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Alton Geoscience performed the following tasks during this investigation: o Prepared a work plan, acquired the necessary permits and located underground utilities. a Drilled the exploratory soil borings and collected soil samples to investigate subsurface conditions. Installed, developed, sampled, and surveyed three ground water monitoring wells. o Analyzed soil and ground water samples. o Prepared this technical report presenting field activities, laboratory results, findings, and conclusions. 3. 0 FIELD ACTIVITIES Alton Geoscience acquired the appropriate SJCPHD permit on March 17 , 1992 , to install three ground water monitoring wells and drill two exploratory soil borings. A copy of the permit is presented in Appendix B. 3 . 1 Soil Borings On March 27 and 31, 1992 , soil borings AB-1, AB-2 , MW-10, MW-11, an< NW-1,V were drilled onsite. MW-10, MW-11, and MW-12 were instal a as 4-inch-diameter monitoring wells. Ground water was first encountered in the borings at approximate depths of 69 to 70 feet below grade (fbg) . Prior to drilling, each boring was hand excavated to approximately 5 fbg to avoid damage to subsurface structures. Soil. Borings AB-1 and AB-2 were drilled using a drill rig equipped with a 6--inch-diameter hollow-stem auger (HSA) ; MW-10, MW-11, and MW-12 were drilled using 10-inch-diameter HSA. Boring locations are shown in Figure 2 . Soil samples were collected at 5-foot intervals starting at 5 fbg to the total depth of each boring. Soil Boring MW--10 was sampled using a continuous-core sampler from 5 fbg to the total depth of the boring. Samples collected from the borings were selectively analyzed based on combustible gas indicator (CGI) readings above 50 parts per million (ppm) or field observations. Drilling procedures and soil sampling protocol are presented in Appendix C and boring logs in Appendix D. Table I presents a summary of results of soil samples analysis. 2