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54NSEI5116S 1p,1.INH£i'I7G11110N 1*--UL'f5 RE10" 1505 Soul^21 Damao,Stotaton,Catdornia - - 3.0 RESULTS 3.1 Soil Baring and Sail sampling On July 2 and 3, 1991, three 10-inch-diameter soil borings (MW-1, MW-2, and MW-3) (" were drilled or site by West Hazmat Drilling Company of Rancho Cordova, C2lifornia (Figure 2). The borings were drilled using a Model CME-75 drill rig under the supervision p of Aes3.'ls personnel. All three borings were drilled to a depth of 55 feet below surface. Soil samples were collected from each boring at 5-foot intervals for hydrogeologic descriptions and possible laboratory analyses. The soil samples were analyzed for TPPH :t as gasoline, BTEX, EDB, and EDC by CAL DHS(l'PH draft and EPA Method 8240/6260. In ad-Jition, the soil samples collected from the drill cuttings were analyzed for organic ,r lead. The laboratory analytical reports and chain-of-custody forms are located in Appendix B. The soils and alluvial materials encountered during the drilling consisted of silty clays from ;n 1 to approximately 25 feet below surface; sand from approximately 25 to 31 feet below surface; silty clays and clayey silts from 31 to 49 feet below surface; sands from r x approximately 49 to 55 feet below surface with soil boring termination in sandy and silty k: clays at 55 to 56.5 feet below surface. Groundwater was encountered during drilling at approximately 46 feet below surface in 4. each of the borings. Soil boring logs are included in Appendix C. Petroleum odors were not present in any soil samples. Measurements for organic vapors �• froon soil samples collected on the PID from soil boring 'l (MW-1) ranged from 0 to 45 ppm; soil boring 2 (MW-2) ranged from 0 to 200 ppm, and soil boring 3 (MW-3) ' indicated readings at 0 ppm. The PID readings are recorded on the soil boring logs located in Appendix C. a 3.2 Groundwater Monitoring Well Installation and Develo meet Four-inch-diameter wells were installed in each boring. The three wells were installed in similar fashion, with the screened interval extending from 35 to 55 feet below surface. The top of the screened interval was placed in silt above the top of static water by approximately 10 feet to allow for groundwater level fluctuations. Refer to Appendix C for wall completion details. The well screen slot size is 0.01 inch and the filter pack material is composed of i2/12 Lonestar sand. All three wells were developed on July 3, 19911, using a drill-truck operated surge block and pump. Ei