They are present everywhere around us: on non-stick pans, certain food packaging, water-repellent clothing, medical equipment, in cosmetics or electronic devices… They are PFAS. Behind this English acronym (pronounced “pifasse”) hide per- and polyfluoroalkyl substances: a family of synthetic chemical compounds incorporating fluorine. Very resistant, they give the products concerned characteristics sought after by individuals and manufacturers alike. The reverse ? PFAS are very poorly biodegradable. They can persist for a very long time in the environment, hence their nickname “eternal pollutants”.
PFAS, which appeared in the 1940s, contaminate soil, surface water and groundwater. Their lifespan allows them to travel and find themselves thousands of kilometers from their place of production and emission, up to the poles or the peaks of the Himalayas. In France, they massively polluted the chemical valley, near Lyon. The Auvergne-Rhône-Alpes Regional Health Agency announced, Monday January 15, that it had measured some of these components at levels above the European reference threshold in tap water received by more than 160,000 people, and requests corrective measures from the municipalities concerned.
There are indeed numerous concerns regarding their consequences on health, which are increasingly studied: by accumulating over the long term and in high doses, PFAS can cause cancer (testicle, prostate, kidney), cause disorders of growth or even failures of the immune system, with a marked risk for pregnant women and fetuses.
To address this industrial, environmental and public health problem, the French government presented an action plan against PFAS in January 2023. It includes in particular “bring to the European level a broad ban to eliminate the risks linked to use or placing on the market” of these components. The European Chemicals Agency made public, in February 2023, a proposal to this effect, supported by Germany, the Netherlands, Denmark, Sweden and Norway, but the discussions are not expected to conclude before 2025 , as soon as possible. Can we do without these substances, when they are everywhere around us?
Uses sometimes adopted for comfort
PFAS form a large family which includes between 4,000 and 10,000 substances, emphasizes to franceinfo Anne-Christine Macherey, toxicologist within the Chemical Risk Prevention unit of the CNRS. Their applications are extremely varied, and often very specific: a viable alternative solution in one case will not necessarily be viable in another. How to find your way there? Which compounds and which uses should be banned? In an article published in 2019, a team from Stockholm University (Sweden) distinguishes three categories of use of PFAS: uses “comfort”uses “replaceable” and uses “essential”.
Among the uses “comfort”, the authors of the article mention dental floss, swimsuits whose fabric repels water or even ski wax. So many products for which there are already PFAS-free alternatives, sometimes less practical, but whose adoption has no disadvantage for “the functioning of society”, summarize the scientists. Thus, biathletes are now prohibited from using wax containing fluorine in competition, and too bad if the races are slower.
To illustrate the uses “replaceable” – products that we could hardly do without, but for which suitable alternatives to PFAS exist – the Stockholm team cites certain waterproof textiles, but mainly points towards “most uses of firefighting foam”. Indeed, in Europe, the majority of areas heavily contaminated by PFAS are due to the use of these foams, particularly in air bases and airports, as pointed out by France 3 Bourgogne-Franche-Comté at the start of 2023. “In firefighting foams, PFAS help absorb oxygen present in the air, which reduces the flames, and therefore weakens and then extinguishes the fire”explained Pierre-Marie Badot, professor of ecotoxicology at Franche-Comté University.
Finally, by uses “essential”researchers in the Swedish capital designate those “necessary for health or safety or other matters of high importance, and for which alternatives have not yet been found”. This may in particular be “certain medical equipment” Or “protective clothing”.
Surprise guests in our kitchens
Comfort uses are easily identifiable. “Many people are not aware that when they pick up a cardboard straw or a pizza box, there are PFAS in it”, which can end up being found in their body or the environment, comments Michael Ryckelynck, professor of biochemistry at the University of Strasbourg, to franceinfo. They allow these containers to resist heat, humidity and grease. This did not prevent the Danish authorities from banning their use in food packaging since July 2020. “If we can get rid of them and avoid them, we might as well ban them. We could very well decide to do without this type of product, Denmark shows it”commented in 2021 on franceinfo Philippe Froguel, geneticist and endocrinologist at the CHRU of Lille.
The same observation can be made about non-stick pans coated with Teflon, a registered trademark behind which a type of PFAS is hidden. They can be advantageously replaced by “the good old cast iron pan”notes Michael Ryckelynck – stainless steel or enamel-coated utensils are also alternatives.
Many waterproof clothing items are still covered in PFAS. Brands specializing in outdoor activities have, however, chosen to no longer use perfluorinated chemicals for several years, and are even making this approach a marketing argument, underlines Pierre Labadie, environmental chemist at the CNRS. As early as 2015, the Danish Ministry of the Environment highlighted, in an 84-page report (PDF file)alternatives to these synthetic compounds for the treatment of textiles.
Alternatives sought in medicine and industry
For firefighting foams, also called extinguishing foams, products without fluorine, and therefore without PFAS, are now available. They are more expensive and require some adjustment to use. But professionals are converting, anticipating a possible change in legislation in Europe.
On the side of industrialists, identified by the government as “significantly emitters”, exit doors are emerging. The Arkema company, targeted by a collective complaint and particularly singled out for its role in pollution south of Lyon, claimed in February 2023 to be “already engaged in a process of completely stopping the use of the only fluorosurfactant still present in its manufacturing processes on the Pierre-Bénite site”. She specifies that she can do without it “from the end of 2024”, “thanks to a substantial investment” in the research and development of alternatives. These promises are not surprising, because its site is probably the most scrutinized in France. The Ministry of Ecological Transition highlights it as a “a precursor to this approach to identifying and reducing PFAS releases”.
In the medical field, where many uses of PFAS can be considered essential and vital (for example for the manufacture of catheters and other invasive devices), significant efforts must still be made to find substitutes. Thus, 20% of drugs contain PFAS, according to a CNRS researcher who is working on an alternative to a compound containing fluorine, widely used because it allows certain drugs to be well assimilated by the body.
A very complicated decontamination
Learning to do without PFAS is all the more urgent as no miracle solution exists to get rid of them once they are distributed in nature. Decontamination processes have been developed, but they are very expensive and can only be applied to restricted areas. To broaden the range of treatments, Michael Ryckelynck and Stéphane Vuilleumier are leading a research project on microorganisms that could be capable of overcoming PFAS. But they also plead for upstream action, by restricting the use of these chemical compounds as much as possible.
“Even if we find a solution [de dégradation des PFAS], this is not why we must continue to do anything. If we produce poisons, and we knowingly know that they are toxic compounds, we must reduce their use as much as possible.”
Michael Ryckelynck, professor of biochemistry at the University of Strasbourgat franceinfo
Not to mention that PFAS pollution can be very diffuse and vary depending on the sources of contamination, warns Stéphane Vuilleumier: “Decontamination does not mean vacuuming your living room.” Faced with the urgency and immensity of the subject, the authorities should not hesitate to put their hands in their pockets, according to Pierre Labadie. “Finding alternative processes has a cost, underlines the chemist. But inaction also has a cost, particularly in health terms.”