Toxic flea treatments are contaminating rivers - here's what to use instead

Scientists have raised concerns over insecticides used to kill fleas found on pets, after a study showed they are poisoning England's rivers.

Fipronil - one of the most commonly used agents in flea treatments - was discovered in 99 per cent of samples taken from rivers. The average level of one especially toxic breakdown product of the pesticide was found to be 38 times over the safety limit.

Fiprinol, and another nerve agent called imidacloprid - also found in the rivers - have been banned from use on farms since 2017, due to the harm they can cause to aquatic life.

Researchers are particularly concerned about the effect on water insects, and, in turn, the fish and birds that depend on them for survival.

'The chemicals are so potent'

Currently, flea treatments are approved without assessment of potential environmental damage. With around 80 per cent of the UK's 10 million dogs and 11 million cats requiring flea treatment, the authors of the latest study say the results are "extremely concerning."

Professor Dave Goulson, part of the team who ran the study, said, “I couldn’t quite believe the pesticides were so prevalent. Our rivers are routinely and chronically contaminated with both of these chemicals.

“The problem is these chemicals are so potent,” he said, even at tiny concentrations.

“We would expect them to be having significant impacts on insect life in rivers.”

Alternative flea treatments

Currently there are 21 licensed veterinary products containing imidacloprid in the UK, and 66 containing fipronil. Many of these are sold without the need for a subscription.

There are, however, some treatments without these chemicals, which are safer for the environment:

Black walnut (for dogs) can be purchased in capsules or liquid formDiatomaceous earth can be sprinkled on carpets to eliminate any fleas thereAny products containing beneficial nematodes (microorganisms that eat flea larvae) can be sprayed on lawns to kill fleasGentle herbal shampoos can be effective, though over-washing can dry out an animal's skinYou can also buy flea repellent products that do not contain harmful chemicals - you should check the label carefully to make sure that the product does not contain fipronil or imidacloprid