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209 476 1" ' AsirSOO <br /> 74' <br /> content per Method 8015. Additionally, the wells will be checked <br /> for the presence of floating product. <br /> ,,;::. <br /> In addition to the above mentioned soil and water samples, one <br /> soil and one water sample will be collected in duplicate and <br /> submitted to the lab for quality assurance; the duplicate samples <br /> ` will be indistinguishable from the other samples. Also one <br /> water rinsate blank will be submitted to check the field decon- <br /> tamination procedures. This blank will use distilled water run <br /> through the sampling bailer as an ordinary sample would. <br /> As the anticipated depth to water is 40 feet, a 4 inch diameter <br /> well will be required in order to accommodate a 4 inch submers- <br /> ible pump. If possible, the well will be installed by the use of <br /> 6 inch hollow stem auger drilling rig. However, the bottom of <br /> the well screen is expected to be a depth of about 60 feet which <br /> may be about the depth limit of the larger diameter hollow stem w <br /> augers. It may be beneficial to make a preliminary boring with a <br /> " .A. <br /> 3 3/4 inch hollow stem auger to find the depth to water and the , <br /> presence of any underlying confining layer, and then drilling <br /> with the larger diameter hollow stem auger to install the well. <br /> ' <br /> The well casing and screen will be made from flush jointed <br /> 'S schedule 40 P.V.C. pipe. The well will be completed with a clean <br /> silica sand pack around the well screen to a height of 3 feet <br /> above the top of the well screen. A one foot thick bentonite <br /> a. seal will be placed on the sand pack and the well annulus sealed <br /> to the surface with a 4% bentonite cement grout. As the area <br /> does have a large volume of truck traffic, some of the wells may <br /> t. be completed in a pavement level vault. A survey marker will be <br /> imbedded in the surface of the cement grout seal, and the rela- <br /> tive elevation of each well will be determined by hand leveling. <br /> During drilling of the monitor wells, soil samples will be <br /> collected using a split-spoon sampler lined with brass rings, 7 <br /> decontaminated between samples by scrubbing with a bristle brush <br /> r <br /> in a solution of potable water and detergent (such <br /> M <br /> as Alconox) , followed by potable water rinse with a final spray r <br /> rinse of distilled water. (Augers and drill bits will be steam <br /> y cleaned with potable water between borings) . Those tubes select- , . <br /> ed for chemical analysis will be capped with teflon-sheeting <br /> . covered by plastic end caps, tightly sealed to the tube by <br /> wrapping with an elastic tape such as electrical tape. Tubes. <br /> will then be labeled and placed on ice in an insulated cooler and ;: '. <br /> delivered to the laboratory. <br /> yy The wells will be developed by a combination of swabbing, bail <br /> ing, and pumpage. Development will continue until the well <br /> discharge water is sediment free, or until a total of ='hours of <br /> 7.77 <br /> s. <br />