PFAS Are Absorbed Through Skin Contact at Higher Levels Than Previously Thought, Study Finds

A new study has confirmed that per- and polyfluoroalkyl substances, also known as PFAS or forever chemicals, are absorbed through human skin. Additionally, researchers found that these chemicals are being absorbed through the skin at higher levels than previously thought.

The research, published in the journal Environment International, set out to investigate the dermal absorption of 17 types of PFAS, including PFOA, exposure to which the American Cancer Society found may increase risk of testicular, kidney, prostate, bladder, breast and ovarian cancers.

The researchers used models that mimicked human skin and tested how the skin could absorb some of the most common PFAS, including those described in the Drinking Water Directive of the EU, which is designed to ensure the safest drinking water for the public. According to a separate study published in April 2024, PFAS have been detected at high levels in groundwater around the world.

But in terms of skin absorption, PFAS can be found on things that come in contact with our skin daily, including waterproof garments, school uniforms, cosmetic products, personal care products, toilet paper and bandages.

“The ability of these chemicals to be absorbed through skin has previously been dismissed because the molecules are ionised. The electrical charge that gives them the ability to repel water and stains was thought to also make them incapable of crossing the skin membrane,” Oddný Ragnarsdóttir, lead author of the study, said in a statement. “Our research shows that this theory does not always hold true and that, in fact, uptake through the skin could be a significant source of exposure to these harmful chemicals.”

The researchers found that 15 of the 17 PFAS they tested were absorbed at substantial amounts. Perfluoropentanoic acid (PFPeA) and perfluorobutane sulfonate (PFBS) had some of the highest absorption rates at 58.9% for PFPeA and 48.7% for PFBS. PFOA had 13.5% absorption into the bloodstream and 38% that stayed in the skin, presenting the potential for long-term absorption.

As The Guardian reported, there have been claims that short-chain PFAS, which have fewer carbons in their compounds, are safer than long-chain PFAS, such as PFOA. But as the researchers found, the short-chain PFAS were still absorbed into skin at high levels.

“This study helps us to understand how important exposure to these chemicals via the skin might be and also which chemical structures might be most easily absorbed,” said Stuart Harrad, co-author of the study and a professor at the University of Birmingham’s School of Geography, Earth and Environmental Sciences. “This is important because we see a shift in industry towards chemicals with shorter chain lengths because these are believed to be less toxic — however the trade-off might be that we absorb more of them, so we need to know more about the risks involved.”