Remedial Action Report Construction Phase

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Area 20 On Apri122, 1999, a lift hoist was encountered in the eastern portion of the Chevron property. A petroleum hydrocarbon odor was noted in a small pocket of soil beneath the lift hoist. In addition, stained soil was observed beneath a pipe which extended approximately 50 feet south from the lift hoist area. The depth of the pipe was approximately six feet below street grade. Soil sample 20-LH- 1-5.0 was collected beneath the lift hoist. Soil sample 20-1-6.0 was collected beneath the north- south pipe. The soil samples were analyzed for NWTPH-HCID with quantification, PCBs, HVOCs, and leachable cadmium, chromium, and lead to characterize the soil and evaluate disposal options. Based on the analytical results for soil sample 20-LH-1-5.0, which indicated heavy oils at a concentration of 6,830 mg/kg, approximately ten tons of lube-oil impacted soil was removed from the lift hoist area for off-site disposaL Confirmation soil sample 20-LH-2-7.0 was collected at the bottom of the excavation and analyzed for NWTPH-Dx. Soil remedial excavation was not required around the north-south pipe. No PCBs, HVOCs, or leachable metals were detected in any of the Area 20 soil samples (Table 12). Petroleum hydrocarbons were not detected in confirmation soil sample 20 LH-2-7.0. 5.7 Former Beri Parking Lot (Area 9) During pre-construction remedial actions, approximately 550 tons of diesel-range impacted soil was removed from Area 9, located in the eastern portion of the Courthouse Square property (Century West 1998b). Based on field observations during the construction phase, additional excavation of contaminated soil was required north of the pre-construction excavation limits. Approximately 30 tons of contaminated soil were removed for off-site disposal. No groundwater was observed in the excavation. Soil sample 9-SP-1 was collected from the excavated soil pile and analyzed for NWTPH-Dx to evaluate disposal options. Diesel was detected in the soil sample at a concentration of 1,030 mg/kg. Confirmation samples 9-14-10.0 through 9-19-10.0 were collected from the bottom of the excavation and analyzed for NWTPH-Dx. Figure 9 shows the location of the samples and the extent of contaminated soil removed from Area 9 during the construction phase. Diesel and heavy-oil range petroleum hydrocarbons were not detected in confirmation soil samples 9-15-10.0 and 9-18-10.0 Diesel was detected at a concentrations of 2,680 mg/kg and 158 mg/kg in confirmation soil samples 9-14-10.0 and 9-19-10.0, respectively. Based on the analytical results, soil sample 9-14-10.0 was further analyzed for PAHs. Acenaphthene, the only PAH detected, was detected at a concentration of 0.063 mg/kg, significantly below the applicable RBCA Tier I RBSLs (Table 13). Construction Phase - Remedial Actions - 18 - 4080600127 Courthouse Square November 9, 1999