The Haw River flows 110 miles from its headwaters in the north-central Piedmont region to the Cape Fear River just below Jordan Lake Reservoir. This 1700-square-mile watershed is home to a variety of fish and wildlife, including blue heron, bald eagle, largemouth and smallmouth bass, bowfin, and bluegill.
The Haw and its watershed also provide drinking water to nearly one million North Carolinians living in and around Greensboro, Burlington, Chapel Hill, Cary, and Durham. Population growth and sewage spills in the area, combined with aging pipes and infrastructure, have overwhelmed the systems put in place 60 years ago to protect clean water.
The results from an extensive Duke research project suggest that perfluoroalkyl and polyfluoroalkyl substances (PFAS) have made their way through drinking water treatment facilities and contaminated the local drinking water in Pittsboro, the Chatham county town of fewer than 5,000 people.
Known as “forever chemicals,” these soluble compounds are used in everyday products like nonstick cookware, carpets, food packaging, stain repellents and water-resistant clothing. The synthetic compounds are also commonly found in firefighting foam and gear, which has led to the contamination of most military bases and airports.
PFAS moves easily through soil and into groundwater and can’t be effectively treated or removed by most water treatment facilities. Reverse osmosis and boiling also don’t work. Unlike many pollutants, PFAS builds up in the human body and even low concentration exposure has been linked to a wide range of cancers, diseases, and negative health effects.
Scientists have known for more than six decades that PFAS has a toxic effect on human health. However, it wasn’t until the last days of the Obama administration that the EPA issued a lifetime health advisory for two of the most widely detected PFAS variants. While there are no enforceable NC state or federal regulations regarding PFAS in drinking water, the non-enforceable EPA health advisory level is 70 ng/L.
In June 2019, a team from Duke’s Nicholas School of the Environment, the Pratt School of Engineering, the Nicholas Institute for Policy Solutions, and the Department of Obstetrics & Gynecology Duke set out to test the Pittsboro drinking water for these complex, non-degradable substances.
The researchers began sampling the Haw River every week to understand the sources of PFAS to the Haw River, evaluate exposure in affected communities, investigate potential health impacts, and provide important information to local stakeholders to help develop local policies and initiatives to mitigate health risks.
By November, 49 Pittsboro residents had volunteered to provide blood and drinking water samples to be tested for the levels of PFAS; 43 returned a second sample in January or February, 2020.
This exposure study concluded that the levels of PFAS found in Pittsboro residents’ blood serum are two to four times higher than the general U.S. population. These levels are also similar to the blood serum results from participants in a similar study conducted in Wilmington as a result of the GenX chemical from the Chemours chemical plant in Fayetteville.
“These data suggest that any drinking water utility drawing water from the Haw or Cape Fear River between Burlington and Wilmington could have similar exposures, and that’s a lot of people,” said lead investigator Heather Stapleton. “There is still more research to be done to understand how PFAS blood levels may impact health.”