Remedial Action Report Construction Phase

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5.8 Former Beri Building (Area 10, UST-12 and UST-13) Area 10 and UST-12 During pre-construction, test pits were completed in the location of a former automobile repair facility in the central portion of the Courthouse Square property (Area 10). Field observations and analytical results from soil samples collected from the test pits indicated no evidence of subsurface contamination (Century West 1998b). During the construction phase, a small pocket of petroleum hydrocarbon contaminated soil and a 250-gallon UST (labeled UST-12) were encountered in this area. The contaminated soil, located approximately 50 feet south of UST-12 (Figure 10), was approximately three feet in diameter and 0.5 feet thick. When discovered, UST-12 was filled with concrete. This UST may be the heating oil UST decommissioned in 1989 as identified in the ESA (Century West 1997a). Approximately one ton of impacted soil was removed for off-site disposal. No groundwater was observed in the excavations. Soil sample UST-12-2-6.0 was collected from the e~cavated soil pile and analyzed for NWTPH- HCID and NWTPH-Dx to evaluate disposal options. Confirmation soil sample UST12-1-9.0 was collected beneath UST-12 forNWTPH-HCID analysis. Confirmation soil sample UST12-3-6.5 was collected from the bottom of the remedial excavation and analyzed for NWTPH-Dx. Figure 10 shows the location of the samples and the extent of contaminated soil removed from Area 10 during the construction phase. No diesel range petroleum hydrocarbons were detected in soil samples UST12-1-9.0 and UST12-3- 6.5 (Table 4). UST-13 During construction activities, on June 7, 1999, a 200-gallon UST (labeled UST-13) was encountered approximately three feet below street grade in the eastern portion of the Courthouse Square property. Figure 10 shows the former location of the UST. No visual or olfactory evidence of contamination was noted in the soil surrounding the UST. After the UST was removed, soil samples UST13-1-8.5 and UST13-2-8.5 were collected approximately six-inches beneath the tank and analyzed for NWTPH-HCID. No groundwater ~~-as observed in the excavation. No petroleum hydrocarbons were detected in soil samples UST13-1-8.5 and UST13-2-8.5 (Table 4). Construction Phase - Remedial Actions - 19 - 4080600127 Courthouse Square November 9. 1999