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Mr.Aragon November 21, 2008 Page 7 of 9 California. The material removed from the Site was characterized as non-hazardous based on the results from the characterization samples provided above. These non-hazardous materials were transported under non-hazardous waste manifests and managed as required by local, state and federal guidance. A total of 387.10 tons of material was excavated and transported off-Site as part of the SPCC Containment Structure work. Attachment B provides the manifests associated with the transport and disposal of the impacted material removed from the Site. 2.3.6 Preliminary Screening Criteria for Comparison with SPCC Confirmation Sample Analytical Results The following preliminary screening criteria for soil above groundwater were presented in the DTSC-approved Workplan, and acted as general criteria for the remediation of the additional impacted material at the Site: ■ 0.9 mg/kg benzo(a)pyrene [B(a)P] equivalent maximum concentration, ■ 100 mg/kg for TPH-g, ■ 500 mg/kg for TPH-d, ■ 1,000 mg/kg for TPH-mo, and ■ Concentrations similar to background levels for metals. These preliminary screening criteria are considered conservative and the presence of these chemicals at or below the screening criteria are expected to be fully protective of human health and/or the environment. 2.3.7 Confirmation Sampling A total of 18 confirmation samples, including two duplicate samples, were collected from the excavation area. Sidewall confirmation samples were collected approximately every 20 linear feet around the boundary of the excavation for a total of 12 sidewall samples (including one duplicate). A total of six bottom samples (including one duplicate) were collected during the excavation activities; however, two of these samples were subsequently superseded either due to elevated concentrations of the constituents of concern (SPCC-B-2-1) or because the excavation needed to be vertically expanded to accommodate the SPCC construction (SPCC-B-3-1). These two samples were replaced by subsequent bottom confirmation samples SPCC-B-2A-2 and SPCC- B-3A-2, respectively. Bottom samples were collected at a rate of one sample per approximately every 625 square feet (i.e. every 25-foot by 25-foot area). Confirmation samples were analyzed on a 24-hour turnaround time to avoid project delays. The as-built locations of the confirmation samples are provided in Figure 4. Confirmation samples were analyzed for PAHs using EPA Method 8310, for TPH-g, TPH-d, and TPH-mo using EPA Method 8015M, and for heavy metals using EPA Method 6010/7000 series. Results from the confirmation samples were compared to the DTSC approved preliminary screening criteria for the Site (see Section 2.3.6) to determine whether or not additional excavation was required. Analytical results for PAHs, expressed as benzo(a)pyrene [B(a)P] equivalents, in the confirmation samples showed elevated concentrations in only one sample (SPCC-B-2-1 at a concentration of 2.05558 mg/kg); however, this sample was removed via excavation and a