Pet medicines polluting rivers with toxic insecticides

Veterinary and environmental groups have called for a ban on insecticides routinely included in pet tick, flea, and worm treatments after harmful concentrations were found in English rivers.

Analysis of official Environment Agency river water quality data by the Rivers Trust and Wildlife and Countryside Link (WCL) revealed that toxic insecticides found in pet medicines are present at 109 of 283 river sites around England.

At all 109 sites, at least one of the five chemicals was above proposed EU levels that are considered safe for aquatic life.

Fipronil was by far the most pervasive, found in 105 (37%) of river sites tested. In all of these sites, levels of fipronil exceeded the Predicted No Effect Concentration (PNEC), the level above which adverse effects for aquatic wildlife can be expected.

Although fipronil has never been used on agricultural crops in England, multiple sites were at over 100 times this level, and two sites at over 1,000 times. The chemical is found in 483 pet products - by far the most of all the chemicals tested.

Imidacloprid – used in 176 pet products – was detected at 22 (8%) out of 283 sites. In just under half of these sites, the amount of imidacloprid was above safe levels for wildlife proposed by the EU’s Environmental Quality Standards (EQS). Imidacloprid was banned for use on outdoor agricultural crops in 2018.

Permethrin was found at just four sites, but all had between three and seven times the “safe” level defined by the proposed EQS. Permethrin has been banned for use on agricultural crops since 2002. 

Dinotefuran and nitenpyram, which the Environment Agency does not test for, are contained in only 12 and nine products respectively. 

All five chemicals are highly toxic to bees, while imidacloprid and fipronil contaminate groundwater. 

Twenty-four environmental and veterinary organisations – including The Progressive Veterinary Association, Veterinary Poisons Information Service, RSPB and The Wildlife Trusts – have written an open letter calling on the UK government to ban these five toxic pesticides from being included in medicines for cats and dogs.

There are more than 300 alternative products available for pet owners, including many major brands such as Nexgard Spectra, Simparica Trio, and Johnson’s, so a ban is highly unlikely to have any impact on animal welfare, the groups pointed out.

Josie Cohen from Pesticide Action Network (PAN) UK said: “It simply makes no sense to block these chemicals from being used on crops in order to protect the environment, while allowing them to be routinely applied by millions of pet owners every month.

“If we want to tackle chemical pollution, then we urgently need to close this loophole. Where alternatives exist, which they absolutely do in the case of pet medicines, chemicals known to be harming wildlife should be taken off the market,” she said.

For the past five years, there has been rising concern among vets regarding the environmental impact of tick, flea, and worm treatments (known collectively as ‘parasiticides’). According to a 2021 survey by the British Veterinary Association, 98% of companion animal vets said they felt concerned about the impact of some parasiticides on the environment, with 42% feeling very concerned. 

Andre Menache, a veterinary surgeon and director of the Progressive Vets Association (PVA) said: “Every industry has a role to play in helping to tackle the nature crisis and vets are no different. We have known about the environmental impacts of parasiticides for many years already. 

“We need to move beyond the plethora of voluntary guidance that exists if we want to reverse wildlife declines. That is why the PVA is supporting the call for a ban on these chemicals,” he added.