Several months ago, a study showed that more than 80 different contaminants were entering Puget Sound in discharge from wastewater treatment plants. What’s worse, some of them were detected in the brain tissue of fish. The substances included metaformin, a drug used to treat diabetes, and fluoxetine, an antidepressant marketed as Prozac. Local officials were concerned not only that the drugs could individually affect the behavior and reproduction of fish like salmon in the Puget Sound, but also that the combination of several different substances might have unpredictable effects.
A new study is looking at streams on the other side of the country, in Baltimore. The Cary Institute of Ecosystem Studies tested the waters and found a different mix of substances—illegal ones—in the form of amphetamine and methamphetamine, not only in the water but also in moss, bacteria, and aquatic bugs.
It’s clear that the bugs aren’t producing the drugs, so where are they coming from? Wastewater treatment plants are not designed to remove substances like these drugs, or many other compounds found in personal care products. That means anything people consume but that is not completely metabolized, as well as any drugs that are flushed down the toilet or chemicals in things like toothpaste and soap that are rinsed down the drain, could eventually end up in receiving waters.
To see what effect the drugs might have on aquatic life, researchers from the Cary Institute set up an artificial stream—complete with all the plants, rocks, and aquatic organisms that would be present in a natural one—and added levels of amphetamine comparable to what had been detected in the Baltimore streams. As this article describes, the natural biofilms that typically develop on rocks did not form as they normally would, and the bugs showed more rapid than normal development. The article notes, “These plants and bugs are the base of the aquatic food web. Birds eat the bugs, as do frogs and fish. As emergent contaminants such as pharmaceuticals and endocrine disruptors become more common in ground and drinking water, they could affect humans,” although it also notes that scientists are calling for further research to determine just what the health effects might be.
