How Sewage Reveals a City's Drug Habits

Cocaine typically goes up your nose. It does a lot of stuff once it's inside your body, like raising your heart rate and blood pressure and creating a burst of energy and euphoria. But then, after the effects die down and your body processes the drug, it goes out the other end. As a result, the wastewater drug users flush down the toilet can contain traces of cocaine – and methamphetamine and cannabis and ecstasy and all kinds of other drugs, depending on habits.

When all the collective flushings of a city's drug-using populace combine in the bowels of the sewer system, a citywide drug profile develops. A new technique has been tested out to read and compare those drug profiles, creating an innovative way to understand and monitor the drug-using habits of different urban populations.