How to make sense of the new findings on 'forever chemicals' in makeup

People who wear makeup such as lipstick or mascara may be absorbing or licking up potentially harmful ingredients that hang around for decades in the environment, according to a new study by researchers in the U.S., Canada and Switzerland.

Those ingredients, known as polyfluoroalkyl substances (PFAS), are rarely disclosed on labels, making them hard to avoid, said the study published Tuesday in the journal Environmental Science & Technology Letters.

What are PFAS and where are they found?

PFAS are a group of more than 9,000 human-made chemicals that contain fluorine bonded to carbon, a strong chemical bond that makes them hard to break down.

"What's really concerning about them is that they're highly persistent," said Miriam Diamond, a University of Toronto professor who co-authored the research. "It'll stick around for years, actually. … Decades."

That's why they're often referred to as "forever chemicals" by scientists. It's also how they can accumulate to high levels over time in the body or the environment.

PFAS have been used for lubricants, stain repellents, waterproofing, non-stick coatings and firefighting foams, and can be found in products ranging from carpets to cosmetics to food packaging.

How harmful are PFAS?

Very few PFAS have been studied in detail, but those that have been are linked to a variety of health effects in humans and animals, including increased risk of cancers, reduced immune response and fertility, and altered metabolism and increased risk of obesity.

Three groups of well-studied PFAS (PFOS, PFOA and LC-PFCAs) are prohibited in Canada because of their risk to the environment. But Health Canada says there's evidence other PFAS that are replacing these are also associated with environmental or human health effects. That's why the government is considering regulating all PFAS as a group.

Diamond noted that it's known that PFAS are "in all of us" as the substances are detected in blood samples, but scientists don't know exactly how people are being exposed to them.

Why did the researchers look for PFAS in makeup?

Studies in Europe and Asia have found dozens of products listing PFAS in their ingredients; they're touted for making products such as foundation, mascara and liquid lipstick more waterproof, durable and spreadable. Increased skin absorption of the product is listed as another benefit.

But it wasn't clear whether these were also in makeup sold in North America.

Environment and Climate Change Canada provided funding to look into that to help understand how PFAS are getting into the environment, Diamond said. Other funding came from the Great Lakes Protection Initiative, the Natural Sciences and Engineering Research Council of Canada and the National Science Foundation.

How did the researchers look for PFAS in makeup?

In the new study, Heather Whitehead, a graduate student in chemistry at the University of Notre Dame in Indiana, and her collaborators looked at 231 cosmetic products purchased in Canada and the U.S., including 17 Canadian products, most of which did not have PFAS listed on the label.

The researchers first tested for fluorine, a key element in PFAS. However, some of the fluorine detected by this way could also have come from other substances, including minerals.

Then the researchers did a more detailed analysis of 29 products with high fluorine levels, specifically finding detectable levels of at least four PFAS, including some that break down into smaller but highly toxic and environmentally harmful PFAS.

What kind of makeup are PFAS found in?

Overall, 52 per cent of the products tested had what the researchers considered to be "high" fluorine. But it was most likely to be found in products advertised as "wear-resistant" or "long-lasting." Tested products with high fluorine included:

• 82 per cent of waterproof mascara.

• 58 per cent of other eye products, such as eyeshadows, eyeliners and eye creams.

• 63 per cent of foundations.

• 62 per cent of liquid lipsticks.

Of the 17 Canadian products tested, only one had a PFAS on the ingredient label.

Many were designed to be applied close to the mouth or eyes, which the researchers said could increase exposure through licking, skin absorption or absorption through the tear ducts.

However, people are likely exposed to PFAS from a variety of sources, and it's not known what levels would be considered harmful in products like makeup. Health Canada says scientific information is limited on the majority of PFAS, although there are guidelines for maximum levels of PFOA and PFOS in drinking water.

Data scientist Xindi Hu previously worked on PFAS detection in drinking water while she was a research associate at Harvard University, but was not involved in the new study. She said translating the data from the study into exposure levels would require modelling based on assumptions about how much was being ingested and how long different PFAS persist.

"Based on the information presented in the paper, it is hard to judge whether these levels are high enough to warrant concern," she told CBC News in an email.

If PFAS are not on cosmetic ingredient lists, where do they come from?

The researchers think they've figured that out by poring through the ingredients list. Some ingredients used to add bulk to a product, such as mica and talc, can be treated with PFAS called PAPs to improve durability. Other ingredients such as methicone, acrylate and silicone polymers come in PFAS-containing versions.

"We speculate that PFAS detected were from these ingredients described on the labels using only their generalized name, for example, methicone, acrylate," the researchers said.

They added that the reported concentrations of those ingredients were consistent with the highest concentrations of fluorine measured in the analysis.

Diamond said that when some of the researchers reached out to the companies that made the cosmetics, many didn't realize there were PFAS in their products, as their supply chains are so complicated.

Hu said the fact that the products don't label PFAS in their ingredient list even though the researchers were able to detect PFAS in them was the most important message from the study. "This makes it challenging for consumers to make informed choices," she added.

Should people avoid makeup containing PFAS? How can they?

Diamond said she thinks consumers should avoid products with PFAS, given that the likelihood of exposure to PFAS when it's in a cosmetic product is very high and the chemicals are linked to negative health effects.

She added that the impact isn't just on the user either, as the product will ultimately get into the air or water. "So I'm not just contaminating myself when I use that product, but I have the potential to contaminate my whole community."

Fortunately, there are makeup options with little or no fluorine in them, the study found. Unfortunately, since PFAS aren't listed in the ingredients, they're hard to identify.

Diamond recommends avoiding products marketed as being waterproof, long-lasting or durable, which were most likely to contain PFAS.

Ultimately, she thinks they should be banned "because they're not necessary."

In the meantime, she hopes the research prompts cosmetic manufacturers to remove PFAS from their products and retailers to consider these ingredients when they market their products.

Haneen Al-Soheli, an Ottawa-based makeup artist and social media influencer, said she sometimes chooses long-lasting and water-resistant products for her clients when they have long events.

She checks the ingredients carefully to make sure they don't trigger allergies or sensitivities, she said, but didn't know PFAS could be in some products.

"I'm actually pretty surprised," she said. "It's my first time hearing that."

Al-Soheli said she believes the findings could increase mistrust of cosmetic products, and agrees with the idea of a ban on PFAS in cosmetics.

"If it can be avoided, 100 per cent, I think these ingredients, these harmful ingredients, should be avoided."

Fe de Leon, a researcher and paralegal at the Canadian Environmental Law Association, which has done research on PFAS in order to address government proposals on such chemicals, called the study findings "pretty significant and startling" as they point to gaps in government requirements for labelling and testing of products.

"This study will, I think, trigger some conversation not only amongst our groups, the NGOs, but certainly a conversation with the government to do more," she said.