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i <br /> Before well development procedures are initiated, the water level and well <br /> ' total depth are measured using the procedures described under Sample <br /> Collection, below. <br /> A surge block is then used to swab the screened interval of the well. A <br /> ' surge block is a rubber disk the size of the inside diameter of the well <br /> casing between two metal plates attached to a length of polyvinyl chloride <br /> pipe. The up and down swabbing motion causes the ground water to move <br /> ' in and out through the screened casing, removing any obstructive silts or <br /> sand bridging that is likely to have occurred while drilling the well. After <br /> ' swabbing the well screened interval with the surge block, ground water and <br /> any accumulated silts or sands, or both, are removed by pumping or bailing. <br /> Equipment used to develop wells is cleaned using the procedures described <br /> ' below. <br /> Sample Collection <br /> Sample collection procedures include equipment cleaning, water-level and <br /> total well-depth measurements, and well purging and sampling. <br /> Equipment qu pment Cieaning <br /> Sample bottles, caps, and septa used in sampling for total petroleum <br /> hydrocarbons as gasoline (TPHG) and diesel were triple rinsed with <br /> high-purity deionized water. After being rinsed, sample bottles were dried <br />' overnight at a temperature of 200°C. Sample caps and septa were dried <br /> overnight at a temperature of 60°C. Sample bottles, caps, and septa were <br /> protected from solvent contact between drying and actual use at the <br /> sampling site. Sampling containers were used only once and discarded after <br /> analysis was complete. <br />' Before the sampling event was begun, equipment that was to be placed in <br /> the well or would come in contact with ground water was disassembled and <br /> cleaned thoroughly with detergent water, and then steam cleaned with <br />' deionized water. Any parts that could have absorbed contaminants, such <br /> as plastic pump valves, bladders, etc., were cleaned as described above, <br /> or replaced. <br /> During field sampling, equipment surfaces that were placed in the well or <br /> contacted ground water were steam cleaned with deionized water before <br /> the next well was purged or sampled. <br /> pjO\Of9010f900020.1 ag D - 2 Rev. 0 December 15, 1992 <br />