ICRA researchers Josep Mas-Pla, Meritxell Gros and Nonito Ros warn, in an article published in The Conversation, about the growing magnitude of the issue of antibiotics in groundwater. Groundwater is essential for urban and agricultural supply, for maintaining river ecosystems and for coping with drought periods. Antibiotic contamination poses risks to both human health and ecological balance.

Urban wastewater —including treated effluents— and livestock manure applied in agriculture are the main sources of antibiotics entering aquifers. Their presence varies depending on the interaction between rivers and aquifers, agricultural practices, human and veterinary consumption, and the hydrogeological characteristics of each system.

Moreover, the underground transport of antibiotics is reactive: these compounds interact with the environment, adsorb onto substrates, degrade, and generate by-products that can be even more toxic.

As emerging contaminants, antibiotics can cause adverse environmental effects even at very low concentrations. They also contribute to the spread of antimicrobial resistance, considered by the WHO as one of the major global threats.

Although the European Union has included some antibiotics in watch lists, there is still no solid regulatory framework to control them, especially in groundwater. This gap makes it difficult to compare results across studies and implement effective corrective measures.

What should be done?
The authors propose strengthening monitoring through:
• Annual general screenings to detect a wide range of emerging contaminants.
• More frequent targeted campaigns focusing on the most common or most toxic antibiotics, to better track hydrogeological dynamics.

Action is needed to ensure safe water for the population and to protect ecosystem health, preventing the spread of antimicrobial resistance from compromising the future effectiveness of these essential medicines.