A new study has found alarmingly high concentrations of human antidepressants in several species of fish in the Niagara River, an important conduit connecting Lake Erie with Lake Ontario.
The researchers discovered the presence of antidepressants and their metabolites in brain tissue in fish such as smallmouth bass, largemouth bass, rock bass, white bass, white perch, yellow perch, steelhead, rudd, bowfin, and walleye.
In the most egregious example, a rock bass had 400 nanograms of a metabolite of the active ingredient in Zoloft, norsertraline, per gram of brain tissue, as well as a cocktail of other drug compounds like the metabolites of Prozac, Celexa and Sarafem. More than half of the fish studied had levels of norsertraline in their brains of 100 nanograms per gram or more.
Lab studies have shown that exposure to these drugs can change fish behavior. While these studies generally expose fish to higher concentrations of the drugs than the levels found in the river, it’s important to keep in mind that the antidepressants in the fish’s brains had accumulated over time, greatly exceeding the levels found in the water of the river itself. For example, the levels of norsertraline found in the brains of three species of bass and the walleye were hundreds of times higher than those of the river water.