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Well Purging <br /> ' Before the sampling event, a bladder pump, pneumatic displacement pump, or <br /> Teflon bailer will be used to purge standing water in the casing and gravel pack <br /> from the monitoring well Monitoring wells will be allowing for stabilization of pH, <br /> conductivity and temperature prior to sampling In most monitoring wells, the <br /> amount of water purged before sampling will be greater than or equal to four <br /> ' casing volumes Some monitoring wells are expected to be evacuated to dryness <br /> after removing fewer than four casing volumes These low-yield monitoring wells <br /> will be allowed to recharge for up to 24 hours Samples will be taken as soon as <br /> ' the monitoring wells have recharged to a level sufficient for sample collection If <br /> insufficient water has recharged after 24 hours, the monitoring well will be <br /> recorded as dry for the sampling event <br /> Field measurements will be recorded in a waterproof field logbook Field data <br /> rP g <br /> sheets will be reviewed for completeness by the sampling coordinator after the <br /> ' sampling event is completed <br /> The pH, specific conductance, and temperature meter will be calibrated each day <br /> before field activities begin The calibration will be checked once each day to <br /> verify meter performance Field meter calibrations will be recorded on a Field <br /> NMeter Log <br /> Well Sampling <br /> ' A Teflon or disposable polyethylene bailer or bladder pump will be the only <br /> equipment acceptable for well sampling When samples for volatile organic <br /> ' analysis are being collected, the pump flow will be regulated at approximately 100 <br /> milliliters per minute to minimize pump effluent turbulence and aeration Glass <br /> bottles of at least 40-milliliters volume and fitted with Teflon-lined septa will be <br /> ' used in sampling for volatile organics These bottles will be filled completely to <br /> prevent air from remaining in the bottle A positive meniscus forms when the bottle <br /> is completely full A convex Teflon septum will be placed over the positive <br /> ' meniscus to eliminate air After the bottle is capped, it is inverted and tapped to <br /> verify that it contains no air bubbles The sample containers for other parameters <br /> will be filled, filtered as required, and capped <br /> ' When required, dissolved concentrations of metals will be determined using <br /> appropriate field filtration techniques When a bailer is used, the sample will be <br /> 1 <br /> ' C-4 <br /> r <br />