Giant Toxic Coal Ash Spill Threatens Animals

Kelly Hearn in Kingston, Tennessee
for National Geographic News
January 23, 2009
It's been called the Exxon Valdez of coal ash—a wakeup call for a fossil fuel industry.

But the recent toxic ash spill in Tennessee is greater in scope than the 1989 oil spill, and despite what some conservationists are calling very real threats, the ash disaster has so far inspired apparently little concern for local wildlife.

On December 22 a billion gallons of poisonous sludge—largely coal ash, a byproduct of coal burning—broke through an earthen dike at the Kingston Fossil Plant. The torrent half-buried area homes and elevated long-running health concerns over heavy metals in the ash.

Those worries, experts say, are not limited to human health. In addition to the animals killed by the initial spill, wildlife may be threatened for years by the trace amounts of arsenic, cadmium, mercury, thallium, and other toxins in the coal ash.

(Related: "Heavy Metal-Eating 'Superworms' Unearthed in U.K." [October 7, 2008].)

"We're concerned about tremendous human health threats but also serious biological threats to animal species," said Stephen Smith, veterinarian and director of the Southern Alliance for Clean Energy.

"Already mussels, snails, and aquatic species are in grave danger, but no one seems to be talking about it."

Other local animals that could be affected include river otters, mink, muskrat, ospreys, and black-crowned night herons, according to the Tennessee Wildlife Resources Agency. No endangered species are believed to inhabit the spill region.

Toxins Accumulating in Animals?

Of the dead animals retrieved from the spill site so far, none had died of poisoning, according to Dave McKinney, chief of the Environmental Service Division of the Tennessee government's Wildlife Resources Agency.

"They were either buried in mud or stranded when a water surge pushed them into fields and forests and then receded," McKinney said.

Even so, he said, "there is certainly the potential that toxins will bioaccumulate"—build up in animals' bodies. "But we're talking months to years, not days to weeks."

State wildlife officials said they have collected live fish and will collect more in the coming months to monitor the situation.

The Tennessee Wildlife Resources Agency says it will work over the next three to five years with the U.S. Fish and Wildlife Service to assess the long-term impact of contaminants from the Kingston spill on animals.

Food Warning

Eventually any toxic effects in animals could work their way up the food chain to humans, officials say.

The Tennessee Department of Environment and Conservation has issued an advisory against eating striped bass caught in rivers around the spill zone as well as a precautionary advisory for catfish and sauger. A precautionary advisory means that children, pregnant women, and nursing mothers shouldn't eat those species, and everyone else should limit consumption to one meal a month.

Conservationists are particularly concerned over the fate of one ecologically important species, freshwater mussels, which live on river bottoms, where sediment and pollution accumulate.

Losing mussels could result in greater pollution levels in area rivers, because a single mussel can filter several gallons of water a day, "improving quality for human use," according to the U.S. Fish and Wildlife Service.

Mussels are also a major food source for ducks, birds, and fish, which could in turn suffer if the mussels are tainted by the ash spill. (Related: "Hatcheries Strengthen Mussel Species on Appalachian River" [December 6, 2005].)

How Dangerous?

Coal ash, or fly ash, is a residue left over from burning coal for power. It is collected in ponds like the one at Kingston in 32 U.S. states, according to the Associated Press. Massive amounts of ash are sold for use in concrete, mulch, construction fill, and other purposes.

The U.S. government considers the ash a health and environmental risk, but the residue remains unregulated, and debate burns over just how toxic coal ash is.

A 1998 study by the Electric Power Research Institute, a nonprofit association allied with the power industry, found that "health risks from coal ash are minimal, whether it is in the form of a waste coal combustion by-product or a material used in construction products."

The study pointed out that heavy metals make up a small proportion of coal ash—and that these same substances occur naturally in rocks and sand.

But other experts point to evidence that the toxins in coal ash—also called coal combustion residues (CCR)—build up in bodies over time, sometimes with lethal effects.

"Whether accidentally discharged into natural aquatic systems or present in impoundments that attract wildlife, CCR appears to present significant risks to aquatic and semiaquatic organisms," Michael McKinney, the chair of the University of Tennessee's environmental-studies program, said in an email.

Specifically, coal-ash spills have caused behavioral and physical problems in some vertebrates and invertebrates, McKinney said. For example, exposure to ash toxins has been found to lead to severe deformations of tadpoles and fish.

Coal-ash exposure has also led to "fish kills and extirpation [local extinction] of some fish species," McKinney added.

Biologist Robert Jenkins of Roanoke College in Virginia witnessed just such an event about 40 years ago on the Clinch River in Tennessee, which was partially filled with sludge from the December 22 spill.

"I saw hundreds of thousands of dead fish at that spill" in 1967, Jenkins said, noting that water alkalinity, or pH levels, shot to 12.0 to 12.7—slightly less alkaline than household bleach—from a normal range of 7.8 to 8.5. "That was a huge chemical shock," he said.

Tests to determine the post-spill alkalinity of the Clinch are pending.

Should Coal Ash Be Regulated?

The U.S. Environmental Protection Agency (EPA) has long held that coal ash poses no substantial risks to the environment.

Currently, the EPA has produced no coal-ash regulations and strongly supports the substance's use in commercial products such as paints, kitchen countertops, concrete, and agricultural products such as mulch.

Jim Roewer, executive director of the industry-funded Utility Solid Waste Activities Group, said that while the EPA may not have broad-ranging regulations governing the ash, individual states do.

Critics, however, see a void and want coal ash declared a toxic substance.

Kert Davies, research director for the environmental group Greenpeace, says hundreds of coal ash dumps across the country lack meaningful oversight.

Green groups are now pointing to the Tennessee spill as evidence of regulatory need, and they're pressing the new U.S. President to act.

A group of six Tennessee environmental groups recently sent a letter to President Obama, requesting that he move to declare coal ash a hazardous waste.

The Southern Alliance for Clean Energy has even filed a lawsuit seeking to force the Tennessee Valley Authority (TVA)—the federally owned utility that produced and stored the ash—to restore ecological health to the spill zone.

Dave Goss, executive director of the industry-affiliated American Coal Ash Association, said, "It doesn't surprise us that people are calling for a re-review of federal regulations.

"We are going to let the science speak for itself. It is dangerous to mix science, policy, and passion."

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