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currently exists at approximately S 5 feet below grade and the flow has vaned from northwest <br /> to northeast. The most recent gradient is depicted on Figure 3. <br /> 4.0 FIELD ACTIVITIES <br /> To further investigate potential soil and groundwater contamination at the subject site, RESNA <br /> performed the additional work discussed in the following sections All field work was <br /> ' performed in accordance with RESNA's Quality Assurance/Quality Control Plan (QA/QC) and <br /> site specific Health and Safety Plan included in RESNA's workplan addendum dated May 9, <br /> 1994 <br /> ' 4.1 Drillin <br /> On May 13, 1994, nine soil borings were advanced under C57 license by Spectrum Exploration <br /> Inc in the vicinity of the former USTs and dispenser island using a hollow stem auger drill ng. <br /> Drilling was supervised by a RESNA geologist Eight of the borings were advanced in <br /> ` accordance with RESNA's May 9, 1994 workplan addendum, and one additional boring was <br /> advanced under verbal authorization from TJUHSD and Mr Mike Infuma of the PHS/EHD <br /> The borings were drilled to the water table, approximately eight feet below grade, to <br /> characterize the extent of residual petroleum hydrocarbon contamination in soil beneath the site <br /> 1 Soil boring locations are depicted on Figure 2 <br /> ' Drill cuttings were logged by a RESNA geologist for characterization of soil type Subsurface <br /> lithology was characterized according to the Unified Soil Classification System and recorded on <br /> 1 boring logs Soil encountered was monitored for organic vapors by placing a small amount of <br /> representative material in a sealed container, then measuring the concentration of vapors <br /> collected in the head space of the container with a photoionization detector (PID) calibrated with <br /> isobutylene to the benzene standard The values obtained at each measurement point were <br /> ' recorded on the boring logs Soil cuttings generated during the drilling process were stored on- <br /> site with the existing soil stockpile, placed on and covered with 6 ml plastic sheeting To avoid <br /> 1500871R 053194 FNL 3 <br /> 1 <br />