Concentrations of antibiotics found in some of the world's rivers exceed safe levels by up to 300 times, a first ever global study has discovered. Researchers looked for 14 commonly used antibiotics in rivers in 72 countries across six continents and found antibiotics at 65% of the sites monitored. 

Ciprofloxacin, 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.

The team said that the safe limits were most frequently exceeded in Asia and Africa, but sites in Europe, North America and South America also had levels of concern showing that antibiotic contamination was a global problem.

The findings are due to be unveiled during two presentations at the annual meeting of the Society of Environmental Toxicology and Chemistry, according to Steve Minsky in NC Well Connect.