Ozone layer, concern for replacement chemicals is growing: They are far from harmless

The danger comes from scPFCAs, persistent chemical substances that derive from the degradation of "ozone friendly" substances

by Federico Coppini
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Ozone layer, concern for replacement chemicals is growing: They are far from harmless

The Montreal Protocol is considered one of the most successful environmental treaties to have been adopted. Signed in 1987, it obliges all countries in the world to regulate the use of chemicals based on chlorofluorocarbons (CFC) that deplete the ozone layer.

A hole had opened in the ozone layer above Antarctica which was expanding more and more each year and in the mid-1980s, a series of threats that this posed to humans finally arose. The problem was that CFCs were then widely used in refrigeration, air conditioning, as solvents and aerosol sprays.

In the following decades, alternative products that were less harmful to the ozone layer were introduced and the hole above Antarctica began to decline. But now the new study "Ice Core Record of Persistent Short-Chain Fluorinated Alkyl Acids: Evidence of the Impact From Global Environmental Regulations", published in Geophysical Research Letters by a team of Canadian researchers reveals that the "ozone friendly" substances that have replaced CFCs are piling up in the environment and can pose a threat to human health.

These chemicals are now widely used by many industries, but they have a problem: these alternatives to CFCs do not decompose in the environment. Canadian scientists led by Heidi Pickard of Memorial University's Department of chemistry (now at Harvard John A.

Paulson School of Engineering and Applied Sciences at Harvard University) have discovered increasing levels of these chemicals in Arctic ice samples dating back to the 1990s and fear that the solution to close the ozone hole may inadvertently damage the environment and threaten human health.

By studying Arctic ice cores dating back to the 1990s, the Canadian team of researchers discovered "dramatically increasing levels" of ozone substitutes called perfluoroalkyl short-chain carboxylic acids (scPFCAs). One of the authors of the Cora Young study, from University of York - Toronto explained to BBC news: "We are seeing much, much larger levels, in the order of 10 times higher than we had seen before the Montreal Protocol.

We don't know much about them and their potential toxicity, but we know that we are subjecting the environment to a great deal of contamination." The compounds detected in the Arctic belong to the same class of perfluoroalkyl substances or PFAS which are sometimes called "forever chemicals" and these long-lasting chemicals are found everywhere: from furniture to clothing, from the packaging of food and to drinking water.

Many researchers fear that there is a correlation between the growing role played by PFAS in our lives and cases of cancer, liver damage, reduced fertility and other health problems. The researchers note that the PFAS-related products present in Arctic ice samples do not degrade in the environment and current water filtration technology is unable to remove them.

But forecasts are that in the future the levels of scPFCAs in the environment will increase significantly. To replace the ozone-eating CFCs, car manufacturers around the world had decided to use a different refrigerant in air conditioning called HFC-134a, introduced in 1992.

While HFC-134a was less harmful to the ozone layer unfortunately, it was a very powerful greenhouse gas, around 1,400 times more than CO2. So the United States and European auto industry agreed to phase out HFC-134a and also stipulated that by 2017 all new cars had to use a different refrigerant for air conditioning: HFO-1234yf.

This is a chemical that did not damage ozone and was not a greenhouse gas but which, unfortunately, when degrading produced short chain PFCA. Young points out, “It has very low global warming potential, but has a much higher propensity to form these persistent products.

It will be another shift again, in which we will see an even more dramatic increase”. According to Canadian researchers, "These chemicals can travel long distances in the atmosphere and often end up in lakes and rivers.

They cause irreversible contamination and can have an impact on the health of freshwater creatures, including crustaceans and worms." There is growing concern also about the possibility that these compounds may have an impact on human health: "They were found in people's bodies in China, so they are likely to be found in people's bodies all over the world,” Young concludes.

“We have done a good job in trying to save the ozone layer, but the unintended consequences are the release of these other chemicals, which present some concerns. They are toxic and in many ways they are not filtered”.