Four environmental groups have asked North Carolina's Environmental Management Commission for a ruling that would force Duke Energy to clean up groundwater contamination near ash ponds at 14 coal-fired power plants.
The power plants where contamination has been found include Duke’s Riverbend and Allen plants on the Catawba River west of Charlotte, and its Marshall plant on Lake Norman.
State officials say contamination has been found at all 14 plants, and that they are working to trace its sources. Coal ash contains metals that can be toxic in high concentrations, but some also occur naturally in soil.
“Iron and manganese do occur naturally, but we’re seeing them at much higher levels than at background wells, suggesting they’re coming from coal ash,” said D.J. Gerken, an Asheville-based attorney for the Southern Environmental Law Center.
High levels found
Other elements that aren’t normally found at high levels, selenium and thallium, have been found at Duke subsidiary Progress Energy Carolinas’ Asheville plant and its Sutton plant near the Cape Fear, he said.
Duke says selenium and thallium exceedances at those two plants have been only sporadic.
The law center represents the Waterkeeper Alliance, which includes Charlotte’s Catawba River Foundation, the Sierra Club, the Asheville-based Western North Carolina Alliance and Cape Fear River Watch in Wilmington.
Duke spokeswoman Erin Culbert said most of the contaminants are iron and manganese, which don’t pose health risks. Readings for other elements have been inconsistent, she said.
Culbert said there’s no evidence that contaminated groundwater has flowed off the sites of Duke Energy Carolinas’ plants in Western North Carolina. “If there were to be a problem found, we’re going to fix it,” she said.
Compliance boundary issue
The contamination documented so far has been found within a 500-foot radius around the coal ponds, called a compliance boundary. The N.C. Department of Environment and Natural Resources has interpreted state rules to say that contamination inside that boundary at power plants built before 1984 isn’t considered a violation.
The law center’s filing asks the environment commission to read the rules differently, forcing Duke to clean up the contamination inside the boundary.
The N.C. Division of Water Quality is still collecting groundwater data from each plant, said spokeswoman Susan Massengale.
Contaminants in excess of state limits have been found at the compliance boundaries at each plant, Massengale said, but some wells unaffected by ash also show contamination. Massengale said she’s aware of none of the contaminants being ruled a violation of state standards. That determination rests on a showing that the contamination didn’t occur naturally.
The commission has 30 days in which to rule on whether it will interpret the rules, Gerken said. If it refuses, the environmental groups can go to court. If it agrees, he said, the commission has 45 more days to review the rules.