Rainbow Darter Responses to Wastewater Effluent in the Grand River Watershed, Ontario

The purpose of this research is to investigate the effects of treated wastewater effluent on reproductive endpoints in rainbow darter (Etheostoma caeruleum). Municipal wastewater treatment plant (WWTP) effluent is a major concern for the health of aquatic ecosystems, as it contains many contaminants that have been shown to cause a wide variety of adverse outcomes. Historically, poor quality effluent from the Kitchener and Waterloo WWTPs has resulted in reproductive system impairments in rainbow darter living downstream in the Grand River, including reductions in sex steroid production and the development of intersex. After the Kitchener WWTP underwent major infrastructure upgrades, these effects were seen to improve to upstream reference site conditions. We are now interested if upgrades to the smaller Waterloo WWTP will also reverse endpoints in rainbow darter downstream of it. The results of this study help build models to describe the sources, treatment and fate of chemicals to better define exposure under various treatment scenarios. This will help link exposure predictions to adverse effects on key ecosystem components and biological responses. It will also be useful in supporting improvements in water management policy and practice. This project will support the research objectives of the project titled Linking Multiple Stressors to Adverse Ecological Responses Across Watersheds, which is a Pillar 1-2 project under the Global Water Futures Program funded by Canada First Research Excellence Fund.