Human skin can absorb ‘forever chemicals’, University of Birmingham researchers discovered, revealing a new pathway for these toxic substances to enter the body. The finding amplifies health concerns as researchers increasingly detect per- and polyfluoroalkyl substances (PFAS) in people worldwide.

PFAS are man-made chemicals that persist in nature and human bodies for a millennium before breaking down. This class of over 12,000 synthetic compounds derived from fossil fuel by-products is used across industries from textiles to construction and found in everyday items like cosmetics, waterproof clothing and non-stick cookware.

The chemicals have been detected globally in water, soil, and wildlife, even reaching Arctic regions. Scientists link PFAS to serious health issues, including cancer, liver damage, decreased immune response and developmental problems.

Recent studies show PFAS accumulating in testicles, breast milk, and unborn children, raising concerns about reproductive health and infant exposure. The full health impacts on children remain unclear.

In Europe, a leader in toxic chemical regulation, daily PFAS exposure already surpasses safety limits set by the European Food Safety Authority. A 2022 study found that food and dust intake alone push PFAS levels beyond these thresholds for both children and adults.

Now, the skin absorption study adds another layer of concern, suggesting that daily contact with PFAS-containing products could significantly increase overall exposure beyond the already harmful levels.

“This study helps us understand how important exposure to these chemicals via the skin might be,” said Professor Stuart Harrad, a co-author of the study.

‘Safe’ PFAS 

The new research challenges long-held beliefs about PFAS. Scientists previously thought the same properties that make these chemicals repel water and stains would prevent skin penetration. Using advanced 3D human skin models, researchers tested 17 common PFAS compounds; 15 showed significant absorption within 36 hours.

“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,” said Oddný Ragnarsdóttir, the study’s lead author.

Contrary to industry claims, shorter-chain PFAS compounds — introduced as ‘safe’ alternatives — were more easily absorbed by the skin. One such compound, commonly found in food packaging and cookware, demonstrated an absorption rate four times higher than longer-chain PFAS.

“We see a shift in industry towards chemicals with shorter chain lengths because these are believed to be less toxic,” Harrad explained. “The trade-off might be that we absorb more of them.”

The findings have significant implications for consumers, who may be unknowingly exposing themselves to PFAS through common products. While experts advise seeking PFAS-free alternatives, the chemicals lurk in countless everyday items, from electronics and carpets to musical instruments, dental floss, and books. Their widespread presence makes complete avoidance nearly impossible, even for the most informed consumers.

“We are continuously surrounded by consumer products that intentionally or unintentionally have things that we probably shouldn’t be using,” Graham Peaslee, a Notre Dame physicist specializing in identifying PFAS in consumer goods, told the Washington Post. “We are coating ourselves in this stuff every day.”

Regulators behind the ball

The mounting scientific evidence concerning the environmental and health dangers of PFAS is pushing regulators to take notice.

In the European Union, some PFAS are already restricted under existing laws and the bloc has set limits for PFAS in drinking water and certain consumer products. The European Chemicals Agency is considering a ban on PFAS, proposed by five member states in 2023.

The United States recently announced a review of the Environmental Protection Agency’s proposed rules to regulate PFAS dumping by industrial facilities involved in metal finishing, meat and poultry, textiles, and steam electric power generation. This marks a first step towards nationwide regulation of these chemicals.

As global regulators move slowly toward action on PFAS, experts worry the genie may already be out of the bottle. True to their moniker, “forever chemicals” take centuries to break down, persisting in the environment and human bodies.

The World Health Organization (WHO) recognizes PFAS as chemicals of concern. In 2022, WHO released guidelines on PFAS in drinking water, recommending combined limits for certain compounds.

PFAS are also addressed under WHO’s work on the Strategic Approach to International Chemicals Management (SAICM), a policy framework led by the UN Environment Programme and WHO that aims to achieve the sound management of chemicals throughout their life cycle to minimize adverse impacts on human health and the environment.

Industry hobbles efforts at international regulation

The fossil fuel, plastics, and chemical industries are deeply interconnected, with giants like ExxonMobil, Saudi Aramco, and Chevron dominating all three sectors. As with climate change, these companies knew about PFAS environmental and health risks decades before the public, according to recent research.

A 2023 study published in the National Library of Medicine found industry documents showing companies knew PFAS were “highly toxic when inhaled and moderately toxic when ingested” by 1970, 40 years before the public health community. The study alleges that companies employed tactics similar to those used by tobacco and pharmaceutical industries to influence science and regulation, including suppressing unfavourable research and distorting public discourse.

Today, industry interests continue to resist international regulation efforts. At Basel Convention talks this week, Russia opposed World Health Organization involvement in a Science Policy Panel on chemicals and waste. The proposed panel, similar to the IPCC’s role in climate change, would provide scientific evidence to treaty parties, potentially leading to tougher, binding rules.

Sources close to the talks say Russia, a major fossil fuel producer, opposes WHO involvement to limit scientific evidence on health impacts. This move could weaken future chemical regulations under the Basel Convention, the legally binding treaty governing transboundary movements of hazardous waste.

Fossil fuel and chemical producers have also stalled progress on a global plastic pollution treaty since talks began in 2022. Major plastics powers led by the United States, Saudi Arabia, China and Russia are blocking efforts to include production caps in the agreement, which would be legally binding if passed. These countries manufacture most of the world’s 380 million tonnes of annual plastic output.

While PFAS and plastics are distinct chemical families, both derive from petroleum products. PFAS often coat plastic products, such as grease-resistant food containers, but aren’t part of the plastic’s chemical structure. This shared origin in fossil fuels links these industries, complicating efforts to regulate either product independently.

PFAS are not the direct focus of the plastics treaty, but environmental experts, the UN Environment Programme, and a coalition of 66 ‘high ambition’ countries led by Norway and Rwanda are pushing for a broader scope. They advocate for a legally binding instrument that could include harmful additives like PFAS and cap plastic production. Major fossil fuel-producing nations oppose these measures.

The negotiations, conducted under UNEP, require consensus, giving significant leverage to those opposing production limits. The next session is scheduled for late 2024.

With 4.4 million tonnes of PFAS released between 1950 and 2015 and production still rising, the health threat posed by these toxic compounds continues to mount. The fossil fuel industry increasingly sees plastics and related chemicals as crucial revenue sources amid pressure to reduce oil and gas production for energy use.

Image Credits: Artur Voznenko, CC, Thijs ter Haar, Florian Fussstetter/ UNEP.