Study: Toxins reaching N.C. lakes, rivers

Duke University researchers have found high levels of arsenic, selenium and other toxic elements in coal ash effluents and in North Carolina lakes and rivers downstream from the settling ponds of coal-fired power plants.

“In several cases, we found contamination levels that far exceeded U.S. Environmental Protection Agencyguidelines for safe drinking water and aquatic life,” Avner Vengosh, professor of geochemistry and water quality at Duke’s Nicholas School of the Environment, said in a news release about the results of a study into the issue.

The study was published in Environmental Science & Technology, a peer-reviewed journal. The Duke University team collected and analyzed more than 300 water samples from 11 lakes and rivers for the study.

Researchers found some of the highest levels in coal ash pond effluents flowing to Mountain Island Lake, a primary drinking water source for Charlotte, and also to the French Broad River in Asheville. The study also found high contaminant levels in Hyco and Mayo lakes, two popular recreational lakes in the northern part of the state.

One of the most striking findings of the study was that arsenic, a highly toxic chemical, is accumulating in the lake systems through retention in lake sediments. “In spite of efforts by some coal-fired power plants to reduce arsenic disposal, even a small quantity of arsenic release could result in long-time accumulation,” said lead author Laura Ruhl, who completed her Ph.D. in Vengosh’s lab this summer and is now an assistant professor at theUniversity of Arkansas at Little Rock.