Pesticide in flea treatment should be more regulated, say Lib Dems

Whilst regulated in other applications, neonicotinoids in pet medicines continue to fall through the cracks, degrading water quality.

By Jed Thomas

The Liberal Democrats are calling for urgent restrictions on toxic pet flea treatments, warning that the insecticides commonly used to protect cats and dogs are quietly contaminating UK waterways and killing wildlife. 

In a recent parliamentary debate, Lib Dem MP Rachel Gilmour pressed ministers to clamp down on over-the-counter flea treatments containing neonicotinoids such as fipronil and imidacloprid.

These chemicals already banned from agricultural use due to their well-documented harm to bees, birds, and aquatic life. 

“Cleaning up our waterways is a key mission of my party,” said Gilmour. “Properly regulating the use of fipronil and imidacloprid – as well as other neonicotinoids – is part of that agenda. The damage these products can do is catastrophic to our natural world.” 

Recently, EnvirotechOnline visited Dr. Leon Barron’s London laboratory to explore the pollution of the Thames – some of which is coming from these pet treatments. Dive in with us:  

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How do pesticides in flea treatments enter waterways? 

Unlike pesticides used on farms, pet flea treatments remain largely unregulated in the UK.  

Products containing neonicotinoids can be bought freely at pet shops, and are often prescribed as a routine precaution—even when no fleas are present.  

Yet scientists are now urging a shift to treatment only when infestations occur, in light of growing ecological concerns. 

Studies have shown that after application, insecticides remain on pets’ fur for up to 28 days, posing risks to human handlers and shedding into the environment.  

Fur tainted with these chemicals is even being found in birds’ nests, where researchers have linked it to higher rates of failed hatching and chick mortality. 

How widespread is neonicotinoid pollution in UK waterways? 

The veterinary use of neonicotinoids may be more pervasive than previously thought. 

Fipronil is currently an ingredient in 66 licensed veterinary products in the UK; imidacloprid appears in 21 more.  

Just one monthly dose for a large dog contains enough imidacloprid to kill 25 million bees.  

Despite their agricultural ban in 2018, Environment Agency testing still found fipronil residue in 98% of UK river and lake samples, and imidacloprid in 66%. 

The Department for Environment, Food and Rural Affairs (Defra) has asked the Veterinary Medicines Directorate to examine the issue. 

Meanwhile, environmental advocates are urging the government to act swiftly. 

Are pesticides becoming more regulated, anyway? 

The debate comes amid broader political momentum to reduce the UK’s dependence on harmful pesticides.  

Earlier this month, the Labour Party pledged to end the controversial practice of granting emergency authorisations for bee-killing pesticides—specifically targeting thiamethoxam, which has been approved for sugar beet crops against scientific advice for four consecutive years. 

“The continued presence of ecologically damaging toxins in our environment seriously hampers efforts to halt biodiversity loss and restore nature,” Craig Macadam of Buglife told The Guardian, welcoming Labour’s stance. “We encourage other parties to bring forward similar policies to reduce reliance on chemicals.” 

Further bolstering this trend, the government has announced a national plan to reduce pesticide use on farms by 10% by 2030—a long-delayed policy campaigners have sought since 2018.  

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The initiative will also introduce a pesticide load indicator, encourage non-chemical pest management techniques, and penalise irresponsible use. 

However, critics argue that the plan falls short by excluding urban pesticide use. Campaigners have warned that pesticides in parks and streets continue to endanger wildlife, pets, and people. 

“The failure to address pesticide use in urban areas is a major flaw,” said Paul de Zylva of Friends of the Earth in a public statement. “The government must commit to the phasing out of pesticide and herbicide use in urban parks and streets, which is unnecessary and risks the health of people, pets, wildlife, rivers and soils.” 

Still, many see the current moment as a turning point in UK pesticide policy, with public awareness, scientific research, and political will finally converging.  

The call to extend environmental protections from the farm to the family pet may be the next logical—and necessary—step. 

As Rachel Gilmour put it, “It’s time to close this loophole. If these chemicals are too dangerous for our crops, they’re too dangerous for our pets—and for our rivers, birds, and bees.”