The team from NC State presented its results during a presentation Tuesday

WILMINGTON -- Residents of the Lower Cape Fear region likely have a "unique" set of man-made chemicals in their blood, researchers from N.C. State University said in a Tuesday presentation.

Researchers found newly identified per- and polyfluoroakyl substances (PFAS) including Nafion byproduct 2, PFO4DA, PFO5DoDA and Hydro-EVE in 99, 98, 98 and 76 percent of the blood samples taken, respectively.

"As far as we can tell, the presence of these chemicals is unique to Wilmington blood," said Nadine Kotlarz, a N.C. State postdoctoral researcher who has worked on the analysis. None of the quartet of chemicals were found in blood samples taken from 20 Triangle-area women in 2008-9 or from 24 Dayton, Ohio, people with high PFAS exposure between 1992 and 2014.

Researchers from the N.C. State Center for Human Health and the Environment did not detect GenX in blood samples, although their detection level was 2 parts per billion -- or 2,000 parts per trillion (ppt). Furthermore, the researchers found better-known PFAS such as C8 and PFOS are found in Wilmington residents' blood at higher levels than most of the country's.

Results are based on samples taken from 345 New Hanover County residents, largely last November, with 44 providing samples in both November 2017 and May 2018 to determine if levels had changes. Researchers tested the samples for 23 PFAS, including GenX and other chemicals associated with Chemours' Fayetteville Works operation.

N.C. State researchers did find the median levels for the newer PFAS chemicals fell from November 2017 to May 2018, but it wasn't clear if the 44 people tested in November and again in May continued drinking the area's tap water after learning of GenX's discovery.

'We know nothing about'

Researchers also told participants it is unclear whether the newly identified PFAS compounds could be impacting their health.

"The unfortunate thing is we have these chemicals that we found in people that we know nothing about. So how do we share it? Do we share it? But I feel we're obligated to share and walk people through our process," said Jane Hoppin, the deputy director of the Center for Human Health and the Environment.

Many of the new chemicals do, however, have long carbon links, raising concerns that they linger longer in the human body. GenX, for instance, has six carbon atoms, which is part of why it was initially believed to be safer than C8's eight carbons.

The newly discovered PFAS chemicals all feature six to eight carbon atoms, Hydro-EVE having eight. The four chemicals' chain lengths -- or total number of carbon, ether oxygen, and sulfur atoms -- range from 10 to 12, all longer than known toxicants C8 and PFOS.

"Questions about half-life in the body are certainly very relevant, and also bioaccumulation," said Detlef Knappe, the N.C. State environmental engineer who was part of the team that initially discovered GenX could be found in the river and in finished drinking water.

GenX not detected

Researchers did not detect GenX, the chemical that started Wilmington's water worries about 17 months ago, in the blood of any of the people tested. That does not mean, however, that GenX is absent from Wilmington residents' blood, as researchers had a lowest detection level of 2,000 parts per trillion.

"It is the limit of our method, so it means we didn't see it above the limit of our method. It's possible it would be there below the limit of our method, but every method has limitations," Kotlarz said.

Researchers told participants in a letter the non-detect levels of GenX likely mean GenX does not remain in blood for long.

An audience of just under 100 people attended Tuesday's meeting at Cape Fear Community College's Union Station.

During an April meeting, the N.C. State team revealed it found GenX in nearly every home whose tap water was tested in October and November 2017.

Wednesday, the U.S. Environmental Protection Agency (EPA) released its draft toxicity report for the level at which people can expect to orally ingest GenX over the course of a lifetime without experiencing adverse effects.

The reference dose for chronic exposure provided in the draft report -- .00008 mg/kg-day -- is not comparable to the parts per trillion (ppt) found in drinking water that Southeastern N.C. residents are familiar with. Rather, it is a number used by health professionals as a starting point in risk assessment.

In a factsheet, the EPA wrote, "The draft reference dose for GenX chemicals suggests that they are less toxic than PFOA and PFOS."

If North Carolina health officials used the EPA's draft reference dose with the same set of assumptions -- largely based on a bottle-fed infant's exposure -- they used in reaching their provisional health goal of 140 ppt, Knappe wrote, the number would drop to 110 ppt.

The EPA will accept comments for 60 days after the draft toxicity assessment is published in the Federal Register before revising it. A factsheet associated with the assessment also stated the federal government does not plan to issue a regulation for GenX.

"Once the assessments are issued," the EPA factsheet stated, "state, tribal, and local partners can use this information to help inform whether local actions are needed to protect public health."

Legacy PFAS remains high

In addition to the four chemicals researchers are describing as "new" PFAS, Wilmington residents have levels of better-studied PFAS chemicals such as C8 and PFOS in their blood that near the levels found in the rest of the country about 20 years ago.

"It suggests that there's been an unusually high exposure to historically used PFAS in Wilmington compared to the United States," Kotlarz said.

For instance, the presentation included a slide showing the Centers For Disease Control and Prevention's (CDC) 1999 National Health and Nutrition Examination Survey found levels of C8 in blood averaged about 5,200 ppt nationally in 1999, dropping to 1,500 ppt nationally in 2015.

Wilmington's residents, meanwhile, maintained levels of about 4,400 ppt in their blood when the N.C. State researchers tested them in November 2017.

Hoppin said, "I think it's a watershed issue. It's unlikely that the people in Wilmington have so much more stain resistant (material) than everybody else in the United States, so I think it's got to be some environmental exposure that contributed to that."

The chemicals can be found in a wide variety of products, including water resistant clothing, upholstered furniture and fast food wrappers, among hundreds of others.

Knappe suggested the Cape Fear watershed itself could provide some answers. In Greensboro, for instance, officials have tracked PFOS levels back to firefighting foam used at Piedmont Triad International Airport.

"A lot of these historical-use compounds are still coming down the river, also," Knappe said, "and one potential reason the levels in the blood didn't decrease in the historical-use compounds is those sources weren't really turned off."

N.C. State researchers are continuing their work, next analyzing urine samples taken along with the blood samples. They are also working on identifying predictors for high levels of PFAS and associating what they could mean for human health.

"We have more work to do," Hoppin said. "We're not going anywhere anytime soon."

Reporter Adam Wagner can be reached at Adam.Wagner@GateHouseMedia.com.