Analysis of government figures has shown that bee-killing pesticides were found in 85 per cent of rivers tested in England.
Green groups looked at Environment Agency data on neonicotinoid pesticides in river areas tested between 2023 and 2024.
These pesticides destroy bees’ nervous systems and research suggests that aquatic insects and mayflies are also vulnerable, potentially impacting fish and bird populations in the wider food chain.
Although neonicotinoids are banned in Europe, they have been approved for use in Britain every year since 2021.
The figures indicate an increase in the share of affected rivers, from 79 percent in 2020 to 2022.
Areas where sugar beet growing and processing are concentrated – particularly the East Midlands and eastern England – had some of the highest detection rates.
Sugar beet is a plant whose root contains a high concentration of sucrose and is grown commercially for sugar production. The by-products also include animal feed made from the leftover pulp.
Seedlings and young plants are vulnerable to viruses that can reduce their size and sugar content. In 2020, a quarter of the UK sugar beet crop was lost, costing £67 million in total economic losses.
The River Waveney in Geldeston, Norfolk. As many as 85 percent of rivers tested in England were found to contain bee-killing pesticides
The largest numbers were found at separate sites on the River Waveney and the River Wensum (pictured)
The largest numbers were found at separate sites on the River Waveney and the River Wensum in the East Midlands, where all five neonicotinoids analyzed were detected.
Other locations where high numbers were detected included the River Nene in the east of England, the River Lugg, the River Tame in the West Midlands, the Sincil Dyke in the East Midlands, the River Ouse in Yorkshire, the River Test to the southeast and the River Chelt to the southwest and the River Douglas to the northwest.
Campaigners also noted that only 27 river sites across England were tested for the pesticides in 2023-2024, compared to 43 sites in 2020-2022, marking a drop of more than a third in the number of sites tested.
They warned that this is an indicative sign of the Environment Agency’s deteriorating resources and the resulting decline in the regulator’s monitoring of the rivers.
During this summer’s election campaign, Sir Keir Starmer said: ‘The new government will ban the neonicotinoid pesticides imidacloprid, Clothianidin and thiamethoxam because of their impact on bees.’
But British Sugar and the National Farmers’ Union (NFU) have applied to use the neonicotinoid Cruiser SB on sugar beet, an anti-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 1.25 billion people.
The River Test (pictured in Overton, Hampshire) was one of the waterways with high levels of neonicotinoids
Richard Benwell, chief executive of Wildlife and Countryside Link, said: ‘The Government should certainly reject the request and double down on agricultural reform to provide generous support to farmers who are dramatically reducing their use of chemicals.
‘The extensive presence of powerful pesticides in rivers is a new smoking weapon in the hands of intensive agriculture and the loss 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 enshrined in law.
‘Pollinating insects such as bees form the basis of a healthy ecosystem and are essential for the pollination of crops.
‘These chemicals are banned because they are extremely harmful to soil, water, nature and human health.
‘The evidence is clear that the environmental risks of neonicotinoids are far too great – there is no place in modern society for their use.’
A spokesperson for Defra said: ‘We are committed to tackling all sources of pollution to clean up our rivers, lakes and seas.
“This administration has made clear that we will change existing policy to ban the use of neonicotinoid pesticides, which pose a threat to bees and other vital pollinators.”