PFluorinated and polyfluorinated alkyl compounds, PFAS for short, are in the pillory not only in Europe because of their properties that are harmful to the environment and health. In the United States and Canada, too, efforts have long been made to replace the “forever chemicals” suspected of damaging the hormone and immune systems with harmless substances.
Many North American manufacturers of single-use packaging for fast food products are already pursuing this goal. They have replaced the smaller PFAS molecules such as PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonic acid), whose exposure risks are known and which have therefore long been banned from being manufactured in Europe, in their containers with larger polymeric PFAS. These long-chain alkyl compounds are considered inert and, because of their size, too heavy to escape from packaging and get into food and the environment. But that is obviously a fallacy, as a study by American and Canadian environmental researchers shows.
Packaging should not become soaked
PFAS are added to countless everyday products – from cosmetics, cleaning agents, all-weather clothing to furniture – because of their fat-dissolving and water-repellent properties. The chemicals can also be found in plastic cups and bowls, as well as in supposedly eco-friendly paper and cardboard fast-food containers. Because the previously added PFAS can easily come into contact with food, many companies have turned their attention to using non-volatile PFAS, which are made up of longer polymer chains.
Since the end of 2022, disposable tableware and packaging made of polystyrene and other plastics can no longer be produced and used in Canada. It has been replaced by a degradable material based on paper and cardboard. Polymer PFAS ensure that such fast food packaging cannot become saturated with fat, oil and water.
But the polymeric PFAS pose a risk that hasn’t received much attention: They can break down into smaller, harmful fluorine-containing molecules, which can then find their way into food and drink, or into the environment if the single-use products are discarded. This is reported by the researchers led by Miriam Diamond from the University of Toronto and Marta Venier from the University of Indiana in Bloomington in the “Environmental Science & Technology Letters”.
Volatile PFAS are degradation products
For their study, the researchers tested 42 different paper packages and bowls that they collected three years ago from fast food restaurants in Toronto and stored for two years at room temperature and in the dark for their fluorine content. The most common PFAS compound detected in the samples was 6:2 FTOH (6:2 fluorotelomer alcohol) – a fluorine-containing chemical known to be toxic. The researchers were able to detect other PFAS in the packaging that they had not suspected. Because this compound was not originally present in the samples collected in 2020, the researchers suspect that it formed over time, for example during the degradation of polymeric PFAS. In fact, Miriam Diamond and her colleagues found that after the samples had been stored for two years, the concentration of the polymeric PFAS they contained had dropped by up to 85 percent.