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1 } 1pPrivged Attorney Work Product re¢ 6.0 INVESTIGATION FINDINGS Bureau Veritas evaluated the data generated during this investigation. Our findings are summarized in the following sections. 6.1 SOIL BORING OBSERVATIONS In general, soils encountered consisted of silty gravel and clayey silt with gravel extendin f 5.0 feet bgs. Damp to moist conditions were encountered in the soil borings, like result rea rainfall. Bureau Veritas did not observe evidence of contaminated soil (e.g., d' of n, o 8 in the borings. No volatile organic compounds were detected in the field PID rea s. 6.2 SOIL ANALYTICAL RESULTS Copies of the laboratory analytical reports are presented in Appendix C. A summary of the analytical testing performed for the soil samples is presented in Table 1. Soil analytical data were compared to the Department of Toxic Substances Control California Human Health Screening Levels(CHHSLs). There currently are no CHHSLs established for GRO, DRO, MRO and VOCs. Therefore, where appropriate, the soil analytical data is compared to San Francisco Bay Regional Water Quality Control Board (SFRWQCB) Environmental Screening Levels(ESLs)for commercial properties and direct exposure soil screening levels for construction/trench worker exposure scenario, where appropriate. The following is a summary of analytical results: • VOCs, GRO, and PCBs were not detected above the laboratory reporting limits, which were below the applicable CHHSLs and ESLs. • DRO concentrations were detected in each of the three analyzed soil samples (BV-1-2'-2.5', BV- 2-2'-2.5' and BV-3-2'-2.5') at concentrations of 6.9 milligrams per kilogram (mg/kg), 24 mg/kg, and 11 mg/kg, respectively. These concentrations are below the RWQCB commercial and construction/trench worker ESLs established at 83 mg/kg and 4,200 mg/kg, respectively. Commercial CHHSLs are not established for DRO. • MRO concentrations were detected in two of the three samples(BV-2-2'-2.5'and BV-3-2'-2.5') at concentrations of 130 mg/kg and 55 mg/kg, respectively. These concentrations are below the RWQCB commercial and construction/trench worker ESLs established at 2,500 mg/kg and 4,200 mg/kg, respectively. Commercial CHHSLs are not established for MRO. 6.3 QUALITY ASSURANCE/QUALITY CONTROL The laboratory completed the quality assurance/quality control (QA/QC) activities required for the samples such as lab control samples and matrix spikes. No QA/QC issues with the analyses were noted in the laboratory reports(Appendix A). The QA/QC parameters for the samples were generally within acceptable limits and suggested that the data is useful for its intended purpose. 4