Methylmercury in Mosquitoes: Impact of a Large Coal-Fired Electrical Utility in Central Ohio

Abstract

<p>Emissions from coal-fired utilities are the major anthropogenic source of mercury (Hg) to the atmosphere. Because some of the emitted Hg may be atmospherically deposited near the source, there are concerns over potential impacts on levels of toxic monomethylmercury (MMHg) in local biota. Recent investigations have suggested a link between atmospheric deposition of inorganic Hg and the accumulation of MMHg in aquatic biota. MMHg concentrations in mosquitoes (Diptera: Culicidae), which are ubiquitous and have aquatic life stages, have been shown to be a useful and sensitive indicator of Hg loadings, including those derived from atmospheric deposition. We investigated the potential impact of a large Hg-emitting (> 500 kg Hg y-1) coal-fired electrical utility on MMHg levels in mosquitoes near the Conesville power station in central Ohio. Adult, host-seeking female mosquitoes were sampled with C02-baited traps at 23 locations within a 60 km radius of the utility during a two-week period in July 2010 as well as two reference sites distant from known combustion sources of Hg. MMHg levels in mosquitoes sampled at locations within a 30-km radius of the plant (n = 12) were comparable to those at locations within a 3060 km radius (n = 11) and the two control sites. These preliminary findings suggest that either 1) little of the Hg emitted from the utility is deposited locally or 2) near-source deposition of Hg emissions from the plant does not have a significant impact on MMHg residues in mosquitoes and, by extension, potentially other organisms in the local food web.</p><p>This presentation occurred at the Wright State University Campus-Wide Celebration of Research, Scholarship and Creative Activities on April 8, 2011</p>