New research shows that rainwater in most places on Earth contains levels of chemicals that “far exceed” safe levels.
These synthetic substances called PFAS are used in non-stick pans, fire fighting foams and water repellent clothing.
Dubbed “chemicals forever”, they persist for years in the environment.
Such is their prevalence now that scientists say there is no safe space on Earth to avoid them.
Stockholm University researchers say it is “vital” to rapidly limit the use of these substances.
Scientists worry that PFAS may pose health risks, including cancer, although research has so far been inconclusive. In recent years they have become increasingly concerned about the proliferation of PFAS.
PFAS stands for poly and perfluoroalkyl substances.
There are about 4,500 of these fluorine-based compounds and they are found in nearly every home on Earth in hundreds of everyday products, including food packaging, non-stick cookware, raincoats, adhesives, paper and paints.
Safety concerns have also been raised regarding the presence of these long-lasting substances in drinking water.
Earlier this year a BBC investigation found PFAS in water samples in England at levels that exceeded European safety levels, but did not exceed the current safety level in England and Wales.
This new study, which looks at four specific chemicals in the class, suggests that levels of a PFAS in rainwater around the world often “far exceed” US drinking water warning levels.
Soil around the world is similarly contaminated, the evidence suggests.
The study results lead the authors to conclude that a planetary boundary has been crossed, that there is simply no safe space on Earth to avoid these substances.
“Here we argue that we are no longer within this safe operating space, because now we have these chemicals everywhere and these safety warnings, we can no longer reach them,” said Professor Ian Cousins, lead author of the University of Stockholm.
“I’m not saying we’re all going to die from these effects. But now we’re in a place where you can’t live anywhere on the planet and be sure the environment is safe.”
While this is undoubtedly a cause for concern, there are some conditions.
Many of these security levels in place are advisory, which means they are not legally enforceable.
Other scientists believe that action on these chemicals should wait until the health risks are more clearly demonstrated.
Much research has been done on the health risks posed by PFAS, and scientists say exposure to high levels may be associated with an increased risk of certain cancers, fertility problems, and developmental delays in children.
However, such associations demonstrate no cause and effect, and other studies have found no connection between PFAS and disease.
But for those who have spent years working closely with PFAS, the evidence in the new research paper underscores the need for a precautionary approach.
“With this background rain, the levels are already above those environmental quality criteria. This means that over time we will have a statistically significant impact of these chemicals on human health,” said Professor Crispin Halsall of the University of Lancaster. He was not involved in the Swedish study.
“And how will it manifest? I’m not sure, but over time it will come out, because we are exceeding those concentrations that will cause damage, due to exposure to humans in their drinking water.”
Removal of the study chemicals from drinking water in treatment plants is possible, if costly.
But getting below US advisory levels is extremely difficult, according to the authors.
As scientists have gained more knowledge about PFAS over the past 20 years, safety warnings have been continuously reduced.
This has also happened with regard to the presence of these chemicals in the soil, and this too is causing problems.
In the Netherlands in 2018, the Ministry of Infrastructure set new limits on PFAS concentrations in soil and dredging material.
But this caused 70% of construction projects that involved the removal of soil or the use of excavated material to be halted. After the protests, the government relaxed the guidelines.
According to the new study, this type of easing of safety levels is also likely to occur with water contamination.
‘If you applied these guidelines everywhere, you wouldn’t be able to build anywhere,’ said Professor Ian Cousins.
“I think they will do the same thing with US drinking water warnings, because they are not practical to enforce.
“It’s not because there’s something wrong with the risk assessment. It’s just because you can’t apply these things. It’s simply impossible, economically, to apply any of these guidelines.”
The key challenge with these chemicals is their persistence, rather than their toxicity, the study authors say.
Although some harmful PFAS were phased out by producers two decades ago, they persist in water, air and soil.
One way PFAS flows into the environment is in the form of tiny particles carried by marine spray into the air and then back to land.
This inability to decompose in the environment means that PFAS are now also found in remote areas of the Antarctic, as recently reported by Professor Halsall.
Although there are measures at European level to limit the use of these chemicals and to find more benign substitutes, there are also hopes that the industry will quickly move away from the use of PFAS.
‘We need persistent chemicals and substances, we want our products to last a long time while we use them,’ said Professor Cousins.
“And while there are conservative voices in the industry, there are also progressive players. I’m very optimistic when I see these progressive industries working together.”
The research was published in the journal Environmental Science & Technology.
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