Are urban areas hotspots for pollution from pet parasiticides?

Topics: Resources and Pollution
Type: Briefing paper
Publication date: March 2023



Authors: Rhys G. G. Preston-Allen, Dr Dania Albini, Dr Leon Barron, Dr Tilly Collins, Professor Alex Dumbrell, Hamish Duncalf-Youngson, Dr Michelle Jackson, Professor Andrew Johnson, Dr Rosemary Perkins, Dr Andrew Prentis, Dr David Spurgeon, Nicole Stasik, Clodagh Wells, Professor Guy Woodward

This briefing considers the environmental impact of pet parasiticides, which are commonly used to kill parasites such as fleas and ticks. It reviews possible routes that chemicals from veterinary parasiticides enter the environment, what impacts they may have on natural ecosystems and how to balance the needs of domestic pets, people, and the environment.

  • Substances that are banned for routine agricultural purposes are still being sold and used for other purposes, including parasiticide treatments for pets
    in the UK.
  • These chemicals can enter the natural environment and their active ingredients are toxic to many freshwater species; even at environmental concentrations as low as 0.013 micrograms per litre for the exemplar chemical in this piece, imidacloprid.
  • Currently, existing legislation only requires a very limited environmental risk assessment for pet parasiticide products before they are authorised for domestic use.
  • Recent technological improvements allow us to detect parasiticides in the environment, though formal monitoring for many of these chemicals remains patchy in the UK.
  • The active ingredients in parasiticides are frequently detected at concerningly high maximum concentrations in UK waterways, predominantly in urban areas (e.g., imidacloprid detected above 1 microgram per litre). These concentrations have been shown to negatively affect aquatic life in controlled laboratory trials and field studies.
  • Exposure to parasiticides may affect vulnerable (i.e., sensitive) species within our rivers, lakes, and ponds – potentially disrupting communities and ecosystem processes. The full extent of the environmental impacts on aquatic ecosystems is yet to be quantified.
  • Increased monitoring, stewardship, and regulation of veterinary parasiticides is needed to minimise potential pollution impacts on freshwater ecosystems.

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