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GROUND ZERO ANALYSIS, INC FIELD PROCEDURES ' Measurement of the Depth to Groundwater in Monitoring Wells s The depth of the groundwater surface in a monitoring well is measured from the top of the well casing to the nearest 0 01-foot with a Solinst or similar electric water-level indicator The well is vented to the atmosphere before obtaining depth-to-water measurements Venting is conducted ' to allow the groundwater to equilibrate to barometric pressure These measurements are used to evaluate the elevation of the groundwater surface in each well and the slope of the groundwater surface across the site ' Well Develo meet ' Ground Zero typically waits minimum of 24 hours after well installation before developing the groundwater monitoring wells to allow the grout to seal Before developing the monitoring wells, a water sample 1s collected for subjective analysis from near the water surface in the well with a ' Teflon bailer cleaned with a laboratory-grade detergent and delomzed water The wells are typically developed with a surge block and pump Well development continues until the discharge water is relatively clear of silt and sand Clay-size sediments derived from the screened portion of ' the formation cannot be entirely eliminated by well development After the wells are purged of stagnant water, a sample is collected for laboratory analysis ' Sub'ective Analysis of Groundwater Samples Groundwater samples are collected for subjective analysis from just below the air-fluid interface in a monitoring well by lowering approximately half the length of a clean Teflon bailer The bailer is retrieved and the water sample examined for floating product, sheen, odor, color, and clarity tGroundwater Sam lin ' The static water level in each well is measured to the nearest 0 01-foot with a Solmst or similar electric water-level indicator cleaned with a laboratory grade detergent and delonized water before use in each well A clean bailer is used to obtain a sample from the surface of the water for ' subjective analysts Approximately 3 to 5 well volumes are purged from each well with a stainless-steel electric submersible pump or dedicated bailer to allow sampling of representative formation water The pump, cables, hoses, and bailers are cleaned with a laboratory grade detergent and water before use in each well The wells are purged until pH, temperature and electrical conductivity of the ' water stabilizes, as measured by portable meters calibrated to a standard buffer and conductivity standard The water level is allowed to recover to at least 80 percent of the initial water level ' prior to sampling A sample of the formation water is then collected from the surface of the water in each of the wells with a dedicated disposable bailer and slowly transferred to laboratory-cleaned sample containers The recovered fluids from sampling each well are directed into 55-gallon liquid waste drums approved for this use by the Department of Transportation until suitable disposal options ' 3 groun&elfonnslfld-proc doe