Cancers, infertility, immunity… “PFAS are a probable risk and have possible effects on health, it’s dizzying”

Une directive européenne de 2020 fixe des teneurs maximales de 0,50 μg/l pour le total des PFAS dans l’eau potable. Midi Libre – JEROME MOUILLOT

What is the effect of perfluorinated and polyfluorinated alkyls (PFAS), or perennial pollutants, a set of at least 5,000 chemical substances that are used in the composition of textiles, kitchen utensils … on our health ? Xavier Coumoul, professor of toxicology, lists the impact of these molecules, while the deputies adopted at first reading, on April 4, a bill aimed at restrict the manufacture and sale of products containing Pfas.

Xavier Coumoul is professor of toxicology and biochemistry at Paris Cité University and director of an Inserm unit which studies the effects of chemicals on health.

For Xavier Coumoul, contradictory studies complicate the situation. DR

There is a lot of talk about the environmental impact of Pfas, how do Pfas differ from other chemical substances ?

Pfas are molecules that contain fluorine, which gives them particularly interesting properties from an industrial point of view, great stability. We distinguish between 4,000 and 12,000, it all depends on the references. Even for us, it’s difficult to know exactly how many there are. It’s a production industry that involves food packaging, textiles… It is found in sofas, kitchen utensils, some pesticide formulations, paints, floor coverings… these molecules, which are classified into thirty different categories, are widely used.

They have the defects of their quality: their chemical and thermal stability means that they are difficult to degrade, not only by humans, by all other living beings. This is a problem in the sense that they are persistent: for several years in human beings, and we find them, undegraded, in the soil, the environment, the environment and the environment. water.

The two emblematic molecules, PFOA and PFOS, persistent organic pollutants, have "half-lives", that is to say an elimination time half of the initial concentrations, several years in humans.

We are talking about very diverse molecules and some of them have suspected endocrine disrupting effects.

They are therefore sometimes present in pesticides, but are not pesticides, and are sometimes endocrine disruptors, without being all endocrine disruptors…

Exactly. This does not mean that all these molecules do not have effects.

What do we know about their effect on health ?

It all depends on which molecule we are talking about. Each molecule will have a different size, a different number of fluorines… This is where it makes you a little dizzy. There are emblematic molecules, PFOA, PFOS, for which pathologies have been identified. But we have a diversity of facts that is extremely difficult to characterize in terms of health.

When we measure the Pfas in the blood and we identify a mixture of Pfas associated with a pathology, for this same pathology, if we look in another population, we will find another mixture from Pfas. The molecules probably have their own effects, and when you mix them, it is extremely difficult to know what disease you will have.

Among the very probable risks identified by the Academies of Medicine and Sciences, the associated pathologies are: kidney cancer, metabolic disturbance with an increase in cholesterol levels, growth retardation in children and reduced blood pressure. immune response.

On PFOA and PFOS, there is less effectiveness in the vaccine response against Covid in people who are the most contaminated. These are likely links. There are other possible effects. Knowing that a Californian is not going to have the same Pfas as a Parisian or a Vietnamese.

"Pfas are detected in the blood of 96 % of Americans"

Whatever it is, whether we are talking about the Californian, the Parisian or the Vietnamese, today, no one there escapes ?

Oh no. Pfas are detected in the blood of 96% of Americans… We can't escape it because it's everywhere.

Have we measured the cocktail effect with other chemicals?

There are many studies, but the conclusions are once again complex. I will give you an example: when we are interested in endometriosis, or male infertility, we will find studies where we make the association with a mixture of Pfas, and others not.

There are probably Pfas which do not have an effect on endometriosis, others which do, but when combined, they can have effects or act in an antagonistic manner. And Pfas which individually have no effect on endometriosis will have some effect if we combine them.

Apart from the probable effects on kidney cancer, increased cholesterol levels, etc. There are things starting to come out about breast cancer, testicular cancer, thyroid disease… We must go further. I think that we will be faced with difficulties in clearly stating that this mixture or that Pfas will be associated with a pathology. There will always be conflicting studies. Not because they have no effect. On the contrary, because they have many effects, but extremely difficult to analyze.

By voting on a bill aimed at reducing their use on April 4, are the deputies protecting the population?< /p>

Given the complexity of the issue, restricting their use, on a health and ecological level, is obvious. This is not a political opinion that I am giving, it is a scientific opinion. All these molecules are associated with a whole bunch of worrying pathologies.

But we remain in an orientation linked to the country's economy: if we restrict their use in the making of clothing, it is because we do not have the right to use them in the manufacture of clothing. rsquo;not produced too much in France… It would have been better if things had gone further in terms of health.

"As soon as you have something new, you have to wash and air"

Stoves are excluded. Yet we all have, in our kitchen, a pan stuffed with Pfas ?

The polymer in the pans is polytetrafluoroethylene, PTFE. Studies show that it is a relatively stable and inert material, and that there is no migration into the food unless heated to 360°.< /p>

But if the pan is worn, there are undoubtedly PTFE particles that are released. This does not mean that there will be a Pfas effect but perhaps a micro-particle effect. And if a PTFE micro-particle is formed, there is no reason why it should not be found in the blood. There are no studies carried out on this.

PTFE is a Pfas ?

You see a string of pearls ? If the pearl is the Pfas, the PTFE is the string of pearls. When you assemble the Pfas together, you form a necklace, a polymer, a less reactive molecule because it is very large. But we don't know what happens in the event of wear and tear, and the industrial process will contaminate the environment around the industry.

Today we are talking about a dizzying increase in cases of cancer among those under 50, we will perhaps discover more obvious links in fifty years with the Pfas…

It’is always the same problem, as we saw with organochlorines…

How can we protect ourselves as a precaution, as an individual, and can we do it ?

The first thing is to wash the clothes before wearing them. When you buy new furniture, you need to air it regularly during the first month. Same thing for a new car. For food, try to limit packaging as much as possible… as soon as you have something new, you have to wash and air it out.

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