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<br /> Well purging <br /> <br /> Using the water level measurements obtained above, three static casing volumes .will be <br /> calculated. This amount of water will be removed, or purged, from the well prior to sampling. <br /> Purging will be accomplished by means of a decontaminated hand bailer. Electrical <br /> conductivity, pH and temperature will be monitored at regular intervals during the purging <br /> process. For wells that go dry prior to the removal of three casing volumes, the three casing <br /> volume requirement will be dropped and the well sampled after three hours. If after three <br /> hours the amount of water recharged is less than required for the total sample volume, <br /> samples will be collected in the prescribed sequence until the water is exhausted. The well will <br /> be sampled again after no more than another three hours to complete the sample suite. <br /> Sampling personnel will note that the samples were not collected "simultaneously", <br /> Sample collection <br /> A decontaminated, bottom-fill Teflon bailer will be used for each well sample collection. To <br /> minimize the potential loss of volatile organics, the following parameter collection sequence <br /> will be followed: <br /> 1) Volatile organic compounds <br /> 2) Total organic carbon <br /> 3) Semi-volatile organic compounds <br /> 4) General chemistry <br /> 5) Trace metals <br /> All sample containers will be completely filled to the top to minimize headspace. Clean <br /> sample containers will be supplied by the laboratory. Containers will be labeled at the <br /> respective well location using a permanent marker. <br /> Sample aliquots for major cations will be filtered through a 0.45 micron filter and acidified <br /> with reagent grade nitric acid in the field to a pB less than 2. <br /> Temperature, electrical conductance and pH will be obtained from each well immediately after <br /> the last sample is collected. Instruments used for field measurements will be calibrated each <br /> day prior to use. Sampling personnel will also note the color, visual observation of turbidity or <br /> sediment and additional comments concerning the sample. <br /> Field quality assurance samples <br /> The following field quality assurance (QA) sampling scheme will be conducted for each <br /> sampling event. The QA samples will be analyzed (in addition to all original samples) and will <br /> be used to check sampling methodology. <br /> Field QA samples will include a trip blank and sampling equipment rinsate blank, both <br /> analyzed for volatile organics only. Trip blanks consist of a water sample provided by the <br /> 2 <br />