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' Beacon Station No.474 December 23, 1997 StOckt i rf ]n ti i n Repgll definition. Borings B-5 and B-6 were drilled at the north end of the east and west dispenser islands, respectively (Figure 2). ' During drilling, soil samples were collected from each boring at five-foot intervals from the ground surface to the total depth of the boring. Soil samples and cuttings were evaluated for ' the presence of petroleum hydrocarbon vapors with a portable organic vapor meter (OVM). Any evidence of petroleum hydrocarbons was recorded on the soil boring logs which contain ' soil descriptions and well completion data (Appendix D). Soil samples were contained in chilled storage for transport to the laboratory for the requested analyses. Upon completion ' of drilling, a groundwater monitoring well was installed in boring MW-6, MW-7, MW-8 and MW-9. Borings B-5 and B-6 were each completed with three nested soil vapor extraction ' wells. ' The sediments encountered during drilling consisted primarily of silts, sands, and clays. The sediments were classified using the Unified Soil Classification System (USCS). A copy of the USCS is shown on the Boring Log Symbol Key included with the boring logs in ' Appendix D. ' The drill cuttings were screened with an OVM, and four samples were collected from the stockpiled cuttings, composited at the laboratory and analyzed for gasoline-range ' hydrocarbons (Table 1). Analytical results were all below laboratory detection levels, precluding the need for drum containment. All cuttings generated during this study were ' stockpiled on and covered with visqueen sheeting until subsequent disposal by Ultramar. ' Moinitori W I' -Raftuatian The 10-inch diameter soil borings MW-6 and MW-8 were each completed as a 4-inch inside diameter(ID) groundwater monitoring well, while and-the 8-inch diameter soil borings MW= 7 and MW-9 were each completed as a 2-inch ID groundwater monitoring well. Each of the ' four monitoring wells was completed with 20 feet of schedule 40 polyvinyl chloride (PVC) well screen with 0.020-inch factory-machined slots. The bottom of the screened interval, ' 1474-12.rpt 4 HORIZON ENVIRONMENTAL INC.