Flea and tick treatments using the insecticides fipronil and imidacloprid are commonly used on pet dogs, whether as spot-on treatments or collars. However, many people have concerns over whether the pesticides come off the dog and get into the environment or even on the people interacting with the dog. And how about dogs that sleep in the same bed with their owners?
A recent study is adding to the growing body of evidence that says we are right to be concerned - that yes, insecticides used on dogs, whether spot-treatments or flea collars, do come off for days. In this latest study, scientists applied spot-on treatments of either fipronil and imidacloprid to 49 dogs.
After 5, 14, and 28 days the dogs were immersed in water for 5 minutes and the levels of the pesticides in the water were measured. Yikes! The pesticides were detected in 100% of all water samples. In fact, even at day 28 it was quite a bit - exceeded safe levels. The researchers said that after being treated, that dogs should not go swimming in water for 4 weeks (far longer than the current 4 day pesticide guidelines).
The study results could explain why these 2 pesticides are contaminating water bodies (e.g., ponds). The researchers write:
"Recent reports reveal widespread fipronil and imidacloprid contamination of fresh waters in the UK despite restrictions on agricultural use, frequently occurring at concentrations that ecotoxicity studies have shown can harm aquatic life.13-15 ... New research has shown that ‘down-the-drain’ household transfer from treated pets, and subsequent entry via wastewater, is a major source of fipronil and imidacloprid freshwater pollution.17 High concentrations and strong positive correlations with dog swimming activity have also been demonstrated in dog swimming ponds, indicating that dog swimming is a further source of surface water pollution.18"
To get a sense of how toxic these 2 pesticides are: both insecticides are banned in the EU for agricultural use, and even have restrictions in agricultural use in the US. Yet, they are commonly used on our pets. Even when taken orally (pills), the dogs excrete the pesticides in their feces and urine, contaminating the environment. The researchers suggest only treating pets when needed with these pesticides, and not when there isn't a need (in other words, don't do "routine prevention" if there isn't a need).
From an article by Michael Le Page in New Scientist: Dogs pollute water with pesticides even weeks after flea treatment
If your dog will jump in the nearest river, pond or lake given half a chance, don’t use spot-on treatments for fleas and ticks, say researchers.
A study has shown that when dogs are immersed in water, their skin and fur can release levels of the active ingredients harmful to aquatic wildlife and the animals that eat them – including birds – for up to 28 days after treatment. ...continue reading "Dogs Pollute Water With Flea and Tick Treatments"