New Study Confirms ‘Forever Chemicals’ Can Be Absorbed Through Human Skin

A groundbreaking study has revealed that toxic synthetic chemicals, often referred to as 'forever chemicals,' can be readily absorbed through human skin. Published in *Environment International*, this research is the first to demonstrate that a wide range of PFAS (perfluoroalkyl substances)—chemicals known for their persistence in the environment—can penetrate the skin barrier and enter the bloodstream.

PFAS are commonly used in various industries and consumer products, such as school uniforms and personal care items, because of their water and stain-resistant properties. While some PFAS have been banned due to their toxicity, many are still in widespread use, and their harmful effects have not been fully explored.

Previously, it was believed that PFAS could not breach the skin barrier, though recent studies have hinted at a connection between personal care product usage and PFAS levels in blood and breast milk. This new study, the most comprehensive of its kind, confirms that these chemicals can indeed be absorbed through the skin.

Dr. Oddný Ragnarsdóttir, the lead author of the study, conducted this research as part of her PhD at the University of Birmingham. She explained, "It was previously thought that PFAS molecules couldn't cross the skin barrier because their ionized state made them water-repellent. Our research shows that this is not always the case, and skin absorption could be a significant source of exposure to these harmful chemicals."

The study examined 17 commonly used PFAS, focusing on those most widely studied for their toxic effects and most regulated under the EU's Drinking Water Directive. The researchers used 3D human skin equivalent models to simulate how these chemicals interact with human skin, finding that 15 of the 17 substances tested showed significant skin absorption.

Notably, perfluoro octanoic acid (PFOA), one of the most regulated PFAS, had an absorption rate of 13.5% with an additional 38% retained within the skin, potentially leading to prolonged exposure.

The findings suggest that PFAS with shorter carbon chains, often used as replacements for longer-chain compounds like PFOA, are absorbed more readily through the skin. For instance, perfluoro pentanoic acid was absorbed at a rate four times higher than PFOA.

Dr. Mohamed Abdallah, a co-author of the study, emphasized the importance of this research, noting, "Our study provides the first insight into how significant skin absorption is as a pathway for exposure to a wide range of forever chemicals. As the industry shifts towards shorter-chain PFAS, it is crucial to assess the risks these alternatives pose."

Professor Stuart Harrad, another co-author, added, "This study helps us understand how exposure through the skin might be more significant than previously thought, especially as the industry moves towards chemicals believed to be less toxic. However, the trade-off could be that we absorb more of these shorter-chain chemicals, making it vital to understand the associated risks."

Source:
Oddný Ragnarsdóttir, Mohamed Abou-Elwafa Abdallah, Stuart Harrad. Dermal bioavailability of perfluoroalkyl
substances using in vitro 3D human skin equivalent models. Environment International, 2024; 188: 108772
DOI: 10.1016/j.envint.2024.108772.