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08 March 2005 <br /> AGE-NC Project No. 02-0962 <br /> Page 8 of 9 <br /> 4.4. GROUNDWATER SAMPLING PROCEDURES <br /> Ground water sample collection will be performed in accordance CVRWQCB guidelines and the <br /> EHD's Recommended Groundwater Sampling Guidelines, dated 15 February 1995. <br /> 4.4.1. Static Water Level Measurements <br /> Before purging and sampling during ground water monitoring events, static water level will be <br /> measured using an electric water level indicator. Water level data will be recorded to the nearest <br /> 0.01-foot from a reference point marked of the top of the PVC well casing.Before and after each use, <br /> the electric oil/water level indicator will be washed in an Alconox solution and rinsed with water. <br /> 4.4.2. Well Evacuation <br /> After measuring the depth to water and prior to sampling, the well will be purged using a <br /> submersible pump to ensure that the ground water sample is representative of the formation,rather <br /> than water standing in the well casing. The well will be purged until: 1)a minimum of three casing <br /> volumes is removed from the well, and/or 2) the field-measured ground water parameters pH, <br /> temperature, and electrical conductivity have stabilized. However, if a well is purged dry prior to <br /> evacuating three casing volumes, a ground water sample will be collected following 80 percent <br /> recovery of ground water level within the well, or within 8 hours of well evacuation. <br /> Purge water,free-product,and decontamination water generated during the ground water sampling <br /> activities will be contained in Department of Transportation (DOT)-approved 55-gallon drums, <br /> which will be appropriately labeled for storage.Drums containing purge water will be stored on-site <br /> pending appropriate removal and disposal. <br /> 4.4.3. Sample Withdrawal <br /> Water samples will be collected from the monitoring wells using a disposable polyethylene bailer <br /> or dedicated teflon tubing used in conjunction with the inertia pump.The bailers are disposed of after <br /> one use and require no decontamination, and the teflon tubing used with the inertia pump is either <br /> dedicated to each well or changed at each sampling event,thereby minimizing cross-contamination <br /> due to sampling devices. Samples will be drawn and collected in such a manner that agitation and <br /> exposure of the groundwater to the atmosphere are minimal. <br /> Advanced GeoEnvironmental,Inc. <br />