St. Louis River Area of Concern Sediment Characterization: Final Report

The Minnesota Pollution Control Agency (MPCA) and Wisconsin Department of Natural Resources (WDNR) are two of the agencies currently working together to implement a comprehensive long-term plan to delist the St. Louis River Area of Concern (SLR AOC). Many of the Beneficial Use Impairments (BUIs) in the AOC are linked to the presence of sediment contaminants. The St. Louis River Sediment Characterization Project was undertaken to evaluate and summarize the levels of sediment contaminants throughout the AOC based on the significant amount of existing sediment contaminant data. This work was done to support the MPCA and WDNR in defining the general level of remedial action needed for sites across the AOC to support BUI removal strategies. It is important to note that the characterization was based solely on sediment contaminant data; multiple lines of evidence are used by the states when conducting site-specific investigations. Teams of staff from MPCA and WDNR determined protocols for sediment characterization, dictated particular datasets to be used in the analysis, and oversaw development of project deliverables. These teams were termed the Minnesota Remedial Assessment Team (MNRAT) and Wisconsin Sediment Assessment Team (WISAT); together the teams constitute the Sediment Technical Team. As part of the project, the AOC was divided into Sediment Assessment Areas (SAAs) for purposes of evaluation and to assist in the prioritization of remediation and restoration activities. The work-products developed as part of the Sediment Characterization project were: * Sediment Assessment Area Chemistry Characterization or "dashboards" * Maps of sediment contaminants for multiple depth intervals * Database queries to assist MPCA and WDNR in conducting independent analysis of the sediment contaminant levels in the AOC * A memorandum describing a systematic approach to assign remedial categories to each SAA for Minnesota This report documents the development of these work products. The dashboards, maps, and remedial categorization memorandum are included as appendices.