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I concentrations of 0.59 milligrams per liter or mg/1 and 0.84 mg/1, respectively. Concentrations of benzene were detected in groundwater samples collected from monitoring wells MW2, MW3 and MW4 at concentrations of 9.5 ug/1, 78 ug/l and 430 ug/l, respectively. The groundwater flow direction was determined to be to the northeast during the June 1993 groundwater sampling event. A total of 23 55-gallon drums containing soil cuttings were generated from drilling operations conducted at the subject site by TMC Environmental, Inc. and McLaren/Hart. The total volume of soil contained within the drums is calculated to be approximately eight cubic yards. 2.0 FIELD ACTIVITIES Mr Michael Collins of San Joaquin County indicated to McLaren Hart that all excavated soil material which was pushed back into the excavation on top of the bottom layer of black plastic sheeting would have to be re-excavated and disposed of at an off-site disposal facility, approved for contaminated soil acceptance, prior to backfilling the excavation. The following sections describe the field activities associated with the soil characterization sampling, excavation procedures, utility repairs and backfilling procedures and repaving. All non-hazardous waste manifests for the transportation and disposal of soil removed from the excavation and removed from the 22 55-gallon drums are included as Appendix I. Site photographs are included as Appendix H. ko Prior to any field work the Health and Safety Plan was updated to reflect the proposed activities at the site The Health and Safety Plan included a task risk analysis and an emergency response plan In addition to the Health and Safety Plan, a utility clearance was conducted by Subtromc Corporation on November 3, 1992 at the excavation location prior to the November 1992 drilling activities. A site plan, Figure 2, was generated delineating the excavation, existing structures and the approximate location of existing underground utilities at the site 2.1 Characterization Soil Sampling and Analyses The soil disposal facility, Landfill, required that characterization soil samples be collected and analyzed from the soil material to be disposed prior to transportation of the soil to the landfill. The landfill required that an eight-part composite sample be collected for every 100 cubic yards of soil proposed for disposal and analyzed for benzene, toluene, ethylbenzene and total xylenes (BTEX) and total petroleum hydrocarbons as gasoline (IPH-G) by the Cahforma LUF17 Method, for volatile organic compounds (VOCs) by EPA Method 8010 and for total petroleum hydrocarbons as diesel (TPH-D) by EPA Method 8015 Modified. The Landfill also requested that an eight-part composite sample be collected for every 500 cubic yards of soil proposed for disposal and analyzed for the total threshold limit concentrations (TTLC) of the CAM 17 metals by EPA Method W10/7000 Series. m121ca2 4