ARCHIVED REPORTS_REMEDIAL INVESTIGATION REPORT 2000

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20 Excavation of the soil contaminants and removal of that soil from the site could possibly res;;lt u. •-A V A AW :al c:cs;::e of the eas:c:n perdcn of tt.e parte:. Ex:atiation and offsite disposal, however, will result in generation of a waste. Presently that waste would be considered hazardous in accordance with the TTLC and STLC levels for lead as set forth in the California Code of Regulations, Title 22. Supplemental test data, specifically the deionized WET data, indicate that a variance from the hazardous classification could possibly be obtained Site mitigation alternatives for the western portion of the parcel are unclear due to the limited data at boring B4. Available data suggest that soil and ground-water contamination is probably localized, however, the source of contamination has not been identified. Unlike the eastern portion of the parcel, ground-water contamination is present. As a result, additional site mitigation alternatives besides those discussed above may be necessary. Site Characterization Additional site characterization efforts are particularly needed to define the extent of soil and ground-water contamination in the vicinity of boring B4. In light of the high correlation observed between the soil gas results and the subsequent verification sampling results, a supplemental soil gas survey on the western portion of the parcel is recommended survey would be conducted in a manner similar to the methods discussed in the June 1993 Work Plan (L-SCE). Following evaluation of the soil gas survey results, a work plan detailing additional soil and ground-water characterization requirements will be prepared. That work plan is anticipated to include additional shallow soil borings to a depth of approximately five feet on both portions of the parcel. Soil samples from these borings would be evaluated for selected metals and organic chemicals (including TPH as oil and organic constituents by EPA 8080 and EPA 8270).