Environmental advocates say Duke Energy’s studies of groundwater near its power plants, including two near Charlotte, contain defects that don’t accurately depict contamination.
The Southern Environmental Law Center, representing advocates, complained to the state environmental agency this week of “critical flaws” in Duke’s work.
Duke stood by its studies.
Duke is assessing groundwater to learn whether ash ponds at its power plants are contaminating private wells. The company has said that, in most cases, contaminants in the wells appear to come from natural sources.
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State regulators have not reached their own conclusions.
More than 200 neighbors of two power plants – Allen in Gaston County and Buck in Rowan County – have been advised not to drink their well water.
The law center charged that, at those plants, Duke failed to test groundwater in deep aquifers closest to private wells, underestimated the speed of contaminated groundwater flows and ignored critical data.
“The assessments we’ve reviewed contain bad science and do not determine the full extent of Duke Energy’s coal ash pollution of our groundwater and drinking water sources,” law center attorney Frank Holleman said in a statement.
In response, Duke said it relied on outside experts who followed state-approved work plans for the groundwater studies.
Duke said some of the law center’s own claims are inaccurate or suggest work that deviates from the state-approved plans. Other claims call for work that Duke already has underway, the company said.
In support of its stance, Duke says high levels of boron – an indicator of ash contamination – have not been found in private wells. It says groundwater isn’t flowing toward those wells in most cases.
Duke notes that two contaminants widely found in private wells – vanadium and hexavalent chromium – are also found far from ash ponds and in municipal water systems.
The state health agency has told plant neighbors that their water meets federal standards despite the presence of those contaminants.
But no federal standards exist for vanadium and hexavalent chromium, which may cause cancer. State officials instead developed safety thresholds based on the odds the contaminants could cause cancer.
“The fact that some well owners many miles from coal ash impoundments and municipal water customers are consuming water with levels at the same level, or higher, leads investigators to believe that vanadium and hexavalent chromium also occur naturally,” the state health agency wrote well owners Oct. 15.
Duke said the letter should be “welcome information” for plant neighbors who have been advised not to drink their well water.
The letter doesn’t mean regulators agree with Duke that contaminants in wells near ash ponds occur naturally, a state spokesman said.
“It’s one step in a bigger process,” said Mike Rusher of the Department of Environmental Quality. “It won’t be the last update to well owners.”