Most of the private wells tested near Duke Energy’s North Carolina coal ash ponds show contaminants above state groundwater standards, state regulators said Tuesday.
Of 117 test results mailed to power plant neighbors in recent days, 87 exceeded groundwater standards, the Department of Environment and Natural Resources said.
In nearly all cases, DENR said, the well water would still meet federal standards for municipal water supplies. But health warnings included with many of the results advised that the water not be used for drinking or cooking.
The result: More uncertainty about whether the contaminants came from coal ash or occurred naturally. And confusion, environmental advocates say, about how to interpret the test results.
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Previous testing documented groundwater contamination at all 14 of Duke’s coal-fired power plants in the state.
Those results found the fingerprints of ash, which contains metals that can be toxic, in some cases. As a result, Duke is supplying water to three well owners near its Asheville plant and agreed to extend a water line at its Wilmington plant.
DENR required the new round of tests, of private wells within 1,000 feet of power plant boundaries, under a state law enacted after ash spilled from a Duke pond into the Dan River last year.
The latest tests found no clear evidence of ash contamination, said DENR assistant secretary Tom Reeder.
“We didn’t see that in these sampling results or any really, really high levels that we would say is well above natural levels,” Reeder said.
The department said iron, manganese and pH were the elements that most often broke the standards. All are found naturally in soil and groundwater, but are also found in coal ash.
Duke said it believes the contaminants are naturally occurring.
“Based on the test results we’re reviewed thus far, we have no indication that Duke Energy plant operations have influenced neighbors’ well water,” the company said in a statement.
Duke said none of the private wells held elevated levels of two ash elements, boron and sulfates, that migrate through groundwater more quickly than other elements. They serve as indicators of ash contamination.
“It’s been our experience that when we do see a (contaminated) plume, it’s led by boron and sulfates,” spokeswoman Erin Culbert said.
Environmental advocates say that doesn’t explain the vanadium that, according to The Associated Press, was reported in private wells around Duke’s Buck power plant near Salisbury.
Vanadium is a naturally occurring element that is also found in ash, although Duke says it is more often associated with petroleum products. The metal possibly causes cancer, the federal Agency for Toxic Substances & Disease Registry says.
“Despite public records showing large amount of vanadium disposed of by Duke Energy, DENR and Duke didn’t test for it in groundwater until we pushed them to do so,” said the Southern Environmental Law Center, which represents advocacy groups that have sued Duke over ash.
DENR’s results letters for Buck refer to different standards and are unclear about how to interpret the findings, added Peter Harrison of the Waterkeeper Alliance. The advocacy group has independently tested groundwater near the Buck plant.
One resident was warned in October not to drink well water because of its vanadium levels, Harrison said. Now, he said, some people whose wells showed less vanadium are getting the same advice while others with higher concentrations aren’t.
“DENR needs to assume a leadership role here and be transparent in explaining clearly to people who received letters telling them not to drink their water,” Harrison said. “DENR owes these people an explanation.”
Letters reporting test results were also sent to residents who live near Duke’s Allen plant in Gaston County, the Marshall plant in Catawba County and the Cliffside, Asheville, Belews Creek, Sutton and Roxboro power plants.
Reeder said tests are underway to learn what metals occur naturally in the soil and groundwater around the power plants. That, combined with analysis of the extent of tainted groundwater, will determine what contaminants came from ash.
“We’ll have a good idea in a couple of months and a more definite answer by fall,” he said.