India, May 14 -- You take an antibiotic. A few days later, you feel better and move on. But the medicine doesn't just enter your body and completely disappear. It passes through your body and enters the environment. Some antibiotics end up in rivers, where they alter microbial life. Given that microbes are everywhere, including inside us, this eventually affects us.

A startling new study published in PNAS Nexus lays this out in global detail. Each year, over 8,500 tonnes of antibiotics consumed by humans are flushed into rivers worldwide. And this number is only from medical use. It does not include antibiotics dumped by pharmaceutical factories or those used in farms to fatten animals. These are well-known sources of environmental conta...