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05 June 2008 <br /> AGE-NC Project No. 95-0141 <br /> Page 7 of 8 <br /> a submersible pump to finish the removal of fine-grained sediment.Developmental purging activities <br /> will be continued until field parameter(pH,electrical conductivity,and temperature)readings have <br /> stabilized and purged water is visually sediment-free. The proposed well will be surveyed relative <br /> to the closest City of Stockton benchmark by a licensed surveyor. <br /> 3.6. GROUND WATER SAMPLING PROCEDURES <br /> Ground water sample collection will be performed in accordance with the EHD's Recommended <br /> Groundwater Sampling Guidelines, ated 15 ruF�ary -CJS —) k <br /> 3.6.1. 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 at 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 /> 3.6.2. Well Evacuation <br /> Subsequent to measurement of depth to water and prior to sampling,the well will be purged using <br /> an inertia pump or submersible pump to ensure that the ground water sample is representative of the <br /> formation, rather than water standing in the well casing. Each well will be purged until: 1) a <br /> minimum of three casing volumes is removed from the well; and/or 2) the field-measured ground <br /> water parameters pH,temperature and electrical conductivity have stabilized.However,if a well is <br /> purged dry prior to evacuating three casing volumes, a ground water sample will be collected <br /> following 80 percent recovery of ground water level within the well, or within 8 hours of well <br /> 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 /> 3.6.3. Sample Withdrawal <br /> Water samples will be collected from the monitoring well using a disposable polyethylene bailer or <br /> dedicated Teflon tubing used in conjunction with a Waterra inertial pump.The bailers are disposed <br /> Advanced GeoEnvironmental,Inc. <br />