Assess the environmental and human health risks of urban effluents in the Quebec City region

Context and project description 

Québec City and Lévis rely extensively on the river: both for drinking water and recreational activities. However, both cities also dump their treated wastewater into it. Furthermore, at this level, the St. Lawrence receives the waste from several other small municipalities located upstream and on the Saint-Charles and Chaudière rivers. Finally, to add to the complexity of the file, the tides turn the currents twice a day, which causes an accumulation and concentration of the wastewater in the emissary sectors, in addition to alternatively transporting it upstream and downstream.

The project consists of creating a team to assess the risks that the effluents have on the ecosystem and on human health. The first phase will see the creation of a multi-expertise team in which the different authorities involved will be represented, and the project will be developed, taking into consideration all aspects, including funding arrangements. Based on the funding obtained, the second phase will see the completion of the project as such. We will study the efficiency of the treatment systems and we will evaluate the toxic effects of effluents on aquatic wildlife, on fish-eating wildlife (mammals and birds), and on humans.


The first stage of the project, which involved establishing a team made up of several experts and finding a source of funding, has been completed. With funding from the Canadian Water Network, the project has provided preliminary results on urban effluents in the Quebec City region. The findings will be used to support the selection of objectives for the 2016–2021 phase. The results of laboratory analyses will be used as a basis for evaluating the risks associated with effluents.

Scientific articles are currently being drafted on the measurement of contaminants present in this effluent stream, which can cause endocrine (hormonal) disruptions, and on the effects measured in fish.

Participating departments 

Government of Canada

  •  Environment and Climate Change Canada

Government of Quebec

  • Ministère du Développement durable, de l’Environnement et de la Lutte contre les changements climatiques
  • Ministère de la Santé et des Services sociaux/Institut national de santé publique du Québec