A new study offers a rare bit of encouraging news in the ongoing battle against environmental pollution: levels of “forever chemicals” – known as PFAS – are declining in a key marine species. Researchers analyzing decades of archived tissue samples found a 60 percent reduction in PFAS concentrations in pilot whales in the north Atlantic between 1986 and 2023,a sign that regulatory efforts to curb production of these persistent pollutants may be yielding positive results. The findings, published this week in PNAS, highlight the complex journey of these chemicals through the food chain and offer a hopeful, though cautious, outlook for ocean ecosystems and potentially human health.
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Persistent Chemicals: Whales Show Declining Levels of PFAS Contamination
There’s encouraging news regarding long-lasting environmental pollutants: Concentrations of PFAS, often called “forever chemicals,” are decreasing in ocean ecosystems. A new study reveals that levels of these substances in pilot whales in the North Atlantic have fallen by 60 percent. This finding offers a hopeful sign that efforts to regulate these chemicals are having a positive impact on marine life and, potentially, human health.
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Pilot whales off the coast of Norway.
A recent analysis indicates that levels of PFAS in the ocean are declining, a positive development after decades of widespread contamination. Researchers found a 60 percent reduction in the concentration of these chemicals in the tissues of pilot whales in the North Atlantic between 1986 and 2023. The findings, published in the journal PNAS, demonstrate the effectiveness of limiting PFAS production starting in the early 2000s.
PFAS (per- and polyfluoroalkyl substances) have been manufactured since the late 1940s. Today, thousands of different chemicals fall into this category. While their structures vary, they all contain a backbone of carbon chains, some or all of which are surrounded by fluorine atoms. The strong carbon-fluorine bonds give rise to the term “forever chemicals.” PFAS are used in a wide range of industrial applications and can be found in cosmetics, cookware, textiles, pesticides, firefighting foams, and electronic devices. Scientists have detected traces of these substances in lakes, rivers, soil, food, and even the human body. However, data on concentrations in the oceans has been limited.
Effective Action to Reduce PFAS Levels
Due to their harmful effects on human and environmental health, a number of PFAS, particularly those with chains of eight or more carbon atoms, were gradually banned starting in the early 2000s. The industry has increasingly shifted to producing alternatives with shorter chains or different atomic groups. Newer generations of these chemicals are more difficult to detect compared to older ones.
The researchers, led by Jennifer Sun and Elsie Sunderland, did not measure individual PFAS compounds. Instead, they analyzed the total amount of organic fluorine compounds in liver and muscle tissue from pilot whales (Globicephala melas). They examined archived tissue samples collected between 1986 and 2023 from animals in the North Atlantic.
Whales, particularly toothed whales, are at the top of the food chain and serve as indicators of marine pollution. The team discovered that four PFAS from the older generation accounted for about three-quarters of the total concentration of fluorine compounds in the tissue. PFAS levels peaked in samples from 2011 and decreased by more than 60 percent by 2023. This decline occurred approximately ten years after the ban on the older, long-chain versions. According to modeling, this delay is due to marine transport processes.
“The cessation of production, which initially occurred voluntarily and was later driven by regulations, has proven to be very effective in reducing the concentrations of these chemicals near the sources as well as in more distant ecosystems,” said lead author Sun, according to a press release.
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