Blue-green Algal Toxin (Microcystin) Levels in Minnesota Lakes

Recent interest in blue-green algal toxins has led to increased monitoring to assess occurrence and levels of toxins in Minnesota lakes. Microcystin (MC), a hepatotoxin, is one of the primary toxins studied in Minnesota and elsewhere in North America. The MPCA has measured MC in numerous lakes across Minnesota as a part of three separate, but related, efforts: 1) A targeted survey conducted in 2006 to assess MC levels in 12 eutrophic lakes in two south-central Minnesota counties to determine the prevalence and seasonal trends in MC and to assess environmental variables associated with elevated MC; 2) A stratified random survey of 50 lakes in Minnesota as a part of the National Lake Assessment Project (NLAP); and 3) Incident-based samples from various lakes during 2004-2007 with reports of severe nuisance algal blooms, potential for human health risk and/or documented dog deaths as a result of algal toxins. This article will focus on the 2006 study and links between MC and other chemical, physical and biological measures. Data from the other two efforts are used to place the 2006 results in perspective and provide a good representation of MC concentrations that may be encountered in Minnesota's lakes. Better understanding of this toxin and its relationship and linkages to other water quality parameters will allow for better risk management andpublic awareness.
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Minnesota Water Research Digital Library
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