Coal ash discovered to have high levels of radiation

© Jon Woo
While coal has been known to contain high levels of radiation for years, a new study shows coal ash is up to 10 times more radioactive than unburned coal. This is particularly startling because coal ash is the second most common type of waste in the US.

The focus in explorations of the hazards of coal waste in regions where it is produced in the United States has previously centered on the heavy metals and toxins that are contained by the ash, but now there is another peril to add to the list, according to researchers at Duke University.

According to study released Wednesday, radioactive contaminants are found in coal ash at rates of up to five higher than in normal soil, and up to 10 times higher than in its parent coal because of the way that radioactivity is concentrated during combustion.

READ MORE: Climate change warrior Soros warms up on coal

Radium isotopes and lead-210 naturally occur in coal, but during combustion "the radium isotopes become concentrated in the coal ash residues, and the lead-210 becomes chemically volatile and reattaches itself to tiny particles of fly ash," according to the study.

“Until now, metals and contaminants such as selenium and arsenic have been the major known contaminants of concern in coal ash,” Avner Vengosh, professor of geochemistry and water quality at Duke and co-author of the study, said in a statement. “This study raises the possibility we should also be looking for radioactive elements, such as radium isotopes and lead-210, and including them in our monitoring efforts.”

Fly ash particles make up the majority of the waste that goes into holding pools and landfills, according to Nancy Lauer, a Ph.D. student in Vengosh’s lab who was lead author of the study.

Duke Energy, the largest utility corporation in the United States, said that it was aware of the study. Duke is the company responsible for a massive 2014 spill that saw 39,000 tons of coal ash and some 27 million gallons of coal ash slurry leak into North Carolina’s Dan River.

“This issue has been researched over many years,” spokeswoman Erin Culbert told WAVY-TV. “The U.S. Geologic Survey notes the majority of coal fly ash is not significantly enriched in radioactive elements, and this does not represent a health concern for plant neighbors.”

Culbert says that Duke Energy has done isotope testing of its own in the past and found no hazard, and that the company might test again in the future if necessary.

“The level of radioactive elements in groundwater near ash basins is either not detectable or extremely low and similar to what’s naturally in the soil,” Culbert said.

Coal ash is usually stored in holding ponds and landfills near coal power plants. Leaks from these ponds can lead to groundwater contamination, and the practice isn’t regulated quite yet.

“I think we have to treat this seriously,” Vengosh told WAVY-TV. “This should be defined as a hazardous waste and therefore should be treated as such.”

The Environmental Protection Agency’s (EPA) first-ever regulations on the disposal of coal ash are set for implementation in October. Under the new rules, all new ash ponds and landfills in the United States must be built with a protective lining underneath to prevent contamination. Existing sites are exempt from this rule, and only need to be cleaned up when it’s found that they are polluting the environment.

READ MORE: Huge coal ash spill in N. Carolina may cost Duke Energy $100 million

The United States generates 140 million tons of coal waste every year, according environmental group Sierra Club, but the effect that this waste has on the environment and public health isn’t clear.

"We don't know how much of these contaminants are released to the environment, and how they might affect human health in areas where coal ash ponds and landfills are leaking," Vengosh told Yahoo News. "Our study opens the door for future evaluation of this potential risk."