Mercury Methylating Bacteria Widespread in Contaminated Streams


Mercury has become a global pollutant due to its release into the atmosphere during coal burning and into freshwater systems as part of agricultural runoff and direct industrial discharge. Once in freshwater systems, specific types of microorganisms are known to transform mercury into methylmercury (MeHg), a highly toxic form of mercury. Scientists from Oak Ridge National Laboratory (ORNL) recently examined the microbial communities from the sediments of six different surface streams in Oak Ridge, Tennessee, to identify bacteria that could be contributing to MeHg production. Using 16S rRNA pyrosequencing, the researchers correlated the presence of a group of known MeHg producers, the Deltaproteobacteria, with MeHg in all of the Hg contaminated streams. Within the Deltaproteobacteria group, Desulfobulbus species are considered to be prime candidates for being involved in Hg methylation in these streams.


Mosher, J. J., T. A. Vishnivetskaya, D. A. Elias, M. Podar, S. C. Brooks, S. D. Brown, C. C. Brandt, and A. V. Palumbo. 2012. “Characterization of the Deltaproteobacteria in Contaminated and Uncontaminated Stream Sediments and Identification of Potential Mercury Methylators,” Aquatic Microbial Ecology 66, 271–82. DOI: https://doi.org/10.3354/ame01563.