Newer forever chemicals aren’t showing up in the ocean like legacy ones – and scientists don’t know why.
Concentrations of forever chemicals in North Atlantic pilot whales have decreased by more than 60 per cent over the last three decades.
Harvard researchers have analysed whale tissue samples from 1986 to 2023, and found that contamination of per- or polyfluoroalkyl substances (PFAS) has fallen despite global production increasing.
The news comes as Europe continues to crack down on chemicals following evidence that chronic exposure has been linked to the promotion of certain cancers, reduced fertility, and issues with the immune system.
However, are the findings worth celebrating – or are newer PFAS simply accumulating elsewhere?
What are forever chemicals?
PFAS are a group of more than 10,000 synthetic chemicals that have become ubiquitous on Earth. Scientists have found them on the peak of Mount Everest, inside human blood, and even in deep-sea dolphins off the coast of New Zealand.
They’re commonly used to make items water- and grease-resistant, such as non-stick cookware and clothes.
However, they can take more than 1,000 years to degrade naturally, hence the name ‘forever chemicals’.
Will whales be free from PFAS?
The study, published in the Proceedings of the National Academy of Sciences, likens the PFAS crisis to “wack-a-mole”, arguing that once researchers understand the exposure and health impacts of one chemical, a new one is developed.
To overcome this, researchers measured bulk organofluorine (which captures the fluorine found in most PFAS compounds) rather than measuring individual PFAS. They then used these measurements as a proxy for total concentrations of PFAS, including newer types of PFAS that are much more difficult to identify on their own.
The research team studied whale tissue samples as the apex predators are considered “sentinels of marine pollution”. This is because their bodies retain chemical exposures for long periods, and they exist in the outer ocean, which demonstrates how PFAS can travel in the natural environment.
Overall, organofluorine levels were primarily made up of four legacy PFAS that all peaked in the mid-2010s and had declined by more than 60 per cent by 2023.
“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 emphasise,” says senior author Elsie Sunderland.
Where are newer PFAS going?
Researchers say the reduction of PFAS surprisingly comes as the production of new PFAS is actually on the rise, raising the question: If most of the newer PFAS aren’t accumulating in the ocean, where are they going?
“Generally, the ocean is thought to be the terminal sink for human pollution on land, but we aren’t seeing substantial accumulation of the newest PFAS in the open ocean,” Sunderland adds.
“While our results are good news for ocean contamination, it suggests newer PFAS may behave differently from the legacy ones.”
The study’s findings highlight the need to place stronger regulations on ongoing PFAS production to mitigate future impacts.
