Antidepressant drugs and their metabolites are building up in the brains of numerous fish species living in the Great Lakes region, new research has found. The species involved include bass, walleye, and numerous others — in other words, fishes that are commonly eaten.
While it’s not common practice in the modern US for people to directly eat the brains of fish (I guess that people have gotten too squeamish over the last century), there are a great many disconcerting implications of the study findings.
Amongst which: If prescription drug compounds and their metabolites are now commonly found as pollutants in freshwater sources, what effect are they having on humans? Is everyone nowadays effectively being drugged on a low-level with mood-altering drugs? Is true, that would certainly explain a lot about the social changes seen in the culture over the last few decades (though electronics and “social media” have no doubt played a part as well, as have other things).
So how are these drugs being released into the Great Lakes and associated bodies of water? Directly, through treatment plant emissions and sewage overflows.
Head researcher Diana Aga, of the University at Buffalo College of Arts and Sciences, commented: “These active ingredients from antidepressants, which are coming out from wastewater treatment plants, are accumulating in fish brains. It is a threat to biodiversity, and we should be very concerned.”
“These drugs could affect fish behavior. We didn’t look at behavior in our study, but other research teams have shown that antidepressants can affect the feeding behavior of fish or their survival instincts. Some fish won’t acknowledge the presence of predators as much.”
So, the fish that are exposed no longer recognize clear threats to their continued survival, and instead behave as if those dangers didn’t exist. That sounds familiar, right?
The press release provides more: “The percentage of Americans taking antidepressants, for instance, rose 65% between 1999-2002 and 2011-14, according to the National Center for Health Statistics. Wastewater treatment facilities have failed to keep pace with this growth, typically ignoring these drugs, which are then released into the environment, Aga says.
“Her new study looked for a variety of pharmaceutical and personal care product chemicals in the organs and muscles of 10 fish species: smallmouth bass, largemouth bass, rudd, rock bass, white bass, white perch, walleye, bowfin, steelhead and yellow perch.
“Antidepressants stood out as a major problem: These drugs or their metabolites were found in the brains of every fish species the scientists studied. The highest concentration of a single compound was found in a rock bass, which had about 400 nanograms of norsertraline — a metabolite of sertraline, the active ingredient in Zoloft — per gram of brain tissue. This was in addition to a cocktail of other compounds found in the same fish, including citalopram, the active ingredient in Celexa, and norfluoxetine, a metabolite of the active ingredient in Prozac and Sarafem.
“More than half of the fish brain samples had norsertraline levels of 100 nanograms per gram or higher. In addition, like the rock bass, many of the fish had a medley of antidepressant drugs and metabolites in their brains.”
It’s notable here that those levels are much higher than the levels found in the bodies of water themselves — which means that they are bioaccumulating over time. The sertraline levels measured in the brains of largemouth bass, rock bass, smallmouth bass, walleye, and white bass, for instance, were roughly 20 times higher than the levels in the water itself. Levels of the metabolites (norsertraline in particular) were even higher — in some cases hundreds of times higher than those found in the waters themselves.
You might be asking yourself right now what researchers know about the effects that these compounds have on animals (whether individually, or in combination) — the truth is that no one really knows. The situation is effectively a vast uncontrolled experiment.
The only thing that can be said for sure is that some research (mentioned earlier in the article) has shown that affected fish behave in ways that aren’t in their best interest — they seemingly lose comprehension of the dangers that predators pose, or perhaps they lose all sense of “danger” or risk at all.
So what can be done to begin delaying with this massive problem? Tighter regulation of wastewater treatment plant emissions would be a good place to start. As it stands, wastewater treatment plants have no obligation to remove pharmaceuticals or their metabolites from the water they are treating — operations are focused, rather, on the removal of human excrement itself and control of disease-causing bacteria.
Aga continued: “These plants are focused on removing nitrogen, phosphorus, and dissolved organic carbon but there are so many other chemicals that are not prioritized that impact our environment. As a result, wildlife is exposed to all of these chemicals. Fish are receiving this cocktail of drugs 24 hours a day, and we are now finding these drugs in their brains.”
An accompanying problem is that untreated sewage is often released into rivers and lakes as a result of various overflow situations. On that count, The Buffalo News recently reported that a half billion or so gallons of sewage + storm water had been released into nearby waterways between May and August 2017.
The findings are discussed in a new study published in the journal Environmental Science and Technology.