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i BOREHOLE DRILLING Boreholes are drilled by a Iicensed drilling subcontractor, using a truck-mounted dnllmg ng equipped with nominal 8-mch-diameter hollow-stem augers During drilling, soil samples for lithologic identification and possible laboratory analysis are collected at five foot intervals in the boreholes Boreholes are drilled to a predetermined depth below the ground surface, are terminated when two consecutive readings indicating hydrocarbons are not present in the soil are collected, or to a depth sufficiently below the groundwater table to allow for proper installation of a groundwater monitoring well To prevent cross contamination during dnUmg, all equipment is steam cleaned prior to and between use at each borehole SOIL SAMPLING DURING DRILLING Soil samples will be collected during the drilling operations for three reasons (1) for field identification of the borehole lithology, (2) for qualitative field screening for the presence of contaminants, and(3)for possible chemical analysis Soni samples will be collected at five foot interN a@s in the borehole The soul samples will be examined in the field and classified according the Unified Soil Classification system In addition to evaluating the borehole lithology, the soil samples will be screened in the field with a photoionization detector (PID) or similar instrument, and the relative permeability of the soil will be qualitatively estimated The lithology, PID reading, and estimated permeability of each sample will be recorded on the borehole log next to the depth interval from which the sample was obtained Selected soil samples will be submitted to a Califorrua Certified analytical laboratory for analysis of total petroleum hydrocarbons as gasoline (TPH-G), and benzene, ethylbenzene, toluene, and xylenes (BETX)using U S Environmental Protection Agency(EPA)Method 5030/8020/8015 Modified Soil samples will be obtained using a 2-inch-diameter by 18-inch-long split-spoon sampler lined with three 6-inch-long thin-walled brass tubes The sampler will be driven its entire length into undisturbed soil, either hydraulically or by a 140-pound drop hammer When the sampler is extracted from the borehole,the brass tubes will be removed and the ends of the tubes will immediately be screened for the presence of hydrocarbons with a PID or equivalent instrument The ends of the selected brass tube will be(1)covered with aluminum foil and plastic caps,which will then be taped with plastic tape to provide an air-tight seal, (2)labeled and placed into up-lock plastic bags, and (3) stored in a cooled ice chest for delivery to the analytical laboratory These procedures minimize the potential for cross contamination and volatilization of volatile organic compounds prior to chemical analysis 241TREP0KMWKPT--1J oc