What are PFAS? What are the risks of these “eternal” chemicals? | Chemical substances

A map identifying more than 17,000 sites in Europe contaminated by perfluoroalkyl substances —​ known as PFAS or, more informally, “eternal chemicals” — was released in February, the same month the European Union announced its intention to ban the use of these persistent compounds.

Entitled Forever Pollution, this work produced by a journalistic consortium reveals that PFAS were found in water, soil and samples of organisms in several European countries. Portugal appears in this document with nine relevant points of contamination, distributed throughout the mainland from Minho to Alentejo, passing through the Lisbon region. What are PFAS, why are they considered potentially harmful, and what risks do they pose to human and environmental health?

What are PFAS?

Perfluoroalkyl substances (PFAS) constitute a vast family of synthetic chemical substances used, since the late 1940s, in various industrial products and processes. These are persistent compounds, that is, they do not degrade easily. There are now thousands of PFAS, with the approximate number varying, depending on the source, between 4700 and 10 000.

Do these substances exist in nature?

No, all PFAS are synthetic. “It takes a lot of energy to produce these compounds. Even if we look in samples of sediments or dated ice, we don’t find anything like that in nature”, explains to PÚBLICO Susan Richardson, professor at the Department of Chemistry and Biochemistry at the University of South Carolina, in the United States.

PFAS are chemicals that impart non-stick properties to frying pans (and other cookware)
Rui Gaudêncio

Why are chemicals called “eternal” chemicals?

The expression “eternal chemicals” comes from forever chemicals, as PFAS are informally called in English. These compounds do not degrade easily – hence the idea of ​​being “eternal” –, persisting in soils, natural water reservoirs and living organisms themselves. This happens because they have connections of the type carbon-fluorine, one of the strongest chemical bonds in organic chemistry.

Where are they used?

Perfluoroalkylated substances are used in various products, equipment and industrial processes. They have very interesting physical-chemical properties, such as durability and the ability to repel oil and water, in addition to high thermal and chemical stability. As such, they are widely used in kitchen utensils, anti-stain textiles, medical devices, cosmetic or personal care products, fire-fighting foams, paints and food packaging.

What are the consequences for human health?

Studies published in scientific journals suggest a relationship between PFAS and certain risks to human health. “Many PFAS have been shown to be toxic to human health. Several [destas substâncias] have been linked to a number of negative impacts on human health, including increased cholesterol levels, reduced birth weight, effects on the immune system, increased risk of cancer and thyroid hormone disruption. report Published in June 2022 by HBM4EUa project funded by the European Union.

What are the main routes of contamination?

Drinking water and food are considered the main routes of contamination for most of the population, says the HBM4EU report on PFAS. “People most at risk of adverse health impacts are those exposed to high levels of PFAS and vulnerable population groups such as children and the elderly,” says one document of the European Environment Agency.

Specific professional groups will have a higher risk of exposure – this is the case of people working in sectors directly linked to the production or handling of PFAS. Military personnel participating in training involving firefighting foams, for example, may also have a higher degree of exposure than civilians.

The greater the exposure, the greater the risk?

Yes. Possible risks depend on the degree and frequency of exposure, as these persistent substances accumulate in the human body. Therefore, following the precautionary principle, the ideal is to limit exposure.

the scientist Susan Richardson recalls that all of us have been, in some way, in contact with materials or environments in which PFAS are present. “Almost every human on Earth has PFAS in their blood”, says Susan Richardson, who says she prefers caution to panic. From disposable paper cups to toilet paper, there are countless products in our daily lives that can present PFAS. It is important, in the opinion of the professor from the University of South Carolina, to try to avoid non-essential products that may contain PFAS.

“There is a Canadian group that has tested various products known to contain PFAS – non-stick frying pans, dental floss, etc. At the end, eventually realized that microwave popcorn containers were the worst [em termos de contaminação por PFAS]”, says Susan Richardson. The scientist says that now she prefers to explode the corn in the pan, in the traditional way, dispensing with packets lined with persistent substances.

Is it impossible to clean sites contaminated by PFAS?

No, there are methods to clean up contaminated water and remediate soils. However, these procedures are expensive and technically sophisticated. That is why it is more strategic to bet on prevention than on depollution. like the microplastics, a large proportion of PFAS can travel long distances and end up contaminating areas where they were never produced or even used on a large scale. One recent study indicated, for example, the presence of 26 types of PFAS in ice from Svalbard, in the remote arctic Norwegian.

What solutions are being considered?

The European Union is currently considering banning PFAS in 2026 or the following year. Germany, Denmark, the Netherlands, Norway (a country that is not part of the EU) and Sweden are already drafting a proposal. This working document provides that companies will have, after the entry into force of the ban, a reasonable window of time to adapt to future rules.

How long will companies have to find alternatives to PFAS?

An interval between 18 months is being considered, according to the Reuters agency, for manufacturers to find “alternatives to more than ten thousand targeted substances”. Among the companies affected by these possible new rules are well-known names such as BASF, 3M, Bayer, Solvay, Merck KGaA and Synthomer.

“PFAS are widely used in consumer products for convenience purposes – raincoats, textiles, cosmetics, etc. These must be deleted as soon as possible. But, of course, there may be critical sectors and industry applications, for which an overnight transition is not possible. The restriction currently proposed by the Member States includes an important list of exceptions (for example, in the medical sector), in order to give the industry time to transition from the use of these materials to safer and more sustainable alternatives”, explained to PÚBLICO Natacha Cingotti, leader for the health and chemicals program at the Alliance for Environment and Health (HEAL), a European not-for-profit organisation.

The extensions of deadlines mentioned by Natacha Cingotti comprise, for the most part, a period between 6.5 and 13.5 years, “providing enough time for the industry to adapt”, says the head of HEAL, in a response sent by email.

Is it possible to replace all PFAS used today?

We do not know. There are applications that are not considered essential that can be replaced by different but acceptable solutions. The treatment that allows food packaging not to become greasy, for example, can now be carried out with wax. However, there are medical or military applications that may be hard to replace.

“The US military cannot find a suitable replacement for PFAS firefighting foams, despite many people saying that there are new foams. Until now, any of the other materials were considered inadequate to perform fire suppression at the level required by the military”, he explained to PÚBLICO mike jonesan independent consultant with more than 30 years of experience in the North American chemical industry, in video call.

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