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On April 9, 1993 , three groundwater monitoring wells and one soil <br /> boring were installed. Soil samples were collected at 5-foot depth <br /> intervals, and selected samples were analyzed for total petroleum <br /> hydrocarbons (TPH as gasoline) , purgeable aromatics (BTE&X) and <br /> total lead. A soil sample was also collected from the previously <br /> excavated soil, which had been stockpiled on-site. <br /> All soil samples were reported as non-detect for total petroleum <br /> hydrocarbons, but BTE&X compounds were detected in one sample from <br /> the soil boring. <br /> Initial groundwater samples indicated contamination in one <br /> monitoring well. However, contamination was not confirmed in the <br /> following two sampling events. <br /> on May 26 and 27, 1993 , approximately 150 cubic yards of <br /> contaminated soil were stockpiled on the north end of the property. <br /> Six samples were collected from the stockpiled soil on July 12 , <br /> 1993 and analyzed for TPH as gasoline and BTE&X. Low levels of TPH, <br /> toluene and xylenes were detected in these samples. <br /> Results of the soil and groundwater investigations were reported in <br /> • the Preliminary Investigation and Evaluation Report (PIER; May <br /> 1993) and the Site Assessment and Groundwater Monitoring Report <br /> (August 1993) , both prepared by GeoAudit. <br /> 2 . 3 Excavation Backfilling <br /> Because of the relatively shallow depth to groundwater (35 feet) <br /> and the total depth of the excavation (28 feet) , the PHS/EHD will <br /> not allow the excavation to be backfilled with contaminated soil. <br /> Treatment of the contaminated soil to remove the petroleum <br /> hydrocarbons will be required before it can be placed back into the <br /> excavation. <br /> 3.0 PROCEDURES <br /> GeoAudit proposes to bioremediate the excavated soil. The <br /> remediation will include the tasks listed below. The biodegradation <br /> process itself is described in a separate attachment. <br /> 1) Prepare a site health and safety plan in accordance with <br /> Occupational Safety and Health Guidance Manual for Hazardous <br /> Waste Site Activities (Prepared by National Institute for <br /> Occupational Safety and Health Administration, U. S. Coast <br /> Guard and US Environmental Protection Agency, 1985. ) <br /> 2) Notify the San Joaquin County Public Health Services - <br /> Environmental Health Division (PHS/EHD) 48 hours prior to work <br /> initiation. <br /> 2 <br />