Water-Polluting Anxiety Drug Helps Fish Live Longer

A drug popularly used to treat anxiety has been found to produce a pollutant that can reduce mortality rates in fish. While this sounds like good news, ecologists are worried that this bizarre consequence of pollution could have a very negative impact on some of the ocean's ecosystems.

This pollution phenomenon was detailed in a recent study and published in the journal Environmental Research Letters.

Jonatan Klaminder, the lead author of the study, explained in a statement that standard ecotoxicological testing has a very narrow focus, searching primarily for pollutants that directly and negatively impact organisms' health.

"Pharmaceuticals, which are designed to improve health, are a new group of contaminants that do not necessarily fit into the traditional view," Klaminder said.

"I think there is a 'bandwagon effect' within the research community," he added, "where the old test and the traditional view of a contaminant is routinely used without reflection about the conceptual flaw implicit in the methods."

According to the study, a low concentration of Oxazepam - a medication used to treat anxiety and insomnia - was found as a common contaminant in surface waters. This pollution was traced back to its source, human wastewater.

Past studies have shown that this drug can increase activity and boldness in Eurasian perch, but the researchers wondered if it did even more than that.

In a controlled experiment, they found that newborn perch lived longer lives, and were less likely to die early if exposed to Oxazepam, compared to an unexposed group.

So what's the problem? Population control, for one, is essential to keeping tenuous ecosystems in check. Overpopulation, and thus overfeeding, can very adversely impact nature. While the exact reasons why Oxazepam results in reduced morality rates among perch was not discussed in detail, the authors of the study do suggest that the drug made them more competitive - thus giving them an unnatural advantage over other species.

"Even though our study focused on one single pharmaceutical contaminant, it is possible that similar effects could be induced by exposure to a whole range of pharmaceuticals that find their way into surface waters, such as antibiotics, painkillers, anti-inflammatory drugs, hormones and antidepressants," said ecologist and co-author Tomas Brodin. "Our conceptual view of a pollutant has, up until now, blocked us from testing for similar effects at environmentally relevant concentrations."

The time to change that way of thought, he argues, is now.