There are elevated levels of leachable per- and polyfluoroalkyl substances (PFAS) in several smartwatch wristbands, US researchers have shown. Fluoropolymers are often employed in such products owing to their oil-and water-repelling properties. The research suggests that some bands contain significant residues of perfluorohexanoic acid (PFHxA) – used as a surfactant during manufacturing – providing an opportunity for skin exposure.
Researchers at the University of Notre Dame in Indiana, tested 22 wristbands across various brands and prices. Particle-induced gamma-ray emission spectroscopy showed total fluorine concentrations indicative of some fluoropolymer content in 15 of them (including two that were not advertised as containing fluoropolymers). Solvent extraction and testing for 20 different PFAS revealed measurable PFHxA in nine bands, including four with levels greater than 1 ppm, as well as some other PFAS.
‘We have never seen extractable concentrations in the part-per-million range (>1000 ppb) for any wearable consumer product applied to the skin,’ stated Graham Peaslee, the study’s leader.
The team suggests that the predominance of PFHxA and the relatively high concentrations suggest it is an integral part of the manufacturing process.
The high levels of PFHxA available, paired with users often wearing these items for more than 12 hours per day, ‘poses an opportunity for significant transfer and subsequent human exposure,’ the researchers warn.
It remains unclear how readily PFHxA transfers into the skin and what sort of health effects such exposure causes, but recent studies suggest that PFAS can pass through human skin under normal conditions, according to Peaslee.
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