Why the Nation's Biggest Environmental Distaster May Be About to Get Worse

This is the second in a series of investigative reports on the fallout from the Tennessee coal ash spill. Research support was provided by the Puffin Foundation Investigative Fund at The Nation Institute.

The Tennessee Valley Authority's efforts to clean tons of toxic coal ash are set to cause a "major toxic event" that could kill entire fish species and send a human health threat slinking up the food chain, according to scientists.

On December 22 the largest industrial spill in US history sent an earthen tsunami consisting of 5.4 million cubic yards of toxic coal ash sludge roiling out of a man-made lagoon and into the Emory River, which flows into the Clinch and Tennessee rivers. The ash clogged a section of the Emory River's navigation canal, forming an underwater "dam" that state and federal officials say could soon cause a flood of toxic backwater. On March 20, in a race to beat spring rains, the TVA -- a federally owned utility company -- began sucking out the toxic-sludge dam with huge hydraulic machines, putting it on land to dry out and be hauled away by trucks.

A handful of scientists are saying that the river-clearing operation will unleash a deadly pulse of selenium, an element found in coal ash that's good for humans in small doses but toxic to people, fish and wildlife at high levels. Water-treatment plants can filter selenium out of drinking water, but humans may still ingest harmful doses by eating contaminated fish and wildlife.

The EPA's hazard summary cites long-term studies showing that exposure to high levels of selenium in food and water have led to discoloration of the skin, loss of nails and hair, excessive tooth decay and discoloration, listlessness and lack of mental alertness. The agency also labels selenium sulfide, a selenium compound, a "probable human carcinogen." The EPA summary says hazard summary: "Acute human exposure to selenium compounds via the oral route has resulted in pulmonary edema and lesions of the lung; cardiovascular effects such as tachycardia; gastrointestinal effects including nausea, vomiting, diarrhea, and abdominal pain; effects on the liver; and neurological effects such as aches, irritability, chills and tremors. Selenium's impacts on animals can also be severe."

"This isn't just about fish and wildlife," said A. Dennis Lemly, a biologist who studied selenium for three decades while working at the US Forest Service. Federal scientists have documented at least a dozen cases where selenium has killed off fish and animal species, the largest selenium-related environmental disaster in US history being at Kesterson National Wildlife Refuge in California. "Fish were poisoned and there were massive deaths and deformities in waterfowl and other aquatic birds," Lemly recently wrote in a technical report. "This episode of contamination was extensively researched and documented by the US Fish and Wildlife Service and the US Geological Survey."

Problems of the Past?

As the dredging operation rolls toward its tenth week, a new scientific report by university scientists painted a picture of a river system that's already "loaded" with toxic levels of selenium. It also found that the unregulated, unlined structure that failed in December could have been the contamination source, quietly leaching selenium for decades. A study conducted at Appalachian State University (ASU) suggests that TVA's dredging operation will not only kick up large amounts of selenium-infused river sediment but will also bear down on a river that's already on a toxic edge. "Preliminary data suggest the selenium in the fish tissues may be the result of legacy selenium from decades of release of this metal from ash settling in ponds at the TVA Kingston plant," the study states. Tom Welborn, an EPA scientist, told The Nation that ASU tests and other studies indicate that the selenium contamination near the TVA's coal plant "appears to be a historic problem," meaning that the selenium contamination has been around for years.