Testing North Carolina Residents for GenX and Other PFAS After Well Contamination, 2018

In June 2017, local health departments in North Carolina asked the state Department of Health and Human Services for guidance on GenX and other per- and polyfluoroalkyl substances (PFAS) found in the Cape Fear River, an important source of drinking water. The contamination came from a plant that manufactured PFAS chemicals. In 2018 the state and CDC tested residents living near the plant to see what had reached their bodies.

What PFAS are

PFAS are a group of human-made chemicals used in industry and consumer products around the world since the 1950s. Most do not break down in the environment and can build up over time, raising human exposure. Limited studies in people suggest some PFAS might affect reproduction, development and the immune system, and raise the risk of certain cancers.

Contaminated wells

The North Carolina Department of Environmental Quality found GenX and other PFAS in surface water, air and private wells near the plant. By April 2018, 837 private wells within 5 miles had been tested. In 207 of them (25%), GenX exceeded the state's provisional drinking water health goal of 140 parts per trillion, and the highest level measured was 4,000 parts per trillion. The manufacturer began supplying bottled water to households whose wells exceeded the goal.

Who was tested

In August 2018, the state health department, working with local health departments, asked CDC to measure GenX and other PFAS in residents' blood and urine. Officials approached the households whose wells had the highest GenX levels and invited one adult and, where possible, one teenager aged 12 to 17 from each. To take part, people had to have lived in the home full time, have used the well as their main drinking water before GenX was detected in 2017, and have no known exposure to PFAS at work.

Of 47 households contacted, 25 (53%) were eligible and agreed. Thirty residents took part — 25 adults and five minors, aged 14 to 79, half of them male. All had lived in the county for at least 10 years, and all had been drinking bottled water for 4 to 14 months before their samples were taken. Each gave blood and urine and answered questions about their background, homes and possible PFAS sources. CDC tested blood for 17 PFAS and urine for 16, and where possible compared the results with national figures from the National Health and Nutrition Examination Survey (NHANES).

What was found

• No GenX. GenX was not detected in the blood or urine of anyone tested.
• Nine PFAS in blood. Two of them were markedly higher than in the national survey: the median level of PFHxS (perfluorohexane sulfonic acid) was 2.1 μg/L against 1.2 μg/L in NHANES, and the median level of linear PFOS (perfluorooctane sulfonic acid) was 5.5 μg/L against 3.2 μg/L. The other seven were at levels similar to or lower than the national figures.
• No differences by group. Blood PFAS levels did not vary with sex, age or years lived in the county.
• Almost nothing in urine. One participant had perfluorohexanoic acid in urine at 0.4 μg/L, close to the limit of detection; the other 15 PFAS tested in urine were not found.

What it means

GenX may have been missing because residents had switched to bottled water months earlier, which could also suggest that GenX leaves the human body relatively quickly. The higher levels of PFHxS and PFOS — two PFAS used in the past that stay in the body a long time — might reflect greater past or ongoing environmental exposure among residents.

Participants learned what could be detected in their own blood and urine after finding out their water was contaminated, received general information about possible health effects of PFAS, and were given guidance on discussing their results with their doctors. The authors note the findings may also help communities, public health agencies and researchers studying PFAS exposure in the future.

Sources

• Jamie R. Pritchett, Jessica L. Rinsky, Beth Dittman, Ariel Christensen, Rick Langley, Zack Moore, Aaron T. Fleischauer, Kate Koehler, Antonia M. Calafat, Rachel Rogers, Laconial Esters, Rodney Jenkins, Faye Collins, Debra Conner and Patrick Breysse, "Notes from the Field: Targeted Biomonitoring for GenX and Other Per- and Polyfluoroalkyl Substances Following Detection of Drinking Water Contamination — North Carolina, 2018," Morbidity and Mortality Weekly Report, CDC: https://www.cdc.gov/mmwr/volumes/68/wr/mm6829a4.htm