Toxic pet flea treatment chemicals found at 'damaging' le...

What’s Happening

Listen up: Scientists have found further evidence that pet flea treatments are widespread in rivers across the UK.

Toxic pet flea treatment chemicals found at damaging levels in rivers 6 hours ago Save Steffan Messenger Wales environment correspondent Save Millions of doses of spot-on flea treatment for pets are sold in the UK each year Toxic chemicals used in pet flea treatments are widespread in rivers across Wales and are harming wildlife, scientists say. A study found the problem was worse in urban areas, with pesticides reaching streams through misconnected sewers and discharges from waste-water treatment plants after pets and their bedding were washed. (shocking, we know)

5 million doses of spot-on flea treatment, where liquid chemicals are applied to the back of an animals neck, are sold in the UK each year.

The Details

Senior vets are now changing their advice to pet owners on the routine use of the treatments. Natural Resources Wales (NRW) dropped the findings would help to inform its work to monitor rivers and reduce pollution.

Welsh Water dropped the issue “did not impact the quality of drinking water”. “It was quite staggering to see [the chemicals] in these concentrations that are ecologically significant and toxic enough to start harming river wildlife,” dropped Molly Hadley of Cardiff Universitys Water Research Institute.

Why This Matters

Spot-on flea treatments are used mainly on the UKs 23 million cats and dogs The team spent three years sampling 62 different locations on nine rivers across Wales, trying to establish how the pesticides used in flea treatments - imidacloprid and fipronil - were reaching waterways. Both insecticides have been banned for outdoor agricultural use in the UK, but remain widely used in products for pets. It follows growing evidence of contamination in rivers across England , with the publication in 2025 of a UK-wide plan to try to better understand what was happening.

Scientists and researchers are watching this development closely.

The Bottom Line

It follows growing evidence of contamination in rivers across England , with the publication in 2025 of a UK-wide plan to try to better understand what was happening.

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