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Is it possible to replace per- and polyfluoroalkyl substances, PFAS or “perennial pollutants” that accumulate over time in soil or water? AFP interviewed manufacturers who produce or use them, and scientists.
Where are PFAS found?
PFAS have been irrigating modern life since the 1940s. These fluorinated elements are found in sports clothing, waterproof textiles, ski waxes, non-stick pans, food packaging, fire extinguishing foams, detergents, cosmetics, medicines, prosthetics , coatings and paints, air filtration or electrolysis membranes, but also on space probe hoses or in microelectronics.
There are thousands of them, in gaseous, liquid or solid form. Their resistance to corrosion, heat or light explains their appeal. But once in nature, they do not disintegrate.
The most dangerous are “the smallest, the most mobile”, soluble in water, Mehran Mostafavi, deputy scientific director of CNRS Chemistry, told AFP.
Polymeric, inert and stable PFAS, like the products used for non-stick coatings on pans, are not problematic under normal use, he says.
“Indeed, without overheating the pans, polytetrafluoroethene (PTFE) does not enter the body, but its manufacture can generate potentially toxic fluorinated surfactants. Likewise, when it is destroyed or recycled, there is the possibility of generating problematic PFAS“, adds Pierre Labadie, research director at the CNRS in environmental chemistry.
Is it possible to do without it?
“We must turn our necks to the idea that eternal pollutants are essential“, estimates Martin Scheringer, professor of environmental chemistry at the Zurich Polytechnic School and president of the group of international experts on chemical pollution (IPCP), who nevertheless highlights the work in progress at European level aimed at defining the derogation concept” of essential use” for PFAS that we cannot do without.
“There are applications that we can do without, others for which alternatives exist, for the pharmaceutical sector it is very complicated,” explains Mr. Mostafavi.
On the industrial side, for Benoit Lavigne, general delegate of the Federation of Electrical, Electronic and Communication Industries (FIEEC), which represents 6,500 companies, it “there will be no energy transition without PFAS“, present in heat pumps or batteries and “wherever there is significant heat exchange”.
“For uses that expose consumers the most“, the approach “must be focused on the substitution” of problematic substances via innovation, “as for food contact packaging” which has just been regulated at European level, believes Magali Smets, general director of France Chimie which represents 3,000 companies.
Provided the replacement is not worse.
Of the 58 possible alternatives to PFAS for food contact listed by the OECD, only 10 were deemed acceptable for their risk profiles.
Chemical manufacturers want PFAS to be maintained in manufacturing processes, therefore “that the manufacturer proves that they are used responsibly“for consumers, employees and the environment”particularly via studies on discharges into water“, underlines Ms. Smets.
Generally speaking, many manufacturers “have already exited PFAS or are in the process of doing so,” notes Mr. Scheringer.
Substitution: the case of cosmetics, ski waxes and fire foams
The OECD has identified 36 PFAS, emulsifiers, stabilizers, water-repellent agents, added to beauty products. The association of manufacturers in the Cosmetics Europe sector committed in October to replacing them by 2026.
The International Ski Federation has banned fluorine wax at the start of the 2023-2024 season.
In France, “replacement fire foams without PFAS have just been qualified after two years of work with the Ministry of the Environment“, indicates Ms. Smets. This “French initiative” needs time to adapt to become established, because it will be necessary to “rinse” the equipment using these foams and define “good practices”.
Destroy PFAS?
“The particularity of these molecules is to present a very strong bond between a carbon atom and a fluorine atom (…) To break this bond, four experimental methods are identified“, explains Mehran Mostafavi, from CNRS Chemistry.
“An +enzymatic+ method developed by biochemists, a method called +sono-chemistry+ creating bubbles at very high temperature where the CF bonds break, a +cold plasma+ method using an electric arc in a PFAS solution, and a so-called +radiolytic+ approach” via ionizing radiation.
“They have proven their effectiveness“, said Mr. Mostafavi, “the challenge now would be to move to an industrial scale“.