Happier—And More Likely to Be Eaten


Medicines that have long been marketed as beneficial for humans are having decidedly different effects on other species. As we take more, they take more as well; 12.7% of Americans over the age of 12 now take antidepressants, up from 7.7% about two decades ago. And researchers are finding correspondingly higher levels of the drugs in fish.

Scientists from the University of Buffalo have documented high levels of antidepressants and other drugs in the brains of fish in the Great Lakes. Two years ago, a study by the NOAA Fisheries’ Northwest Fisheries Science Center and the University of Washington found similar results in the Puget Sound. The source in both cases is effluent from wastewater treatment plants, which do not filter out the drugs. The drugs can be detected in the water itself, but they accumulate in the brains of fish, which show levels up to 20 times higher than in the water.

What exactly are the effects of the drugs? The results are mixed: As this article reports, “Fish respond similarly to humans on antidepressants. They are less risk-averse and, it appears, happier.” Their decreased sense of danger, though, makes them more likely to be eaten by predators. “These sorts of changes could trigger the collapse of an entire fish population, or even seriously disrupt the biodiversity of the lakes—the largest freshwater ecosystem in the world,” according to the article.

Other effects are just as disturbing. Researchers at McMaster University have shown that as fish are exposed to more toxins—not only antidepressants but also contraceptives and various chemicals found in personal care products—they expend more energy to deal with the effects, leaving less energy for growth and reproduction.

The article suggests that improved oxidation processes—which would involve expensive upgrades to the treatment plants—could filter out a good portion of the drugs, but upgrading the 1,400 or so treatment plants surrounding the Great Lakes alone would be costly, and communities don’t yet see a strong enough incentive to make that investment. SW_bug_web

  • Jonathan McClelland.

    This article makes me want to take anti-depressants, but it’s a catch-22, knowing that I would be making the problem worse would make me feel guilty and lead to another round of anti-depressants. I guess I’ll just go fishing instead, which will be more mentally rewarding than before, knowing that I’m doing something to remediate the problem ( assuming I don’t use a municipal waste system to recycle the fish I ate. I always wondered why fisher persons seem so jolly and relaxed.

  • Dr Edo McGowan.

    The current underlying design of today’s wastewater treatment plants (WWTPs) reaches back to 1930s technology. These are big and inefficient systems requiring large staff numbers and a big footprint. But, these are familiar designs and operators are comfortable with this older technology. As bacteria digest the various solids, these solids are often turned into solutions and the WWTPs do a very poor job in dealing with materials in solution. This is why we have pharmaceuticals in our water resources.
    Newer designs are extant but these designs create bureaucratic problems. The newer designs require a vastly smaller staff and the foot print is about 20% of the typical WWTP. Thus, shifting to one of these more modern systems, because it sees the demise of expensive bureaucratic empires, makes the transition politically difficult.
    But that is a policy issue. Here is what the modern systems do not do. By removing solids ahead of digestion, the bacteria do not convert solids into solution. The remaining water is easier to disinfect. The removal of solids ahead of digestion also allows solids compression and dewatering such that when the dewatered solids are fed into a fluid bed, the caloric energy, nearly equivalent to coal, can be converted to a syn-gas that has about the same BTU as natural gas. This can be collected to run machinery, thus this eliminates sludge disposal with its associated environmental and public health issues and costs. Because the bacteria and xenobiotics are destroyed in the fluid beds, this helps reduce environmental contamination and the spread of antibiotic resistance, something currently an issue with standard WWTPs.


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