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Escaping Mercury

September 12, 2006

By setting off a chain reaction, global warming may cause centuries’ worth of stored mercury to escape back into the environment.


Liberating a toxic prisoner. I’m Bob Hirshon and this is Science Update.

Wildfires raging at unprecedented intensities in the north may be unleashing massive amounts of mercury into the environment. The mercury has accumulated harmlessly over thousands of years in the soils of wetlands, including a type of soil called peat found in northern North American forests. But Michigan State University ecologist Merritt Tueretsky says that in just a few decades, forest fires in these regions have more than doubled in size—a result of global climate change.

MERRITT TUERETSKY (Michigan State University):
Forest fires don’t just burn forests. And our data show that when peat layers within boreal wetlands burn, it releases very large quantities of mercury into the atmosphere.

While that in itself isn’t so dangerous, she says the mercury could disperse over long distances and eventually find its way into the food chain, where it becomes highly toxic.

I’m Bob Hirshon, for AAAS, the science society.