EACH YEAR, HUMANS produce, prescribe, and ingest more antibiotics than they did the year before. Those drugs have done wonders for public health, saving millions from infections that might otherwise have killed them.
But the drugs’ influence persists in the environment long after they’ve done their duty in human bodies. They leach into the outside world, where their presence can spur the development of “antibiotic resistant” strains of bacteria. In a new study that surveyed 91 rivers around the world, researchers found antibiotics in the waters of nearly two-thirds of all the sites they sampled, from the Thames to the Mekong to the Tigris.