Fish on Contraceptives and Birds on Prozac Could Spell Disaster for the Environment
The pharmaceutical cocktails we flush down the toilet could be contributing to a worldwide fall in wildlife populations, according to new research.
Birds on antidepressants and fish on birth control are just a few of the cases studied in a forthcoming issue of Philosophical Transactions of the Royal Society B. The report, titled Medicating the Environment: Assessing Risks of Pharmaceuticals to Wildlife and Ecosystems, puts together 18 recent studies on the topic.
“There’s growing evidence that pharmaceuticals are being detected in different parts of the environment and different ecosystems,” Kathryn Arnold, a University of York researcher, said in a video explaining the paper.
So far, the research has shown that small doses of the antidepressants and birth control that make their way into waterways can have big effects on animal reproduction, appetite, and behavior.
“With thousands of pharmaceuticals in use globally, this issue presents approaches for prioritizing which products have the potential to cause harm to wildlife and ecosystems,” Arnold wrote in the report.
“Given the many benefits of pharmaceuticals, there is a need for science to deliver better estimates of the environmental risks posed by pharmaceuticals,” Arnold wrote.
But how do our drugs get into the environment and animal food chain?
Humans who take pharmaceuticals—a rising number every year—excrete a certain amount of drugs, which are flushed to a sewage treatment center.
Birds can feed on worms and maggots at sewage treatment plants, ingesting the pharmaceuticals. Low doses go untreated at such facilities and end up in rivers and lakes. Finally, drug-contaminated waste made into fertilizer can end up in farm fields and thus enter the food chain.
So what animals are being harmed?
One study led by Tom Bean at the University of York looked at the common starling, a bird that feeds on worms found at wastewater treatment plants. Scientists gave birds doses of the antidepressant Prozac equivalent to what they would ingest by eating worms. The result: The birds stopped looking for food at dawn and dusk—key feeding times.
“Our data suggest that fluoxetine [the drug in Prozac] at environmentally relevant concentrations can significantly alter behavior and physiology,” according to the study.
Karen Kidd at the University of New Brunswick led a study that showed that an entire lake’s ecosystem can be affected when contraceptives change the behavior of fish.
The researchers put low doses of synthetic estrogen—the hormone found in many birth control pills—into an experimental lake in Canada. That ended up nearly wiping out the lake’s entire population of fathead minnow. The lake’s trout, which feed on the minnows, declined between 23 percent and 42 percent.
“Our results demonstrate that small-scale studies focusing solely on direct effects are likely to underestimate the true environmental impacts of oestrogens in municipal wastewaters,” Kidd wrote in the report.
Arnold hopes certain drugs are included on the European Union’s newly established water pollution watch list.
“Because there are so many financial, social, and health benefits of pharmaceuticals, we can’t just have an outright ban on certain drugs because they have some potential effect on wildlife,” Arnold explained. “The evidence base isn’t there yet, but we’re gathering data as a research community, and hopefully that will feed into future environmental policies.”