Many everyday products, such as the coatings of non-stick pans or our favorite beauty products, contain PFAS in their composition. These substances, until now unknown to the general public, are at the heart of debates in France. Indeed, on April 4, 2024, deputies adopted a bill aimed at prohibiting the presence of these “eternal pollutants” in clothing, cosmetics and ski waxes, from 2026. But, what does the term PFAS mean, where are they found and what are the risks for health and the environment? We take stock with Bruno Ameduri, Director of Research at the CNRS at the Institut Charles Gerhardt Montpellier (ICGM).
What are PFAS, these per- and polyfluoroalkyl substances?
Behind these four letters “PFAS” is the term “per- or polyfluoroalkyl substances”, a family of several thousand chemical compounds. The latter have been widely used in industry since the 1940s due to their non-stick properties, for example in waterproofing paints or paints resistant to high heat or aggressive agents.
Bruno Ameduri, Director of Research at CNRS, divides PFAS into two categories:
- THE “low mass molecules”, also called “organic molecules”. Among them, we can find PFOS, PFOA and PFNA, already in the crosshairs of health authorities. These last “are water solublemobile and toxic, persistent, able to cross the cell membrane and remain in the blood (said to be bioaccumulative)”explains the specialist before specifying, “it is particularly these molecules which are the subject of debate”.
- THE “large molecules”, also called “macromolecules”. In this category we find fluoropolymers, used in particular for non-stick coatings, in aeronautics, optical fibers or even in batteries or membranes for fuel cells in hydrogen vehicles. According to Bruno Ameduri, these molecules are “insoluble in water, non-toxic, and do not cross the cell membrane. They are not bioaccumulative”. The specialist specifies that “These macromolecules are essential in the manufacture of materials for which there is no alternative. Since the accident of the Space Shuttle Challenger, which exploded 75 seconds after takeoff, the addition of fluoropolymers in the seals has added reliability and safety. The latter are biocompatible because “because many people have artificial veins, or cardiovascular prostheses, and coronary artery bypass grafts are made of fluoropolymers”specifies the specialist.
Why are PFAS called “forever pollutants”?
Over the years, the use of PFAS has become prevalent in industry and the composition of everyday objects, leading to environmental pollution.
To understand the difficulty of degrading PFAS, we must look at their chemical composition. Indeed, “they are very chemically stable”, explains Bruno Ameduri. In organic chemistry, “The carbon fluorine bond is extremely stable and very difficult to cut. It is for these thermal and chemical stability properties that we find them in many industrial applications”. Also, to cut this connection “carbon-fluorine”they must be heated to 800 degrees or via an electronic bombardment technique.
It is this difficulty in degradation which leads to environmental pollution, particularly for low mass compounds.“which are often water-soluble and pass into seas, soils, rivers and are found everywhere”, like in the human body.
PFAS: what are the health effects?
Currently, research on the health consequences of PFAS is still being studied but, it is not uncommon to find PFAS in the blood. The analysis of 152 people (including some public figures like Nagui or Mélanie Laurent) and carried out in March 2024 by the environmentalist deputy Nicolas Thierry reveals that “94% of them are contaminated by at least one PFAS”.
Their presence in the human body can be explained, again, at the chemical level, notably via organic fluorine. “It should be noted that the enzymes generated by the human body to break down viruses are not capable of breaking down PFAS, which causes low-mass PFAS to remain in the blood,” explains Bruno Ameduri. Also, it is not uncommon to find PFAS at doses “more or less high, namely a few micrograms per liter, which is equivalent to a few drops in an Olympic swimming pool”. In addition, there are thousands of PFAS, each with their own specificity. Also the knowledge relating to these substances is not yet known exactly.
The toxicity of PFAS is still unknown. Previous research on rats “showed that no effect was observed even at concentrations of PFOA or PFOS of 50-70 ppm (Part per million, Editor’s note). Negative effects on cholesterol were noted at 75ppm”
Among the most exposed people who have been the subject of studies, we find the case of firefighters in the United States, who were very exposed to PFAS, the latter using firefighting foams which included PFAS in their composition. Over time, researchers have noticed an increase in cases of cancer or prostate problems or leukemia.
If studies are carried out to determine the exact consequences of PFAS, ANSES notes that “scientific work on certain known PFAS shows that they can have deleterious effects on humans”, such as :
- an increase in cholesterol levels,
- cancers,
- effects on fertility and fetal development, on the liver, on the kidneys, etc.
How to protect yourself from PFAS?
Among the action levers, it is possible to choose the place to live and favor those where the presence of PFAS is rarer. For sources of pollution of industrial origin, a interactive map drawn up thanks to the work of the international collaborative survey “Forever Pollution Project” and published in February 2023, provides an overview of the contamination of Europe by low-mass PFAS substances.
Likewise, depending on the region, it is possible to consult the reports from the Regional Health Agency. But among the sources of pollution, the history of the region can play a role. “In 1966, there was a fire at the Feyzin refinery. To extinguish the fire, quantities of cubic meters of PFAS were spilled. Therefore, as these are stable and persistent products, we note that there are still remains of extinguishing foam used during this fire”.
To limit risks, we can also select and check the constituents included in the composition of the products we use on a daily basis, whether in the choice of cosmetics, clothing or even disposable food packaging.
Thanks to Bruno Ameduri, Director of Research at the CNRS at the Institut Charles Gerhardt Montpellier (ICGM).
Additional sources:
- PFAS: very persistent chemical substances – National Social Security Agency (ANSES)
- PFAS: “eternal pollutants” found in 94% of people tested, according to a study – franceinfo – 03/21/2024
- “Eternal pollutants”: explore the map of Europe of PFAS contamination – Le Monde 02/23/2023
- An update on PFAS – National Institute of Health and Medical Research (INSERM)
- Fascinating Fluoropolymers and Their Applications – Bruno Ameduri, Sergey Fomin – Elsevier 2020