samples will be collected and transferred into laboratory supplied containers. Ground <br /> water samples for TPH-g, BTEX and fuel additive compounds will be collected into 40-m1 VOA <br /> vials containing 0.5-m1 of hydrochloric acid (18%) as preservative. Samples may also be collected <br /> for TPH-d analysis in 1-liter amber glass containers without a preservative. Following collection the <br /> samples will be placed on ice and kept in a cooler until delivered to the laboratory for analysis. <br /> Chain-of-custody protocols will be used to document sample custody transfer from the field to the <br /> analytical laboratory. A chain-of-custody form will accompany the samples. <br /> Advanced GeoEnvironmental,Inc. <br />