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0 <br />PJ9 9390313.00D <br />n <br />polyethylene. All sampling containers will be used only once and <br />discarded after analysis is complete. <br />When use of a positive displacement Teflon and stainless steel bladder <br />pump is required, the pump is cleaned as described above and reassem- <br />bled. Organic -free water is then pumped through to obtain a pump <br />blank. The pump effluent is sampled and analyzed for the indicator <br />compounds trichloroethylene, tetrachlorothylene, benzene, toluene, <br />xylenes, and ethybenzenes; the results of the analysis must be below <br />the instrument detection limit <br />for each parameter before the pump is <br />taken to the site for use. <br />During field sampling, all equipment surfaces that have been placed in <br />a well are cleaned before sampling subsequent wells. This cleaning is <br />performed by steam cleaning the equipment with deionized water. <br />Water -Level and Well Total Death Meal=ments <br />Prior to <br />purging and sampling, the water level in the well will be <br />measured with an electric sounder. A reel -mounted, two -conductor, <br />coaxial cable connects the control panel to the sensor. The water <br />level is measured by lowering the sensor into the well. A low -current <br />circuit is completed when the sensor makes contact with the water, <br />which serves as an electrolyte. The current is amplified and fed into <br />an indicator light and audible buzzer, thus signaling when water has <br />been contacted. A sensitivity control compensates for very saline or <br />conductive water. Cable markings are stamped at 1 -foot increments for <br />depth <br />control. Depth to water measurements are recorded to the <br />nearest 0.01 foot. Well total depth is measured by lower the probe to <br />the bottom of the well. Well total depths are recorded to the nearest <br />0.5 foot. Before and after each use, the sounder will be decontami- <br />nated by steam cleaning. <br />PJ9 9390313.00D <br />n <br />