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i I 04 February 2000 AGE-NC Project No. 95-0167 Page 7 of 8 recorded to the nearest 0.01 foot from a reference point marked of the top of the PVC well casing. Before and after each use, the electric oil/water level indicator will be washed in an Alconox solution and rinsed with water. 4.3 .2. Well Evacuation Subsequent to measurement of depth to water and prior to sampling, the well will be purged using a submersible pump to ensure that the ground water sample is representative of the formation, rather than 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 pH, temperature and electrical conductivity 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 level within the well or within 8-hours of well evacuation. Purge water, free-product, and decontamination water generated during the ground , water sampling activities will be contained in DOT-approved drums which will be appropriately labeled for storage. Drums containing purge water will be stored on-site pending appropriate removal and disposal. 4. 3 .3 . Sample Withdrawal Water samples will be collected from the monitoring wells using disposable polyethylene bailer. These bailers are disposed of after one use and require no decontaminating, thereby minimizing cross contamination due to sampling devices. Samples will 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. 4.3 .4. Sample Handling Ground water samples will be collected into laboratory supplied containers. Ground water samples to be analyzed for TPH-g, BTEX and fuel additives will be collected into 40-m1 VOA vials containing 0.5-m1 of hydrochloric acid as preservative. Following collection, the samples will be placed on ice and kept in a cooler until delivered to the laboratory for analysis . Chain-of-custody protocols will be used to document sample custody transfer from the field to the analytical laboratory. A chain-of-custody form will accompany the samples. I