Duke study finds harmful level of element in lakes caused by energy plant

Research conducted by Duke University reported high levels of selenium in fish in lakes adjacent to Duke Energy power plants.

Selenium, often found in coal ash, is naturally occurring and beneficial to aquatic life at low levels. But at slightly higher levels, it can cause abnormal development in fish and aquatic birds, according to the study published in the journal of Environmental Science and Technology Feb. 6.

Study leader Jessica Brandt, a Ph.D. candidate at Duke’s Nicholas School of the Environment, said in an email the problem isn’t specific to Duke Energy.

“The issue of elevated selenium in freshwater lakes is a consequence of many factors including lake size and depth, hydrological connectivity to freshwater inputs and outputs and the rate of element loading from the ash pond to the freshwater system,” she said.

The results are important during the policymaking process to determine where or if energy companies can discharge waste to fresh waterways, she said.

Researchers tested water, sediment and fish from six North Carolina lakes, three with a history of high selenium levels and three without, in early 2015.

Selenium levels in 83 percent of fish muscle samples from Sutton Lake exceeded EPA criteria for safe levels. More than a quarter of the samples from Mayo Lake exceeded the same criteria. Samples from Mountain Island Lake were low enough to meet EPA regulations.

Erin Culbert, communications manager at Duke Energy, said in an email there has been no evidence of declining fish health in Sutton Lake in more than three decades of observation.

“Catch rates, reproduction and relative weight are typical measures of fish health,” Culbert said. “All three demonstrate a thriving fish population in Sutton Lake.”

Culbert said Duke Energy has already taken significant steps to reduce selenium.

“The Sutton and Riverbend coal plants have retired, and ash basins are being safely closed,” she said. “The Mayo Plant continues to operate to serve customers and already uses the latest technology for managing ash dry in a lined landfill.”

Frank Holleman, senior attorney at the Southern Environmental Law Center, said Duke Energy has suffered legal consequences for coal ash pollution in the past.

Because of legal action taken by the SELC in 2013, Duke Energy stopped producing electricity by burning coal at the Sutton Lake plant and has moved its coal ash storage from unlined storage bins that were contributing to pollution, Holleman said.

But he said the situation at Mayo Lake is worse.

“We have a state and a separate federal lawsuit against Duke for its illegal pollution at Mayo Lake,” Holleman said. “We are seeking to require that it remove its ash from the leaking lagoon and move it to Duke’s next door dry line landfill.”

Culbert said fish tissue selenium levels at Mayo Lake are declining and there is not evidence of impaired fish health. The unlined ash basin will close, she said.

“In fact, annual monitoring shows relative weights of largemouth bass indicate healthy, robust fish,” she said.

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