Samples of raw water — which has not yet been treated at the plant — were collected by scientists with the NC PFAST Testing Network from April through November 2019. The NC PFAST Testing Network is composed of scientists from seven universities working under the auspices of the NC Policy Collaboratory, which is funded by the state legislature and grants.
The sampling sites were chosen in consultation with the NC Department of Environmental Quality. The full dataset was released this month.
- Researchers looked for 15 to 47 types of PFAS compounds in raw water supplies, either from wells or surface water, depending on the utility.
- Of the 320 public utilities whose raw water supply was tested, nearly half had a sample that contained PFAS concentrations above the reporting detection level. (See chart below.)
- When broken down by the number of samples, of the 405 collected — 44%, or 178 — had at least one type of PFAS compound above the reporting detection level.
Because of a lack of federal regulations, there are a wide range of goals and thresholds for these compounds in drinking water — none of them enforceable. The state health department has set an provisional goal of 140 ppt for GenX. The EPA has set a recommended threshold of 70 ppt for PFOA and PFOS combined. And NC DEQ has stated that no one should drink water with levels of any individual PFAS above 10 ppt.
None of the samples exceeded the thresholds for GenX or PFOS and PFOA combined. However, 42 of the raw water samples had individual PFAS levels of 10 ppt or greater.
The scope of the study did not trace the industrial sources of the contaminants, only their presence or absence.
The highest total PFAS concentration was detected in the Haw River, the water supply for Pittsboro, at 844.8 ppt. For GenX, the highest level was 29.3 ppt in Pender County, which gets its water from the Cape Fear River. And the sum of PFOA and PFOS, two compounds that have been phased out, reached 57.5 ppt in the raw water supply for the Orange County Water and Sewer Authority. OWASA gets its water from the Cane Creek Reservoir and University Lake; it serves customers in Chapel Hill and Carrboro.
The hotspots in eastern North Carolina were primarily in the Lower Cape Fear River Basin, part of which has been contaminated with PFAS by the Chemours Fayetteville Works plant. However, farther upstream there were also spikes — in Smithfield, West Johnston County, Harnett County, Cary and the Harris Nuclear Plant Water Supply system.
In the Upper Cape Fear River Basin some industrial users and airports in Greensboro, Burlington and Reidsville are responsible for contaminated discharge. Even water systems not typically associated with PFAS contamination had hits, including Bessemer City, South Granville County and Tarboro.
PFAS levels in raw drinking water supplies
*Spike at Wrightsville Beach was at a well that had been closed.
Fields marked with dashes mean concentrations were below reporting limits. Some water system supplies were tested more than once and on different dates. Water systems without detections are not listed.
(Source: NC PFAST Testing Network)