Evidence collection2 February 2021
Published 2 February 2021 | Updated 18 November 2024
Introduction
A paper recently published in Science of the Total Environment has received coverage in both the national and veterinary press, raising concern about the extent to which commonly used parasiticides for companion animals may contaminate the environment. A summary of the paper is available.
Press coverage
- Carrington, D. (2020) Pet flea treatments poisoning rivers across England, scientists find [The Guardian] [online] Available from:
https://www.theguardian.com/environment/2020/nov/17/pet-flea-treatments-poisoning-rivers-across-england-scientists-find [accessed 29 January 2021] - Potential role of flea products in pesticide contamination of rivers [CABI] [online] Available from: https://www.cabi.org/VetMedResource/news/67068 [accessed 29 January 2021]
- Loeb, J. (2020) Contaminated rivers are ‘deeply troubling’. Veterinary Record, 187 (11), pp. 425-425. https://doi.org/10.1136/vr.m4612
References
- Forbes, A. (2021) Environmental risk assessment of veterinary parasiticides used in cattle. Livestock 26 (1) pp. 15 -25 https://doi.org/10.12968/live.2021.26.1.15
Other relevant resources
- Yoder, L.E. et al. (2024) Dog swimming and ectoparasiticide water contamination in urban conservation areas: A case study on Hampstead Heath, London. Science of The Total Environment, 955, 176686. https://doi.org/10.1016/j.scitotenv.2024.176686
This paper aimed to assess the contribution of dog swimming to the detection of selected pet ectoparasiticides in aquatic habitats in protected urban green spaces, and to understand dog owners’ knowledge and perceptions of the use of flea and tick treatments and their potential environmental risks.
- Perkins, R. et al. (2024) Down-the-drain pathways for fipronil and imidacloprid applied as spot-on parasiticides to dogs: Estimating aquatic pollution. Science of The Total Environment, 917, 170175. https://doi.org/10.1016/j.scitotenv.2024.170175.
This paper aimed to estimate the contribution of ‘down the drain’ contamination from washing dogs and their bedding as well as from handwashing following treatment with Fipronil and Imidacloprid.
European Legislation
European legislation requires that all veterinary medicines undergo an environmental risk assessment (ERA) based on their expected use. The ERA is an evaluation of the possible hazards to the environment posed by a veterinary medicine.
The purpose of the ERA is to:
- identify potential environmental hazards and risks
- identify the need for specific risk-minimisation measures, where appropriate
- ensure appropriate labelling is in place for users and healthcare professionals
There are two phases to the ERA. Phase 1 is an environmental impact assessment which considers the medicine’s active substance and excipients, its method of administration, target species and proposed pattern of use.
Phase 2 is an ecotoxicological assessment, which is tier-based and structured around the risk quotient (RQ) which provides an indication of the likelihood of adverse effects on the environment. Medicines whose phase 1 assessment concludes that their environmental exposure is not negligible (e.g. PECsoil value higher than 100 µg/kg) have to undergo the phase 2 ecotoxicological assessment. This generally applies to veterinary medicines used for aquaculture, intensively reared terrestrial animals, or pasture animals.
Currently the assessment for veterinary products used in companion animals is limited to phase 1, as exposure from veterinary medicinal products used in companion animals has been considered negligible in the scope of the current environmental risk assessment framework.
However, a recent concept paper, published by the European Medicines Agency (EMA) challenges the conclusion that environmental risk associated with these products is always negligible, and calls for a review of the current blanket exclusion of a higher-tier risk assessment for all these products. The concept paper recommends the development of a more detailed reflection paper, on whether the current approach for the environmental risk assessment of Veterinary Medicinal Products containing parasiticides, that are used in companion animals, remains scientifically justified and the need and feasibility of mitigation measures for such products.
- Veterinary Regulatory: Environmental risk assessment of veterinary medicines [European Medicines Agency] [online] Available from: https://www.ema.europa.eu/en/veterinary-regulatory/marketing-authorisation/environmental-risk-assessment-veterinary-medicines#phase-i:-environmental-impact-assessment-section [accessed 29/1/2021]
- Concept paper for the development of a reflection paper on the environmental risk assessment for parasiticide veterinary medicinal products used in companion animals [European Medicines Agency] [online] Available from: https://www.ema.europa.eu/en/documents/scientific-guideline/concept-paper-development-reflection-paper-environmental-risk-assessment-parasiticide-veterinary_en.pdf [accessed 29/1/2021]
Other publications from the EMA indicate that the effect of veterinary medicines on the broader environment is a subject of interest.
- Antimicrobial resistance in the environment: considerations for current and future risk assessment of veterinary medicinal products [European Medicines Agency] [online] Available from: https://www.ema.europa.eu/en/antimicrobial-resistance-environment-considerations-current-future-risk-assessment-veterinary [accessed 29/1/2021]
- Assessing the toxicological risk to human health and groundwater communities from veterinary pharmaceuticals in groundwater
[European Medicines Agency] [online] Available from: https://www.ema.europa.eu/en/assessing-toxicological-risk-human-health-groundwater-communities-veterinary-pharmaceuticals [accessed 29/1/2021]
VMD strategy
It should also be noted that the recently published Regulatory Science Strategy from the Veterinary Medicines Directorate (VMD) includes, as part of their goal of ‘Strengthening a life cycle approach to benefit-risk assessment’, the proposal to ‘Improve the evaluation of environmental and residues adverse events’ (2.4.3).
The strategy document notes that there is growing concern regarding the impact of pharmaceuticals in the environment, both in relation to their potential effects on ecosystems and effects on human safety.
The strategy goes on to list the steps that the VMD will look to undertake in order to improve the evaluation of environmental and residues adverse events. These will include:
- understand the existing systems of environmental monitoring (of terrestrial and aquatic systems), for chemicals used as veterinary medicines in the UK.
- research and develop appropriate guidance on the risks of secondary exposure from household contamination, and exposure of bees and other pollinators, from topically administered veterinary medicines for companion animals.
- evaluate the need for post authorisation environmental monitoring programmes for those compounds considered to be a high risk to ecosystems.
Reference
VMD Regulatory Science Strategy (2020) [VMD] [online] Available from: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/936195/PCDOCS-_1853658-v8-Regulatory_Science_Strategy_17.11.20.pdf [accessed 29/1/2021]
Further reading
While there is already a wide literature base available regarding the impact of pharmaceuticals on the environment these papers are mostly published in journals that cover toxicology and environmental science. For those who would like to read more about this subject the following may be of interest.
- Anthe, M. et al (2020) Development of an aquatic exposure assessment model for Imidacloprid in sewage treatment plant discharges arising from use of veterinary medicinal products. Environmental Sciences Europe, 32, no. 147 (2020). https://doi.org/10.1186/s12302-020-00424-4
- Perkins, R., Whitehead, M. and Goulson, G. (2021) Dead in the water: comment on “Development of an aquatic exposure assessment model for imidacloprid in sewage treatment plant discharges arising from use of veterinary medicinal products”. Environmental Sciences Europe, 33, no. 88 (2021) https://doi.org/10.1186/s12302-021-00533-8
- Cuthbert, R. J. et al. (2014) Avian scavengers and the threat from veterinary pharmaceuticals. Philosophical Transactions of the Royal Society B: Biological Sciences https://doi.org/10.1098/rstb.2013.0574
- Hutchinson, T.H. et al. (2014) Comparative metabolism as a key driver of wildlife species sensitivity to human and veterinary pharmaceuticals. Philosophical Transactions of the Royal Society B: Biological Sciences https://doi.org/10.1098/rstb.2013.0583
- LaLone, C.A. et al. (2014) Leveraging existing data for prioritization of the ecological risks of human and veterinary pharmaceuticals to aquatic organisms. Philosophical Transactions of the Royal Society B: Biological Sciences https://doi.org/10.1098/rstb.2014.0022
- Küster, A. and Adler, N. (2014) Pharmaceuticals in the environment: scientific evidence of risks and its regulation Philosophical Transactions of the Royal Society B: Biological Sciences https://doi.org/10.1098/rstb.2013.0587
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