Some PFAS chemicals are declining in English rivers but others are appearing

The River Wye in Derbyshire, EnglandDave Porter/Alamy The concentration of two of the most well-studied PFAS forever chemicals are showing a strong downward trend in English rivers. The finding adds to a mixed story for the power of global restrictions. The levels of perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in English rivers have fallen by 30 per cent and 29 per cent, respectively, over the past decade, according to a new report by scientists at the Environment Agency (EA), a UK government green regulator. Both of these human-made chemicals take a long time to break down in the environment. The International Agency for Research on Cancer recently designated PFOA as carcinogenic to humans, and both forever chemicals have been linked to reproductive health and developmental impacts as well as other serious health issues. Advertisement if( window?.adverts?.addToArray ) { window.adverts.addToArray( { "pos": "mid-article-slot" } ); } Read more Fish-based pet food may expose cats and dogs to forever chemicals Under the United Nations Stockholm Convention on Persistent Organic Pollutants, the use of PFOS was restricted from 2009, and the use of PFOA was restricted from 2019 – although there were country-specific caveats on which uses they applied to. They had both been used in non-stick coatings on consumer products as well as in industrial processes. Both were also used in firefighting foams, a major source of PFAS pollution entering the environment, with a ban on PFOA in firefighting foams only coming into force in the UK in 2025. Rob Bradburne, the EA’s chief scientist, describes his group’s results as proof that the global ban was “a really positive move”. But, he adds that the huge range of PFAS chemicals is going to “complicate the story”. An issue that is clear in the dataset for England is that while these two main PFAS have declined, many other “forever chemicals” that are being used to replace them – such as short-chain PFAS and fluorotelomer compounds – have now emerged in the environment at detectable levels. Free newsletter Sign up to The Earth Edition Sign up to newsletter There are around 10,000 chemicals defined as PFAS, and they are used in a huge range of products and processes, from cosmetics to industrial lubricants. But the health and environmental impacts of many of these chemicals are relatively understudied. One of the short-chain PFAS that is now particularly widespread across the world is trifluoroacetic acid (TFA) – which can form when pesticides, refrigerants and pharmaceuticals break down in the environment. The EA report confirmed that TFA is widespread in England, and a separate study published this week confirmed that it is also widespread across the UK more generally. “These findings add to the growing weight of evidence that PFAS pollution must be tackled at source if we are to protect our environment and our health,” says Hannah Evans, who worked on this second study and works with the UK environmental charity Fidra. “Other countries are already progressing towards this end… The UK cannot afford to fall further behind,” says Evans. Read more Wastewater treatment plants funnel PFAS into drinking water Currently, the EU is looking at a blanket ban on all PFAS chemicals, so that when specific chemicals are prohibited they aren’t simply replaced by another PFAS that may also eventually be identified as harmful and persistent in the environment. The UK government has said it is following this closely but has given no timescales on when a similar policy might be introduced. Alistair Boxall at the University of York, UK, says that the decline in legacy pollutants and increase in short-chain replacements was observed in a recently published European-wide monitoring study he took part in. He believes the change shows why bans that target the entire group of chemicals could offer a better way forward. “We seem to always be playing catch-up with chemicals like PFAS, so need to be much more agile in the way that we monitor and manage these substances. The idea of using grouping approaches could help,” says Boxall. Patrick Byrne at Liverpool John Moores University, UK, says that the grouping approach is useful and something that scientists have argued strongly for. Plant biology provides inspiration for PFAS replacement Forever chemicals are renowned for their durability and their non-stick properties, but they persist for years in the environment. An alternative inspired by plants doesn’t have the same problem He also says that the story isn’t over for PFOS and PFOA. Though they are decreasing globally, it’s important to remember they are still highly persistent and found in almost every water body. The levels of PFOS being recorded are still, in many cases, higher than the UK and EU Environmental Quality Standard, which is set to reflect the concentration above which the chemical will affect ecosystems. Currently, PFOS is the only individual PFAS with such a standard in England, but others are under development. “This report adds to our growing understanding of how PFAS enter our environment, but we must not wait for a complete picture before acting,” says Chloe Alexander, a campaigner at Wildlife and Countryside Link, an umbrella organisation in the UK that brings together many volunteer and charitable groups. “History is full of late lessons from early warnings, where ignored science allowed preventable harm to become widespread and, in some cases, irreversible,” says Alexander. “The longer it waits, the greater the risks to people and wildlife – and the higher the costs of clean-up and toxic waste disposal.”