Aerial view of Presque Isle State Park on Lake Erie. Image: U.S. Army Corps of Engineers via Wikimedia Commons

Lake Erie is on Prozac, reports National Geographic.

Tiny concentrations of fluoxetine, the active ingredient in Prozac, are killing off the E.coli bacteria in the lake, says scientist Steve Mauro, whose team made the discovery.

While killing bacteria that could harm people might seem like a good idea, Mauro questions what happens to the other bacteria that are supposed to be a part of the ecosystem, National Geographic reports.

The low levels of fluoxetine do not harm people but they damage the reproductive systems of mollusks and could even affect fish brains, says Mauro. He suspects the fluoxetine could combine with other chemicals and have an adverse effect on the lake.

Chemicals like fluoxetine find their way into the water through dumped pills or in the urine of the drug’s users, but Presque Isle State Park, where Mauro obtained the sample, is sewage free. This could indicate that the fluoxetine spreads through the lake, he says.