The world’s rivers are awash in prescription drugs, with 14 commonly used commonly used antibiotics in rivers in 72 countries across six continents.
The most prevalent antibiotic found by the researchers from the University of York was trimetheropin, a common drug used to treat urinary tract infections, which was found in 307 of the 711 sites monitored.
Metronidazole, which is used to treat bacterial infections including skin and mouth infections, exceeded safe levels by the biggest margin, with concentrations at one site in Bangladesh 300 times greater than the ‘safe’ level.
The research team compared the monitoring data with ‘safe’ levels recently established by the AMR Industry Alliance which, depending on the antibiotic, range from 20-32,000 ng/l.
Ciproflaxacin, which is used to treat a number of bacterial infections, was the compound that most frequently exceeded safe levels, surpassing the safety threshold in 51 places.
Dr John Wilkinson, from the Department of Environment and Geography, who co-ordinated the monitoring work said no other study had been done on this scale. He said: “Until now, the majority of environmental monitoring work for antibiotics has been done in Europe, N. America and China. Often on only a handful of antibiotics. We know very little about the scale of problem globally.
Professor Alistair Boxall, Theme Leader of the York Environmental Sustainability Institute, said: “The results are quite eye opening and worrying, demonstrating the widespread contamination of river systems around the world with antibiotic compounds.
“Many scientists and policy makers now recognise the role of the natural environment in the antimicrobial resistance problem. Our data show that antibiotic contamination of rivers could be an important contributor.”