E. coli and other microbes in the Great Lakes are dying off thanks to traces of Prozac in the water, scientists find—and that’s not necessarily good news. “Your immediate thought is, 'Well, that's good, because they're not supposed to be there anyways,” a scientist tells National Geographic. “But what about all the other bacteria that are supposed to be there and part of that ecosystem?”
Prozac’s active ingredient, fluoxetine, is found in very low quantities in the lakes. “It doesn't appear to be at a level that would be harmful to humans,” notes the scientist. Still, mixed with other chemicals, it could take a toll on the ecosystem. Fluoxtine can enter waterways when it is flushed down the toilet in urine, or when people dump pills. It's been detected in water nowhere near a sewage output, however, suggesting it is widespread.