How ‘Forever chemicals’ have tainted all of Earth’s rainwater?

An alarming new study has found no rainwater anywhere on Earth is safe to drink anymore, as “forever chemicals” are appearing in rain around the globe. : Those forever chemicals stem from products including fast food containers and wrappers, cleaning products, water resistant clothing and personal care products such as shampoo.

Ian Cousins, a professor of environmental studies at Stockholm University, said the results of the study, which he helped author, were startling.

“I was surprised that even in the remotest areas on Earth, that the levels in rainwater, for example in Antarctica and on the Tibetan plateau, are above the recently set U.S. EPA health advisories for drinking water,” Cousins said.

The reduced effects of vaccines in children has been the main driver of the EPA standards for rainwater being lowered, Cousins said. Severe impacts like cancers and liver enlargement occur at much higher levels of exposure to the forever chemicals.

“The safe levels have dropped over the last 20 years as we’ve gradually gotten a better understanding of the toxicity of these substances,” Cousins said. “The safe levels keep dropping with time.”

The problem of chemicals in drinking water is one Cousins says society will have to live with for the foreseeable future.

“I don’t think any of us can avoid this low-level exposure,” Cousins said.

Is drinking rainwater safe?

New evidence suggests it may be riskier than previously thought. : A person dips their hands in rainwater collected in a barrel. (Image credit: Shutterstock)

If you stick out your tongue on a rainy day, you might think the drops you’ve tasted are the same as the water that comes out of your tap. But rainwater actually contains many microscopic ingredients that get filtered out before it is pumped into your home.

So is it safe to collect and drink rainwater?

There are a number of contaminants that can end up in the rainwater, such as bacteria, viruses, parasites, dust, smoke particles and other chemicals, according to the Centers for Disease Control and Prevention (opens in new tab) (CDC). If you collect rainwater from a roof, it could also contain traces left by animals, such as bird poop, and if the roof or drainpipes are old, materials such as asbestos, lead and copper could also end up in your tank. If rainwater is stored in an open container, it also may be full of insects and decaying organic matter, such as dead leaves. For these reasons, the CDC advises against collecting and drinking rainwater but recommends using it for other purposes, such as watering plants.

Do we need to be worried about PFAs in the rainwater?

While the recently published research article did not include studies of samples collected in India, the nature of PFAs and the wide geographical breadth of samples and the nature of PFAs means that the results can be extrapolated to India, according to lead author Ian Cousins, who spoke to over an email interaction regarding the same.

How can these chemicals be removed from rainwater?

While there is no known method that can extract and remove PFAs from the atmosphere itself, there are many effective, albeit expensive, methods to remove them from rainwater that has been collected through various rainwater harvesting methods. One way to do this would be to use a filtration system with activated carbon. The activated carbon will need to be removed and replaced regularly. Also, the old contaminated material must be destroyed.

Recently, Science reported a cheaper method that EPA researchers led by William Dichtel and Brittany Trang stumbled upon by chance. The researchers first placed a PFA compound in a solvent called DMSO (dimethyl sulfoxide). They then mixed it with sodium hydroxide (lye) in water. They found that when this mixture was heated up to boiling temperature, the PFA compound began to degrade. However, this method doesn’t work for all PFAs and only works for certain PFA subsets.