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Bee-killing pesticides found at wildlife-threatening levels in rivers around the country

22 September 2023

Wildlife campaigners are warning that harmful neonicotinoid pesticide levels can be found in rivers around England, according to new research published today.

The warning comes as environmental groups wait to hear if one banned toxic neonicotinoid pesticide – Thiamethoxam - will be approved by the Government for English sugar beet farm use for a fourth consecutive year. This issue was discussed at the latest meeting of the Expert Committee on Pesticides on 12 Sept and it is likely the Government is currently considering its decision on the use of Thiamethoxam (in Cruiser SB) for 2024 crops.

The Rivers Trust and Wildlife and Countryside Link conducted new analysis of neonicotinoid pesticides using official Environment Agency data from the last three years (2020-2022), for the ‘Chemical Cocktail’ campaign, and found that [1]:

  • 1 or more of 5 harmful neonicotinoids analysed were found in more than 1 in 10 English river sites tested by the Environment Agency (29 of 283 sites) [2]
  • At 55% of these 29 sites one or more neonics were above the EU’s proposed Environmental Quality Standard (EQS) – the level deemed safe for aquatic wildlife. With 21% of sites having one or more neonics at over 4 times the safe level.
  • The neonics Clothianidin and Imidacloprid were most prevalent and most exceeded the proposed EQS. 28% of Clothianidin site detections and 47% of Imidacloprid site detections were over the proposed EU safe levels. See embargoed maps and data
  • The highest neonic concentrations were detected in the East of England, South East and West Mids in rivers including the Rivers Ivel, Waveney, Nene, Ouse and Tame. The highest number of neonics found at single sites were detected in Yorks and Humber, the West Mids and E of England. Further details in the spreadsheet here
  • The research clearly identifies an issue with neonics in our rivers. But nature charities are warning that these figures are likely to be just the tip of the iceberg when it comes to the amounts of harmful neonicotinoid pesticides in our rivers and the number of rivers affected. Poor monitoring is very probably hiding the true scale of impact of neonics in our waterways.

Nick Mole, policy officer at PAN UK, said: “The ongoing presence of neonicotinoids and other pesticides in the UK’s waterways is hugely concerning. These chemicals are harming aquatic ecosystems and wider biodiversity at a time when we should be doing everything possible to protect and increase nature throughout the UK. There must be no more ‘emergency’ extensions for the use of banned pesticides and the UK government must introduce a robust, effective and well-funded monitoring system for all UK waterbodies as a matter of urgency.”

Soil Association Head of Farming Policy Gareth Morgan said: “It is deeply concerning to see that these harmful chemicals are still threatening our precious pollinators and rivers. This latest evidence is the direct consequence of the failure to support farmers to find long-term, sustainable solutions that do not threaten wildlife. Year after year this failure to help farmers has led to the suspension of the so-called ban on these bee-harming pesticides. With so much of British wildlife in decline, it is critical that the government stops kicking the can down the road on this issue. Organic and agroecological farmers are proving that food can be produced without pesticides. Government must act now to help all farmers switch to nature-friendly practices across their entire farms. We must stop simply reaching for another toxic solution.”

Barnaby Coupe, land use policy manager at The Wildlife Trusts, says: “This research reveals that our rivers and waterways are plagued by a cocktail of neonicotinoid pesticides, despite these chemicals being banned since 2018. These pesticides continue to poison our rivers and are highly toxic to water wildlife. They are also particularly harmful to insects including bees that provide essential pollination services to farmers.

“It is completely unacceptable that the Government is allowing these chemicals to pollute the environment when the evidence for the disastrous impact of neonicotinoids grows year on year. It has ignored the science and the advice of its own experts in granting repeat authorisations to apply toxic neonicotinoids to our countryside, and the result is much diminished wildlife. The Government must do more to support farmers to move away from a reliance on these pesticides and stop authorising the use of banned chemicals.”

Sandra Bell, campaigner at Friends of the Earth, said: “These results tell us that toxic pesticides stay in the environment for a very long time, and that their use in farming and pet products is polluting our rivers and posing risks to aquatic wildlife. The government’s long-promised strategy to help farmers reduce their reliance on pesticides has failed to materialise, and year after year a banned bee-harming pesticide has made its way back onto our fields, against the advice of the government’s own experts. The dire health of our rivers has been the subject of much public anger – it would be incredibly irresponsible, and deeply unpopular, to grant yet more emergency use of these banned toxic chemicals which would put both rivers and bees at risk again.”

Additional quotes from Buglife and UK Youth For Nature are in the notes to editors.[3]

The 5 neonicotinoid pesticides analysed are all on the EU’s proposed Water Framework Directive Priority Substances list. The 5 neonicotinoids analysed include:

Acetamiprid (still authorised for UK use, it bioaccumulates and is highly toxic to birds and earthworms and moderately toxic to mammals and most aquatic organisms);

Clothianidin (banned for outdoor crop use across Europe from 2018, known to be highly toxic to honeybees with high potential to leach to groundwater. It is a breakdown product of Thiamethoxam and is persistent in water, both of which are likely to explain its continued detection after being banned);

Imidacloprid (banned on crops since 2018, is proven to reduce aquatic insect levels with a knock-on toxic impact on bird population). Its high presence in our waters, despite the ban, is likely due to continued use in tick and flea treatments. This is a worrying finding and adds to evidence that this, and other similar substances banned from outdoor crop use, should also be banned from veterinary medicines);

Thiacloprid ( banned in 2020 due to potential human health impacts and ability to remain in groundwater);

and Thiamethoxam (also banned since 2018, acutely toxic to pollinators and very toxic for aquatic wildlife with long-lasting effects. While there were limited detections of Thiamethoxam, Clothianidin presence - as a breakdown product of Thiamethoxam - is a good indicator that Thiamethoxam has polluted waterways).

Neonicotinoids are known to be highly toxic to bees and other pollinators with just one teaspoon enough to kill 1.25 billion bees according to some experts, see further background info here. The most well-known neonicotinoid is Thiamethoxam, which is contained in the aphid pesticide Cruiser SB. Despite being a banned outdoor substance across Europe since 2018, the Government granted an exemption for sugar beet farmers to use Thiamethoxam for 2021, 2022, and 2023 crops due to beet yellow virus risk from aphids (although the 2021 permission was later revoked after a cold winter reduced the viral risk).

The emergency authorisations went against the recommendations of the Government’s own scientific advisers, the UK Expert Committee on Pesticides, and against Government guidance that emergency authorisations should not be granted more than once. Despite the UK Government advocating a global pesticide reduction target at CO15 last year and promising that post-EU our approach on chemicals would be ‘better’ than the EU’s, the UK is allowing pesticides to be used that are banned in the EU due to their toxicity. There are now 36 pesticide active substances that are permitted for use in the UK but not the EU. And in January 2023 the EU Court of Justice declared that emergency authorisations of prohibited neonicotinoid-treated seeds are not in line with EU law.

Tessa Wardley, Director of Communications and Advocacy at the Rivers Trust, said: “These highly toxic pesticides can have a devastating and lasting impact on our rivers and the wildlife that live in them. Our new analysis shows neonicotinoids at worrying levels at multiple sites. But this is likely to be just a drop in the ocean of neonicotinoid river pollution. Environment Agency monitoring of pesticides in our rivers is sorely lacking. Monitoring is infrequent and practically non-existent during wet weather when the risk of rapid flushing of these and other pesticides into our rivers is greatest. If we are to get a grip on this potentially devastating source of river pollution, we need effective monitoring that can actually reveal the scale of the problem.”

The main problem with neonicotinoid and other pesticide detection in rivers is that the pesticides are water soluble and breakdown. Though some can persist in water for months, or in some cases years, they will usually only be detected in large quantities when they are running off farm fields during periods of high rainfall. Yet monitoring staff rarely conduct surveys during such conditions and testing can be very infrequent, with some sites tested just once per year - clearly insufficient to capture periods of high pollution. So these chemicals are likely vastly under-reported in official data.

While proponents of neonicotinoid use may argue that the lack of continued detection means the pesticide is not an issue for wildlife or habitats, the science shows otherwise. Even minute traces of these toxic chemicals in crop pollen or wildflowers play havoc with insects’ ability to forage and navigate, with catastrophic consequences for survival. Studies have also shown pesticides to be highly toxic to aquatic life even at low concentration levels. The effects of pesticide exposure to the environment are contributing to rapid declines in insect populations, including a 64% decline in flying insect abundance in the UK between 2004 and 2022.

Nature organisations are calling for politicians to put in place improved monitoring of the problem, stronger rules on the use of chemicals affecting wildlife and public health, and tougher requirements on polluting industries, by:

  • Delivering more rigorous and better-funded monitoring, including static sampling to ensure pesticide pollution is effectively monitored, reported and assessed.
  • Phasing out known toxic chemicals from all but vital uses and regulating similarly structured chemicals in groups, to prevent replacing damaging chemicals with others.
  • Specific measures to address the chemical cocktail effect: including assessments of possible interactions before any new chemical is allowed on the market
  • A pay-rise for nature-friendly farming – doubling the environmental land management scheme’s budget to reward farmers that make environmentally-friendly changes
  • Making polluters pay – by implementing a Nature Recovery Obligation that requires mandatory reporting and mitigation plans, alongside a levy for polluting big businesse

Environment organisations are encouraging the public to demand action for nature from our political leaders, including tackling farming and chemical pollution in our rivers, by signing a joint letter:


Notes to editors:

  1. Supporters of the Chemical cocktail campaign include: Wildlife and Countryside Link, The Rivers Trust, CHEM Trust, Surfers Against Sewage, Buglife, WildFish, Fidra, Pesticide Action Network UK, The Wildlife Trusts, The National Trust, Whale and Dolphin Conservation, British Canoeing, The Institute of Fisheries Management, The Soil Association and the Pesticide Collaboration.
  2. The Rivers Trust and Wildlife and Countryside Link analysed neonicotinoid data in the Liquid chromatography-mass spectrometry (LC-MS), non-target database, which is the only Environment Agency database which contains neonicotinoid findings. The findings were analysed against proposed Annual Average EU EQS levels for each pesticide
  3. Additional quotes:

    David Smith, Advocacy and Social Change Officer at Buglife, said:
    “The continued presence of ecologically damaging banned substances in our environment seriously hampers efforts to halt biodiversity loss and restore nature. Environmental organisations have been raising awareness of this issue for years, yet progress has been far too slow. Banned neonicotinoids are still for sale in domestic flea treatments and derogations are routinely authorised to use pesticides which harm pollinators and pollute freshwaters. The Government must clean up its act, stop these chemicals from being used, and take monitoring seriously to ensure it can meet its biodiversity commitments.”

    Joe Wilkins, Head of Campaigns at UK Youth for Nature, said:
    "Time and time again, we are seeing banned substances receiving "emergency" approval for use from this government. Yet they seem intent on ignoring the real emergency: the current status of our rivers and lakes. Overcome by a chemical cocktail of invisible pollutants, our world-famous waterways are being choked of life with many no longer safe for people or nature. Supporters say this is to secure food security but the use of extremely harmful substances is not the way forward and will only serve to make the issue worse. We need a well-planned and well-managed change to our food system in the UK, not the piecemeal and environmentally damaging one we see today."

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