This page has been archived on the Web

Information identified as archived is provided for reference, research or recordkeeping purposes. It is not subject to the Government of Canada Web Standards and has not been altered or updated since it was archived. Please contact us to request a format other than those available.

Waterborne Pathogens

Elevated E. coli bacteria levels can adversely affect recreational waters and result in beach closures | Photo: Corel CorporationWaterborne pathogens are disease-causing microorganisms that contaminate water supplies. They have contributed to outbreaks of waterborne disease in communities like Walkerton, ON (E. coli O157:H7 and Campylobacter sp. in 2000), North Battleford, SK (Cryptosporidium sp. in 2001), and Toronto, ON (Legionella pneumophila in 2005). Between 1974 and 2001, Health Canada and the Public Health Agency of Canada identified 288 waterborne disease outbreaks that were related to drinking water in Canada.   

Waterborne pathogens can pose a threat to surface or ground water supplies used for drinking, recreation, irrigation, shellfish, or livestock and wildlife needs. They are frequently associated with fecal pollution which comes from diverse sources such as municipal wastewater, agricultural fecal wastes, or wildlife fecal droppings. Fecal pollution problems are widespread across Canada, and result in many "boil water" advisories, beach closures, and closures of shellfish areas every year. However, scientific advances in fields like microbial source tracking are helping to identify critical sources of fecal pollution, and to guide targeted, cost-effective clean-up actions.

In addition to posing a threat to human health, waterborne pathogens are also a threat to animal health, as well as aquatic ecosystem health and biodiversity. Outbreaks of avian botulism have killed large numbers of waterfowl across the country, and emerging fungal and viral pathogens may be contributing to declines in populations of amphibians, fish and other aquatic species.

Water S&T Research

Environment Canada is investigating microbial source tracking techniques for determining the sources of fecal pollution contaminating beaches around the Great Lakes. Research collaborations with municipal partners like the City of Toronto are helping to identify stormwater outfalls with unexpected sewage cross-connections, and other fecal pollution sources that can be targeted for cost-effective clean-up efforts.

Researchers are also examining the occurrence of waterborne pathogens, such as Campylobacter species and E. coli pathotypes, in aquatic ecosystems used as sources of drinking water and for recreation. Further studies are providing a better understanding of the potential health risks associated with contamination from municipal wastewater effluents and bird fecal droppings which can contaminate Great Lakes beaches.  

Environment Canada has formed partnerships with universities and the Ontario Region of Peel to investigate the occurrence of Campylobacter, Giardia, Cryptosporidium, and culturable enteric viruses in Lake Ontario. These results will assist municipalities and source water protection groups in developing source water protection plans to reduce the risks of waterborne pathogen contamination at offshore drinking water intakes.      

Joint projects with Agriculture and Agri-Food Canada, the Public Health Agency of Canada, Health Canada, and provincial and university partners have helped to develop a water quality benchmark for waterborne pathogens in agricultural watersheds, under the National Agri-Environmental Standards Initiative (NAESI). 


To learn more, visit these websites:

Date modified: