Chemists invented PFAS in the 1930s to make life easier: Nonstick pans, waterproof clothing, grease-resistant food packaging and stain-resistant carpet were all made possible by PFAS. But in recent years, the growing number of health risks found to be connected to these chemicals has become increasingly alarming.

PFAS – perfluoroalkyl and polyfluoroalkyl substances – are now either suspected or known to contribute to thyroid disease, elevated cholesterol, liver damage and cancer, among other health issues.

They can be found in the blood of most Americans and in many drinking water systems, which is why the Environmental Protection Agency in April 2024 finalized the first enforceable federal limits for six types of PFAS in drinking water systems. The limits – between 4 and 10 parts per trillion for PFOS, PFOA, PFHxS, PFNA and GenX – are less than a drop of water in a thousand Olympic-sized swimming pools, which speaks to the chemicals’ toxicity. The sixth type, PFBS, is regulated as a mixture using what’s known as a hazard index.

Meeting these new limits won’t be easy or cheap. And there’s another problem: While PFAS can be filtered out of water, these “forever chemicals” are hard to destroy.

My team at the University of Notre Dame works on solving problems involving contaminants in water systems, including PFAS. We explore new technologies to remove PFAS from drinking water and to handle the PFAS waste. Here’s a glimpse of the magnitude of the challenge and ways you can reduce PFAS in your own drinking water:

Every five years, the EPA is required to choose 30 unregulated contaminants to monitor in public drinking water systems. Right now, 29 of those 30 contaminants are PFAS. The tests provide a sense of just how widespread PFAS are in water systems and where.

The EPA has taken over 22,500 samples from about 3,800 of the 154,000 public drinking water systems in the U.S. In 22% of those water systems, its testing found at least one of the six newly regulated PFAS, and about 16% of the systems exceeded the new standards. East Coast states had the largest percentage of systems with PFAS levels exceeding the new standards in EPA tests conducted so far.

Under the new EPA rules, public water systems have until 2027 to complete monitoring for PFAS and provide publicly available data. If they find PFAS at concentrations that exceed the new limits, then they must install a treatment system by 2029.

How much that will cost public water systems, and ultimately their customers, is still a big unknown, but it won’t be cheap.

The EPA estimated the cost to the nation’s public drinking water systems to comply with the news rules at about US$1.5 billion per year. But other estimates suggest the total costs of testing and cleaning up PFAS contamination will be much higher. The American Water Works Association put the cost at over $3.8 billion per year for PFOS and PFOA alone.

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