Effects of Pharmaceuticals on Aquatic Organisms

There are a number of active ingredients found in medications and personal care products that can impact the quality of our rivers and aquatic habitats, but two in particular are receiving increased attention: estrogens or other endocrine disruptors (compounds that affect normal hormonal levels) and anti-depressant and obsessive-compulsive medications (for more information on endocrine disruptors click here). The previously mentioned 2006 USGS study specifically notes native fish populations downstream of the wastewater treatment plant showed symptoms of endocrine disruption, or a “feminization effect;” these impacts include fish developing both female and male reproductive organs and decreased numbers of males in the population. Ultimately reproductive and gender imbalances within a species can lead to population declines or worse.

Studies on the effects of anti-depressants and obsessive-compulsive regulators on aquatic life note the chemicals contained in these medications are likely the primary cause of other aquatic species disorders, including premature spawning in shellfish and the inability of damaged fish fins to heal. They also cause slower heart rates in the Daphnia water flea; a lowered heart rate is one indicator of potentially broad physiological effects.

Smaller aquatic organisms like water fleas have a short lifespan, which means that multiple generations will be exposed to a contaminant. This could have a catastrophic impact on a species’ sustainability. In addition, reduced numbers or the loss of species at the bottom of the food chain impacts higher level species that depend on these organisms for food or other benefits. 

For more information about Pharmaceuticals in Our Waterways, please contact Cecily Smith at csmith@prairierivers.org.

Visit a compilation of websites, research studies, and news articles on pharmaceuticals in the enviroment at our Pharmaceuticals Resource Library.