Toxic substances 2016-2021

Develop a risk assessment project for the environment and for health related to urban effluents in the Quebec City region

Québec City and Lévis rely extensively on the river, both for providing drinking water and recreational activities. Both cities also dump their treated wastewater into the river. Furthermore, at this level, the St. Lawrence receives 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 current 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. 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.  

Study the effect of Montreal wastewater ozonation on aquatic organisms

On its own, the City of Montreal dumps 50% of Quebec’s wastewater. Several contaminants, such as medication residue, flame retardants or health care products are found in the river. Montreal’s wastewater also contains pathogenic organisms. The municipality therefore decided to use an ozonation technique to eliminate the pathogens. Once in the water, the ozone transforms into oxygen, which in itself does not create pollution. However, the ozone is also a very powerful oxidizing agent that can transform some of the river’s contaminants into even more toxic by-products. Furthermore, aquatic life can suffer from an excess of oxygen carried by the wastewater treated by ozonation.

The researchers in this project will study the ways in which ozonation affects the aquatic organisms. Additionally, they will identify the risk substances and verify how they transform and accumulate in aquatic wildlife throughout the food chain.

Study the presence of cancer medications in the St. Lawrence and their associated effects

There are few studies on the effects of cancer medications on aquatic organisms. Although they are present in weak concentrations in municipal effluents, we suspect that they are toxic for, and cause mutations and cancer in, DNA cells in aquatic organisms. However, since they do not degrade much in the traditional wastewater treatment plants, these medications, excreted by the patients, may be detected in aquatic environments.

It is therefore important to build knowledge on the potential dangers associated with these substances to determine the risks they present for the aquatic environment. Researchers will update the methods to analyze these river contaminants. They will monitor their presence in the river waters near Montreal and in Lake Saint-Pierre. Finally, they will study the effects these medications have on invertebrates and fish.

The data produced from this study will determine the extent of the problems associated with the presence of cancer medications in the St. Lawrence River. These results will be used to identify the additional knowledge requirements for these substances.

Share the scientific knowledge on organic contaminants, including emerging contaminants of concern

Sediment contamination in the river’s water has greatly reduced over the last 40 years with the ban on using several organic substances, effective environmental monitoring, wastewater remediation and public awareness. Despite these efforts, new contaminants continue to be found, such as siloxanes, phthalates, polybrominated diphenyl ether (PBDE) and nanoparticles.  
This new project aims to create a platform for meetings where researchers can share their knowledge and develop shared strategies for studying the contaminants present in the river ecosystem. Such exchanges are essential given the complexity of the river. Indeed, changes in current and water levels, the presence of different bodies of water that may influence the dispersion of contaminants and their effects endanger aquatic wildlife.