Update: Health Canada released their decision on March 31, 2017 to not ban atrazine and to conduct a second review of the pesticide to investigate environmental and health risks associated with surface and drinking water contamination.  

Joint blog with Karen Ross, Equiterre and Muhannad Malas, Environmental Defence 

One of the most commonly used pesticides in Canada could be in the water flowing from your tap. Last week, we released our drinking water test results from Toronto and Montreal and found atrazine—a pesticide linked to hormone disruption – in our tap water. The levels found in our tests were above the European Union (EU) standards but below the less cautious Canadian Drinking Water Quality Guidelines.

And while Europe banned it thirteen years ago due to environmental concerns over groundwater contamination, Health Canada proposed to continue its use. This is concerning because scientific evidence demonstrates that exposure to atrazine may have serious effects on amphibians and animals, such as impacts on reproduction and development. Some studies also suggest harmful effects on human reproduction and development at concentrations in water similar to those analyzed in the Montreal and Toronto tap water samples. Health Canada concluded that the risks atrazine poses are not harmful to our health and the environment. On the brink of the final decision by Health Canada, we are calling on the Minister of Health to ban atrazine.

A little background:

Atrazine is a pesticide used extensively to kill weeds in corn and sorghum fields in Ontario and Quebec. It is known for its hormone disruption effects in fish, frogs and humans. Because atrazine was banned in the EU, Canada’s Pest Management Regulatory Agency (PMRA) was required by law to conduct a special review of the pesticide in 2013.

The EU banned atrazine due to its concern over observed groundwater contamination and its potential future contamination. Consequently, the PMRA decided to only focus their atrazine study on groundwater contamination in Canada – a source of drinking water for only 30 per cent of Canadians. While this is an important consideration, 70 per cent of Canadians get their drinking water from surface water.

The PMRA’s narrow review on atrazine neglected vital health and environmental data including:

  • Contamination of drinking water from surface water sources
    Most people living in Toronto and Montreal – cities in the two provinces in which atrazine is heavily used for agriculture – get their drinking water from the Lake Ontario and the St-Lawrence River. Despite the fact that atrazine is commonly detected in Toronto’s municipal drinking water sources and has been found in Montreal tap water with levels that exceed the EU contamination standard, the PMRA did not consider to test surface water in its review.
  • Impacts on aquatic ecosystems from surface water contamination
    The PMRA review also excluded the impacts of this pesticide on aquatic life. Scientific evidence shows that atrazine can feminize frogs and other amphibians, negatively affect the basic functioning of bees, affect the diversity of soil microorganisms and the health of earthworms, and affect photosynthesis in algae and other aquatic plants. Atrazine also threatens other species including fish and reptiles due to its hormone-disrupting properties.
  • Farmers’ health and other vulnerable groups
    The review also did not consider the health impacts of the use of atrazine on farmers, farm workers, pesticide applicators, and farming communities who are most exposed to atrazine on a day-to-day basis, particularly during the growing season.
  • Synergistic effects of atrazine and other toxic chemicals in the environment
    When atrazine mixes with other active ingredients in the environment, the impact is often much more concerning than the impact of atrazine alone. For example, the presence of atrazine and nitrates in drinking water may result in a higher chance of developing non-Hodgkin’s lymphoma.

Canadians need an immediate ban on atrazine

Canadians should not have to worry about whether drinking water will put their health at risk. And while using certain specialized water filters can help reduce your exposure, the onus should not be placed on individual citizens to find ways to protect themselves.

The only equitable and sustainable solution to fully protect Canadians and aquatic environments is to ban atrazine altogether from agricultural use. That’s why we, along with Équiterre, are asking the federal government to protect Canadians by banning atrazine.

Sign our petition to make your voice heard and urge the Minister of Health to ban atrazine immediately.




Karen Ross, Ph.D.
Project Manager – Pesticides and Toxic Substances