Concentrations of antibiotics in some of the world’s rivers exceed ‘safe’ levels by up to 300 times, according to a global study of some of the most iconic water bodies including Thames and Tigris.
Researchers from theUniversity of York in the UK looked for 14 commonly used antibiotics in riversin 72 countries across six continents and found antibiotics at 65 per cent ofthe sites monitored.
“Until now, the majority of environmental monitoringwork for antibiotics has been done in Europe, North America and China — oftenon only a handful of antibiotics. We know very little about the scale ofproblem globally,” said John Wilkinson, from the University of York.
“Our study helps fill this key knowledge gap with databeing generated for countries that had never been monitored before,” saidWilkinson.
Metronidazole, which is used to treat bacterial infectionsincluding skin and mouth infections, exceeded safe levels by the biggestmargin, with concentrations at one site in Bangladesh 300 times greater thanthe ‘safe’ level.
In the River Thames and one of its tributaries in London,the researchers detected a maximum total antibiotic concentration of 233nanograms per litre (ng/l), whereas in Bangladesh the concentration was 170times higher.
The most prevalent antibiotic was trimethoprim, which wasdetected at 307 of the 711 sites tested and is primarily used to treat urinarytract infections.
The researchers compared the monitoring data with ‘safe’levels recently established by the AMR Industry Alliance which, depending onthe antibiotic, range from 20-32,000 ng/l.
Ciproflaxacin, which is used to treat a number of bacterialinfections, was the compound that most frequently exceeded safe levels,surpassing the safety threshold in 51 places.
The team said that the ‘safe’ limits were most frequentlyexceeded in Asia and Africa, but sites in Europe, North America and SouthAmerica also had levels of concern showing that antibiotic contamination was a”global problem.”Sites where antibiotics exceeded ‘safe’ levelsby the greatest degree were in Bangladesh, Kenya, Ghana, Pakistan and Nigeria,while a site in Austria was ranked the highest of the European sites monitored.