OTTAWA, Sept. 5 (Xinhua) -- Researchers have discovered high concentrations of human antidepressants in the brains of fish found in the Niagara River of Canada, according to CTV Tuesday.
CTV said that a study published in the journal Environmental Science and Technology detected the pharmaceutical drugs in the brain tissue of 10 different species, including bass and walleye.
The discovery raises serious environmental concerns since the Niagara River connects two of the Great Lakes, Lake Erie and Lake Ontario between Canada and the United States
Researchers say the antidepressant buildup could affect fish behaviour and potentially disrupt the aquatic ecosystem.
Although scientists say the levels of antidepressants found in the fish do not pose a risk to people who eat them, the environmental risks are real.
The study looked for a variety of pharmaceutical drugs and chemicals found in personal care products while testing the organs and muscles of the Niagara River fish.
Antidepressants or their metabolites, the products of metabolic reactions, were found in the brains of every fish species studied.
The highest concentration was found in a rock bass, which had about 400 nanograms of norsertraline, a metabolite of sertraline, the active ingredient in antidepressant Zoloft, per gram of brain tissue. Metabolites of active ingredients found in drugs Celexa, Prozac and Sarfem were also found in rock bass.
Overall, more than half of the fish brain samples had norsertraline levels of 100 nanograms per gram or higher.
The research raises questions about the effectiveness of wastewater treatment plants.
Wastewater treatment processes focus on removing human excrement and killing disease-causing bacteria. But remnants of antidepressants found in urine, as well as many other chemicals in the wastewater, are largely ignored.
