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23 April 1999 <br /> AGE-NC Project No. 95-0100 <br /> Page 7 of 7 <br /> parameters have stabilized. However, a well is purged dry prior to evacuating three casing volumes, <br /> a ground water sample will be collected following 80 percent recovery of ground water within the <br /> well or within 8-hours of well evacuation. <br /> 4.5.3. Sample Withdrawal <br /> Water samples will be collected from the monitoring well,following 80 percent recovery of ground <br /> water within the well, using-a disposable polyethylene bailer. These bailers are disposed of after one <br /> use and require no decontaminating, therefore 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 /> 4.5.4. Sample Handling <br /> Ground water samples will be collected into laboratory supplied containers. Ground water samples <br /> for BTEX, TPH-g, and oxygenates analyses will be collected into 40-m1 VOA vials containing <br /> 0.5-m1 of hydrochloric acid as preservative. Following collection the samples will be placed on ice <br /> and kept in a cooler until delivered to the laboratory for analysis. Chain-of-custody protocols will <br /> be used to document sample custody transfer from the field to the analytical laboratory. A chain-of- <br /> custody form will accompany the samples: <br /> 4.6. EQUIPMENT DECONTAMINATION <br /> All sampling tools used for sample collection will be thoroughly rinsed with clean water after being <br /> washed with a solution of Alconox. Hollow-stem augers will be steam-cleaned prior to each boring. <br /> All down-hole drilling equipment will be pressure washed prior to starting each boring. <br /> All sampling tools used for ground water sample collection, except for disposable bailers, will be <br /> thoroughly rinsed with clean water after being washed with a solution of Alconox. <br /> Decontamination water generated during the ground water sampling activities will be contained in <br /> DOT-approved drums which will be appropriately labeled for storage. Drums containing <br /> decontamination water will be stored on-site pending appropriate removal and disposal. <br />