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19 November 1999 AGE-NC Project No. 99-0604 Page 9of10 the measurement device will be washed and rinsed with water. 4.5.2. Well Evacuation Subsequent to measurement of depth to water and prior to sampling, the well will be purged using a submersible pump or a disposable bailer to ensure that the sample is representative of the _ formation_, rather than of water standing in the well casing. The well will be purged until: 1) a minimum of three casing volumes is removed from the well; and/or 2) the field-measured ground water parameters have stabilized. However, if a well is purged dry prior to evacuating three casing - volumes, a ground water sample will be collected following 80 percent recovery of ground water within the well or within 8-hours of well evacuation. 4.5.3. Sample Collection Water samples will be collected from the monitoring well using a disposable polyethylene bailer. These bailers are disposed of after one use and require no decontaminating,thereby minimizing c,o,s _ contamination due to sampling devices. Samples IA1111 be drawn and collected in such a manner that agitation and exposure of the ground water to the atmosphere is minimal. Sample containers will be filled using the appropriate disposable sampling attachment which allows controlled flow out of the bottom of the bailer by lifting up on the check valve. 4.5.4. Sample Handling Ground water samples will bq_ool-lected into laboratory supplied containers. Ground water samples for TPH-g, BTEX an�fitel Oxygenate nalyses will be collected into 40-ml VOA vials containing 0.5 ml hydrochloric acid as presen?ative. Following collection the samples will be placed on ice and kept in a cooler until delivered to the laboratory for analysis. Chain-of-custody forms will be used to document sample custody transfer from the field to the analytical laboratory, and accompany the samples. 4.6. EQUIPMENT DECONTAMINATION All sampling tools used for sample collection will be thoroughly washed with a solution of Alconox and rinsed with clean water prior to use at each sampling location. Hollow-stem augers will be steam-cleaned prior to advancing each pilot boring. Advanced GeoEn%ironmental,Inc.