Rainwater on the entire Earth is unsafe to drink. Even in Antarctica. Even on the Tibetan Plateau. 

A recent scientific study at Stockholm University and ETH Zurich University emphasized the warning and gave the details, many of which are already known but we needed another knock on the head. 

The reason rainwater is unsafe to drink, among other reasons, is due to rain containing what are called “forever” chemicals – everywhere. 

Forever chemicals are human-made substances, per – and poly-fluoroalkyl substances – let’s call them PFAS for now on – that are in consumer and industrial products. You can find PFAS chemicals in non-stick and stain-repellent properties. They’re found in a lot of household food packages, electronics, and even cosmetics and cookware. And they end up in our rainwater. 

Forever chemicals are – well, forever. They don’t break down in the environment. We’re stuck with them. And as time goes on, our world (and bodies) becomes more saturated with them. 

The common belief used to be that the chemicals would be diluted over time in our oceans and that would be the end of it. But a recent study showed something that any fifth-grader might have figured out – water from the ocean goes into the atmosphere and then comes down again as rain, where it is deposited into freshwaters (rivers, mountain streams) and soil. 

And now those PFAS’s are at unsafe levels on Earth. 

Due to their ability to continuously recycle into our atmosphere, and because the effects are irreversible and could be dangerous to our health, it is important that PFAS be restricted even more than they have already been. 

Over the past 20 years, many of these chemicals have been phased out of manufacturing, after it was discovered that the chemicals could have adverse effects on human health, But since PFAS are “forever chemicals,” it’s safe to say they are still with us. 

Admittedly, most people don’t go outside when it’s raining and consume large amounts of rainwater. And an occasional ecstatic moment of a drizzle on your tongue on a sizzling hot day won’t kill you. In industrialized nations, our water is filtered. So even though there may be other known reasons to not trust our water supply, filtering does help get rid of many unsafe substances.

Rainwater does play a large role in some countries’ water systems, and since the PFAS can cause cancer and other health problems, countries will have to improve their filtration systems.

According to the EPA, traditional drinking water treatment technologies are not able to remove PFAS. Advanced filtration systems are needed, such as technologies that include activated carbon adsorption, ion exchange resins, and high-pressure membranes (nano-filtration or reverse osmosis). They can be used in drinking water treatment facilities, in water systems in hospitals or individual buildings, or even in homes at the point-of-entry, where water enters the home, or the point-of-use, such as in a kitchen sink or a shower. Nano-filtration or reverse osmosis systems are recommended for home use. Most, but not all, PFAs can be removed.

The toxic levels within rainwater could cause fertility problems, increased risk of cancer, and developmental delays in children, so there is a lot of cause for concern.

“It cannot be that some few benefit economically while polluting the drinking water for millions of others, and causing serious health problems,” says Dr Jane Muncke, managing director of the Food Packing Foundation in Zurich.

“In view of the impacts of humanity’s chemical footprint on planetary health, it is of great importance to avoid further escalation of the problem of large-scale and long-term environmental and human exposure to PFAS by rapidly restricting uses of PFAS wherever possible,” the article concludes. “Furthermore, as has been stated by ourselves and others before, society should not continually repeat the same mistakes with other persistent chemicals.”

The study was published last week in the journal “Environmental Science and Technology.”

Removing the chemicals from the environment entirely is another issue. We may not be opening our mouths and drinking rainwater, but it is falling on everything around us – including our entire food supply, and everything we need to sustain us. 

For more information about drinking water technologies available for removing PFAS, visit EPA’s Drinking Water Treatability Database. This interactive literature review database contains more than 65 regulated and unregulated contaminants and covers 34 processes commonly employed or known to be effective. Users can search by contaminant or technology.

Citation: Outside the Safe Operating Space of a New Planetary Boundary for Per- and Polyfluoroalkyl Substances (PFAS), Ian T. Cousins*, Jana H. Johansson, Matthew E. Salter, Bo Sha, and Martin Scheringer, Environmental Science and Technology, August 2, 2022