Reviewed by Lexie CornerDec 19 2024
A study published in Environmental Science & Technology Letters by researchers at the University of Notre Dame has identified per- and polyfluoroalkyl substances (PFAS) in fitness trackers and smartwatch bands.
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Researchers tested 22 watch bands from various brands and price ranges purchased in the United States. Many of the bands were made with fluoroelastomers, a synthetic polymer commonly used to enhance resistance to perspiration, skin oils, and lotions.
The findings revealed high concentrations of perfluorohexanoic acid (PFHxA), a type of PFAS, in nine of the 22 bands tested. Notably, higher PFHxA levels were found in more expensive bands, costing over $15.
This study is the first to report on the presence of PFAS in smartwatch and fitness tracker 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.
Graham Peaslee, Study Co-Author and Professor Emeritus, Department of Physics and Astronomy, University of Notre Dame
Since the 1950s, PFAS have been widely used in both consumer and industrial products. Known as “forever chemicals,” their durable chemical structure makes them resistant to degradation, allowing them to persist in soil and groundwater for decades.
Manufacturers use PFAS to make products resistant to heat, water, and stains. Over the years, Peaslee and his lab have identified PFAS in various consumer and industrial items, including plastic containers, textiles, firefighter gear, eye drops, dental floss, fast-food wrappers, cosmetics, feminine hygiene products, and artificial turf.
PFAS can transfer from treated surfaces to skin, dust, and air, leading to exposure through ingestion, inhalation, and dermal absorption. Peaslee and his team highlighted this as a particular concern for wearable consumer products.
Few studies so far have been published regarding the dermal absorption of PFAS. 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.
Alyssa Wicks, Graduate Student and Study Lead Author, University of Notre Dame
A 2019 Pew Research study found that 1 in 5 Americans wear fitness trackers or smartwatches. According to a different study, users spend an average of eleven hours a day wearing wearable technology.
To ascertain the material's total fluorine content and pinpoint the precise kind of PFAS present, Peaslee's lab tested samples using liquid chromatography-tandem mass spectrometry and particle-induced gamma-ray emission ion beam analysis. One obvious indicator of the presence of PFAS is elevated fluorine levels.
Both new and used watch bands were included in the study, with samples categorized by price. Bands costing less than $15 were labeled "inexpensive," those priced between $15 and $30 were classified as "midrange," and bands exceeding $30 were designated as "expensive." Of the three bands classified as expensive, all were found to contain significantly higher levels of fluorine.
Fifteen of the 22 bands we tested had a high percentage of total fluorine concentrations, and nine contained PFHxA. The others used some other unidentified surfactant that was not in our targeted analysis.
Alyssa Wicks, Graduate Student and Study Lead Author, University of Notre Dame
Significant levels of detectable fluorine were found in 12 of the 14 midrange-priced bands and all three of the expensive bands tested. In contrast, less than 1% of total fluorine was detected in all five of the low-cost bands.
Exposure to PFAS, or "forever chemicals," has been linked to various health concerns, including immunosuppression, hormonal imbalances, developmental delays in children, low birth weight, accelerated puberty, high blood pressure during pregnancy, and increased risks of certain cancers, such as kidney and testicular cancer.
Peaslee noted that the findings highlight the need for further investigation into the exposure risks associated with PFAS in watch bands.
Heather Whitehead, a former doctoral student in Peaslee’s lab and Notre Dame graduate, contributed as an author of the study.
Journal Reference:
Wicks, A., et al. (2024) Presence of Perfluorohexanoic Acid in Fluoroelastomer Watch Bands. Environmental Science & Technology Letters. doi.org/10.1021/acs.estlett.4c00907.