Recent Study: PFA and Skin Absorption

PFA Presence

Known as “forever chemicals”, per- and polyfluoroalkyl substances are ever-prevalent and have been linked to adverse health issues. They are commonly found in various products, and have even been found in food and drinking water. Recent research indicates that some PFAs can also be absorbed through skin exposure to the chemicals. Environmental chemists from University of Birmingham in England found that PFAs exposed to 3-D human skin models could cross the skin barrier, with the possibility of traveling into the bloodstream.

PFAs refer to a series of thousands of human-made chemical compounds which are known for their near unbreakable carbon-fluorine bonds, hence the “forever” nickname. Since the 1940s these compounds have been produced for products like nonstick pans and water-repellent fabrics. But research has shown that PFAs are difficult to degrade, prevalent in the environment, and harmful to human health. The U.S. Environmental Protection Agency set guidelines and limits in June 2022 due to alarming levels of PFAs in drinking water.

The Experiment

Past studies and research have suggested skin absorption as a possible route of exposure, but were data sparse. For example, one study found that a type of PFA could enter rat skin, but environmental chemist Stuart Harrad countered, stating that rat skin does not directly mimic that of a human. 

17 PFAs that come in contact with skin were analyzed in the new study by Harrad, Oddný Ragnarsdóttir and Mohamed Abdallah. In the lab, they dissolved each PFA in methanol and applied 500 nanograms per square centimeter to lab-grown human epidermis cells for up to 36 hours.

The Results

For each compound, researchers analyzed the amount which crossed the skin barrier, was absorbed within the surface of the skin, and not absorbed. Researchers found that 11 PFAs out of the 17 were able to cross the skin barrier, with ones with 4-7 carbon atoms absorbing more easily. They concluded that there is no certainty that PFAs will enter the bloodstream, but have been able to enter the skin.

Real-life scenarios may not reflect the behavior shown in the study as environmental scientist at the University of Toronto, Miriam Diamond, notes. Skin is thinner in areas like the eyelids and thicker in places like the feet, which can lead to differences in absorption levels. Dosages used in the experiments were also higher than what an individual would be exposed to normally. Regardless, she urges the importance of being cautious of PFAs in clothing and personal care products, as prolonged contact is a source of exposure.

Citations

O. Ragnarsdóttir, M.A. Abdallah and S. Harrad. Dermal bioavailability of perfluoroalkyl substances using in vitro 3D human skin equivalent models. Environment International. Volume 188, June 2024

O. Ragnarsdóttir, M.A. Abdallah and S. Harrad. Dermal uptake: An important pathway of human exposure to perfluoroalkyl substances? Environmental Pollution. Vol. 307, August 15, 2022

Tsanni, Abdullahi. “Some ‘forever Chemicals’ May Be Absorbed through Our Skin.” Science News, 31 July 2024, www.sciencenews.org/article/forever-chemicals-pfas-skin.