Methylmercury Levels Spiked After Tennessee Coal Ash Spill | Chemical & Engineering News
 
 
2
Facebook
Latest News
Web Date: January 3, 2013

Methylmercury Levels Spiked After Tennessee Coal Ash Spill

Environmental Disaster: Bacteria in nearby rivers transformed mercury from the spill into more harmful form
Department: Science & Technology
News Channels: Environmental SCENE, Analytical SCENE
Keywords: mercury, methylmercury, coal ash, spill, Tennessee
[+]Enlarge
Sludge Pile
Coal ash from a 2008 power plant spill buried this yard, which is shown just after the spill. A new study has found that ash from the spill caused mercury contamination in local rivers.
Credit: Avner Vengosh
20130103lnj1-coalash
 
Sludge Pile
Coal ash from a 2008 power plant spill buried this yard, which is shown just after the spill. A new study has found that ash from the spill caused mercury contamination in local rivers.
Credit: Avner Vengosh

A large 2008 coal ash spill at a Tennessee power plant tripled the levels of potentially harmful mercury in parts of two of the state’s rivers, according to a new study (Environ. Sci. Technol., DOI: 10.1021/es303639d). Researchers found that bacteria converted mercury from the spill to methylmercury, a form that is biologically available to wildlife.

Earlier sediment studies conducted by the Environmental Protection Agency and the state focused mainly on total mercury and did not find levels of concern, leading authorities to conclude in part that elevated mercury in the systems was likely caused by previously recognized contamination from nuclear weapons processing in the 1900s. But a team led by Heileen Hsu-Kim, an aquatic chemist at Duke University, took a more detailed look. “EPA might have been a little too quick to judge that mercury was not a problem,” she says.

In an earlier study Hsu-Kim and her team established a mercury isotope signature for the spill that allowed them to map where mercury from the coal ash had accumulated (Environ. Sci. Technol., DOI: 10.1021/es303111). In analyzing samples from these contaminated spots in the Clinch and Emory Rivers, the researchers found that bacteria converted about 2% of spill mercury to methylmercury--enough to raise methylmercury levels as much as three times as high as baseline levels in places. Further work could establish the extent of the risk of toxicity to wildlife, if any, according to Hsu-Kim.

Future environmental studies of mercury pollution, performed for instance to assess the impact of wastewater treatment plants or coal ash storage facilities, should focus on the biologically troubling, though more difficult to measure, methylmercury, Hsu-Kim says. Current methods focus on total mercury. “If the test is not really meaningful environmentally,” she asks, “then what’s the point of it in the first place?”

 
Chemical & Engineering News
ISSN 0009-2347
Copyright © American Chemical Society
Comments
Tim Seitz  (January 4, 2013 12:28 PM)
Where is Al Gore on this issue? What is he doing about this? Tennessee is his home state.
Barbara Evans  (January 5, 2013 2:48 PM)
So they sent the coal ash to Perry County Alabama, where it sits in a landfill right by a poor African American neighborhood, and nobody, but nobody gives a damn about them.
Dennis Hammond  (March 27, 2013 11:28 PM)
The fact that the sludge from the spill in the river was removed and treated as a toxic material and transported in lined, leakproof railcars to be resettled in a lined hazardous waste site tells you something. If there wasn't anything wrong with the material, why did they treat it as hazardous? The EPA knows it is and has the tests to prove it, check website, and were beaten down by government and private interests worrying about classifying coal ash waste as hazardous and the economic effect on the economy which they mush consider more important than human and wildlife health.
Bruce Vigon  (January 8, 2013 12:23 PM)
Agree that the toxicologically relevant form is what should be measured, but the risk of the elevated methylated mercury doses to receptors is what is important, not the fact that the localized concentration levels are 3X baseline.
Leave A Comment