Scientists have issued a stark warning against drinking untreated rainwater anywhere on the planet, citing widespread contamination by toxic synthetic chemicals.
A study published in the journal Environmental Science & Technology by researchers from Stockholm University found that concentrations of per- and polyfluoroalkyl substances (PFAS) in atmospheric precipitation exceed environmental and drinking water safety guidelines worldwide.
According to the researchers, rainwater contains these chemicals regardless of where it falls, from densely populated urban centers to remote regions such as Antarctica and the Tibetan Plateau.
The persistent circulation of PFAS in the atmosphere means that even the most pristine ecosystems receive rainwater containing chemical concentrations that exceed drinking water safety benchmarks.
PFAS LINKED TO HEALTH AND ENVIRONMENTAL RISKS, RESEARCHERS SAY
Researchers from Stockholm University explained that all PFAS are extremely persistent in the environment or break down into other extremely persistent PFAS, earning them the nickname “forever chemicals.”
Exposure to certain PFAS has been associated with a range of serious health risks, including cancer, learning and behavioral problems in children, reduced fertility in women, increased cholesterol levels, and immune system problems.
The researchers also explained how these chemicals enter and continuously circulate through the atmosphere.
“Other volatile PFASs that were historically used in consumer products were emitted into the environment. In the atmosphere, some of these volatile PFAS can degrade into the four PFAS, which do not degrade further,” they said.
“The four PFAS are involatile and will be deposited on the Earth’s surface after they have formed in the atmosphere, for example, when they are washed out of the atmosphere by rain. These volatile PFAS have also been phased out, but their levels in the atmosphere do not appear to be declining.”
PFAS are commonly found in consumer products such as non-stick cookware, waterproof clothing, and food packaging, among others.
Because of their exceptionally strong chemical bonds, many PFAS resist natural degradation and can persist in the environment and the human body for extended periods.
Researchers also found that these chemicals continuously circulate through Earth’s water cycle.
When ocean waves break, sea spray aerosols carry PFAS from contaminated seawater back into the atmosphere. Wind currents then transport the chemicals across the globe before they return to Earth’s surface through rain, snow, and fog.
PFAS LEVELS EXCEED SAFETY LIMITS
Over the past two decades, scientific understanding of PFAS toxicity has advanced significantly.
In response to growing evidence linking even low levels of exposure to potential health risks, regulatory agencies have substantially lowered their recommended limits for PFAS in drinking water.
To put current contamination levels into perspective, researchers evaluated four specific perfluoroalkyl acids (PFAAs) detected in rainfall worldwide.
Their findings showed that concentrations of perfluorooctanoic acid (PFOA) in rainwater globally exceed the drinking water health advisory levels issued by the US Environmental Protection Agency (EPA) at the time of the study.
Similarly, perfluorooctane sulfonate (PFOS) was found to exceed strict environmental and health guidelines across the geographic regions examined.
Elevated PFAS concentrations were also detected in precipitation from remote high-altitude and polar environments, highlighting the global reach of the contamination.
“There has been an astounding decline in guideline values for PFAS in drinking water in the last 20 years. For example, the drinking water guideline value for one well known substance in the PFAS class, namely the cancer-causing perfluorooctanoic acid (PFOA), has declined by 37.5 million times in the U.S.” said Ian Cousins, lead author of the study and professor at Stockholm University’s Department of Environmental Science.
He continued, “Based on the latest U.S. guidelines for PFOA in drinking water, rainwater everywhere would be judged unsafe to drink. Although in the industrial world we don’t often drink rainwater, many people around the world expect it to be safe to drink and it supplies many of our drinking water sources.”
RESEARCHERS WARN OF IRREVERSIBLE GLOBAL CONTAMINATION
Based on their findings, the researchers concluded that the global distribution of PFAS represents a significant milestone in environmental science, suggesting that humanity has crossed a planetary boundary for chemical pollution.
Unlike localized environmental disasters that can be addressed through targeted cleanup efforts, widespread atmospheric PFAS contamination is extremely difficult to reverse.
The study highlighted the enormous costs associated with reducing PFAS contamination in drinking water supplies, while removing these persistent chemicals from rainwater across the natural environment remains practically impossible.
Dr. Jane Muncke, managing director of the Food Packaging Forum Foundation in Zurich, who was not directly involved in the study, also raised concerns about the environmental and public health costs of PFAS pollution.
“It cannot be that a few benefit economically while polluting the drinking water for millions of others, and causing serious health problems.”
Muncke added, “The vast amounts that it will cost to reduce PFAS in drinking water to levels that are safe must be paid by the industry producing and using these toxic chemicals.”
Moving forward, the research team urged governments worldwide to restrict non-essential uses of PFAS and adopt measures that prevent persistent synthetic chemicals from entering and accumulating in the global environment.
