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r 15 April 2003 AGE-NC Project No. 02-0950 Page 9 of 10 r 4.5.1. Static Water Level Measurements r Before sampling and during groundwater 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 water. r 4.5.2. Well Evacuation Subsequent to measurement of depth to water and prior to sampling, the well will be purged using an inertia pump or a disposable bailer 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 casing-water volumes has been removed from the well; and/or 2) the field-measured ground water parameters,pH,temperature and 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 within the well or after a minimum of 1 hour but within 8 hours of well evacuation. r 4.5.3. Sample Withdrawal r Water samples will be collected from the monitoring well using a disposable polyethylene bailer or a dedicated teflon tubing used in conjunction with the inertia pump.The bailers are disposed of after one use and require no decontaminating and the teflon tubing used with the inertia pump is either dedicated to each well or changed at each sampling event,thereby minimizing cross contamination due to sampling devices. Samples will be drawn and collected in such a manner that agitation and •r exposure of the groundwater to the atmosphere is minimal 4.5.4. Sample Handling Ground water samples will be collected into laboratory-supplied 40-m1 volatile organic analysis (VOA)vials containing 0.5 ml of hydrochloric acid as preservative,one-liter amber glass containers without a sample preservative and 16-oz plastic bottles containing 5 milliliters of nitric acid as a sample preservative. Care will be taken to ensure that visible air bubbles are not present in the vials after filling and capping. Following collection the samples will be appropriately labeled,placed on ice and kept in a cooler until delivered to a DHS-certified analytical laboratory for analysis. Chain- of-custody protocols will be used to document sample custody transfer from the field to the r laboratory; a chain-of-custody form will accompany the samples. �+ Advanced GeoEnvironmental,Inc. r