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ZINNA Working To Restore Nature Laboratory analyses of soil samples collected at five foot intervals from 10 0 to 40 0 feet in the well boring did not detect the presence of gasoline constituents above the method detection limits (Table 1) The depth to groundwater beneath the site was recorded at approximately 38 feet below grade. Historical analyses of groundwater samples collected from monitoring well MW1 indicate that groundwater beneath the site has not been impacted by petroleum hydrocarbons (Table 2) July 1992 Excavation On July 23, 1992, under the direction of RESNA, excavation activities were initiated The excavation was performed by Falcon Energy Associates (Falcon Energy, license #584524) using a backhoe tractor Visible hydrocarbon impaction of soil was evident to a depth of approximately 6 to 6 5 feet below grade PID measurements detected vapors intermittently to approximately 8 feet below grade Analytical results of confirmation soil samples collected from the excavation floor and sidewalls (Table 1) indicated hydrocarbon impacted soils remained in place along the northern wall of the excavation and under the high voltage concrete encased electrical lines which transversed the • excavation All excavated materials were transported to the City of Stockton Municipal Service Center where they were placed on asphalt and covered by 6 mil plastic sheeting Approximately 300 cubic yards of native and backfilled soil were excavated from the subject site and stockpiled at the City Service Center Subsequent to excavation and soil sample collection, the open excavation was backfilled with clean engineered sand under the requirements set forth by the City of Stockton Public Works Department The limits of the excavation are shown on Figure 2 These activities defined the approximate extent of soil contamination with exception to the area north of the product line The PHS/EHD requested additional subsurface investigation be performed to define residual soil contamination at the site FIELD ACTIVITIES The following scope of work was based upon data collected from previous site investigations The work was designed to define to northern extent of remaining impacted soil in the vicinity of the underground gasoline product line The field work was performed by RESNA personnel in accordance with RESNA's letter workplan dated October 12, 1993 OW01481Reports\LR-20294 FNL 2