In early April, the Environmental Protection Agency placed its first-ever limits on these “forever chemicals” in drinking water as evidence mounts that chemicals in contaminated water can pose health risks to people even at the smallest detectable levels of exposure. Per- and polyfluoroalkyl compounds (PFAS) are a man-made class of thousands of carbon-fluorine bonded compounds developed to make products and coatings that repel grease, water, oil, and heat. Known as “forever chemicals,” PFAS can persist in the environment for centuries.
PFAS are known to enter the body through contaminated food and water, and through inhaling contaminated air. However, until now it was thought that PFAS could not penetrate the skin barrier. This study adds to the limited evidence proving that dermal exposure to PFAS can lead to dermal absorption.
Graham Peaslee, a physics professor at the University of Notre Dame who frequently tests for PFAS in everyday products, said waterproof makeup like mascara, long-lasting matte lipstick and waterproof clothing are examples of products that contain PFAS that can be absorbed through the skin. Peaslee, who was not involved in the study, said the chemicals are found in hundreds of household, personal care and beauty products, including cosmetics, water-repellent clothing, hand sanitizers and other stain-removing products. PFAS are commonly associated with several types of cancer, infertility, high cholesterol, low birth weight, and adverse effects on the liver, thyroid, and immune system.
New Research Extending single subject results study When PFOA was mixed with sunscreen and applied to the skin, the researchers concluded that PFAS can be absorbed into the skin. Using a cultured human skin model that mimics real skin, the researchers investigated the absorption potential of 17 commonly used synthetic “forever chemicals.” They then assessed how much crossed the skin barrier and entered the bloodstream, the total amount absorbed solely by the skin, and the total amount not absorbed at all.
They found that compounds with shorter carbon chains were more easily absorbed into the bloodstream than longer ones, said Harrad, professor of environmental chemistry at the University of Birmingham. Smaller chemicals are more likely to penetrate the skin barrier and accumulate in the blood.
“This is a low molecular weight [PFAS] For example, substances introduced as replacements for PFOA are said to be more easily absorbed through the skin.
A five carbon chain compound, perfluoro-n-pentanoic acid (PFPeA), was absorbed through the skin into the bloodstream about 60 percent, while a four carbon chain compound, perfluorobutanesulfonic acid (PFBS), was absorbed into the bloodstream about 50 percent.
But other compounds with nine carbons, such as perfluorononanesulfonic acid (PFNS), did not penetrate the bloodstream at all.
But the researchers predict that longer carbon chains could eventually enter the bloodstream over time after being absorbed through the skin. Over the 36 hours monitored in the study, only about 14% of the eight-carbon perfluorooctanoic acid (PFOA) was absorbed into the bloodstream, but more than 38% was absorbed through the skin. None of the PFNS entered the bloodstream, but about 70% was absorbed through the skin.
“We think it’s unlikely that it would go back the other way. It’s not going to get out of the skin. It’s more likely that it will migrate through the skin,” Harrad said. The amount that migrates through the skin depends on the amount of product used, the concentration of PFAS, and the type of PFAS in the product.
Cosmetics containing PFAS applied directly to the skin can penetrate the skin more quickly than fabrics or clothing containing PFAS, because in the latter products, the PFAS must first be released from the product materials before being absorbed into the skin through sweat or oils, Harrad said.
“We are surrounded by consumer products that, intentionally or not, contain substances that we probably shouldn’t be using,” Peaslee said. Absorption can be increased in areas with thinner skin, such as the neck, groin and armpits, he said.
But Peaslee, who says the main source of exposure to PFAS is drinking water, isn’t sure how much of that exposure is through skin contact.
“We cover ourselves with this stuff every day, so over time, a lot of this stuff could get through our skin and seep in at an incredible rate,” Peaslee said.
Katie Pelch, an environmental health scientist at the Natural Resources Defense Council, an environmental group, said the study raises concerns about regular showering and bathing in contaminated water, as well as swimming in water with high levels of PFAS.
The study looks at immune, hormonal and developmental effects, as well as the same group of chemicals linked to various cancers. Pelch said that once PFAS are in the body, the type of exposure doesn’t change the potential health risks.
“These chemicals are not metabolized in the body, so they are unchanged when they enter the body through the mouth or digestive system or enter the bloodstream,” Pelch said.
the only 8 states It has taken steps to limit PFAS in personal care products. The study looked at five chemicals that are included in the EPA’s new drinking water standards.
Harrad says the next step in her research is to expose cultured human skin models to a variety of consumer products containing PFAS and monitor absorption. She suggests consumers avoid cosmetics that contain PFAS and look for PFAS-free products.
He said people “need to be conscious of what’s actually in their products and be proactive, mindful consumers about these things.”
