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Warning signal on PFAS polluted state of UK’s fish, with freshwater fish containing up to 1000 times EU safe levels

4 December 2023

  • Environment groups are urging the Government to regularly test fish set for human consumption for PFAS forever chemicals, as freshwater fish are so heavily contaminated.
  • Hundreds of officially monitored small freshwater fish samples tested for PFOS in English rivers were contaminated at between 10 to 1000 times the proposed new EU safe level for wildlife.
  • Levels of PFAS contamination could in fact be many hundreds more times over the safe level, as only two PFAS contaminants are tested for in fish by the Government
  • If just one portion of these freshwater fish were eaten per month this would exceed the safe threshold of PFOS for people to consume over a year

New Wildlife and Countryside Link and Rivers Trust analysis of official Government data has revealed that levels of just one toxic PFAS forever chemical – Perfluorooctane sulfonic acid (PFOS) in English freshwater fish are on average 301 times higher than proposed new EU safe levels for wildlife. [1]

Though the types and size of freshwater fish the Environment Agency monitors are generally not used for human consumption, the worrying levels of PFOS found in them sounds alarm bells for the state of fish that people do eat. [2].

Environment groups are warning that the high levels of forever chemical contamination in English freshwater fish mean not only that greater monitoring of both marine and freshwater fish for human consumption is needed, but that drastic action is needed to reduce PFAS pollution into our rivers and ocean. They say that the Government’s plans for PFAS protections, outlined in a PFAS Risk Management Option Analysis (RMOA) in April, fall far short of the mark.

The actual amount of PFAS contamination in fish could actually be even higher still than the new findings. While PFOS is banned in the UK, there are more than 10,000 other per- and poly-fluoroalkyl substances (PFAS) which are still widely used, mainly to make materials heat, water, flame or stain resistant, and these can pollute our environment for generations. The Environment Agency only test fish for PFOS and Perfluorooctanoic Acid (PFOA), not other types of PFAS. Findings of such high levels over safe limits are highly concerning, particularly alongside new findings on high levels in drinking water, given that some PFAS are proven to damage the immune systems and have other health impacts for wildlife and humans.

Dr Richard Benwell, CEO of Wildlife and Countryside Link, said: “Toxic forever chemicals are present in wildlife, rivers and streams and may even be in the food we eat. The true level of contamination is likely to be even higher because the Environment Agency only test fish for two types of PFAS out of thousands currently in use and don’t test the fish that we routinely consume in the UK. Government must act now to stop the chemical cocktail building up in our rivers and ocean. We need better monitoring of our waters, wildlife and of the fish we eat, and regulations that can quickly prevent chemically-similar substances from entering our environment in the first place.”

Anneka France, Technical Manager at The Rivers Trust, said: “Toxic levels of PFOS contamination in freshwater fish serves as a critical warning, akin to the canary in the coal mine, potentially signalling a much wider issue in our environment and food chain. Despite PFOS restrictions for over a decade, other forever chemicals with similar or heightened toxicity remain in widespread use and continue to accumulate around us. We urgently need more robust regulations and proactive monitoring to address these complex chemical cocktails, and Government must take immediate action to safeguard our environment, wildlife, and public health.”

Dani Jordan, Director of Communications and Campaigns at Surfers Against Sewage: “Not only are our rivers and ocean suffering from sewage overload they are also being choked by a chemical cocktail. It’s worrying to see this level of contamination of freshwater fish in our rivers, and it raises the question of what is happening with marine fish that aren’t monitored. Fish being contaminated by unsafe levels of toxic forever chemicals is bad news for us all, with wildlife and human health paying the price. We need clean waters that are safe for children to play in, for fish to swim in and for people to drink – now is the time for the Government to end water pollution.”

The Environment Agency tests for both PFOS and PFOA (the two most widely detected PFAS chemicals) in freshwater wildlife – known as biota-testing. But as there is no Environmental Safety Standard set for PFOA in biota under current UK legislation, our analysis focused on PFOS.

PFOS findings relating to food consumption

While the small freshwater fish monitored by Government would be unlikely to be consumed, the levels of PFAS pollution found in them are a good indicator of wider fish pollution and the urgent need to monitor levels in the fish people consume.Recent US research showed freshwater fish as a significant source of American exposure to PFAS chemicals, with one fish portion equivalent to drinking PFAS contaminated water every day for a month. The new research published today shows a similarly worrying picture in pollution of English freshwater fish. [3] If a portion of these freshwater fish was to be eaten every month it would be equivalent to more than the amount considered safe to consume over a whole year based on standards set by the European Food Safety Authority (EFSA).

It should also be noted that these are minimum figures for likely contamination in small freshwater fish. Not only do they just look at one type of PFAS forever chemical (PFOS), when thousands of these chemicals are in use, PFAS substances are known to build-up over time, and concentrations could possibly be higher in larger fish that would be destined for our dinner tables.

PFOS findings in wildlife

Environmental Quality Standards set safe concentrations of PFAS, and other chemicals, in animal and plantlife (biota) to protect top predators and humans from secondary poisoning.

The new analysis used Environment Agency data to compare levels of PFOS against the existing UK EQS standard and found that a third of sampling sites (28 out of 93) exceeded the safety threshold, with some exceeding the EQS by up to five times.

When assessed against much stricter new proposed EU EQS standards the findings were much starker. Concentrations of PFOS in fish at more than two thirds of river sites were found to exceed EU proposed new safe levels for PFAS by more than 100 times, with fish in one river at more than 1000 times the proposed EU EQS.[4] What is even more concerning is that the proposed EU EQS assesses 24 PFAS chemicals in combination and our analysis assessed just one. Therefore if all 24 were tested for the results could be potentially many more hundreds of times over this proposed safe level.

This worrying level of PFAS contamination is likely to have big impacts for wildlife. The known effects on fish include disruption to reproduction, thyroid activity, metabolism and development. And toxic forever chemical pollution has a wider impact, building up at greater concentrations in animals higher up the food chain, with a 2022 study finding multiple PFAS in all 50 otters tested. In marine mammals, PFAS exposure has been linked to impacts on immune, blood, liver and kidney function in bottlenose dolphins, immune function in sea otters and has even been linked to neurological impacts in polar bears.Government is being urged today by environmentalists to match the ambition of tougher standards and controls the EU is proposing, including a ban of 10,000 PFAS chemicals, and to go further with a polluter levy on industries to tackle the chemical pollution they have created. In addition to asking for stronger future protections, experts are also urging the Government to ensure it is actually monitoring for these harmful chemicals in the food we eat by implementing regular monitoring of 24 key PFAS in fish, livestock and poultry destined for human consumption.

Members of the public are being encouraged to back calls to politicians to go further, faster for nature’s recovery, including implementing a ‘make polluters pay’ levy:


Notes to Editors:

1. Mean concentration of PFOS after multiplying by a relative potency factor of 2 was 23 ug/kg, this is compared to a proposed EQS of 0.077 ug/kg

2. Methodology comparing to current UK and proposed EU EQS for wildlife: On behalf of Wildlife and Countryside Link, the Rivers Trust analysed the Environment Agency’s Water Quality Data Archive data on PFOS in biota (fish and molluscs). They compared median average concentrations for the 93 sampling sites the Agency holds data on for PFOS in biota, using data for 2016-2022. These median concentrations were measured against the existing UK Environmental Quality Standards (EQS) and proposed EU EQS – both detailed below.

PFOS is a Priority Hazardous Substance under the UK Water Framework Directive and the Environmental Quality Standard (EQS) for biota is set at 9.1 μg/kg (wet weight).

Under proposed new EU EQS standards, PFOS will be assessed as part of a sum of 24 PFAS substances. Within this standard the EQS for biota would be 0.077 μg/kg (wet weight combined for all 24 PFAS).In this standard each PFAS chemical is weighted according to its potency relative to the most prevalent PFAS chemical - PFOA. This is referred to as their Relative Potency Factor (RPF). PFOS is weighted at 2 times the potency of PFOA, therefore all PFOS detections are doubled in this analysis, when comparing to the proposed new standard) to reflect the RPF weighting they would have in the proposed new EU standard.

Methodology for fish consumption figures: The Rivers Trust also analysed, for Wildlife and Countryside Link, Environment Agency data on PFOS in biota at 93 sites. This was measured against European Food Safety Authority (EFSA) safety thresholds for PFAS in food consumption and was also used in calculations recreating the methodology from a recent US study to assess safety for food consumption.EFSA set a tougher safety threshold for PFAS in food consumption – a group tolerable weekly intake (TWI) of 0.0044 μg/kg of body weight per week - focused on are perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), perfluorohexane sulfonic acid (PFHxS). This amounts to a safe weekly threshold for a 70 kg adult of 7.76 ng/ml.

The US study estimated blood serum increases in PFOS through consumption of locally caught freshwater fish. Following the method used in Barbo et al., 2023.:

Clearance factor (cf) = 8.1 * 10-5 L/kg/day Serving weight = 227 g Person weight = 70 kg Median PFOS ng/kg in WQA wet weight samples = 5795 ng/kg

EFSA tolerable weekly intake of 4 PFAS = 4.4 (ng/kg body weight/week)

Using the above clearance factor and EFSA TWI of PFAS the tolerable increase of PFOS in blood serum is 7.76 mg/ml. We estimate the increase of PFOS concentration in blood serum when these freshwater fish are eaten once a week, once a month, once every 3 months and once a year. A person would have to eat fish from English rivers 12 times a year to increase their blood serum concentration above the EFSA TWI of 7.76 mg/ml.

3. Median concentration in the US study is 11.88 ug/kg in England it is 7.27 ug/kg

4. Mean measured whole fish concentrations of PFOS (wet weight, RPF 2) assessed against the proposed EU biota EQS of 0.077 μg/kg

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