Floodwaters caused by Hurricane Florence in September 2018 reach the L.V. Sutton combined-cycle gas plant in Wilmington, N.C.
Duke Energy Corp. is blasting a study by a Duke University professor that shows that an eastern North Carolina lake has been "contaminated by multiple coal ash spills," most of which were unreported. The company said the contamination found in the lake is not indicative of a widescale problem at waterways near its coal ash sites.
"It is ludicrous to compare decades-old ash at the bottom of a manmade wastewater facility to anything found in conventional lakes and rivers," Duke Energy spokesperson Bill Norton said in an email. "This wastewater facility did exactly what it was designed to do, serve as a buffer between our former coal plant and the Cape Fear River to keep the public and environment safe."
Duke University's Nicholas School of the Environment issued a news release June 3 outlining research that shows "evidence of multiple unmonitored coal ash spills" in Sutton Lake, which is adjacent to Duke Energy's L.V. Sutton combined-cycle natural gas plant.
"Our results clearly indicate the presence of coal ash at the bottom of Sutton Lake and suggest there have been multiple coal ash spills into the lake from adjacent coal ash storage facilities after, and even before, floodwaters from Hurricane Florence caused major flooding in 2018," Avner Vengosh, professor of geochemistry and water quality at the Nicholas School of the Environment, said in the release.
Vengosh led the research, which included collecting and analyzing sediments from Sutton Lake and nearby waterways in 2015 and 2018. Vengosh and his colleagues published their findings May 24 in Science of the Total Environment, a leading international peer-reviewed journal.
"The levels of coal ash contaminants we detected in Sutton Lake's sediments, including metals with known environmental impacts, are similar to or higher than what was found in stream sediments contaminated by the 2008 Tennessee Valley Authority coal ash spill in Kingston, Tennessee, or the 2014 Dan River spill here in North Carolina," Vengosh said.
The lake, which is on the Cape Fear River, is now used for recreational boating and fishing.
However, Norton said, "[T]here's really no comparison between Sutton Lake" and other waterways adjacent to the company's coal ash sites.
Duke Energy said Sutton Lake was "designed, constructed and operated as a permitted and integral part of the coal plant wastewater treatment system for decades."
"As such, it is not surprising that the lake sediment shows evidence of coal plant operations," Norton said, adding that the lake was not designated as public waters until 2014.
"Duke Energy has monitored Sutton Lake's fish community for many years and our data indicates a healthy, self-sustaining and balanced fish community," Norton added.
Following flooding at the L.V. Sutton site in September 2018 caused by Hurricane Florence, Duke Energy told S&P Global Market Intelligence that the lake does not store coal ash. The company described the lake as a 1,100-acre reservoir built in 1972 that supplied cooling water to the now-retired and demolished L.V. Sutton coal plant.
Norton added that "no substantial quantities of ash were released to Sutton Lake" from the hurricane or other major flooding events.
The company does store about 5.7 million tons of coal ash on-site, including in two ash basins and a new lined landfill.
Duke Energy said one large breach and several smaller breaches as a result of Hurricane Florence caused water to exit the lake into the Cape Fear River and into the natural gas plant property. The breaches prompted the company to take the gas plant offline for several weeks, but officials said water quality remained "well protected" near its coal ash sites.
"Even after Hurricane Florence, state regulator testing of the Cape Fear River demonstrated water quality remained protected and people remained safe from coal ash impacts," Norton said.