Scientists have uncovered a new mechanism that may help break down highly persistent PFAS pollutants.
PFAS have earned the nickname “forever chemicals” for a reason. These industrial compounds are so chemically durable that they can survive in the environment and inside the human body for years or even decades. They have been detected in drinking water, food packaging, rainwater, and human blood around the world, making them one of the most difficult pollution problems scientists face today.
Now, researchers may have uncovered an important clue for finally breaking them apart instead of simply filtering them out.
A new study found that intense ultraviolet light can trigger the destruction of PFAS without requiring additional chemicals. More importantly, the researchers identified the key player behind the reaction: hydrogen radicals, highly reactive particles formed from water during UV exposure.
The results challenge earlier theories about how PFAS degradation occurs. Previous studies suggested that other reactive species were mainly responsible. By identifying hydrogen radicals as the primary factor, the researchers gained a clearer picture of the chemical reactions involved.
Why the Discovery Matters
Understanding the mechanism behind PFAS breakdown could help scientists develop more effective treatment systems.
Hydrogen radicals are highly reactive and capable of attacking PFAS molecules by removing fluorine atoms. Over time, this weakens the compounds and breaks them into smaller, less persistent substances. The researchers also found that the reaction works best under high-energy UV light, especially at wavelengths below 300 nanometers.
According to Associate Professor Zongsu Wei of Aarhus University, who led the study, the findings could guide the development of better cleanup technologies.
“We know that PFAS are extremely stable because of the strong carbon-fluorine bonds, and breaking those bonds is the main challenge. By identifying hydrogen radicals as a dominant driver, we now have a clearer direction for how to design more efficient and sustainable technologies to actually destroy these chemicals, rather than just removing them,” he says.
Moving Beyond Filtration
Wei noted that many current methods only transfer PFAS from one place to another instead of fully eliminating them.
“Today, many technologies can filter PFAS out of water, but they don’t eliminate them. The real goal is degradation: to break the molecules down completely. Understanding the mechanism is essential if we want to achieve that in a green and scalable way.”
The researchers caution that the new findings are not an immediate solution to PFAS pollution. The breakdown process remains relatively slow, and intermediate compounds can still form during treatment. Even so, identifying the main chemical driver marks an important advance in understanding how these pollutants might eventually be destroyed more effectively.
The study suggests that even highly persistent contaminants may be vulnerable when scientists fully understand the chemistry behind them.
Reference: “Mechanistic Insights into Per- and Polyfluoroalkyl Substance (PFAS) Photolysis under Intensified Simulated Solar Light” by Lu Bai, Shuang Luo, Jan Thøgersen, Xingaoyuan Xiong, Zheng Guo and Zongsu Wei, 17 April 2026, Environmental Science & Technology.
DOI: 10.1021/acs.est.5c16178
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