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Neonicotinoid insecticide toxicity to aquatic organisms: Addressing key knowledge gaps on toxicity thresholds, mixtures and mitigation strategies using buffer zones


Pesticide impacts to aquatic ecosystems are a national and global concern. This research project aims to investigate a class of insecticides known as the neonicotinoids which represent the largest selling insecticide class and seed treatment in the global market. In Canada, they are widely used on diverse field crops that represent the bulk of the nations’ agricultural production: canola (oilseed rape), cereals, soybeans and corn, and are frequently detected in prairie wetlands. Although the acute toxicity of neonicotinoids to mammals, fish, and birds is generally lower than for many other insecticides, extremely low doses can exert measurable toxicity to a wide range of arthropods, especially insects and some crustaceans which are important food for fish and wildlife. Most of the toxicity research to date has focused on imidacloprid, with relatively few published studies on other neonicotinoids, namely thiamethoxam and clothianidin, which are widely used in Canada.

The current study will investigate long term low-level toxicity to aquatic invertebrates of imidacloprid, clothianidin and thiamethoxam based on field realistic exposure concentrations. In addition, the cumulative or additive toxicity of different neonicotinoid mixtures to aquatic invertebrates will be assessed. Finally, the study will examine wetland vegetation and buffer zones as a mitigation strategy to ameliorate transport and retention of neonicotinoid insecticides in water.

This project builds on existing research to ultimately inform Canadian government regulators and risk assessors about the safety and use of neonicotinoid insecticides. Experimental approaches will include a combination of controlled laboratory experiments, semi-controlled field (i.e. limnocorral) studies, and field surveys. The outcomes of the project will lead to better informed risk assessment practices and contribute to generating scientifically-based recommendations on Canada’s water quality criteria for neonicotinoids in order to preserve the biological integrity of aquatic ecosystems.

Program Name

National Contaminants Advisory Group (NCAG)


2014 - 2017


Central Canada: Lake Winnipeg, Nelson River Drainage Basin

Principal Investigator(s)

Christy Morrissey
Assistant Professor, Department of Biology and School of Environment and Sustainability
University of Saskatchewan, Saskatoon, Saskatchewan

Karsten Liber
Professor and Director, Toxicology Centre
University of Saskatchewan, Saskatoon, Saskatchewan

Team Member(s)

John Headley, Environment Canada, Saskatoon, SK

Kerry Peru, Environment Canada, Saskatoon, SK

Iain Philips, Saskatchewan Watershed Authority, Saskatoon, SK

Michael Cavallaro, University of Saskatchewan, SK

Anson Main, University of Saskatchewan, SK

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