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.
This sad state of affairs is casting the poor performance of wastewater treatment plants in the spotlight. Lead scientist Dr. Diana Aga of the University of Buffalo College of Arts and Sciences said that they are failing to keep up with the times.
According to the National Center for Health Statistics, the number of Americans taking antidepressants rose by a startling 65 percent between 1999-2002 and 2011-2014. In Canada, meanwhile, nine percent of the population takes antidepressants. Part of the problem is that wastewater treatment facilities are simply not keeping pace with the rise in antidepressant use.
Wastewater treatment tends to focus on killing the bacteria that cause diseases and extracting any solid matter, like human feces. This approach ignores antidepressants, which are found in the urine of people who take them, in addition to other worrying chemicals found in personal care products and pharmaceuticals.
In July, a serious sewage dumping incident saw a black cloud take over the Niagara River and a foul smell permeate the air, prompting a criminal investigation into the actions of the Niagara Falls Waste Water Treatment Plant.
These incidents expose the fish and other wildlife in the river to high amounts of toxins in a short period of time, compounding the damage caused by the steady stream of toxins they are normally exposed to.
While this particular study did not examine the behavior of the fish, past research has shown that antidepressants affect their feeding behavior and their survival instincts, causing them to ignore dangerous predators.
In a release issued by the university, Aga said: “It is a threat to biodiversity, and we should be very concerned.”
The study’s co-author, Dr. Randolph Singh of the University of Buffalo, said that such changes could disrupt the fragile balance among species that maintains the stability of the ecosystem. While humans are unlikely to be in danger because fish brains are not normally consumed, the effects on the environment are not yet fully known.
Their findings were published in the Environmental Science & Technology journal.