Lake Sediment Contaminant Levels In Minnesota

The location and extent of contaminated lake sediments in Minnesota is not well characterized. In some instances, contaminated sediments may pose an ecological risk to aquatic biota and piscivorous wildlife either through direct exposure or as a source of contaminants for bioaccumulation through the food chain (e.g., mercury). Contaminated sediments may also pose a risk to terrestrial flora and fauna if these sediments are dredged and applied to land. Very little guidance is provided in 40 Code of Federal Regulations (CFR) Part 35 of the Clean Water Act on the analysis of sediments for Clean Lakes projects. Limited sediment contaminant data are available from Minnesota lakes and the state of Minnesota has not developed sediment quality criteria or guidelines. Likewise, few federal criteria or guidelines are available for sediment contaminants although several summaries have been prepared for the U.S. Environmental Protection Agency (U.S. EPA) on this topic including Bolton et al. (1985) and an unpublished summary for U.S. EPA Region V (U.S. EPA, 1991). The U.S. EPA has developed sediment quality criteria for the nonionic organic compounds: acenapthene, dieldrin, endrin, fluoranthene, and penanthrene (U.S. EPA, 1994a) Sediment quality criteria development is underway for the metals: cadmium, copper, nickel, lead, and zinc (U.S. EPA, 1994b). In addition, several Canadian jurisdictions have prepared some sediment quality guidelines. These factors and requirements by U.S. EPA Region V, to include some sediment analysis as a part of the states' lake water quality assessment efforts, led to the development of the current study