You are here:
Mercury contamination in fish in midcontinent great rivers of the United States: Importance of species traits and environmental factors
Citation:
WALTERS, DAVID M., K. A. BLOCKSOM, J. M. LAZORCHAK, T. M. JICHA, T. R. ANGRADI, AND D. W. BOLGRIEN. Mercury contamination in fish in midcontinent great rivers of the United States: Importance of species traits and environmental factors. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 44(8):2947-2953, (2010).
Impact/Purpose:
The purpose of this research project is to provide methods, tools and guidance to Regions, States and Tribes to support the TMDL program. This research will investigate new measurement methods and models to link stressors to biological responses and will use existing data and knowledge to develop strategies to determine the causes of biological impairment in rivers and streams. Research will be performed across multiple spatial scales, site, subwatershed, watershed, basin, ecoregion and regional/state.
Description:
We measured mercury (Hg) concentrations in whole fish from the Upper Mississippi, Missouri and Ohio Rivers to characterize the extent and magnitude of Hg contamination and to identify environmental factors influencing Hg concentrations. Concentrations were generally lower than those reported for other regions such as the upper Midwest and Northeast United States. Mercury exceeded the risk threshold for belted kingfisher (the most sensitive species considered) in 33-75% of river length compared with 1-7% of river length for humans. Concentrations were lower in the Missouri than the Mississippi and Ohio Rivers, consistent with continental-scale patterns in atmospheric Hg deposition. Body size and feeding guild were the best predictors of Hg concentrations, which were highest in large-bodied top predators. Site geochemical and landscape properties were weakly related with fish Hg, and relationships were often counterintuitive or inconsistent among feeding guilds. For example, sulfate is associated with higher fish Hg concentrations, but was negatively correlated with Hg in five of six fish guilds. Variables such as pH, acid neutralizing capacity, and total phosphorus did not occur at levels associated with high fish Hg concentrations, partially explaining the relatively low Hg values we observed.