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*WVV yaw 20 December 2000 AGE-NC Project No. 95-0100 Page 7 of 8 4.3. GROUNDWATER SAMPLING PROCEDURES Groundwater sample collection will be performed in accordance with pertinent applicable sampling protocols, details of which are presented below. 4.3.1. Static Water Level Measurements Before sampling and during quarterly ground water monitoring, static water level will be measured using an electric water level indicator. Water level data will be 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 measurement device will be rinsed with detergent and with water. 4.3.2. Well Evacuation After measurement of depth to water and prior to sampling, the upper water in the well will be purged using a disposable bailer or pump to ensure that the 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 to five well-casing, water volumes have been removed from the well; and/or 2) the field-measured ground water parameters have stabilized. However, if well is purged dry prior to evacuating a minimum of three well-casing water 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. Ground water generated during the ground water sampling activities will be contained in DOT-approved drums which will be appropriately labeled for storage. Drums containing ground water will be stored on-site pending appropriate removal and disposal. 4.3.3. Sample Withdrawal Water samples will be collected from the monitoring well, following 80 percent recovery of the initial ground water level within the well, using a 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.