Government publishes plan to address presence of chemicals from pet flea and tick treatments in UK waterways

25 July 2025

The Cross Government Pharmaceuticals in the Environment (PiE) Group has published (22 July) their roadmap outlining plans to address the presence of chemicals from topical pet parasiticide products in UK rivers and streams, focussing on fipronil and imidacloprid. Despite being banned from agricultural use in the UK in 2017 and 2018, these compounds have emerged in recent years as substances of high concern for environmental toxicity, leading to concerns about pet parasiticides as a potential source of environmental contamination.

As outlined by Francine Fernadez, Senior Environmental Safety Assessor at the Veterinary Medicines Directorate (VMD) in her presentation as part of BSAVA’s One Health: One Team stream at BSAVA Congress which included Defra, VMD and the Environment Agency (EA), the published plan covers a series of short- medium- and long-term actions aimed at reducing the environmental presence of pet flea and tick treatments while protecting animal welfare together with both animal and human health.

Communication and Education

In the short-term, the VMD will collaborate with veterinary professionals and industry stakeholders to improve pet owner awareness regarding the responsible use and disposal of flea and tick treatments.

This action aligns with recommendations from the BVA, BSAVA and BVZS joint Policy Position on the responsible use of pet parasiticides, published in September 2021. Following on from the Policy Position, a suite of practical resources was created to support veterinary professionals in small animal practice and their clients.

Evidence Gathering

In the medium-term, actions are focussed on building a comprehensive, evidence-based understanding of the environmental impacts of flea and tick medications, alongside evaluating the potential consequences of changing use patterns on animal and human health.

To support this step, the VMD has commissioned research to investigate the pathways through which parasiticides enter aquatic ecosystems and is working closely with the EA to assess the environmental risks posed by these substances. Additionally, the Group will work with the devolved environmental protection agencies1 to harmonise approaches and determine overall trends for fipronil and imidacloprid levels in the environment, as well as investigating other potential sources, including off-label and illegal use. Another strand will focus on the potential consequences of changes in parasiticide use on animal health and welfare, and public health.

Part of the evidence gathering process will involve the VMD and Defra collaborating with veterinary professionals to assess how changes in product usage might impact on animal welfare, animal health and public health. The PiE Group will encourage veterinary professionals to generate and use evidence to determine the optimal use of cat and dog topical parasiticides. The group will use all evidence gathered to inform future policy activities.

Regulatory Actions

In the long term and based on the evidence collected, the PiE Group will support a review of international environmental risk assessment guidelines2 and consider future regulatory approaches to mitigate environmental risks. This includes establishing agreed Environmental Quality Standard (EQS) values for fipronil and imidacloprid across the devolved nations. The VMD will also consider the environmental risk assessment process for pet parasiticides working within the international regulatory framework, using the data collected to support a review of the VICH3 Environmental Risk Assessment guidelines.

Access the Roadmap

For details of the roadmap in full, access the following link: Cross-government Pharmaceuticals in the Environment Group Roadmap – GOV.UK

BSAVA/ BVA/ BVZS Policy Position

The Government action plan aligns closely with the BVA/BSAVA/BZVS joint Policy Position on the responsible use of pet parasiticides, and the recommendations contained within it. The joint position emphasises a One Health approach, acknowledging the potential for unintended ecosystem harm from pet parasiticides. Key recommendations from the Position include the role of veterinary professionals and their approach to risk-based prescribing, identification of areas for future research, a review of the requirements for environmental impact assessment of companion animal parasiticide products and the need for clear information for owners about the use of parasiticides.

Pharmaceuticals in the Environment Group

The PiE Group was established by the VMD in 2023 with the intention of collaborating with stakeholders from across Government, industry and the veterinary profession including BSAVA, to support further research and evidence gathering and to shape future policy. The Group’s core objective is the development of a co-ordinated strategy to reduce the impact of pharmaceuticals on the environment (biodiversity) and human health, prioritising improved user guidance, evidence gathering, stakeholder collaboration, and potential regulatory refinements. The first priority for the Group is to gain a better understanding of the possible sources of fipronil and imidacloprid and to explore measures to reduce their levels in the environment.

BSAVA Perspective

BSAVA recommends that companion animals are treated for parasites using a risk-based approach, taking into account individual circumstances, zoonotic potential and the potential adverse impact on the environment.

Further resources

BSAVA Scientific Position Statement on parasite control: https://bsava.com/position-statement/parasite-control/

Joint Policy Position with BVA, BSAVA and BVZS on the responsible use of parasiticides for cats and dogs: https://bsava.com/wp-content/uploads/2023/04/bva-bsava-and-bvzs-policy-position-on-responsible-use-of-parasiticides-for-cats-and-dogs.pdf

Joint guidance produced with BVA, BSAVA and BVZS to help veterinary professionals practise responsible, risk-based use of parasiticide products for dogs and cats: Responsible use of parasiticides for cats and dogs: The five-point plan

A suite of client-facing communications produced by BVA, BSAVA and BVZS which includes a leaflet, posters and a slideshow which can be displayed in practice waiting rooms.

BSAVA library collection on parasiticides: https://www.bsavalibrary.com/content/parasiticides

BSAVA Small Animal Formulary: Guidelines for responsible parasiticide use: https://www.bsavalibrary.com/content/formulary/backmatter/canine-and-felineguidelinesforresponsibleparasiticideuse

NOAH (National Office of Animal Health) Use It Right, Treat Them Right, campaign promoting the responsible use of anti-parasitic medicines for pets

References

  1. The Environment Agency, the Scottish Environmental Protection Agency, Natural Resources Wales and the Northern Ireland Environment Agency
  2. All flea and tick treatments authorised in the UK have undergone an environmental risk assessment (ERA). This is a requirement for all veterinary pharmaceuticals authorised by the VMD. Currently, for pharmaceuticals for companion animals, the ERA is limited to an exposure assessment, known as a Phase I assessment. This is based on VICH (International Cooperation on Harmonisation of Technical Requirements for Registration of Veterinary Medicinal Products) guidelines.
  3. the International Cooperation on Harmonisation of Technical Requirements for Registration of Veterinary Medicinal Products – a trilateral (EU-Japan-USA) programme aimed at harmonising technical requirements for veterinary product registration.