Fitness trackers and smartwatch bands are the latest consumer products found to contain per- and polyfluoroalkyl substances (PFAS), according to new research from the University of Notre Dame.

In a study published in Environmental Science & Technology Letters on Wednesday, researchers tested 22 watch bands purchased in the U.S. from various brands and at a range of price points. Many of the bands were manufactured using fluoroelastomers, a synthetic polymer used to make rubber material resistant to sweat, skin oils and lotions. Results showed that nine of the 22 bands tested contained elevated levels of a type of PFAS called perfluorohexanoic acid (PFHxA). Elevated levels of PFHxA were more prevalent in higher-priced watchbands, or those costing more than $15.

The study is the first to address PFAS in fitness trackers and smartwatch bands.

“The most remarkable thing we found in this study was the very high concentrations of just one PFAS — there were some samples above 1,000 parts per billion of PFHxA, which is much higher than most PFAS we have seen in consumer products,” said Graham Peaslee, co-author of the study and professor emeritus in the Department of Physics and Astronomy.

PFAS have been widely used in consumer and industrial product applications since the 1950s. With a nearly unbreakable chemical structure, they do not degrade or break down, contaminating soil and groundwater systems and persisting in the environment for decades — earning them the name “forever chemicals.” Manufacturers use forever chemicals to make products resistant to water, heat and stains. Over the years Peaslee and his lab have detected PFAS in several industrial and consumer products, including fast-food wrappers, cosmetics, feminine hygiene products, eye drops, dental floss, plastic containers, textiles, firefighter gear and artificial turf.

The chemicals also migrate from treated surfaces onto skin and into dust and air, creating multiple paths of exposure including inhalation, ingestion and dermal absorption. Peaslee and his team cited this as a significant concern regarding wearable consumer products.

“Few studies so far have been published regarding the dermal absorption of PFAS,” said Alyssa Wicks, a graduate student in Peaslee’s lab and lead author of the study. “One article published earlier this year by a European research group found that a couple types of PFAS had significant transfer through the skin. That initial study only examined around 20 of the 14,000 known types of PFAS, and more studies are needed to better understand how PFAS travel through the skin.”

An estimated 1 in 5 Americans wear smartwatches or fitness trackers, according to a 2019 Pew Research study. Another study found consumers wear their wearables an average of 11 hours per day.

Peaslee’s lab tested samples using particle-induced gamma-ray emission ion beam analysis and liquid chromatography tandem mass spectrometry to determine the material’s total fluorine content and identify the specific type of PFAS present. High fluorine levels are a telltale sign of the presence of PFAS.

New and used bands were included in the study. The samples were also broken down by price point. Bands with price points less than $15 were listed as “inexpensive,” while those between $15 and $30 were considered “midrange” and those more than $30 were classified as “expensive.” Three of the bands tested were considered expensive, and all three contained significantly elevated levels of fluorine.

“Fifteen of the 22 bands we tested had a high percentage of total fluorine concentrations, and nine contained PFHxA,” Wicks said. “The others used some other unidentified surfactant that wasn’t in our targeted analysis.”

All three of the bands identified at the expensive price point and 12 of the 14 bands at the midrange price point contained highly elevated quantities of measurable fluorine. All five inexpensive bands contained very little total fluorine, measuring less than 1 percent.

Forever chemicals have been linked to multiple health conditions including immunosuppression, hormonal dysregulation, developmental delays in children, low birth weight and accelerated puberty, high blood pressure in pregnant women, and an increased risk of certain cancers, such as kidney and testicular cancer.

Peaslee said the results suggest that a more comprehensive study is needed to test the levels of PFAS band wearers are exposed to.

Heather Whitehead, a Notre Dame graduate and former doctoral student in Peaslee’s lab, was also co-author of the study.

Read more about how Notre Dame is tackling the problem of forever chemicals.

Contact: Jessica Sieff, associate director of media relations, 574-631-3933, jsieff@nd.edu