Bee-killing pesticides have been found in 85 per cent of rivers tested in England, analysis of government figures has revealed.
Green groups looked at Environment Agency data on neonicotinoid pesticides in river sites tested between 2023 and 2024.
These pesticides destroy bees’ nervous systems and research indicates aquatic insects and mayflies are also vulnerable, with potential implications for fish and bird populations in the wider food chain.
While neonicotinoids are banned in Europe, they have been authorised for use every year in the UK since 2021.
The figures indicate an increase in the proportion of rivers affected, up from 79 per cent in 2020 to 2022.
Areas where sugar beet farming and processing is concentrated – particularly the East Midlands and East of England – had some of the highest detection rates.
Sugar beet is a plant whose root contains a high concentration of sucrose and that is grown commercially for sugar production. By-products also include animal feed that is made with the remaining pulp.
Seedlings and young plants are vulnerable to viruses that can reduce their size and lower sugar content. In 2020, a quarter of the UK’s sugar beet crop was lost, costing £67million of total economic loss.
The River Waveney in Geldeston, Norfolk. As many as 85 per cent of rivers tested in England have been found to contain bee-killing pesticides
The largest numbers were found at single sites on the River Waveney and River Wensum (pictured)
The largest numbers were found at single sites on the River Waveney and River Wensum in the East Midlands, where all five of the neonicotinoids analysed for were detected.
Other sites that had high numbers detected included the River Nene in the East of England, River Lugg, the River Tame in the West Midlands, Sincil Dyke in the East Midlands, River Ouse in Yorkshire, River Test in the South East, River Chelt in the South West and the River Douglas in the North West.
Campaigners also noted that only 27 river sites across the whole of England were tested for the pesticides in 2023-24, down from 43 sites in 2020-2022, marking a fall of more than a third in the number of sites tested.
They warned that this is an indicative sign of the worsening resources of the Environment Agency and the resulting decline in river monitoring by the regulator.
During this summer’s election campaign, Sir Keir Starmer said: ‘The new government will ban neonicotinoid pesticides imidacloprid, clothianidin and thiamethoxam due to their impact on bees.’
But British Sugar and the National Farmers’ Union (NFU) have applied to be allowed to use neonicotinoid Cruiser SB on sugar beet, which tackles a plant disease known as virus yellows.
If approved, it will mark the fifth year in a row of emergency use of neonicotinoids.
Cruiser SB is based on the pesticide thiamethoxam, which is highly toxic to bees – just one teaspoon is enough to kill 1.25billion.
The River Test (pictured in Overton, Hampshire) was among other waterways with high levels of neonicotinoids
Richard Benwell, Wildlife and Countryside Link chief executive, said: ‘The Government must surely deny the request and redouble farming reforms to offer generous support for farmers who cut right down on chemical use.
‘The extensive presence of potent pesticides in rivers is another smoking gun in the hands of intensive agriculture and the decline of nature.’
Barnaby Coupe, senior land use policy manager at the Wildlife Trusts, said: ‘The UK Government’s pledge to end the emergency use of these bee-killing pesticides must be signed into law.
‘Pollinating insects like bees are the foundation of a healthy ecosystem and are essential for pollinating crops.
‘These chemicals are banned because they are extremely harmful for soils, water, wildlife and human health.
‘The evidence is clear that the environmental risks from neonicotinoids are far too great – there is no place in modern society for them to be used.’
A Defra spokesman said: ‘We are committed to tackling all sources of pollution to clean up our rivers, lakes and seas.
‘This government has been clear that we will change existing policies to ban the use of neonicotinoid pesticides that threaten bees and other vital pollinators.’
