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� 4.0 FIELD INVESTIGATION This section describes the field tasks performed as part of this investigation. Ms. Margaret Lagorio, Lead Senior Registered Environmental Health Specialist (RENS) with SJCEHD, was on-site in February 1996, to monitor drilling activities, grouting procedures, monitoring well construction, and soil and groundwater v sampling. Mr. Harlin Knoll, Senior REHS with SJCEHD, represented Ms. Lagorio during the April 5, 1996, groundwater sampling event. 4.1 SOIL BORING INSTALLATION On February 20 and 21, 1996, four soil borings were drilled on the subject site under the supervision of David Bean, RG, PSI Senior Hydrogeologist, and Christine Gunther, PSI Environmental Specialist. These borings (MW-1, MW-2, MW-3, and SB-4) were drilled in the area of the former UST to determine if soil and/or groundwater petroleum hydrocarbon contamination from the operation of the UST remained on-site. Soil boring MW-1 was drilled upgradient (south) of the former UST location. MW-2 was drilled downgradient (north) of the former UST location, inside the Suburban Propane building. MW-3 was drilled slightly east of the former tankhold. Soil boring SB-4 was drilled at a 30 degree angle through the former tankhold and under the south wall of the building. A drilling location map is presented in Appendix A. The borings were drilled to twenty feet bgs by Gregg Drilling & Testing, Inc., of Martinez, CA, using eight-inch outer diameter (OD) hollow-stem augers. A Simco 2400 drill rig was used for borings MW-1, MW-2, and SB-4. A Mobile B- 53 rig was used to drill MW-3. Boring logs derived from an interpretation of the soil samples are provided in Appendix B. Soil cuttings generated from the borings were placed in 55-gallon drums. The drums were labeled and stored on-site pending laboratory analytical results of the soil samples. PSI will arrange for the disposal of these drums upon closure of this site. 4.2 SOIL SAMPLING Four discrete soil samples were collected from each of the soil borings. One of y these soil samples, taken at or below the top of the water table, was submitted to the laboratory from each boring. Specifically, the depths of the samples submitted for laboratory analysis were: 10.5-11 feet bgs from MW-1, MW-2, and MW-3, and 9-9.5 feet bgs taken from SB-4. Soil samples were taken with a California split spoon sampler containing 2-inch diameter brass sleeves. Upon retrieval of the sampler, the soil-filled brass sleeves were covered with Teflon on each end, capped with polyethylene caps, and labeled. The brass sleeves were 6