Ozone deal has led to contaminant problem

EDMONTON— A landmark environmental agreement that helped close the ozone hole in the 1990s has led to new chemical contaminants forming in the atmosphere and accumulating on land.

“The Montreal Protocol was probably one of the best regulations out there to involve all the countries at once,” said Heidi Pickard, one of nine researchers whose findings were published Thursday.

“But, of course, you have these unintended consequences.”

The Montreal Protocol, which came into force in 1989, banned chlorofluorocarbons, or CFCs, that were used in refrigerators, air conditioners and aerosol sprays. They were destroying the ozone layer, which helps protect the planet from damaging ultraviolet solar radiation.

It has been signed by 197 parties and is considered the world’s most successful environmental agreement. But the chemicals used to replace the banned ones are breaking down in the atmosphere into new contaminants known as shortchain fluorinated alkyl acids.

They don’t seem to be as toxic as other long-lived contaminants such as dioxins. They are, however, highly persistent, said co-author Amila De Silva of Environment Canada.

“They’re known as forever chemicals.”

At least one of the chemicals is known to be toxic to plants. Others harm freshwater insects. Others accumulate in plants, including food crops.

Their concentration in ice cores from two High Arctic locations has increased about sevenfold since 1990, said coauthor Alison Criscitiello from the University of Alberta.