Remedial Action Report Construction Phase

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5.4 Former Goldberg Property (Area 23 and UST-11) Area 23 During construction activities on May 6, 1999, excavation was performed in the former locations of a heating-oil UST and an above ground storage tank in the northern portion of the former Goldberg property. Limited information was available regarding releases from the UST (Century West 1996b). Soil sample 23-1-13.5 was collected from contaminated soil observed in the excavation and analyzed for NWTPH-HCID to evaluate disposal options. Based on the analytical results, which indicated diesel at a concentration of 687 mg/kg, approximately 18 tons of diesel- impacted soil were excavated from Area 23 for off-site disposal. Groundwater was not observed in the excavation. Confirmation soil samples 23-2-14.5 through 23-6-14.0 were collected from the bottom of the excavation and analyzed for NWTPH-Dx. Figure 7 shows the location of the samples and the extent of contaminated soil removed from Area 23. No petroleum hydrocarbons were detected in the Area 23 confirmation soil samples (Table 9). Although groundwater was not observed in the Area 23 excavation, dewatering was performed for construction purposes from Sump 4 near Areas 19 and 23. The sump was located approximately 30 feet southwest of Area 23. After pumping from the sump for at least 24 hours and allowing groundwater to recharge, a water sample labeled SW-Influent was collected from the sump on May 19, 1999 for NWTPH-Dx and BTEX analysis. Figure 4 shows the location of Sump 4. Diesel was not detected in the water sample SW-Influent collected from Sump 4 on May 19, 1999 (Table 15). BTEX concentrations in this sample were significantly below the applicable RBCA Tier I RBSLs (Table 15). UST-11 On April 13, 1999, a 1,750-gallon UST (labeled UST-11) was encountered approximately three feet below street grade in the southern portion of the Courthouse Square property. Figure 7 shows the former location of the UST. No visual or olfactory e~~idence of contamination was noted in the soil surrounding the UST. After the UST was removed, two soil samples (labeled UST-11E-9.0 and UST-11 W-9.0 ) were collected approYimately six-inches beneath the tank and analyzed for NWTPH- HCID. Groundwater was not observed in the excavation. No petroleum hydrocarbons were detected in soil samples UST-11E-9.0 and UST-11 W-9.0 (Table 4). Construction Phase - Remedial Actions - 1~- 4080600127 Courthouse Squaze November 9, 1999