Study finds much arsenic in sediment downstream from TVA coal-ash spill

The environmental risks of coal ash may be worse than previously thought, says a new study from Duke University. Researchers found arsenic in water samples drawn below sediment downstream after the 2008 coal-sludge spill at the Tennessee Valley Authority power plant in Kingston, Tenn., Paul Quinlan of Environment & Energy News reports. In more than 220 samples drawn from sediment 18 months after the spill, the water had arsenic levels of 2,000 parts per billion. EPA's safety threshold for arsenic is 10 parts per billion in drinking water and 150 parts per billion for protection of aquatic life.

"The take-away lesson is we need to change how and where we look for coal-ash contaminants," author and geochemist Avner Vengosh told Quinlan. "Risks to water quality and aquatic life don't end with surface water contamination, but much of our current monitoring does." He added, "It's like cleaning your house. Everything may look clean, but if you look under the rugs, that's where you find the dirt." EPA is expected to release in the coming months its final ruling on whether to classify combustion ash from coal-burning power plants as hazardous waste.

Vengosh calls the EPA's impending decision as the "defining moment" in the coal-ash debate. "At more than 3.7 million cubic meters, the scope of the TVA spill is unprecedented, but similar processes are taking place in holding ponds, landfills and other coal ash storage facilities across the nation," Vengosh told Quinlan. "As long as coal ash isn't regulated as hazardous waste, there is no way to prevent discharges of contaminants from these facilities and protect the environment." (Read more, subscription required) Opponents of greater regulation have argued that high levels in sediment should not be cause for great concern because sediment is rarely disturbed.