By Catherine Clabby

Let’s call it hexavalent chromium ping pong.

The state’s new Democratic administration came under fire this week over newly announced limits on how much hexavalent chromium, a dangerous element, will be allowed in well water very near coal ash pits.

The limit in question is a performance standard for water filtration systems that Duke Energy will install in some 175 homes within a half mile of its coal waste pits. At 10 parts per billion (ppb), the limit is more than 140 times higher than a hotly debated 0.07 ppb health advisory threshold that state toxicologists established 2015.

Debates over what was might be the proper threshold for human exposure to elements such as chromium-6 (also called hexavalent chromium) have raged inside state regulatory agencies.

“These new standards protect Duke, not the families,” said a statement released Wednesday from the Salisbury law firm Wallace & Graham, which represents some coal ash neighbors. “They fly in the face of guidance from North Carolina’s own Department of Health and Human Services.”

But at 6:37 pm on Wednesday DEQ shared a press release revealing that its newly announced limit could be temporary. That’s because DEQ Secretary Michael Regan, it turns out, is directing an advisory science panel to investigate whether revisions to state standards on hexavalent chromium are needed.

Fraught history

Internal and external debates over what levels of hexavalent chromium are safe in drinking water were among the most controversial aspects of Republican Gov. Pat McCrory’s management of the state law forcing Duke Energy to clean 100 million tons of coal ash. The debates were high profile in the Republican’s unsuccessful re-election campaign, too.

Resignation Fuels Suspicion
Criticism over the state’s response to possible coal ash risks in well water praised has been cited as a factor on former Gov. Pat McCrory’s failed re-election bid. Photo credit: Catherine Clabby

DEQ and the state Department of Health and Human Services sent do-not-drink advisories in 2015 to well owners near coal ash waste dumps who had hexavalent chromium exceeding the .07 ppb level in their well water samples. Despite opposition from long-tenured public health staff within DHHS, political appointees in the two agencies later rescinded those advisories in 2016 saying the advisories were too strict and out of step with national standards.

EPA limits on all forms of chromium in public drinking water, long expected to be tightened up, are currently less strict at 100 ppb, for instance.

When court depositions taken in the spring of 2016 revealed the length and depth of the internal disputes about safe levels of the metal, the state’s former health director and a former DEQ assistant secretary attacked Ken Rudo, a state toxicologist. They accused him of questionable and inconsistent scientific conclusions that stirred unnecessary fear and confusion.

Saying those accusations were dishonest distortions, state epidemiologist Megan Davies resigned in protest.

DEQ, in a written explanation of its new and maybe temporary standard, noted initially that the 0.07 ppb health standard is a non-enforceable calculation that estimates the level at which a pollutant would have no known health effects. The 10 ppb standard, on the other hand, is based on the state’s groundwater quality standards, enforceable rules set by the Environmental Management Commission.

A draft document from April first reported by Charlotte’s WBTV News on Tuesday offers evidence that internal differences have persisted over safe limits for hexavalent chromium within state government. Referring to DEQ’s water filtration standard of 10 ppb, the unsigned memo notes:

“Protecting people from exposure to unregulated contaminants is a function of public health. DEQ functions with regulated contaminants in drinking or ground waters under specific conditions (e.g. remediation, public water supplies, etc.)… The Occupational and Environmental Epidemiology Branch (OEEB) will continue use (sic) the health screening level of 0.07 ug/L for hexavalent chromium for its determination of health risk.”

Well owner Amy Brown talks to reporters at a press conference in Raleigh Thursday. She was flanked by Democratic leaders.
Well owner Amy Brown talks to reporters at a press conference in Raleigh in 2016. She was flanked by Democratic leaders Reps. Larry Hall (D-Durham), Valerie Foushee (D-Hillsborough) and Sen. Terry Van Duyn (D-Asheville).

Amy Brown, an outspoken critic of Duke Energy who lives near the Allen Steam Station in Belmont, said Wednesday afternoon that she felt like she was experiencing deja vu after hearing about the filtration standards, which she thinks are too low.

“It feels like we’re getting the it’s-ok-to-drink letter all over again,” she said. “Where is the science behind this?”

Some Republican activists have been quick to point out this week that the administration lead by Democrat Roy Cooper appeared to be managing hexavalent chromium less aggressively than candidate Cooper promised to. A headline in the conservative-leaning North State Journal took direct aim at the sitting governor. It read: “Cooper backtracks on well water campaign promise.”

But in a hastily arranged conference call at 6:40 pm on Wednesday, DEQ and DHHS staff members said DEQ Secretary Regan had planned since March to take steps to evaluate the adequacy of the new 10 ppb standard. Regan is directing his Science Advisory Board on Toxic Air Pollutants, whose mission is being expanded, to evaluate new health data and convene a public forum to decide if state groundwater standards for hexavalent chromium and other chemicals need to be changed.

That news wasn’t included in the performance standard announcement, staff said, because so many department members have been consumed by responding to revelations about GenX. That unregulated but controlled chemical has been detected in the Cape Fear River, which feeds public drinking water supplies.

Duke Energy’s obligation to install filtration systems at some homes near its coal waste is just one requirement of the state’s Coal Ash Management Act, passed in 2014 and revised last year. The systems being installed are expected to usually perform better than the newly announced state standard, utility spokeswoman Erin Culbert said.

“These treatment systems typically produce water below 1 ppb for those substances,” Culbert said. “The final water quality depends on the well water before treatment, and each system’s components will be customized based on that specific well owner’s results.”

One more thing to note: Research not long ago concluded that hexavalent chromium in drinking wells near Duke Energy waste originates from natural sources, not coal ash, in North Carolina. That said, it’s not yet certain where contaminated groundwater detected under the coal ash waste in this state may one day end up.

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Catherine Clabby (senior environmental reporter) is a writer and editor. A former senior editor at American Scientist magazine, Clabby won multiple awards reporting on science, medicine and higher education...

One reply on “More Scuffles Over Hexavalent Chromium”

  1. I cannot accept that the plan to convene a scientific advisory board to finalize a number would not have been included in the announcement that 10 ppb was the right level. And that the reason it was not discussed was because deq was too busy dealing with Genx? Here is a news flash – they aren’t dealing with Genx – and how much additional time would it have cost to include the strategy of a SAB in the announcement?

    Of course, Cooper was going to listen to scientists – fine – show me one scientist who thought 10 ppb was the right answer – just 1. I would also like to know whose idea it was to deep-six the draft memo written by scientists this year saying 0.07 ppb was the right number? I have heard it was Mandy Cohen dhhs politico.

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