(Beyond Pesticides, November 20, 2020) Many pet owners likely do not consider what is actually in the flea treatments they administer to their animals. That should change, and recent research demonstrates why. Scientists sampling rivers in England found extreme contamination with two neurotoxic pesticides commonly used in flea products for dogs and cats: fipronil and the neonicotinoid imidacloprid. In many instances, the concentrations in the waterways were far higher than accepted “safe” levels. Though these compounds are banned for agricultural uses in the United Kingdom (UK), risk assessment for them, as used on animals, has been minimal because of the assumption that the amounts used for veterinary treatments would mean far-less-significant environmental impact than might be expected with agricultural-scale use. This research out of the University of Sussex voids that assumption, and the researchers recommend “re-evaluation of the environmental risks posed by pet parasite products, and a reappraisal of the risk assessments that these products undergo prior to regulatory approval.”

Apart from being an active ingredient in flea treatments for pets, fipronil is used in insect baits, and in turf management and agriculture in the U.S. It is highly toxic to insects, including bees, to birds, and to aquatic invertebrates. (It is particularly harmful to dragonflies.) Health-wise, it has damaging effects on the neurological, reproductive, endocrine, and renal and hepatic systems, and is a possible human carcinogen. Fipronil can have negative health impacts on pets themselves, including skin irritation, convulsions, incoordination, lethargy, and other effects.

Imidacloprid, a neonicotinoid pesticide, is commonly used — aside from pet treatments — in U.S. agriculture, and in lawn and turf management. Commonly considered less problematic than fipronil, it is nevertheless also toxic to bees, birds, and fish and other aquatic organisms; it has some reproductive impacts in humans. Its environmental impact on such organisms was demonstrated in a 2017 risk assessment, through which EPA found that, “[C]oncentrations of imidacloprid detected in streams, rivers, lakes and drainage canals routinely exceed acute and chronic toxicity endpoints derived for freshwater invertebrates.”

Reference:

https://beyondpesticides.org/dailynewsblog/2020/11/flea-treatment-pesticides-found-to-contaminate-waterways/