Tennessee Coal Ash Contaminated With Radioactivity and Arsenic

by Bill Chameides | January 29th, 2009
posted by Erica Rowell (Editor)

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Duke researchers have analyzed samples of ash from the recent spill at the TVA’s Kingston plant. They found that while the river water seems to be clean there are elevated amounts of radium.

Remember that huge spill of coal ash at the Tennessee Valley Authority’s Kingston coal-fired power plant on December 22nd? New measurements by Duke University scientists confirm not only the presence of toxic metals like arsenic but also dangerous levels of radioactivity. (See press release.)

How Fossil Fuels Work

Fossil fuels work because they contain hydrocarbons: compounds made of hydrogen and carbon atoms. Burning hydrocarbons produces water (H2O), carbon dioxide (CO2), and heat – heat that can be used to drive a turbine to make electricity or to power an engine.

Natural gas is almost entirely composed of a hydrocarbon (CH4) and is the cleanest burning of the fossil fuels. Coal on the other hand is composed of lots of stuff besides hydrocarbons, including sulfur, nitrogen, and metals, some of them radioactive – it’s the dirtiest of the fossil fuels. In addition to CO2, coal combustion produces air pollutants such as sulfur oxides, nitrogen oxides, and particulate matter, and it leaves behind solid waste called coal ash. The ash can be as much as 10 to 15 percent of the original weight of the coal and contains all the stuff in coal that does not go up in the smoke stack: lots of carbon as well as a wide variety of metal oxides (more on this here [pdf]). To this mix is added the compounds removed from the power-plant gaseous effluent to meet air quality standards; these include sulfur-, nitrogen-, and now mercury-containing compounds.

It is estimated that coal-fired power plants in the United States produce about 125 million tons of ash per year (find more information here). I had naively assumed that the ash was put to use in some way, for example as a substrate for building materials. But according to an industry trade group survey [pdf], only somewhere between 15 to 40 percent of the ash produced annually over the past four decades was put to use.

This means that most of the coal ash is simply dumped into a holding pond or landfill and allowed to accumulate. The Environmental Protection Agency estimated that in 1999 some 600 coal ash holding ponds and landfills were in operation at U.S. coal-fired power plants. A more recent New York Times article reported there are some 1,300 coal ash dump sites in the United States — “most of them unregulated and unmonitored.” More than 60 of these sites have had documented water contamination due to leakage from these ponds (see detailed information here).

Duke Researchers Find that River Is Clean but Radioactive Materials Are Disturbing
It is an understatement to say that before December 22 of last year, most of us did not give a lot of thought to all that coal ash accumulating in our backyards. But that has now changed. (It turns out that coal waste is the second largest waste stream in the United States, right after trash.) My colleagues at Duke’s Nicholas School of the Environment, Dr. Avner Vengosh and his graduate student Laura Ruhl, decided to go to Kingston, Tennessee, to take some samples of the ash and analyze its contents.

Not surprisingly, they found high levels of arsenic in a partially dammed tributary of the Emory River. Arsenic and other toxic metals (such as lead and mercury) had been found in earlier water samples collected and analyzed by scientists from Appalachian State University. The encouraging news is that Vengosh and Ruhl found that the river water itself is clean; only trace levels of arsenic were detected in the water flowing beyond the dammed tributary, suggesting that “in less than three weeks since the spill, river flow has diluted the arsenic content.” This indicates that the threat to drinking water quality may be minimal.

However, in addition to the high concentrations of toxic metals like arsenic, my Duke colleagues found elevated amounts of two radioactive forms of radium: radium-226 and radium-228. Radioactive radium, found naturally in the Earth’s crustal material including coal, is produced from the radioactive decay of uranium. But just because it occurs naturally, does not mean it is benign. EPA classifies radium as cancer-causing to humans (see details here [pdf]).

So, the coal sludge is polluted with arsenic and radioactivity, but the river water looks to be clean. So no big deal, right?  Maybe not. As the sludge dries out, the ash picked up by the wind as dust (scientists refer to this as particulate matter) will be carried into the atmosphere. Once there, this dust can be inhaled by people, where it can be deposited on the linings of their lungs giving them unwelcome doses of radioactivity and toxic metals. For this reason, Vengosh believes that “preventing the formation of airborne particulate matter from the ash … seems essential for reducing possible health impacts.”

Something for the folks in Roane County to think very carefully about, but I wonder if the concern raised by Vengosh and Ruhl’s measurements go well beyond the Kingston plant to all the coal-fired power plants and their coal ash dumping sites throughout the United States. Is dangerous particulate matter being liberated from them regularly? And if so, what risks might they pose to the people living near these plants?

More Information

“Analysis Shows Exposure to Ash from TVA Spill Could Have ‘Severe Health Implications” –

Photo Gallery of Kingston Plant Ash Spill –

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  1. Owl
    Jul 6, 2009

    Looks like TVA is having a time of getting rid of its coal ash. Now the folks in Alabama don’t want it. Not to worry though. The elected officials of Cumberland County, TN think its a great idea to have this stuff hauled through residential subdivisions and dumped in an old coal mine which only impacts middle class white folk and is located only a few miles from FairField Glade Resort. Perfect! And who’s going to benefit? Wright Bros. Construction, a large and powerful road building company represented by former TDEC attorney William Penny, now considered one of the best environmental attorneys in Tennessee and defender of those inconvenienced by pesky environmental regulations. The “good old boy” network is still up and running here in rural Tennessee. Where are you on this EPA? Zzzzzzzzzz.

  2. hix1050
    Jan 31, 2009

    From “…burning coal at the average 1000 MWe power plant produces about 13 tons of thorium per year. That thorium is recoverable from the power plant’s waste ash pile. One ton of thorium will produce nearly 1 GW of electricity for a year in an efficient thorium cycle reactor. Thus current coal energy technology throws away over 10 times the energy it produces as electricity. ” To which you can add the energy value of the uranium in coal ash.

    • Peter Morcombe
      Dec 29, 2009

      hix1050 Liked your comment. Once the fossil fuel has gone, Thorium has the potential to keep our civilisation going for 10,000 years. Probably time enough to develop fusion power technology! Would like to establish direct communication with anyone interested in Liquid Fluoride Thorium Reactors (LFTR) or sub-critical reactors based on scaling up the Spallation Neutron Source (SNS).

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