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ASSOCIATES I NC . I pits were backfilled with native material. Petroleum hydrocarbons were detected in the fifth test pit starting at a depth of approximately four feet bgs. In an attempt to define the extent of the spill, impacted soil was excavated until the sidewalls of the pit exhibited no evidence of petroleum hydrocarbons. Soil was excavated to a depth of approximately 14 feet bgs, the estimated depth to ' groundwater. ATC collected confirmation samples from the excavation sidewalls and bottom. A grab sample was collected from the groundwater after it seeped into the excavation. Excavated soil was stockpiled on visquene plastic on site. Analytical results indicated the presence of petroleum hydrocarbons in soil collected from the ' bottom of the excavation and in the grab groundwater sample. Soil and groundwater analytical results are summarized in Tables 1 and 2, respectively. ' 2.0 PURPOSE AND CLEANUP OBJECTIVES ' The purpose of the site investigation performed was to try and define the lateral and vertical extent of impacted soil and groundwater. The purpose of the interim remediation performed was to attempt to remove the vertical extent of impacted soil in an effort to expedite remediation of the impacted soil and groundwater in the vicinity of the surface spill. Results of the interim remediation will be used to evaluate alternatives for a final remediation plan to reduce ' concentrations in soil and groundwater to levels which protect human health, safety and the enviroment. ' 3.0 METHOD AND PROCEDURES All work described herein was performed in accordance with ATC's Workplan for Site 9' Investigation and Remediation at the D'Arcy Parkway Road Extension Site, Lathrop, California, dated March 30, 1998, which was approved with minor modifications by PHS/EHD. The scope of work included obtaining permits, excavating the vertical extent of impacted soil, groundwater extraction, advancing four soil borings using direct push technology, soil and grab groundwater sampling, and the laboratory analysis of selected soil and groundwater samples. 1 3.1 Interim Remediation On April 2, 1998, ATC conducted additional excavation to remove the vertical extent of impacted soil in an effort to expedite remediation of the impacted soil and groundwater in the vicinity of the surface spill. Excavation was performed by Stokley Construction. Initially, groundwater in the pit was at a depth of approximately 9 feet bgs. Evergreen Environmental extracted approximately 500 gallons of groundwater from the excavation using a vacuum truck. Groundwater was decreased to a depth of approximately 12 feet bgs. w:182254�swnrpL&C 2