Levels of Older “Forever Chemicals” May Be Declining in the Open Ocean

Polyfluoroalkyl substances (PFAS) are everyday household chemicals that have left a significant mark on the natural world. Since they were first invented in the 1930s, PFAS have been incorporated into cleaning products, water-resistant fabrics, nonstick cookware, shampoo, and eye makeup. PFAS break down very slowly in the environment. Through groundwater contamination and bioaccumulation, PFAS have become ubiquitous. Researchers have found these chemicals in human and animal blood, rainwater, and even Arctic ice caps.¹ The presence of these chemicals in our bodies and the environment has become a major concern for scientists, as high levels have been linked to harmful health effects.

Over the years, companies synthesized thousands of different types of PFAS. This has made it harder for researchers to understand the scale of the PFAS contamination problem.

In a new study, researchers at Harvard University have found that levels of some PFAS in the bodies of North Atlantic pilot whales have declined by 60 percent.² The findings suggest that efforts to phase out older, legacy PFAS in the early 2000s have begun to feed through to the environment. The study also suggests that new approaches can assess the impact of these phased-out PFAS as well as that of new chemicals that previously have proven harder to measure. The research was published in Proceedings of the National Academy of Sciences.

A New Technique to Measure PFAS

Legacy PFAS, like perfluorooctanoic acid (PFOA), were removed from production chains in the early 2000s after high-profile legal cases showed how the chemicals damaged health. But since then, companies have often simply replaced these chemicals with new PFAS. Jennifer Sun, an environmental scientist at Harvard University and a coauthor of the new study, said in a statement, “We have a lot less information about what is going on with many newer compounds that have been produced to replace the phased-out legacy PFAS.”

Sun and her colleagues, who were led by Elsie Sunderland, an environmental scientist at Harvard University, wanted to develop an analysis technique that could respond to the proliferation of new PFAS more flexibly. Rather than searching for individual PFAS molecules, the team measured bulk organofluorine, which reflects levels of the halogen fluorine within PFAS. This approach meant that the team captured levels of old and new PFAS in their analysis.

To test out their new technique, Sun and her team analyzed pilot whale tissue samples from archives maintained by collaborators in the Faroe Islands, located between Iceland and Norway. Pilot whales, which are actually large dolphins, feast on squid and cod across the North Atlantic, amassing PFAS in their bodies through bioaccumulation. As these animals live far from shore, PFAS levels in their blood are used as proxies for how widely these chemicals affect the environment. The researchers measured tissue samples dating from 2001 to 2023.

They found that the majority of the organofluorine they measured was derived from four older PFAS. Levels of these chemicals peaked in the 2010s, but had significantly declined by the last year analyzed.

“Production phase-outs, which were initially voluntary and later driven by regulation, have been quite effective at reducing concentrations of these chemicals in near-source communities as well as more remote ecosystems, which I think is very positive and important to emphasize,” said Sun.

Where Have Newer PFAS Gone?

This hopeful finding arrives in a less positive global context: Production of new PFAS is rising. The results suggest that the chemical may move around our environment in unexpected ways. “While our results are good news for ocean contamination, it suggests newer PFAS may behave differently from the legacy ones. It underscores the need to place stronger regulations on ongoing PFAS production to mitigate future impacts,” said Sunderland. “Generally, the ocean is thought to be the terminal sink for human pollution on land. But we are not seeing substantial accumulation of the newest PFAS in the open ocean. So, where are they?”