Researchers Discover Changed Behavior in Fish Exposed to Treated Wastewater

Dec. 6, 2017
Behavioral changes leave fish more vulnerable to predators

Scientists from Environment Canada, Climate Change Canada and McMaster University have uncovered changes from standard behavior in fish inhabiting an area downstream from a wastewater treatment plant.

Locationally, the study gathered gold fish at various markers downstream from the Dundas Wastewater Treatment Plant in the Cootes Paradise watershed. After testing the blood plasma of the collected fish, the results displayed the inclusion of several common antidepressants after analysis.

Upon further examination, it was found that the increased serotonin levels resulting from the drugs were affecting the swimming behavior of the fish. Specifically, the closer the fish were to antidepressant exposure, the bolder and less anxious they became. This led the fish to be more explorative, making them more susceptible to predators.

“Taken together, our results suggest the fish downstream of wastewater treatment plants are accumulating pharmaceuticals and personal care products at levels sufficient to alter neurotransmitter concentrations and to also impair ecologically-relevant behaviours,” says Jim Sherry, a research scientist with Environment Canada and lead author of the study.

Beyond the behavioral changes, researchers also discovered molecular changes in the fish resulting from the drugs which inflicted liver injury and compromised lipid metabolism.

The scientists behind the work hope this study raises awareness among the Canadian community regarding the need for safe water reuse.


Image courtesy Institute of Chemical Research of Catalonia (ICIQ).
All images courtesy of Ecosorb.