Pollution from emerging contaminants such as psychoactive drugs has been recognized as a major threat to aquatic ecosystems. With 270 million consumers worldwide, these drugs reach surface water through sewage effluents or improper disposal of drugs. Psychoactive drugs such as antidepressants and antipsychotics are designed to affect humans at trace concentrations. Since signaling pathways are conserved between vertebrates and invertebrates taxa, these drugs can also affect aquatic species. The focus of this project will be to assess the sub-lethal effects of psychoactive drugs. Small-scale experiments in the lab will be linked to large-scale outdoor mesocosm experiments. Lastly, the impact of different wastewater treatment techniques on the effects of psychoactive drugs will be assessed.