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-GROUND ZERO ANALYSWINC. %..1 <br /> FIELD PROCEDURES <br /> Measurement of the Depth to Groundwater in Monitoring Wells <br /> The depth of the groundwater surface in a monitoring well is measured from the top of the well <br /> casing to the nearest 0.01-foot with a Solinst or similar electric water-level indicator. The well is <br /> vented to the atmosphere before obtaining depth-to-water measurements. Venting is conducted <br /> to allow the groundwater to equilibrate to barometric pressure. These measurements are used to <br /> evaluate the elevation of the groundwater surface in each well and the slope of the groundwater <br /> surface across the site. <br /> Well Development <br /> Ground Zero typically waits minimum of 24 hours after well installation before developing the <br /> groundwater monitoring wells to allow the grout to seal. Before developing the monitoring <br /> wells, a water sample is collected for subjective analysis from near the water surface in the well <br /> with a Teflon bailer cleaned with a laboratory-grade detergent and deionized water. The wells <br /> are typically developed with a surge block and pump. Well development continues until the <br /> discharge water is relatively clear of silt and sand. Clay-size sediments derived from the <br /> screened portion of the formation cannot be entirely eliminated by well development. After the <br /> wells are purged of stagnant water, a sample is collected for laboratory analysis. <br /> Subieetive Analysis of Groundwater Samples <br /> Groundwater samples are collected for subjective analysis from just below the air-fluid interface <br /> in a monitoring well by lowering approximately half the length of a clean Teflon bailer. The <br /> bailer is retrieved and the water sample examined for floating product, sheen, odor, color, and <br /> clarity. <br /> Groundwater Sam lin <br /> The static water level in each well is measured to the nearest 0.01-foot with a Solinst or similar <br /> electric water-level indicator cleaned with a laboratory grade detergent and deionized water <br /> before use in each well. A clean bailer is used to obtain a sample from the surface of the water <br /> for subjective analysis. <br /> Approximately 3 to 5 well volumes are purged from each well with a stainless-steel electric <br /> submersible pump or dedicated bailer to allow sampling of representative formation water. The <br /> pump, cables, hoses, and bailers are cleaned with a laboratory grade detergent and water before <br /> use in each well. The wells are purged until pH, temperature and electrical conductivity of the <br /> water stabilizes, as measured by portable meters calibrated to a standard buffer and conductivity <br /> standard. The water level is allowed to recover to at least SO percent of the initial water level <br /> prior to sampling. <br /> A sample of the formation water is then collected from the surface of the water in each of the <br /> wells with a dedicated disposable bailer and slowly transferred to laboratory-cleaned sample <br /> 3 <br /> groundzelformslfld-pros.doc <br />