Laserfiche WebLink
Geosyntec'' <br /> consultants <br /> 1.2.1 UST Site 517 <br /> Two 4,000-gallon steel tanks, most likely containing diesel and leaded gasoline, were <br /> installed west of Building 517 to supply fuel for ground transportation vehicles. Both <br /> USTs were removed in March 1990,and the area was backfilled and repaved with asphalt. <br /> Since the tank removal, two environmental investigations and a groundwater monitoring <br /> event have been conducted to characterize the extent of residual contamination in the area <br /> (Environmental Risk Services Corporation [ERS], 2008a). Per the RWQCB's analysis, <br /> the site meets nearly all general and media-specific criteria for closure under the LTCP <br /> program (RWQCB, 2017). The highest concentrations of total petroleum hydrocarbons <br /> (TPH) as gasoline (TPHg; 610 milligrams per kilogram [mg/kg]) and total petroleum <br /> hydrocarbons as diesel (TPHd; 160 mg/kg) were detected at 6 feet below ground surface <br /> (bgs) at soil boring 517-3 (RWQCB, 2017; ERS, 2008a) as shown in Figure 2. Soil <br /> samples and chemical test data from the soil boring adjacent to the previous highest area <br /> of detection for TPHg and TPHd (soil boring 517-3) are required to fill the data gap <br /> (RWQCB, 2017 and 2018a). Based on the concentrations of TPHg and TPHd in boring <br /> 517-3, TPHg and TPHd will be analyzed to address LTCP media-specific criteria for <br /> petroleum vapor intrusion to indoor air. <br /> The potential presence of naphthalene and methyl-tert-butyl-ether (MTBE) in the soil <br /> from 0 to 5 feet bgs could not be evaluated because the chemicals were not analyzed in <br /> previous investigations(RWQCB,2017).Naphthalene and MTBE will be analyzed to fill <br /> the data gap. <br /> 1.2.2 UST Site 605 <br /> Building 605 housed a pump station for the Fire Water Protection System at RRI. The <br /> pumps were driven by an electric motor,with a standby gasoline engine-driven generator <br /> in case of power failure. A single 1,000-gallon steel gasoline UST had been installed to <br /> power the standby generator. The UST was decommissioned sometime prior to 1984, <br /> excavated, and removed in December 2000. Two environmental investigations were <br /> conducted prior to the tank removal, and an additional investigation and a groundwater <br /> monitoring event have been conducted since the tank removal, which characterized the <br /> extent of residual contamination(ERS, 2009). Per the RWQCB's analysis,the site meets <br /> nearly all general and media-specific criteria for closure under the LTCP program <br /> (RWQCB, 2017). <br /> 20190122- FINAL UST Data Gap Work Plan 2 22.01.2019 <br />