Perpetual chemicals: "Switching to PFAS-free is not a luxury project"

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Martin Scheringer is a private lecturer in the Department of Organic Environmental Chemistry at ETH Zurich and Professor of Environmental Chemistry at Masaryk University in Brno, Czech Republic. Together with Mohamed Ateia, he has written a much-noticed essay in the journal Science, in which suggestions are made as to how the world should deal with the problem of per- and polyfluorinated alkyl compounds (PFAS), which are likely to haunt us for centuries as eternal chemicals.

heise online: PFAS were once considered miracle substances. Virtually indestructible, with fantastic material science properties. We used them everywhere, be it in the frying pan in the kitchen, under our skis when cross-country skiing or in numerous industrial applications. When did people start to realize that this class of materials could be a problem?

Martin Scheringer: The major manufacturers of PFAS, 3M and DuPont, were already aware of this in the 1960s. There is now extensive research on what the companies knew early on - and internal documents prove that they knew a lot early on. However, this knowledge was not made public. General scientific research only began to investigate PFAS around the year 2000.

heise online: How widespread are the substances in nature? Does the term "eternal chemicals" really fit or is it a bit of a misnomer?

Scheringer: The term may be a bit casual, but it accurately describes the central property of PFAS, namely their enormous stability. This stability - in environmental chemistry it is called "persistence" - means that PFAS will actually remain in the environment for centuries or even longer. And there are no natural sources for these substances, meaning they are truly foreign substances and form a toxic "footprint" of human activity.

heise online: PFAS comprise a large group of 10,000 substances. Are all of them problematic and in what form?

Scheringer: The uniform and also problematic property of all PFAS is their high persistence. Persistence is so problematic because it means that the substances are present for a very long time, even in places far away from the original sources (because they are dispersed around the world by wind and water). As long as PFAS are released into the environment, the concentrations in the environment and also in people's bodies continue to rise because the PFAS are not broken down.

Sooner or later this leads to concentrations being reached at which toxic effects occur. PFAS can lead to a wide range of toxic effects, for example liver and kidney damage, testicular cancer, kidney cancer, thyroid damage, lipid metabolism disorders, a reduction in sperm count and a reduced immune response after vaccinations.

heise online: Have regulators and industry reacted in time to start phasing out use? Is it even possible in principle?

Scheringer: If you look at the quantities of PFAS already present in the environment and also in the bodies of millions of people, you come to the conclusion that the switch from PFAS to fluorine-free alternatives was initiated too late. Whether and how this change is possible differs greatly from application area to application area. In some areas it is easy and has already been achieved, especially in consumer products where PFAS were used for impregnation and also in fire-fighting foams.

In other areas it is more difficult, especially in various industrial applications of PFAS. One problem with switching is that PFAS are used extremely widely and diversely, so there is no one-size-fits-all answer. In any case, the change is already underway in many areas. An important question here is also why the regulatory substance evaluation system for PFAS did not raise a red flag earlier. We are still investigating this question.

heise online: But is it simply enough to replace problematic PFAS with other, less problematic alternatives?

Scheringer: In many cases, yes. This is possible in consumer products in particular, but also in very demanding applications such as the aforementioned fire-fighting foams, and increasingly also in batteries and fuel cells. However, it depends very much on the application, and because there are so many different applications, the question cannot be answered uniformly or only briefly.

heise online: What do we know about the alternatives? You don't swap PFAS for PFAS, do you?

Scheringer: No, you certainly shouldn't replace PFAS with PFAS, because then you have the expense of changing, but you still don't solve the problem. Alternatives to PFAS must, of course, be thoroughly investigated and tested. There are established procedures for this; these methods are called "Assessment of Alternatives".