Pesticides commonly used as flea treatments for pets are contaminating English rivers

When I stopped using flea collars on my pets, after a few months I realized I felt better.  I didn't realize that the way I felt was not as good as I should feel.  I now rely on flea combs, which are more work, but healthier for me and my pets and the environment.

https://www.eurekalert.org/pub_releases/2020-11/uos-pcu111620.php

News Release 16-Nov-2020
University of Sussex

Researchers at the University of Sussex have found widespread contamination of English rivers with two neurotoxic pesticides commonly used in veterinary flea products: fipronil and the neonicotinoid imidacloprid. The concentrations found often far exceeded accepted safe limits.

These chemicals are banned for agricultural use due to the adverse environmental effects, but there is minimal environmental risk assessment for pesticides used on domestic cats and dogs. This is due to the assumption that there are likely to be fewer environmental impacts due to the amount of product used.

But there is growing concern that this assumption may be incorrect. To investigate this, Professor Dave Goulson and Rosemary Perkins from the University of Sussex analysed data gathered by the Environment Agency in English waterways between 2016-18. They found that fipronil was detected in 98% of freshwater samples, and imidacloprid in 66%.

Rosemary Perkins, a PhD student at Sussex and a qualified vet, said: "The use of pet parasite products has increased over the years, with millions of dogs and cats now being routinely treated multiple times per year".

•••••

While some of these products can be purchased only with a veterinary prescription, others can be bought without a prescription from pet shops, supermarkets, pharmacies and online. Many pet owners receive year-round preventative flea and/or tick treatment from their vet practice via healthcare plans.

•••••

While, in most rivers, imidacloprid was found to pose a moderate risk, in seven out of the 20 rivers sampled there was a high environmental risk.

Co-author Professor Dave Goulson said "Fipronil and imidacloprid are both highly toxic to all insects and other aquatic invertebrates. Studies have shown both pesticides to be associated with declines in the abundance of aquatic invertebrate communities. The finding that our rivers are routinely and chronically contaminated with both of these chemicals and mixtures of their toxic breakdown products is deeply troubling."

•••••

The paper, published in Science of the Total Environment, notes that the highest levels of pollution were found immediately downstream of wastewater treatment works, supporting the hypothesis that significant quantities of pesticide may be passing from treated pets to the environment via household drains.

Bathing of pets treated with spot-on fipronil flea products has been confirmed as a potentially important route to waterways for fipronil via sewers, and the washing of hands, pet bedding or other surfaces that have come into contact with treated pets are potential additional pathways for entry to sewers. Other pathways for contamination of waterways includes swimming and rainfall wash-off from treated pets. The strong correlation between fipronil and imidacloprid levels across the river sites tested suggest that they may be coming from a common source.

•••••