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<br />measurement in parts per million by volume (ppmv). <br /> <br />Depth to water below the top of casing will then be measured <br />with a decontaminated electronic (Olympic) water level <br />indicator. Measurements will be recorded to the nearest 0.01 <br />foot. <br /> <br />The possible presence of immiscible layers will be evaluated <br />using a decontaminated, clear PVC or Teflon bailer. The <br />presence of light-phase organics ("floaters") will be evaluated <br />first by lowering the bailer to a depth of approximately two <br />feet below the top of the water column in the well. The bailer <br />will then be retrieved and visually examined for immiscible <br />light-phase liquids. If present, the thickness of the <br />immiscible layer will be measured and the liquid decanted and <br />preserved for analysis. <br /> <br />The presence of dense-phase organics ("sinkers") will then be <br />determined by lowering a dual valve bailer to the base of the <br />well. The bailer will then be retrieved and visually examined <br />for immiscible dense-phase liquids. If present, the thickness <br />of the immiscible layer will be measured and the liquid decanted <br />and preserved for analysis. <br /> <br />The total depth of the well below the top of the casing will <br />then be sounded with a water level indicator. Measurements will <br />be recorded to the nearest 0.01 foot. <br /> <br />Well purqing <br /> <br />Using the water level measurements obtained above, three static <br />casing volumes will be calculated. This amount of water will be <br />removed, or purged, from the well prior to sampling. Purging <br />will be accomplished by means of a decontaminated hand bailer. <br />Electrical conductivity, pH and temperature will be monitored at <br />regular intervals during the purging process. For wells that go <br />dry prior to the removal of three casing volumes, the three <br />casing volume requirement will be dropped and the well sampled <br />after three hours. If after three hours the amount of water <br />recharged is less than required for the total sample volume, <br />samples will be collected in the prescribed sequence until the <br />water is exhausted. The well will be sampled again after no <br />more than another three hours to complete the sample suite. <br />Sampling personnel will note that the samples were not collected <br />"simultaneously". <br /> <br />If the headspace measurement indicates the presence of organics <br />or if a light or dense immiscible layer is observed, the purge <br />water will be temporarily stored on-site in covered 55-gallon <br />drums. Disposal alternatives for the stored purge water will be <br />addressed after analysis of the water sample has been received <br />from the laboratory. <br /> <br />6 <br />