Sediment Quality Conditions in the Lower St. Louis River, Minnesota/Wisconsin

The lower St. Louis River has special significance due to its geographic boundary shared by Minnesota and Wisconsin, proximity to Lake Superior, and economic, social, and recreational importance to the area. In particular, this waterway provides critical habitat to benthic invertebrates (bottom-feeding organisms), fish, and waterfowl species and provides an economic venue for Great Lakes shipping and business in the Duluth-Superior Harbor. Economic development of this area over the past 130 years has contributed a mixture of contaminants to this waterway, including polycyclic aromatic hydrocarbons (PAHs), mercury and other metals, and polychlorinated biphenyls (PCBs). Some of these contaminants have accumulated in the sediments over time, resulting in concern about their potential ecological and human health effects.