‘Forever chemicals’ in rainwater exceed safe levels


PFAS has been found in rain in Tibet

New research shows that rainwater in most places on Earth contains levels of chemicals that “significantly exceed” safety levels.

These synthetic substances called PFAS are used in non-stick pans, firefighting foam and water-repellent clothing.

Called “forever chemicals,” 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.

The researchers from Stockholm University say it is “very important” that the use of these substances is quickly limited.

Scientists fear that PFAS may pose health risks, including cancer, although research so far has been inconclusive. They have become increasingly concerned about the spread of PFAS in recent years.

PFAS stands for poly- and perfluoroalkyl substances.

There are about 4,500 of these fluorine-based compounds, and they are found in almost every home on Earth in hundreds of everyday products, including food packaging, non-stick cookware, rain gear, glue, paper and paint.


Firefighting foam often contains PFAS chemicals

Safety concerns about the presence of these long-acting substances in drinking water have also been raised.

Earlier this year, a BBC investigation found PFAS in water samples in England at levels that exceeded European safety levels, but did not exceed current safety levels in England and Wales.

This new study, which looks at four specific chemicals in the class, suggests that levels of one PFAS in rainwater across the globe often “significantly exceed” US drinking water advisory levels.

Soil around the world is similarly contaminated, evidence suggests.

The study’s findings 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.

“We’re arguing here that we’re not in this safe operating zone anymore, because now we have these chemicals everywhere, and these safety advisories, we can’t achieve them anymore,” said lead author Professor Ian Cousins ​​from Stockholm University.

“I’m not saying we’re all going to die from these effects. But we’re at a place now where you can’t live anywhere on the planet and be sure the environment is safe.”

While this is undoubtedly cause for concern, there are some caveats.

Many of these security levels in place are advisory, meaning they are not legally enforceable.

Other researchers believe that measures against these chemicals should wait until the health risks are more clearly proven.

Much research has been conducted on the health risks posed by PFAS, and researchers say that exposure to high levels may be associated with an increased risk of certain cancers, fertility problems and developmental delays in children.

However, such associations do not prove cause and effect, and other studies have found no link between PFAS and disease.

But for those who have worked closely with PFAS for many years, the evidence in the new research paper underscores the need for a precautionary approach.

“In this background rain, the levels are higher than the environmental quality criteria that are already in place. So that means that over time we are going to have a statistically significant impact of these chemicals on human health,” said Professor Crispin Halsall from the University of Lancaster. He was not involved in the Swedish study.

“And how will that manifest? I’m not sure, but it will come out over time, because we’re exceeding the concentrations that are going to cause some harm, because of exposure to humans in their drinking water.”

Removing the chemicals in the study from drinking water at treatment plants is possible, if it is expensive.


Rainwater across the planet exceeds US safety guidelines, scientists say

But getting below the US advisory levels is extremely challenging, according to the authors.

As scientists have gained more knowledge about PFAS over the past 20 years, the safety advice has been steadily lowered.

It has also happened with regard to the presence of these chemicals in soil – and that also creates problems.

In the Netherlands, the Ministry of Infrastructure in 2018 set new limits for concentrations of PFAS in soil and dredging material.

But this led to 70% of construction projects involving the removal of soil or the use of excavated material being stopped. After protests, the government relaxed the guidelines.

According to the new study, this kind of relaxation of safety levels is likely to happen with water pollution as well.

“If you applied these guidelines everywhere, you wouldn’t be able to build anywhere,” Prof Ian Cousins ​​said.

“I think they will do the same with the US drinking water advisories, because they are not practical to use.

“It’s not because there’s anything wrong with the risk assessment. It’s just because you can’t use these things. It’s simply impossible, from an economic standpoint, to use any of these guidelines.”


A Dutch construction site – many projects in the country had to stop due to restrictions on PFAS

The main challenge with these chemicals is their persistence, rather than their toxicity, the study authors say.

While some harmful PFAS were phased out by manufacturers two decades ago, they persist in water, air and soil.

One way in which PFAS passes through the environment is in the form of tiny particles that are carried in sea spray into the air and then back to land.

This inability to break down in the environment means that PFAS are now found even in remote areas of Antarctica, as reported by Prof Halsall recently.

While there are moves at European level to limit the use of these chemicals and find more benign substitutes, there is also hope that the industry will quickly move away from using PFAS.

“We need persistent chemicals and substances, we want our products to last a long time while we use them,” Prof Cousins ​​said.

“And while there are conservative voices in the industry, there are progressive players as well. I’m very optimistic when I see these progressive industries working together.”

The research has been published in the journal Environmental Science & Technology.

Follow Matt on Twitter @mattmcgrathbbc.

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