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in KLEINFELDER 4 FIELD ACTIVITIES Kleinfelder collected a total of twelve (12) soil samples from four soil boring locations on site All of the soil borings were advanced using hollow stem auger Two-inch diameter groundwater monitoring wells were installed in three of the four borings 4.1 Drilling and Soil Sampling The borings were advanced using a truck-mounted drill rig equipped with 8-inch hollow stem augers Soil cuttings from the soil borings were placed adjacent to each boring All borings not used for monitoring well construction were backfilled by pumping a neat cement grout with approximately 2 percent bentonite added to reduce shrinkage �1 While drilling, an experienced environmental engineer or geologist classified the subsurface soil and logged the boreholes A copy of the Unified Soil Classification System used to classify the soil and a log key are provided in Appendix A Descriptions of the sample intervals and the soil encountered in each boring are also presented in Appendix A Kleinfelder's Field Procedures for drilling and sampling are provided in Appendix B A copy of the drilling permit obtained from San Joaquin County is provided in Appendix C Boring B-1 was advanced to a depth of 45 5 feet below grade surface (bgs) Free groundwater was encountered at 45 5 instead of the published depth of 60 feet bgs Because of the photwonization detector (PID) readings present in the samples at that depth, the boring was abandoned immediately in an attempt to avoid contaminant migration into groundwater The boring was abandoned by pumping it from the bottom up with neat ' cement The other three borings (B-2, B-3, and B-4) were advanced to depths of 59 5 feet, 60 feet, and 55 feet respectively Groundwater monitoring wells MW-1, MW-2, and MW-3 were constructed in borings B-2, B-3, and B-4 respectively Generally the soil encountered beneath the site consisted of clays in the upper 5 feet, interbedded sandy clays and silty clays from approximately 5 to 30 feet bgs, sands from approximately 30 to 38 feet bgs, clays from approximately 39 to 47 feet bgs Silty sands from approximately 47 to 52 feet bgs, and clays from 50 feet to the bottom of our borings (approximately 60 feet bgs) 4.2 Qualitative Field Screening To provide a qualitative indication of the presence of volatile organic constituents in the soil and to monitor the constituent concentrations in the breathing zone, a portable organic vapor analyzer was used to screen the samples in the field A photo-ionization detector (PID) was used to measure total ionizable compounds in parts per million by volume (ppmv) of vapor Soil samples obtained were screened in the field, and the PID readings were recorded on the boring logs PID readings ranged from 0 to 2,000 ppmv Hydrocarbon odors were present in most of the soil samples except those from sample No 84382 MW-3 ETH and wc194 Copyright 1994 Kleinfelder, Inc Page 6 of 11