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18 June 2010 <br /> AGE-NC Project No. 95-0135 <br /> Page 6of7 <br /> be continued until field parameter (pH, electrical conductivity, and temperature) readings have <br /> stabilized and purged water is visually sediment-free. Additionally, well-head elevations will be <br /> surveyed by a licensed surveyor. <br /> i 4.4. GROUNDWATER SAMPLING PROCEDURES <br /> Ground water sample collection procedures are outlined below. <br /> I <br /> I <br /> 4.4.1. Static Water Level Measurements <br /> i <br /> Before purging and sampling the ground water monitoring wells,static water level will be measured <br /> using a Solist water level meter. Water level data will be recorded to the nearest 0.01 foot from a <br /> reference point marked of the top of the PVC well casing. Before and after each use, the electric <br /> water level indicator will be washed in-an Alconox solution and rinsed with water. <br /> i <br /> 4.4.2. Well Evacuation <br /> i <br /> Subsequent to measurement of depth to water and prior to sampling, wells will be purged using a <br /> using a Waterra inertia pump and dedicated tubing or disposable polyethylene bailers to ensure the <br /> ground water sample is representative of the formation,rather than water standing in the well casing. <br /> Wells will be purged until: 1)a minimumof three casing volumes is removed from the well;and/or <br /> 2) the field-measured ground water parameters:pH, temperature and electrical conductivity have <br /> stabilized.However,if a well is purged dry prior to evacuating three casing volumes,a ground water <br /> sample will be collected-following 80 percent recovery of ground water level within the well or <br /> 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 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 /> 4.4.3. 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 or with disposable polyethylene bailers, feflon tubing used-with <br /> _ the inertia.-pump is either dedicated,to-each well changed_at each sampling event,thereby <br /> minimizing cross contamination due to sampling devices; disposable bailers are disposed of after <br /> i <br /> i <br /> Advanced GeoEnvironmental,Inc. <br /> I <br /> i <br /> a r <br />