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21 May 2007 <br /> AGE-NC Project No. 04-1045 <br /> Page 6 of 7 <br /> 3.4. GROUNDWATER SAMPLING PROCEDURES <br /> Ground water sample collection will be performed in accordance with the EHD's Recommended <br /> Groundwater Sampling Guidelines, dated 15 February 1995. <br /> 3.4.1. Static Water Level Measurements <br /> Before purging and sampling during ground water monitoring events, static water level will be <br /> measured using a Solist water level meter. Water level data will be recorded to the nearest 0.01 foot <br /> from a reference point marked of the top of the PVC well casing. Before and after each use, the <br /> electric oil/water level indicator will be washed in an Alconox solution and rinsed with water. <br /> 3.4.2. Well Evacuation <br /> Subsequent to measurement of depth to water and prior to sampling,the well will be purged using <br /> a ueing-(Waterra inertia pump and dedicated tubing to ensure that the ground water sample is <br /> representative of the formation,rather than water standing in the well casing.The well will be purged <br /> until: 1)a minimum of three casing volumes is removed from the well;and/or 2)the field-measured <br /> ground water parameters pH, temperature and electrical conductivity have stabilized. However, if <br /> a well is purged dry prior to evacuating three casing volumes, a ground water sample will be <br /> collected following 80 percent recovery of ground water level within the well or within 8-hours of <br /> well evacuation. <br /> Purge water,free-product,and decontamination water generated during the ground water sampling <br /> activities will be contained in DOT-approved drums which will be appropriately labeled for storage. <br /> Drums containing purge water will be stored on-site pending appropriate removal and disposal. <br /> 3.4.3. Sample Withdrawal <br /> Water samples will be collected from the monitoring well using a dedicated teflon tubing used in <br /> conjunction with the inertia pump. The teflon tubing used with the inertia pump is either dedicated <br /> to each well or changed at each sampling event, thereby minimizing cross contamination due to <br /> sampling devices.Samples will be drawn and collected in such a manner that agitation and exposure <br /> of the groundwater to the atmosphere are minimal. <br /> Advanced GcoEnvironmental,Inc. <br />