Rainwater around the world contains levels of “forever chemicals” that are unsafe to drink, a study suggests.
Per- and polyfluoroalkyl substances (PFAS), linked to cancer, permeate homes and environments.
PFAS levels across the planet are uncertain, and the substances must be contained, scientists say.
Rainwater is no longer safe to drink anywhere on Earth under US pollution guidelines, according to a team of environmental scientists.
That’s because rainwater all over the planet now contains dangerous chemicals called per- and polyfluoroalkyl substances (PFAS). In an article published in the journal Environmental Science & Technology on August 2, researchers at the University of Stockholm, who have been studying PFAS for a decade, found evidence that these substances have spread throughout the atmosphere, leaving no place untouched.
There are thousands of PFAS, all man-made, used in food packaging, water-repellent clothing, furniture, carpets, nonstick coatings on pots and pans, firefighting foam, electronics, and some shampoos and cosmetics. During production and daily use, they can be released into the air. They also leak into seawater and are aerosolized in sea spray. From there, they spread through the atmosphere and fall back to earth in rain.
They are often called “forever chemicals” because they hang around for a long time without breaking down, allowing them to build up in people, animals and environments.
PFAS have been found in Antarctica and in Arctic sea ice. Their prevalence across the planet is a danger to human health, as peer-reviewed studies have linked them to some cancers, reduced fertility, reduced vaccine response, high cholesterol and developmental delays in children.
Like microplastics, it is difficult to identify all the long-term health effects of PFAS exposure because they include so many different compounds and they are so widespread in the environment. The new paper suggests that everyone on Earth is at risk.
Below EPA limits, “rainwater everywhere will be judged unsafe to drink”
Perhaps the most notorious of these substances are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). In June, the Environmental Protection Agency tightened its guidelines for how much PFOA and PFOS can safely be present in drinking water, based on new evidence about health effects.
Previously, the EPA had set the acceptable level for both substances at 70 parts per trillion. The new guidelines cut this by a factor of up to 17,000 – limiting safe levels to 0.004 parts per trillion for PFOA and 0.02 parts per trillion for PFOS.
Researchers from Stockholm University assessed the levels of PFOA, PFOS and two other PFASs in rainwater and soil across the planet, and compared them to regulatory limits. Levels of both substances in rainwater “often greatly exceed” EPA limits, the study authors concluded.
“Based on the latest US guidelines for PFOA in drinking water, rainwater everywhere would be judged unsafe to drink,” said Ian Cousins, lead author of the study and professor in the Department of Environmental Sciences at Stockholm University, in a press release.
“Even though we in the industrial world don’t drink rainwater often [directly]many people around the world expect it to be safe to drink, and it supplies many of our drinking water sources,” Cousins added.
The paper also found that soil across the globe was “ubiquitously contaminated” with PFAS. Because PFAS persist for so long and cycle through the planet’s oceans, atmosphere and soil so efficiently, scientists expect levels to continue to be dangerously high.
Ultimately, the researchers conclude that PFAS have exceeded the safe “planetary limit” for human health.
“It is vitally important that PFAS use and emissions are rapidly curtailed,” they wrote.
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