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' EEC 51462 01 Un3First 5tocl,ton _Member 24 NM 3 3 Pre-UST Discovery Results Laboratory test results from both the surface and subsurface samples indicate that soil in the construction area had been impacted by motor oil and gasoline range petroleum hydrocarbons and VOC constituents consistent with those found in petroleum products and cleaning solvents Based on the laboratory test results, combined with the knowledge that this portion of the site was a gasoline service station, the source of the impacted soil may be associated with former service station activities The constituents that were detected in soil samples are typical of what could be expected to be found at an automotive service station which utilized parts cleaning solvents Wastes from parts cleaning solvents were frequently placed in waste oil storage tanks at gasoline service stations Based on the relatively shallow depth (<20 feet) of the impacted soil, and since this portion of the ' subject site was in the process of being developed into a new parking area, EEC determined that the most cost effective remediation solution would be the excavation and offsite disposal of the impacted soil Removal activities are detailed in the following section ' 4.0 PRE UST DISCOVERY REMEDIATION ACTIVITIES Following the assessment and delineation of the hydrocarbon and VOC impacted soil, EEC developed a remediation workplan which was verbally approved by the SJCEHD on November 12, 2003 A copy of the workplan is included in Appendix D As described above, excavation and offsite disposal was selected as the most cost effective remedial method The remediation activity is described in more detail below 4.1 Sod Excavation and Confirmation Sampling On November 17, 2003, EEC excavated the previously delineated hydrocarbon and VOC impacted soil Excavation was accomplished utilizing a backhoe The location of the excavation is shown on Figure 4 Impacted soils were stockpiled onsite until samples could be collected for disposal profiling purposes This excavation was begun in the area of highest contamination as determined by samples analysis (Section 3 3), and extended laterally to the north, south, east and west The extent of the impacted soil was determined by visual evidence, PID readings, and laboratory data from the previous investigation The final excavation dimensions were approximately 30 feet by 60 feet by 8 5 feet deep 1 Once excavation activities were complete, EEC collected eight confirmation samples from the excavation under the direction of SJCEHD Sample locations are shown on Figure 4 Samples were collected in stainless steel sleeves with the use of a hand sampler and transported to CLS laboratory for analysis of TPH full range scan by EPA method 8015 and VOCs by EPA method 8260 Three additional soil samples were collected from the stockpiled soil for profiling purposes All three samples were analyzed for TPH full scan by EPA 8015, VOC by EPA 8260, and Title 22 metals 6