A new study published in the Environmental Science and Technology journal found that high concentrations of antidepressants were building up in the brain tissue of bass, walleye and several other common fish found in the Great Lakes region.
Discovered in the brain tissue of 10 fish species in the Niagara River, researchers suspected the antidepressants were spewing from nearby wastewater plants.
"These active ingredients from antidepressants, which are coming out from wastewater treatment plants, are accumulating in fish brains," Diana Aga, lead scientist, said. "It is a threat to biodiversity, and we should be very concerned."
According to Aga, though her study didn't directly examine the effect of drugs on fish behavior, the presence of the drugs could have an effect on fish survival instincts, as some swimmers won't react to a nearby predator.
In one fish alone, a rock bass, the scientists found 400 nanograms of norsertraline per gram of brain tissue. Norsertraline is an active ingredient in Zoloft, which is used to treat depression, OCD and PTSD.
In addition to the norsertraline, the same fish had traces of citalopram and norfluoxetine, which are found in Celexa, an antidepressant, and Prozac and Sarafem, which also treat depression, OCD, bulimia and panic disorders.
More than half of the fish collected by the group had at least 100 nanograms per gram or higher of norsertraline in their brain tissue along with several other antidepressant ingredients.
Though the findings do raise concern, the officials added that more studies must be conducted in order to get the full picture of what's going on in the region.
The research team, aided by the efforts of scientists at Thailand's Ramkhamhaeng University and Khon Kaen University, found their specimens in the Niagara River that connects Lake Erie and Lake Ontario, two the of five great lakes.