Sewage Dumps, St Lawrence River, Quebec, Canada

Government-approved raw sewage dumps compromise water quality and put species at risk against the wishes of local Mohawk and Francophone communities.

The St Lawrence Estuary (SLE) is linked to multiple cities including Quebec City, Longueuil and Montreal, and borders on the United States. The region serves as a site of high-scale international trade and industrial production which places the estuary under immense economic pressure. Industrial practices place the ecosystem of the estuary at risk to multiple sources of waste pollution, including marine vessel noise, chemical discharge and spills. In addition, the municipal governments of the cities mentioned above have periodically approved untreated sewage dumps into the river when pipe repairs are needed. Government officials have said that the billions of litres of raw sewage dumped into the St Lawrence have no negative impact on the ecosystem, despite a lack of comprehensive evidence to support that claim. The sewage dumps have not been proven to be an immediate cause for concern, but ecological consequences typically manifest throughout longer periods of time. A visible consequence of mismanagement of the estuary is the continuous population decline of the St Lawrence Beluga whale. This species has suffered the historical impacts of overhunting throughout European settlement and now suffers from reproductive deficiency caused by industrial chemical pollution. The raw sewage dumps that this project describes have been conducted within the last three years, because of this recency, there is a lack of research available to prove the direct impacts on ecological functions. However, the bioaccumulative effects of now-banned chemicals, such as Polybrominated diphenyl ethers (PBDEs) and Dichlorodiphenyltrichloroethane (DDT), show us that species and ecosystems suffer from long-term consequences of poor waste management. Sewage contains harmful bacteria, such as E. coli, that can make

humans very sick. When sewage is released into a waterbody the bacteria

in the sewage take oxygen out of the water which can kill fish and other

aquatic life. The solids suspended in sewage can turn water murky,

further impairing the ability of fish to breath and making it difficult

for them to see.

Sewage also contains diverse range of

contaminates that we don’t want in our waterways. There are nitrates and

phosphates that encourage algae growth, heavy metals that can

bioaccumulate in fish, as well as micro plastics, pharmaceuticals and

whatever else people and industry (irresponsibly) put down their drain.

A fundamental aspect of this issue is that decisions on waste management are made exclusively by municipalities, without adequate consultation of local stakeholders and Indigenous communities who are impacted by the resulting ecological damage. This reflects a greater structural power imbalance that has been formed through long histories of colonial conquest and exploitation. Some of the visible impacts of these processes are the widespread displacement of Indigenous communities; loss of traditional knowledge, practices, and livelihood; and loss of biodiversity in the St Lawrence ecosystem. In 2015 the sewage dump in Montreal was protested by both Indigenous communities and other activists. An online petition garnered over 95,000 signatures while Kahnawake Mohawks blocked an access ramp to the Mercier Bridge to protest the sewage dump into the St. Lawrence River and held a railway protest. The Federal Government also also ordered for the city to put the plan on hold while Environment Canada conducted an independent scientific review. In the end the city dumped 4.9 billion liters, down from the initial proposed 8 billion.
Basic Data
NameSewage Dumps, St Lawrence River, Quebec, Canada
SiteMontreal, Longueuil, Quebec City
Accuracy of LocationMEDIUM regional level
Source of Conflict
Type of Conflict (1st level)Waste Management
Type of Conflict (2nd level)Landfills, toxic waste treatment, uncontrolled dump sites
Water treatment and access to sanitation (access to sewage)
Specific CommoditiesWater
Industrial waste
Domestic municipal waste
Chemical products
Biological resources
Project Details and Actors
Project DetailsDocumented dumping of untreated sewage into the St Lawrence Estuary:

Longueuil, November 2018 - 160 million litres

Quebec City, February 2018 - 46 million litres

Montreal, November 2015 - 4.9 billion litres

These raw sewage dumps occur to allow for infrastructure repair, with the justification by government officials that there is no better alternative and that there will be no resulting environmental damage. The lack of impact on treated drinking water is held as evidence for that claim. This overlooks the proven toxicity levels found in aquatic species, such as the Beluga whale, that have accumulated over long periods of time from various sources of industrial pollution. A comprehensive environmental impact assessment is needed in order to truly understand the potential damage that high levels of raw sewage will have on the ecosystem. This assessment must also be conducted independently from the entities that approve the dumps.
Level of Investment (in USD)2.2 million CAD for Montreal Dump
Type of PopulationSemi-urban
Start Date01/10/2015
Relevant government actorsLocal municipalities of Quebec City, Montreal, and Longueuil

Federal Government

Environment Canada
Environmental justice organisations and other supportersMohawk Council of Kawnawakhe
The Conflict and the Mobilization
Intensity of Conflict (at highest level)MEDIUM (street protests, visible mobilization)
When did the mobilization beginPREVENTIVE resistance (precautionary phase)
Groups MobilizingIndigenous groups or traditional communities
Local ejos
Local government/political parties
Social movements
Ethnically/racially discriminated groups
Recreational users
Local scientists/professionals
Forms of MobilizationArtistic and creative actions (eg guerilla theatre, murals)
Community-based participative research (popular epidemiology studies, etc..)
Creation of alternative reports/knowledge
Development of a network/collective action
Development of alternative proposals
Media based activism/alternative media
Official complaint letters and petitions
Public campaigns
Street protest/marches
Arguments for the rights of mother nature
Appeals/recourse to economic valuation of the environment
online petition that garnered over 95,000 signatures; activists and concerned citizens participated in a clean-up of the shores around the Old Port – a symbolic gesture meant to say “we don’t want any more waste in our river.”; Kahnawake Mohawks blocked an access ramp to the Mercier Bridge to protest the sewage dump into the St. Lawrence River.
Environmental ImpactsVisible: Biodiversity loss (wildlife, agro-diversity), Surface water pollution / Decreasing water (physico-chemical, biological) quality
Potential: Groundwater pollution or depletion, Reduced ecological / hydrological connectivity
Health ImpactsPotential: Other environmental related diseases
Socio-economic ImpactsVisible: Loss of landscape/sense of place
Potential: Loss of traditional knowledge/practices/cultures, Loss of livelihood
OtherLoss of eco-tourism potential.
Project StatusUnknown
Pathways for conflict outcome / responseNew Environmental Impact Assessment/Study
Development of AlternativesCritics claimed that Montreal had years to come up with another plan which could have entailed building a back-up interceptor for example, amongst other options.
Do you consider this as a success?No
Sources and Materials

The Fisheries Act, specifically the The Wastewater Systems Effluent Regulations.


Guise, S. D., Martineau, D., Beland, P., & Fournier, M. (1995). Possible mechanisms of action of environmental contaminants on st. lawrence beluga whales (delphinapterus leucas). Environmental Health Perspectives, 103, 73. doi:10.2307/3432415

Martineau, D., Lemberger, K., Dallaire, A., Labelle, P., Lipscomb, T. P., Michel, P., & Mikaelian, I. (2002). Cancer in wildlife, a case study: Beluga from the st. lawrence estuary, québec, canada. Environmental Health Perspectives, 110(3), 285-292. doi:10.1289/ehp.02110285

Pendleton, R. M., Hoeinghaus, D. J., Gomes, L. C., & Agostinho, A. A. (2015). Trophic downgrading results in complex ecosystem dynamics in experimental tropical floodplain food webs. Hydrobiologia, 760(1), 15-28. doi:10.1007/s10750-015-2299-9

Simond, A. E., Houde, M., Lesage, V., & Verreault, J. (2017). Temporal trends of PBDEs and emerging flame retardants in belugas from the st. lawrence estuary (canada) and comparisons with minke whales and canadian arctic belugas. Environmental Research, 156, 494-504. doi:10.1016/j.envres.2017.03.058


CBC "Longueuil to dump 160 million litres of raw sewage into St. Lawrence River"
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CBC "Quebec City to dump 46 million litres of sewage waste into St. Lawrence River"
[click to view]

CBC "Flushgate a success but lacked 'social acceptability:' Denis Coderre "
[click to view]

Media Links

"Your guide to Montreal's hidden Indigenous character"
[click to view]

"Kahnawake Mohawks hold railway protest against planned sewage dump"
[click to view]

"Call of the Baby Beluga"
[click to view]

Other Documents

Avoid all contact with water photo from CBC:
[click to view]

Meta Information
ContributorRae Costain, Ariane Lecompte, Juli Oshada & Zoe Martin | University of Victoria
Last update29/12/2018