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1.+ hn KLEINFELDER 3 FIELD ACTIVITIES 3.1 DRILLING AND SOIL SAMPLING On September 27 and 28, 1993, eight borings were drilled in the vicinity of the three removed aboveground fuel oil storage tanks (Plates 3 and 4). Kleinfelder contracted Spectrum +- Exploration, Inc. of Stockton to perform the drilling. The borings were drilled to a maximum depth of 31.5 feet below ground surface. The borings were drilled using a truck-mounted drill rig equipped with 6-inch outer diameter hollow stem augers. While drilling, soil samples were collected at approximately 5-foot intervals for FID field organic vapor screening and soil logging. An experienced environmental geologist classified the soil, logged the stratigraphy of the boring, and collected undisturbed soil samples for potential laboratory analysis. A copy of the Unified Soil Classification System used to classify the soil and a log key are provided in Appendix A (Plates A-1 and A-2). Descriptions of the �- soil encountered in each boring and identification of the sampling intervals are also presented in Appendix A (Log of Borings, Plates 3 through A-10). Kleinfelder's Field Procedures for drilling and sampling are provided in Appendix B. Soil encountered in the borings consisted of sand and silty sand from ground surface to approximately 10 feet. Silt and sandy silt extend vertically to between 20 feet and 25 feet. Sand and silty sand reoccurred to the maximum depth drilled of 31.5 feet. Free water was not observed in the soil borings and is estimated to be approximately 35 feet below the ground surface. 3.2 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 (OVA) was used to screen the samples in the field. A Foxboro flame-ionization detector (FID) was used to measure total ionizable compounds in parts per million by volume �- (ppmv) relative to a methane calibration standard. ,r Each sample was screened in the field, and the FID readings were recorded on the boring logs. FID readings were 0 ppmv with the exception of B-4 which had a low FID reading of 0.8 24-220152-EOo/GR1-01(1993 Page 3 of 7 October 27, 1993 Copyright 1993 Kteinfelder I nc.