Scientists warn rainwater is unsafe to drink

The levels of so-called forever chemicals in rainwater exceed the most stringent standards developed by health and environmental agencies. Scientists that produced the study, which started in 2010, say they only covered four out of thousands of the fluorine-based compounds and warn that the long-term effects of exposure are still unknown.

One can’t avoid microplastics. They are everywhere from the depths of the ocean to the middle of the Amazon forest. Air is excessively polluted in most places where people live, and new damaging effects are still being discovered. Scientists have even found that eggs from chickens kept outdoors in Australia contain 40 times more lead than commercially-produced eggs because of soil contamination.

A study by researchers from Stockholm University and ETH Zürich shed more light on another class of pollutants – PFAS or per- and polyfluoroalkyl substances. The man-made fluorine-based compounds degrade extremely slowly, so they are also called persistent or forever chemicals.

PFAS are present in wide range of products

The scientists discovered that rainwater nearly everywhere on the planet contains PFAS in quantities that makes it unsafe to drink. They referred to the most stringent standards, which were developed by health and environmental agencies in the United States and European Union.

There are possible links between persistent chemicals and numerous health issues

The study started in 2010 and it covered only four perfluoroalkyl acids (PFAAs), a subgroup within 4,500 known forever chemicals. PFAS are usually water and oil repellents, resistant to heat and stains. It made them popular with producers of a wide range of products including non-stick pans, firefighting foam, clothes and adhesives.

Numerous studies indicated PFAS could be related to fertility issues, obesity, cancer, diabetes and developmental delays, though the results are still inconclusive. In particular, the US has sharply cut the allowed levels amid suspicion that the chemicals could be weakening the immune response to vaccines among children.

Emissions of forever chemicals are in decline but they keep accumulating

Still, PFAS levels in human tissue sharply decreased in the past two decades and the levels measured in the environment haven’t grown, said Ian Cousins, the study’s lead author, who teaches environmental organic chemistry at Stockholm University. He explained it was the guidelines that became stricter, by “millions of times.” Emissions also dropped in recent years in most countries, but the forever chemicals have nowhere to go.

Research results showed that even in Antarctica the levels of PFAS in rainwater are excessive when compared to US standards for drinking water. In the Tibetan plateau, they are 14 times higher than recommended!

It will take decades or centuries for PFAS to dilute into the deep oceans, Cousins warned and added that advanced water treatment solutions are expensive. Society should not continually repeat the same mistakes with other persistent chemicals, the authors stressed.

They went further to suggest that with PFAS humanity exceeded one of the nine planetary boundaries, the one for novel entities. It applies at least to many areas inhabited by humans, they said and pointed to wide contamination of rainwater, surface water and soil.

The planetary boundary of chemical pollution or novel entities is the fifth out of nine that some scientists claim has been exceeded

According to the scientific concept of planetary boundaries, they demarcate the remarkably stable state Earth has remained within for 10,000 years – since the dawn of civilization. The planetary boundary of chemical pollution or novel entities is the fifth that some scientists claim has been exceeded. The first four were global warming, destruction of wild habitats, loss of biodiversity, and excessive pollution with nitrogen and phosphorus.

Several other planetary boundaries are related to the release of novel entities, the study reads. For instance, the ones for stratospheric ozone depletion and climate change.