Fish on Antidepressants: Venlafaxine Contamination in Our Waterways

Wastewater treatment plant effluents (WWTPE) represent a pervasive source of pharmaceutically active compounds in surface waters, with the serotonin and norepinephrine reuptake inhibitor venlafaxine (VEN) frequently detected at elevated concentrations in receiving waters worldwide. VEN is a chiral pharmaceutical administered as a racemic (50:50) mixture of R- and S-enantiomers, which exhibit distinct pharmacological activities and can be selectively degraded or enriched in effluent depending on treatment processes. However, little is known about the stereoselective toxicological effects of VEN in fish. This work investigates the effects of VEN exposure on Etheostoma caeruleum (rainbow darter) using transcriptomic profiling. Overall design: Wild Etheostoma caeruleum (rainbow darter) were collected from the Grand River, ON, Canada, and brought to the lab. Fish were allowed to acclimate and depurate for two weeks before being exposed to 1 µg/L of either the R- or S-enantiomer of venlafaxine for 14 days. Liver tissue was analyzed for transcriptomic responses to each enantiomer.