New research “proves for the first time” that toxic PFAS chemicals are absorbed through human skin at much higher concentrations than previously thought.
Although models and research indicate that the dangerous chemicals are absorbed through the skin, researchers from the University of Birmingham say they used lab-grown tissue similar to human skin to determine how much of a dose of PFAS compounds can be absorbed included.
The paper found that “dermal absorption may be an important source of exposure to these harmful chemicals,” said lead author Oddný Ragnarsdóttir.
PFAS are a class of approximately 16,000 compounds used to make products resistant to water, stains and heat. They are called “forever chemicals” because they do not break down naturally and build up in people. The chemicals have been linked to cancer, birth defects, liver disease, thyroid disease, declining sperm counts and a range of other serious health problems.
Humans are most exposed through water and food, but in recent years researchers have increasingly looked at inhalation and dermal absorption. The latter is of particular concern because of the wide range of products that contain PFAS and come into contact with the skin. These include bandages, waterproof clothing, makeup, personal care products, upholstery, baby products and guitar strings.
Researchers applied samples of 17 different PFAS compounds to the three-dimensional tissue model and were able to measure the proportion of the chemicals that were absorbed.
The skin absorbed ‘substantial’ amounts of 15 PFAS, including 13.5% PFOA, one of the most toxic and common types of the chemical. With longer use, the skin absorbed an additional 38% of the PFOA dose. U.S. regulators have found that virtually no level of exposure to PFOA in drinking water is safe.
PFOA is a relatively larger compound, and smaller “short-chain” PFAS that the industry is now producing more often and is claimed to be safer were absorbed in higher concentrations – up to nearly 60% of one dose of a short-chain compound was absorbed through the skin.
“This is important because we are seeing a shift in industry towards chemicals with shorter chain lengths, as these are thought to be less toxic – but the trade-off could be that we absorb more of them, so we need to know more about the risks associated with that,” said co-author Stuart Harrad.
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Some scientists and industry officials argue that PFAS used in personal care or makeup products are not absorbed because the molecules are ionized, allowing them to repel water.
“Our research shows that this theory does not always hold,” says Ragnarsdóttir.