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GROUND ZERO ANALYSIS, INC <br /> FIELD PROCEDURES <br /> • <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 wells, <br /> a water sample is collected for subjective analysis from near the water surface in the well with a <br /> Teflon bailer cleaned with a laboratory-grade detergent and deionized water The wells are <br /> typically developed with a surge block and pump Well development continues until the discharge <br /> water is relatively clear of silt and sand Clay-size sediments derived from the screened portion of <br /> the formation cannot be entirely eliminated by well development After the wells are purged of <br /> stagnant water, a sample is collected for laboratory analysis <br /> . Subiective Analysis of Groundwater Samples <br /> Groundwater samples are collected for subjective analysis from dust below the air-fluid interface in <br /> a monitoring well by lowering approximately half the length of a clean Teflon bailer The bailer is <br /> retrieved and the water sample examined for floating product, sheen, odor, color, and clarity <br /> Groundwater Sampling <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 for <br /> 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 80 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 /> containers The recovered fluids from sampling each well are directed into 55-gallon liquid waste <br /> 3 <br /> groundzeltormq\tid-pros,doc <br />