University of Coimbra study shows that urban streams are polluted by pharmaceuticals

A study led by researchers from the Faculty of Science and Technology at the University of Coimbra (FCTUC), in collaboration with the Faculty of Pharmacy (FFUC), has concluded that urban streams are polluted by a wide range of pharmaceuticals, which have an impact on aquatic organisms and ecosystems.

“The literature review has shown that urban streams, in addition to rivers, are critical freshwater ecosystems when it comes to pharmaceutical pollution. Flowing through densely populated areas, they often have low flow rates and poor dilution capacity, making them susceptible to high levels of pollution, which are then transported to larger rivers," warns Maria João Feio, a researcher at the FCTUC's Department of Life Sciences (DCV) and the Marine and Environmental Sciences Centre (MARE).

The study, published in the prestigious journal Water Research, aimed to assess the extent of pharmaceutical contamination in urban rivers and its impact on aquatic ecosystems and organisms. Experts conducted a bibliographic review of scientific studies from around the world.

“The review identified 139 pharmaceuticals across 49 urban streams, belonging to ten therapeutic groups, in 13 countries across four continents, with a predominance of anti-inflammatories and anticonvulsants. Drug metabolites were also found, but they were analysed to a lesser extent,” says Fernanda Rodrigues, a doctoral student in environmental engineering.

The research team found drugs such as diclofenac, ibuprofen, and paracetamol (painkillers, anti-inflammatories, antipyretics, and anaesthetics); clarithromycin and erythromycin (antibiotics, antifungals, and antihistamines); fluoxetine and ciprofloxacin (psychiatric drugs); estrone, 17β-estradiol, and ethinyl estradiol (hormones); and gemfibrozil (lipid regulators).

In Portugal, the team analysed three urban streams and identified a total of eight drugs in the water. In one of the streams, the antidepressant fluoxetine was found to pose a high risk to aquatic invertebrates.

According to the experts, "the effects on aquatic organisms and ecological processes ranged from bioaccumulation, endocrine disruption, impaired growth, and inhibition of reproduction to increased mortality, hatching disorders, morphological changes, and a decrease in gross primary production and biomass."

This study provides an overview of the issue of pharmaceuticals in urban rivers and streams. It also highlights the need for further research, particularly in Portugal and Europe, where the team is currently investigating the problem. “To protect the health of ecosystems, aquatic organisms, and human health within a One Health approach, it is essential to understand how these pharmaceuticals enter river ecosystems, minimise their entry, and eliminate these pollutants from the water," the researchers conclude.

The scientific article “Pharmaceuticals in urban streams: A review of their detection and effects in the ecosystem” , which also had the participation of researchers Luísa Durães, Nuno Simões, André Pereira and Liliana Silva, is available here.