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.
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.”