Baseline Risk Assessment: Former Petroleum Refinery and Bulk Storage Terminal
Rhode Island
Roux Associates was retained to conduct a baseline risk
assessment to evaluate the need for remedial action at a former
petroleum refinery and bulk storage terminal.
Regarding contaminated soil issues, the risk assessment saved our client millions of dollars in remediation costs to comply with published soil remediation criteria. Regarding surface water and groundwater issues, the risk assessment demonstrated that impacts to these media did not pose public health risks, so no remedial action was necessary.
Prior to Roux’s involvement, a large-scale soil removal action had been proposed and accepted by the Rhode Island Department of Environmental Management (RIDEM). Roux determined that this course of action would not be a cost-effective remedy. Roux completed additional remedial investigation activities and prepared a baseline risk assessment work plan.
The work plan outlined overall risk assessment methodologies and recommended specific technical and regulatory guidance to be followed. Once approved, the risk assessment was implemented in the following phases:
Data Evaluation- Exposure
Assessment
- Toxicity
Assessment
- Risk
Characterization
Submissions were provided to RIDEM for approval after each phase.
The phased risk assessment approach enabled RIDEM to provide its input at key junctures. This ensured regulatory buy-in with Roux’s data evaluation methods and key assumptions.
A summary report was prepared indicating that soil removal was not necessary in most areas of the site. In one area where calculated cumulative risk levels exceeded the regulatory 10E-5 threshold value, the risk assessment was used to focus soil removal action in a limited area to reduce risk.
Concentrations of constituents throughout another section of the former refinery exceeded published criteria. Based upon the success of the previous baseline human health risk assessment at the Site, a second baseline human health risk assessment was recently completed. Risks associated with exposure to groundwater, surface water and sediment were determined to be below the risk threshold, so no remediation has been proposed. For minor portions of the site where soil concentrations exceeded the risk threshold, remediation has been proposed.