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' borings and monitoring wells were installed at several locations surrounding the area where the <br /> point of release has occurred. Upon assessing the data gathered during many years of monitoring <br /> ' events, it has been determined that the over excavation of the heart of the contamination plume <br /> along with any other impacted soil surrounding the very saturated center of the plume be <br /> completed. This source removal remedial task would be completed to begin a overall forward <br /> momentum to cleanup and remediate the soil impacted. <br /> Upon completing the task of soil excavation, the area may still have some detectable total <br /> petroleum hydrocarbons that will remain as a halo effect of the original plume. The remedial <br /> taction for this residual will be discussed later in another phase. <br /> The excavation will be back filled and compacted with clean imported gravel, base rock and the <br /> ' surface finished off to asphalt cap over the area impacted. All of the contaminated soils removed <br /> will be relocated to the open lot immediately to the east of the excavation area. This land is <br /> owned by George's Service and will be an excellent staging location for the loading and final <br /> ' disposal of the contaminated spoils to Forward Landfill in Manteca, Ca. or Vasco Landfill in <br /> Livermore, Ca.. All soil removed during the excavation will be placed on 6-mill poly plastic and <br /> covered each day at the end of excavation activities. <br /> Field monitoring would also be performed with a Thermodine 580B Photoionization detector, <br /> calibrated with isobutelene. Laboratory soil & water sampling analysis would be completed on <br /> ' discrete samples collected. The submital of these samples would be determined by the on sight <br /> registered geologist or his representative. <br /> ' The laboratory would be requested to run the analysis for the presence of Gasoline <br /> Hydrocarbons, Volatile Aromatics and Oxygenates (M.T.B.E., D.I.P.E., E.T.B.E., T.A.M.E., <br /> T.B.A, 1,2 DCA, EDB). <br /> 1 <br /> 1.3 SITE SPECIFIC GEOLOGY <br /> The geology of this site is typical of the San Joaquin Central Valley region. During the <br /> installation of several borings Mike Niemi of Geological Technics completed a detailed lithology <br /> of the subsurface at the site. Please see Geological Technics report in the attachments. <br /> 1.4 REMEDIAL ACTION GOALS <br /> The following tasks are the proposed remedial action goals presented by Del-Tech to address the <br /> remedial actions proposed at this site: <br /> 1.4.1 Source removal of the heart of the contamination plume. <br /> 1.4.2 Loading and transportation of the contaminated soil to Forward Landfill in <br /> Manteca, Ca. or to Vasco Landfill in Livermore, Ca. <br /> 1.4.3 Due to the very shallow water table (< 8 to 12 feet ) the exposure and <br /> oxygenation of the water table at the capillary fringe to enhance insitu biological <br /> action. As a possible option depending on the unknown condition of the open <br /> excavation a engineered sparging system could be installed within the pit. This <br /> DEL-TECH Page 2 8/15/00 <br />