Traces of painkillers and other household chemicals in treated wastewater effluent may be affecting fish reproductive behavior, finds research published in Nature magazine (Richard Lovett, “Wastewater chemicals dampen fish behavior.” Nature. 12 Nov 2010.)

This research further enhances understanding of the potentially many effects of treated wastewater containing even small amounts of pharmaceuticals and chemicals. These new studies are shedding some light on the behavioral implications on wildlife, not just the physical and anatomical effects.

Following an experiment comparing fathead minnows exposed to traces of pharmaceuticals to unaffected minnows, a chemist at the College of Wooster in Ohio, found differences in male minnows’ level of interest to guard their nests. Males in water containing pharmaceuticals were noticeably less interested in driving off artificial “bait” minnows placed near their nests, Nature reports.

A common anti-inflammatory painkiller may have similar effects on wildlife, according to a study by an environmental toxicologist. Zebrafish placed in water containing 50 micrograms per litre (50 parts per billion) of the non- steroid painkiller elicited noticeably less interest in reproductive behavior- such as chasing and touching noses- than zebra fish not exposed.

She concludes that even though there were no observed anatomical or physiological changes in the fish, they were nonetheless affected by exposure to levels of the pharmaceutical.

Both studies point to potentially long term effects in the reproductive behavior of fish in water containing pharmaceuticals and chemicals.