London School of Hygiene & Tropical Medicine

A new study in the Proceedings of the National Academy of Sciences describes the first global-scale estimate of active pharmaceutical ingredient (API) pollution in the world’s rivers. The truly global consortium of authors worked together to pool sample results for 61 API, including 21 antimicrobials, from 1052 locations along 258 rivers in 104 countries.

Many of the most contaminated sites were located in areas of low- and middle-income countries that received inputs of untreated sewage or waste from pharmaceutical manufacturing. Two antimicrobials (metronidazole & sulfamethoxazole) were among the contaminants detected in the highest concentrations across study sites, and concentrations of antibiotic residues were an average of 3-4 times high in Africa than any other continent.

In more than a quarter of sites, one or more API was detected in unsafe concentrations that may exert selective pressure on mircroorganisms or harm aquatic organisms.

This work is innovative in that it represents the first attempt to capture a global picture of API distribution in the world’s waterways, it tested for a much larger panel of APIs than most previous surveillance studies, and it used a single sampling and analysis technique, facilitating comparison across all sites.