The drugs can lead to drug-resistant bacteria and deadly infections.
(...) What Wilkinson and Boxall found is that 470 of those sites contained antibiotics, which come from sources including human excrement and drug manufacturing activity. Many of these antibiotics occur at concentrations above what the Antimicrobial Resistance (AMR) Industry Alliance—a group of private sector companies that aims to address the threat of antibiotic-resistant bacteria—says is safe. Here “safe” refers to those levels above which the alliance says bacteria can start to develop antibiotic resistance. According to Boxall, those levels can range anywhere from 20 to 32,000 nanograms per liter of water, depending on the antibiotic.
At Ghana’s Odaw River, concentrations of antibiotics like metronidazole, used to treat things like skin and mouth infections, exceeded safe levels by a factor of 68. The Odaw, though, is not the worst-off river. More than 110 of the 711 sampled sites have concentrations that exceed safe levels by factors of up to 300. Rivers in Bangladesh, where concentrations hover around 40,000 nanograms per liter, are among the worst of that group.