Rainwater has become undrinkable

Due to human activities, rainwater today accumulates toxic levels of per- and polyfluoroalkyl substances (or PFAS). per- and polyfluoroalkyl substances). These chemicals are non-stick and organofluorine compounds widely used in industry for their waterproofing properties or great resistance to heat. The problem: these toxic products remain in the environment and are found in the blood and in some human and animal organs. A new study by researchers from Stockholm University and ETH Zurich shows that PFAS levels in rainwater (and snow) far exceed the limits set by health watchdogs.

Toxic rainwater, even in Antarctica!

There are several thousand PFASs that have been used in a range of consumer products since the 1940s: in food packaging, waterproof clothing, furniture, carpets, non-stick coatings on pots and pans, fire retardants, electronics, and even some shampoos and cosmetics.

PFAS are released into the air during the production and use of these products; they also seep into the oceans and result in sea spray. Thus, they disperse into the atmosphere and return to Earth in the form of rain or snow. Let’s face it, we don’t directly consume rainwater, but it is used to supply a large number of drinking water sources!

>>Also read: Will Earth run out of drinking water soon?

Traces of PFAS have been detected in rainwater from several parts of the world, including Antarctica.

PFAS persist for a very long time without breaking down (hence the name “permanent chemicals”) and gradually accumulate in living organisms and the environment. We have discovered their presence as far as Antarctica and on the Tibetan Plateau! This is a particularly troubling finding, especially since several studies have suggested that exposure to high levels of certain PFAS may have harmful health effects.

In particular, these substances can cause reduced fertility, developmental delays in children, increased risk of certain cancers (especially prostate, kidney, and testicular cancer), decreased immune defenses (including decreased vaccine response). hormonal imbalance, increased cholesterol level, etc. However, as with microplastics, their long-term health effects are difficult to determine comprehensively because they contain many different compounds.

Limit values ​​are always processed downwards

Over the past 20 years, threshold values ​​for PFAS in drinking water, surface water, and soil have decreased significantly due to new knowledge about their toxicity. For example, the limiting concentration of perfluorooctanoic acid (PFOA), a known carcinogen, has been reduced by 37.5 million times in the United States, says Ian Cousins, a professor in Stockholm University’s Department of Environmental Sciences and lead author of the study.

>>Also read: Microplastics: we ingest at least 300 a day

Cousins ​​and his colleagues have conducted several field analyzes and studies on the transport of PFAS in the atmosphere over the past decade. They found that concentrations of these toxic products have not decreased significantly since 2010, despite the fact that their production has been regulated and even eliminated by major manufacturers in the United States (such as 3M, DuPont, Daikin, and Miteni). Japan and Europe.

(A) PFOA, (B) PFOS, and (C) sum of four perfluoroalkyl acids (PFOA + PFNA + PFHxS + PFOS) in wet sediment collected from around the world from 2010 to present. Dotted lines indicate health recommendations from the EPA, the European Union, and Denmark. Credits: Cousins ​​et al., Environmental Science & Technology (2022)

In June 2022, the United States Environmental Protection Agency (EPA) lowered its guidelines for the amount of PFOA and PFOS (perfluorooctane sulfonic acid) in drinking water, based on new evidence of health effects: these substances are now limited to 4 pg/. L and 20 pg/L, respectively. However, levels of these two substances today far exceed these limits. Rapidly limiting the use and emissions of PFAS is vital for researchers.

“New Planet Exceeded”

Not only are PFAS inherently very persistent, but certain natural processes, particularly sea spray, tend to constantly transfer them from the surface environment to the atmosphere. ” Due to the global spread of PFAS, the irreversibility of PFAS exposure, and the associated biological effects, new planetary thresholds for PFAS have been exceeded. researchers write. In other words, levels in environmental media are now higher than guideline values ​​everywhere, and no region of the world is immune.

>>Also read: Plastic rain: what is its origin and what are its health consequences?

The authors of the study compare the danger of PFAS to that of plastic pollution – plastics also stay in the environment for a very long time. The difference is that PFAS are invisible and therefore the public cares less about them. As the effects of these substances, which are essentially irreversible, are better and better known, it becomes urgent to limit the use of these products.

The significant costs that would be required to reduce PFAS in drinking water to levels that are safe according to current scientific knowledge must be borne by the industry that produces and uses these toxic chemicals. It’s time to act The managing director of the Food Packaging Forum Fund in Zurich, who did not participate in this study, Dr. Jane Muncke says.

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