Contaminants in the Upper Mississippi River histo

Authors: James G Wiener Mark B Sandheinrich

Publish Date: 2010/01/06

Volume: 640, Issue: 1, Pages: 49-70

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Abstract

We synthesized information on selected contaminants in the Upper Mississippi River summarized regulatory measures enacted to reduce pollution and described biotic and ecosystem responses to regulatory actions Contamination of the river with mercury and lead rapidly followed settlement of the basin by European immigrants in the mid1800s Metal contamination peaked in the 1960s and has since decreased substantially DDT its degradation product DDE and PCBs biomagnified to concentrations that adversely affected wildlife in upper trophic levels National USA environmental regulations enacted from 1972 to 1991 reduced discharges of wastes from point sources improved wastewater treatment and reduced or banned the production or usage of certain chemicals such as DDT PCBs and lead Responses to these regulatory measures include reductions in ecosystem contamination reductions in biotic exposure and recovery of affected wildlife populations Recovery from pollution has been slow however and we conclude that proactive approaches focusing on prevention are highly preferable to reactive approaches in management of toxic substances Past successes in reducing pointsource pollution which is greatest near urban areas do not extend to nonpointsource pollution given that the existing regulatory framework does not adequately address nonpoint sources The river continues to receive hundreds of recently synthesized chemicals and the behavior and effects of most of these compounds in aquatic ecosystems are largely unknown Emerging contaminants and recently discovered mechanisms of adverse biological effects such as endocrine disruption pose continuing challenges to scientists and environmental managers concerned with the ecological health of this riverine ecosystemThe lead author JGW was supported by the University of Wisconsin System Distinguished Professors Program and the UWL Foundation during the preparation of this manuscript We thank Bruce Monson Laura Solem Minnesota Pollution Control Agency Candy Schrank Wisconsin Department of Natural Resources and Patricia McCann Minnesota Department of Health for providing data and related information from their state fishcontaminant monitoring programs and thank Brian Stemper US Fish and Wildlife Service for providing trend data on harvest of mink in the Upper Mississippi River Wildlife and Fish Refuge Constructive comments on an earlier draft were provided by Steven Balogh Thomas Custer and Candy Schrank

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