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of the positive displacement (bladder) pump tubing will be cleaned by heating the tubing <br /> overnight at 120°C with a low-flow, inert air source. <br /> Once the bladder pump is cleaned and reassembled, a pump blank will be obtained by pumping <br /> organic-free water through the bladder pump assembly. The pump effluent will be sampled and <br /> analyzed by USEPA Method 601. The pump effluent analysis results must be below the method <br /> reporting limit for each parameter before the pump is taken to the site for use. <br /> During field sampling, equipment surfaces that are placed in the well or contact groundwater will <br /> be steam cleaned with deionized water before the next well is purged or sampled. <br /> Water-level and Total Well-depth Measurements <br /> Immediately before a monitoring well is purged, the water level and total well depth will be <br /> measured using an electric sounder as described in the previous section, Groundwater Elevation <br /> Survey. The electric sounder will be decontaminated by being rinsed with deionized water after <br /> each use. <br /> Well Purging <br /> Before sampling occurs, standing water in the casing and gravel pack will be purged from the <br /> monitoring well using a dedicated Well Wizard®bladder pump, pneumatic displacement pump, or <br /> Teflon bailer. Monitoring wells will be purged according to the protocol presented in Figure A-1. <br /> In most monitoring wells, the amount of water purged before sampling will be equal to or greater <br /> than four casing volumes. Some monitoring wells are expected to be evacuated to dryness after the <br /> removal of less than four casing volumes. These low-yield monitoring wells will be allowed to <br /> recharge for up to 24 hours. Samples will be taken as soon as the monitoring wells have recharged <br /> to a level sufficient for sample collection. If insufficient water has recharged after 24 hours, the <br /> monitoring well will be recorded as dry for the sampling event. <br /> ' Field measurements will be recorded in a waterproof field logbook. Figure A-2 shows an <br /> example of the water sample field data sheet on which field data are recorded. Field data sheets <br /> will be reviewed by the sampling coordinator after the sampling event is completed. <br /> The pH, specific conductance, and temperature meter will be calibrated each day before <br /> beginning field activities. The calibration will be checked once each day to verify meter <br /> performance. Field meter calibrations will be recorded on a field data sheet(see Figure A-2). <br /> Well Sampling <br /> A Teflon bailer or bladder pump will be the only equipment acceptable for well sampling. When <br /> samples for volatile organic analysis are being collected with a bladder pump, the pump flow will <br /> be regulated to approximately 100 milliliters per minute to minimize pump effluent turbulence and <br /> aeration. Glass bottles of at least 40 milliliters volume and fitted with Teflon-lined septa will be <br /> SAC\SAWES\S&APR0C.D0C-95\w:1 3 <br />