Groups disagree on post-Florence water contamination

Did a breach at Duke Energy’s L.V. Sutton plant in Wilmington, North Carolina, that stores coal ash last month contaminate a nearby river? It depends on whom you ask.

The North Carolina Department of Environmental Quality’s early test results seem to match plant owner Duke Energy’s claims that the breach, caused by high waters from Hurricane Florence, has not harmed the Cape Fear River.

Tests from the environmentalist group the Waterkeeper Alliance show the opposite: arsenic levels more than 71 times higher than the state’s drinking-water standard.

Coal ash — industrial waste created by coal-burning power plants — is stored in ash basins in the ground. It is one of the largest forms of industrial waste, according to the US Environmental Protection Agency, and it contains heavy metals including arsenic, lead and mercury, which can pose serious health risks to humans and animals.

The hurricane caused a series of breaches in a cooling lake at the plant. Duke said that the coal ash basins remain stable and although there were discharges from the cooling lake to the river, they are “not harming water quality downstream.”

State testing done on September 25, 26 and 27 found that levels of all metals were below state water quality standards — with one exception. Dissolved copper showed a “slight” elevation, which officials said was the same upstream, downstream and at the Sutton Lake breach. Too much copper in drinking water can cause liver damage and kidney disease.

The state said it will continue to take samples in the area to make sure the company is in compliance with its permit to operate in North Carolina and to provide a “more complete snapshot” of water conditions at the facility and downstream.

Waterkeeper Alliance, the environmental group, says its tests, on samples taken September 21, show much more serious problems.

“The water in the Cape Fear River next to Duke’s Sutton plant had twice as much arsenic in it as the toxic gray coal ash slurry spilling straight out of the pipe into the Dan River in 2014,” said Donna Lisenby, global advocacy manager for the Waterkeeper Alliance.

In the 2014 spill — one of the largest coal ash spills in US history — government records showed, 39,000 tons of ash and 27 million gallons of ash pond water were released by another Duke Energy facility. It is unclear how much coal ash was released into the river from the new L.V. Sutton plant breaches.

“The Cape Fear sample also had higher levels of chromium, lead, manganese and selenium,” Lisenby said of the new test results. Depending on the concentration of these metals, exposure can be dangerous for humans and animals.

The explanation for these vastly different results may be in the timing, said Avner Vengosh, a professor of geochemistry and water quality in the Division of Earth and Ocean Sciences at the Nicholas School of the Environment at Duke University.

The tests were done at different times, and the concentration of the contaminants can change, said Vengosh, who was not involved with any of the testing. He also believes it’s too early to tell whether the river is in trouble.

“It will be impossible to capture any true measure of contamination, given the huge flow of water when they were doing this testing,” he said. “The real question the state is not addressing is if coal ash particles got into the river and the extent of that.”

Vengosh and a team of researchers conducted a study after the largest coal ash spill in US history, in Kingston, Tennessee, in 2008. Testing in open water at the time of the spill showed very low amounts of contaminants because coal ash, he said, does not easily leach into the water. It takes time for the heavy metals that come with the ash to become an environmental problem. It was only after the team tested the sediment and extracted the water trapped there that they found a large concentration of contaminants.

In the future, to get accurate results, the water trapped near the sediment and the sediment itself in the Cape Fear River will need to be tested to see whether these heavy metals and other contaminants have accumulated, Vengosh said. If so, they can pose a “huge risk for the ecological system.”

“From my point of view, calling the current test results ‘contamination’ or not really is not the issue, because it doesn’t tell us anything,” he said. “What matters over time is how much coal ash has been released into the river, what happened to the coal ash, how much it migrated along the river. Where was it deposited? Is it in the breach area, or is it elsewhere? That is the real issue and the critical question that will need to be addressed to determine if this spill had an impact or not.”