St. Louis River Area of Concern Sediment Assessment Areas

The St. Louis River is the second-largest tributary to Lake Superior. The lower estuary culminates in the Duluth-Superior Harbor, which is the largest freshwater seaport in North America. In 1987, concerns over environmental quality conditions prompted the designation of the lower St. Louis River as one of 43 Great Lakes Areas of Concern (AOCs). This includes the segment from Cloquet, Minn., to Lake Superior.<br/><br/>Due to sediment contamination, the St. Louis River AOC has several impaired uses, including degradation of bottom-feeding invertebrate communities, increased incidence of fish tumors and other abnormalities, fish consumption advisories, and restrictions on dredging. Some sediment-derived contaminants also appear to be carried by the water column to Lake Superior, the most pristine Great Lake.<br/><br/>The work products developed were:<br/>-Sediment Assessment Area chemistry characterization (dashboards) <br/>-Maps of sediment contaminants for multiple depth intervals<br/>-Database queries to assist in conducting independent analysis of the sediment contaminant levels in the AOC<br/>-Memorandum describing a systematic approach for assigning contaminant-level categories to each assessment area<br/><br/>The polygons included in this data product depict boundaries of the St. Louis River Area of Concern sediment assessment areas [SAAs].