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's" +' —lir ,Ir _ EEO 01 <br /> WE <br /> g y k <br /> During sampling, the geologist used a field photoionization detector (PID) to characterize <br /> the relative levels of hydrocarbons. Field instruments such as the PIU are useful for <br /> indicating relative levels of hydrocarbon vapors, but do not detect the concentration of <br /> hydrocarbons present with the same precision as laboratory analyses. One of the sampies <br /> in brass sleeves nOL selected for laboratory analysis at each sampling interval was testes in <br /> the field using an PID. This testing was performed by placing the intake probe of the PID <br /> against the soil after opening the brass container. <br /> Logging of Barings <br /> Soil cuttings and samples were logged using the Unified Soil Classification System. Samples <br /> not selected for chemical analysis and the soil in the sampler shoe were extruded in the field <br /> and examined using visual and manual methods. Logs include records of texture, color, <br /> P=+ moisture, plasticity,consistency,blow counts,:+•,d any other characteristics noted along with <br /> evidence for the presence of hydrocarbons such as soil staining, obvious product odor, and <br /> PID readings. After terminating the borings, they were backfilled using a tremic pipe with <br /> a cement-bentonite slurry to surface grade. <br /> Drill Cuttings <br /> Drill cuttings evaluated as having hydrocarbon conce:urations greater than 100 parts per <br /> million were separated fron-, those evaluated as having less than 100 parts per million. <br /> Evaluation was based either on snit discoloration or on measurements made using a <br /> photoionization detector or similar instrument. Readings were taken by placing the intake <br /> probe of the instrument near the soil in the brass sleeve promptly after opening the sampler. <br /> The drill cuttings from the borings drummed in the December 1988 event were placed on <br /> and covered with plastic sheeting in the May 1990 event. <br /> Ground-Nater Monitoring Well Construction <br /> The wells were constructed using clean 2-inch-inner-diameter, thread-jointed, Schedule 40 <br /> polyvinyl chloride (PVC) casing. No chemicals, glues, or solvents were used in well <br /> construction. The screened portion of the well consisted of factory-perforated casing with <br /> 0.020-inch-wide slots and extended from the total depth of the boring to about 10 feet below <br /> grade. Solid Casing was set from the top of the screen to several inches below surface grade. <br /> AAp/ied GeDS,ystems <br />