Percentage of river sites that tested positive for unsafe levels of antibiotics. 35 percent of river sites tested in Africa exceeded safe limits for concentrations of antibiotics. Data: Alistair Boxall and John Wilkinson. Graphic: The Guardian
Percentage of river sites that tested positive for unsafe levels of antibiotics. 35 percent of river sites tested in Africa exceeded safe limits for concentrations of antibiotics. Data: Alistair Boxall and John Wilkinson. Graphic: The Guardian

By Natasha Gilbert
26 May 2019

(The Guardian) — Hundreds of rivers around the world from the Thames to the Tigris are awash with dangerously high levels of antibiotics, the largest global study on the subject has found.

Antibiotic pollution is one of the key routes by which bacteria are able develop resistance to the life-saving medicines, rendering them ineffective for human use. “A lot of the resistance genes we see in human pathogens originated from environmental bacteria,” said Prof William Gaze, a microbial ecologist at the University of Exeter who studies antimicrobial resistance but was not involved in the study.

The rise in antibiotic-resistant bacteria is a global health emergency that could kill 10 million people by 2050, the UN said last month.

The drugs find their way into rivers and soil via human and animal waste and leaks from wastewater treatment plants and drug manufacturing facilities. “It’s quite scary and depressing. We could have large parts of the environment that have got antibiotics at levels high enough to affect resistance,” said Alistair Boxall, an environmental scientist at the University of York, who co-led the study.

The research, presented on Monday at a conference in Helsinki, shows that some of the world’s best-known rivers, including the Thames, are contaminated with antibiotics classified as critically important for the treatment of serious infections. In many cases they were detected at unsafe levels, meaning resistance is much more likely to develop and spread. […]

The researchers tested 711 sites in 72 countries and found antibiotics in 65% of them. In 111 of the sites, the concentrations of antibiotics exceeded safe levels, with the worst cases more than 300 times over the safe limit.

Lower-income countries generally had higher antibiotic concentrations in rivers, with locations in Africa and Asia performing worst. They peaked in Bangladesh, where metronidazole,used to treat vaginal infections, was found at more than 300 times the safe level. The residues were detected near a wastewater treatment facility, which in lower-income countries often lack the technology to remove the drugs. [more]

World’s rivers ‘awash with dangerous levels of antibiotics’