Superfund Record of Decision (EPA Region 4): Savannah River Site (USDOE), Motor211 Shops Seepage Basin (716-A), Aiken, SC., June 26, 1998

摘要

The Motor Shops Seepage Basin (716-A) (MSSB) is listed as a Resource Conservation211u001eand Recovery Act (RCRA) 3004(u) solid waste management unit/Comprehensive 211u001eEnvironmental Response, Compensation, and Liability Act (CERCLA) unit in Appendix 211u001eC of the Federal Facility Agreement (FFA) (FFA 1993) for the Savannah River Site 211u001e(SRS), in Aiken, South Carolina. The selected alternative was developed in 211u001eaccordance with CERCLA, as amended, and to the extent practicable, the National 211u001eOil and Hazardous Substances Pollution Contingency Plan (NCP). The selected 211u001eremedy for MSSB is No Action. Investigation of this operable unit was performed 211u001eto determine if hazardous substances had been released to the environment. The 211u001eBaseline Risk Assessment indicated that there were no signficant released to the 211u001eenvironment. The Baseline Risk Assessment indicated that there were no 211u001esignificant releases to the environment. Therefore, it appears that either there 211u001ewere no significant discharges of hazardous materials to the seepage basin or 211u001enatural remediation processes (i.e., bioremediation) have reduced the levels of 211u001ehazardous materials to the extent that they no longer pose risk to human health 211u001eor the environment. The Baseline Risk Assessment considered both the future 211u001eresidential and future industrial land use scenarios. Benzo(a)pyrene was the only 211u001epreliminary constituent of concern (human health) detected in the soil at MSSB. 211u001eBenzo(a)pyrene was detected only int he top foot of soil at levels which give 211u001erisk values greater than 1 x 16(-6) (but less than 1 x 10(-4)) for the future 211u001eadult/child resident. Further uncertainty analysis indicated that benzo(a)pyrene 211u001eshould not be considered a constituent of concern for the MSSB due to: (1) low 211u001efrequency of detection; (2) unit history that strongly suggests it came from an 211u001eadjacent source; and (3) conservative methodology was utilized in the risk 211u001eassessment. No ecological or contaminant migration constituents of concern were 211u001eidentified at this unit. Therefore, No Action is the appropriate remedy and a 211u001efive year ROD review will not be required. The South Carolina Department of 211u001eHealth and Environmental Control has modified the SRS RCRA permit to incorporate 211u001ethe No Action remedy.