A number of toxic chemicals can be absorbed by the skin and get into the bloodstream, new research has proved.
The study involved 17 ‘forever chemicals’ – PFAS (perfluoroalkyl substances) – which do not break down in nature.
PFAS are commonly used in industries and products like school uniforms and personal care products due to their water and stain repellent properties.
Despite some of these chemicals being banned, a number are still commonly used but their effects on the body have not been fully examined.
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PFAS’ ability to get into the body by being breathed in or through food and water, is already well known.
Their health effects include a lowered immune response to vaccination, impaired liver function and lower birth weight.
Historically, it was thought that PFAS could not be absorbed through the skin, although more recent studies have found a link between personal care products and PFAS found in the blood and breast milk.
This study from the University of Birmingham is the first comprehensive piece of research to look at the extent to which PFAS breach the skin barrier. It has shown that most of those tested can get into the body through the skin.
Lead author of the study, Dr Oddný Ragnarsdóttir, said: “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.
“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 17 PFAS tested included some of the most widely used and most studied in terms of their toxic effects. Importantly, they correspond to chemicals which are regulated by the EU Drinking Water Directive.
The research used 3D human skin equivalent models, which use laboratory grown tissues that contain the same properties of human skin. These models were exposed to each chemical to see how much was absorbed, not absorbed, or retained within the models.
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Chemicals with longer carbon chains had lower levels of absorption, while those with shorter chains were absorbed more easily.
Study co-author, Dr Mohamed Abdallah, said: ‘Our study provides first insight into significance of the dermal route as pathway of exposure to a wide range of forever chemicals. Given the large number of existing PFAS, it is important that future studies aim to assess the risk of broad ranges of these toxic chemicals, rather than focusing on one chemical at a time.”
Study co-author, Professor Stuart Harrad, added: “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. 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.”
Read the full study in Environment International.
