Urgent measures are needed to address environmental contamination by veterinary antibiotics, new research suggests

The widespread use of antibiotics in human and veterinary medicine has led to a new class of emerging contaminants in the environment, as both original compounds and as substances resulting from the breakdown of antibiotics. This new study provides insights to guide risk management and identify further research needs around the use of veterinary antibiotics. 

Veterinary antibiotic chemicals enter the environment through several routes: the improper disposal of drugs, ineffective treatment of wastewater, waste streams from antibiotic production, and human and animal waste. Although the environmental concentrations of antibiotics are often very low, their continuous release and persistence in the environment can increase the abundance of resistant bacteria. There are global concerns around anti-microbial resistance (AMR) caused by the increasing use of antibiotics, with this having been identified by the European Commission and EU member states as one of the top three priority health threats.  

Several EU measures currently addressing AMR include targets to reduce antibiotic consumption in humans, rules to limit antibiotic use in livestock and strengthened environmental monitoring to prevent contamination of soil and water. There are additional proposals for new EU legislation to ensure there are environmental risk assessments for all relevant pharmaceuticals and to promote more environmentally friendly products.  

This study evaluated chronic and acute effects of veterinary antibiotics across different antibiotic classes in European aquatic environments. 

Researchers identified studies containing toxicity data of veterinary antibiotics and focused on freshwater and saltwater wildlife. They reviewed 162 studies and examined information on the class of drugs, group of species, duration of exposure, observed effects, lethal levels and effective concentrations (LC and EC). LC is the concentration of a substance that kills 50% of an observed sample population of a species and EC is the concentration that causes a defined effect in 50% of them. 

The studies covered 10 classes of antibiotics and 17 groups of species, including different types of bacteria and algae alongside animals such as molluscs and arthropods. 

Researchers investigated the stress levels caused by the chemicals to aquatic communities, to attempt to estimate safe limits. The study showed a widespread presence of veterinary antibiotics in sewage treatment plant effluent, influent, hospital/industrial effluent and surface water.  

The results indicate that classes of antibiotics known as fluoroquinolones, tetracyclines, sulphonamides and macrolides are a priority to address in the aquatic environment due to their prevalence and their potential impact. Many of these are also known to induce resistance among bacteria and are associated with specific resistance genes. 

The concentrations present demonstrate that each class of antibiotic presents its own set of ecological challenges, which complicates the task of mitigation, and suggests that there needs to be a multifaceted approach to risk management. There can be a framework applied to assessing ecological risk, different values and impacts of antibiotics on freshwater and saltwater species. 

The findings clearly highlight the need to address the contamination of aquatic ecosystems by veterinary antibiotics and the implications this has for environmental and human health. It also calls for further research to bridge existing knowledge gaps and to develop strategies targeted to the type of antibiotic, to mitigate adverse effects, including risk assessment of the possible cocktail effects of combined antibiotic pollutants in the environment. 

Reference: 

Albarano, L., Suarez, E.G.P., Maggio, C., La Marca, A., Iovine, R., Lofrano, G., Guida, M., Vaiano, V., Carotenuto and M., Libralato, G. (2024) Assessment of ecological risks posed by veterinary antibiotics in European aquatic environments: A comprehensive review and analysis. Science of The Total Environment Volume 954: 176280. Available from: https://doi.org/10.1016/j.scitotenv.2024.176280.  

To cite this article/service:  

“Science for Environment Policy”: European Commission DG Environment News Alert Service, edited by SCU, The University of the West of England, Bristol.  

Notes on content: 

The contents and views included in Science for Environment Policy are based on independent, peer reviewed research and do not necessarily reflect the position of the European Commission. Please note that this article is a summary of only one study. Other studies may come to other conclusions.