Contaminant in Mitchell Water Plant drinking water (copy)

The chemical compound PFOS emerged as a problem for the Greensboro water system during 2014, when researchers participating in a nationally required testing program found it at troublesome amounts in water from the Mitchell Water Treatment Plant.

FAYETTEVILLE — The PFOS problem with Greensboro’s drinking water took center stage briefly Tuesday in a daylong, regional meeting authorities held to discuss what to do about the gigantic class of industrial chemicals that includes the compound used for decades in firefighting.

Most of the “community engagement” session held by the U.S. Environmental Protection Agency focused on the related GenX compound that sullied the Cape Fear River and that has dominated environmental debate in North Carolina for the last year or so.

But Greensboro water official Mike Borchers also gave a 20-minute presentation about the city’s efforts to find the source and eliminate the substance causing trouble locally, perfluorooctane sulfonate, often found in firefighting foams used to smother industrial, highway and aviation blazes.

He recounted how discovering its presence at relatively high levels in a special EPA testing program several years ago triggered continued monitoring and a search for the source, which eventually led officials upstream from the Lake Brandt reservoir to Piedmont Triad International Airport and the surrounding industrial area where aqueous firefighting foams have been heavily used over the years.

“We’ve met with the airport, FedEx, HondaJet and others,” the assistant director of the city Department of Water Resources said of the so-far fruitless search for a major hot spot.

Borchers noted that companies in the area voluntarily inventoried storerooms to check for PFOS-containing substances: “I’m pleased to announce that it’s been a very collaborative effort.”

Borchers attended the event with interim Assistant City Manager Steve Drew, and they said afterward that it was an opportunity to get Greensboro’s PFOS problem before a larger audience of experts and to network with some of the nation’s most knowledgeable people when it comes to the massive chemical class that includes nearly 5,000 known substances and many more that environmental scientists have yet to decode.

After Borchers’ presentation, he and Drew met briefly with EPA official Thomas Speth of the agency’s risk management and research laboratory. Speth’s interest had been sparked by a remark Borchers made in his talk that he and other water department officials would love to develop a formula that could help them predict the time lag between when high PFOS readings are found near PTI and when they show up as a problem at the Mitchell plant miles away.

“He has some potential resources that might be able to help us with that,” Borchers said.

The public meeting at Fayetteville’s Crown Coliseum Complex was EPA’s public-review session for the southeastern states on the class of chemicals that includes PFOS, known in scientific parlance as “per- and polyfluoroalkyl substances,” a huge class of chemicals that for decades have been used in making everything from carpeting to microwave popcorn bags, water resistant clothing and emergency foams.

It was the fourth in a series of such regional meetings this summer. Communities across the country are having problems with these compounds to the extent that EPA held a national summit in Washington earlier this year to share information and determine next steps to take. Then-EPA director Scott Pruitt pronounced dealing with the issue one of the agency’s foremost objectives.

Greensboro’s problem with PFOS has been aggravated by another member of the same chemical family, PFOA, a substance used in years past to make Teflon and other nonstick surfaces. EPA has established a non-enforceable health advisory of 70 parts per trillion in drinking water as the recommended limit for the two related substances in combination.

Greensboro’s most recent combined reading in water from the Mitchell Plant was 96 ppt, following closely on the heels of a previous round of tests that found 80 ppt of the PFOS/PFOA combination. PFOS has always made up the vast majority of the contamination, Borchers and other city officials have said.

The more recent findings led the city to stop production at Mitchell, make immediate plans to add rented equipment capable of lowering the contaminant to acceptable levels, and — until the rented equipment can be installed — rely more heavily on the Townsend Treatment Plant and on purchasing more water from the Piedmont Triad Regional Water Authority and surrounding communities.

Long term, the city plans to install a multimillion-dollar, carbon-based filtration system capable of removing roughly 90 percent of PFOS, PFOA and some other related pollutants.

At Tuesday’s meeting, EPA officials said they were close to formally labeling PFOS and PFOA as hazardous substances, which would ultimately set strict limits on their presence in drinking water and likely make more resources available to communities battling them.

EPA’s Speth also was part of the panel discussion in which Borchers participated. In his comments as a panelist, Speth spoke highly of the “granular activated carbon” treatment technology that Greensboro has selected to eventually add at the Mitchell plant as a permanent fix. Speth included it among several technologies that all had pluses and minuses, but which he said could be effective when properly deployed and closely monitored.

The daylong meeting drew an audience of several hundred for three panel discussions that lasted much of the morning into the early afternoon and preceded a five-hour hearing for residents from the region to lend their voices to the debate.

EPA officials promised Tuesday to continue working closely with the state Department of Environmental Quality, communities and residents in confronting such challenges. But they held out little hope that putting limits on PFOS, PFOA, GenX and a dozen or so relatives currently under review would solve the problem.

“It’s a complex set of chemicals,” said Andrew Gillespie, associate director of EPA’s exposure risk lab in Research Triangle Park.

Gillespie said there are about 4,900 known forms of related compounds and many more forms unknown to regulators.

“They are everywhere,” added Laurence Libelo, chief of science policy for the agency’s Office of Superfund Remediation and Technology Innovation. “No soil sample does not contain some.”

But there’s hope in continued efforts to find solutions, said Peter Grevatt, director of the EPA’s office of ground water and drinking water.

“We don’t know everything about these chemicals,” he acknowledged, “but we have some of the best scientific minds working to understand them.”

Contact Taft Wireback at 336-373-7100 and follow @TaftWirebackNR on Twitter.

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