Update On State Of The St. Lawrence Monitoring Indicators: Physical-chemical and contamination (Room BC)

Changes in Water Level and Flow in the St. Lawrence River

Picture of André Bouchard

André Bouchard

Senior Project Engineer
Hydrology and Ecohydraulics Section
Meteorological Service of Canada
Environment Canada


André Bouchard received his degree in geological engineering from Université Laval in 1987. He joined Environment Canada’s St. Lawrence Centre in 1988 to study the effects of acid precipitation on Quebec’s lacustrine ecosystems. In January 1997 Mr. Bouchard joined the Meteorological Service of Canada’s Water Survey, where he managed several projects on current-meter measurements using hydroacoustic technologies, on the modernization of the federal hydrometric network in Quebec, on hydrometric data management through the new hydrometric workstation, on the hydrological characterization of the St. Lawrence River (Montréal-Trois-Rivières portion) as part of the Hydrology and Ecohydraulics section’s activities for developing ecohydraulic models of the St. Lawrence River, and on the migration to hydrodynamic model operations for the St. Lawrence River at the Canadian Meteorological Centre.


Water flow fluctuations in Sorel are on the order of 14 000 m³/s (6000 to 20 000 m³/s). Alternating high and low flows have been observed there since 1930. Since 2002, there have been a few low-flow events, including one in 2007 and another in 2012. However, the low flows of recent years have not been record-breaking. The flow pattern in the St. Lawrence has changed as a result of numerous human interventions in the 1960s, making it difficult to determine a historical trend. Although the river’s 2 main inputs are regulated, there is limited margin for managing extreme high- and low-flow events. The new regulation plan being considered for Lake Ontario takes into account not only the requirements of the original plan (shipping, hydroelectric generation, etc.) but also issues like erosion and the environment.


In the existing water-level regulation plan, decisions are based primarily on considerations related to hydroelectricity and marine transportation of goods. The new regulation plan will be designed to take into account environmental issues by incorporating more indicators. The plan will be released for public consultation shortly, but no date is available at this time. The flow in Lake Saint-Pierre is calculated based on inputs, including all lateral ones.

The scope of the presentation does not allow for any conclusions concerning use of air cushion vehicles and their potential impact on the natural environment or biodiversity.

The impact of the rising tide cycle on freshwater flow at Quebec City may prove fairly significant. This presentation does not enable us to assess whether water flow is much higher at Quebec City than it was three decades ago.

Water Quality in the Fluvial Section 1995–2010

Picture of Serge Hébert

Serge Hébert

Coordinator, Surface Water Quality Monitoring Networks
Direction du suivi de l’état de l’environnement
Ministère du Développement durable, de l’Environnement, de la Faune et des Parcs (MDDEFP)


Trained in biology and water sciences at Université Laval and at INRS University’s Eau Terre Environnement Research Centre, Serge Hébert has been a water quality specialist at the Direction du suivi de l’état de l’environnement at Quebec’s Ministère du Développement durable, de l’Environnement, de la Faune et des Parcs (MDDEFP) since 1991. He is currently coordinator of surface water quality monitoring networks and has conducted several studies on water quality in the St. Lawrence River.


Despite a few year-to-year fluctuations between 1995 and 2010, there were no trends in the annual percentage of monitoring stations with satisfactory or good water quality (average 72%). In the reaches of the St. Lawrence near Quebec City there were no significant trends in the concentration of suspended particles and phosphorus, the median values of these parameters being 10.3 and 0.026 mg/L, respectively. By contrast, there has been a rise in the concentration of fecal coliforms, with the estimated values going from 107 CFU/100mL at the start of the period to 171 CFU/100mL at the end of the period.


There are three main issues to be monitored:


  1. Swimming remains problematic in certain parts of the river. Additional remediation efforts (disinfection and sewer overflows), particularly for municipal contamination, will help reintroduce this use. The City of Montréal will be implementing disinfection infrastructure, which will eventually improve the situation.

  3. Our intervention efforts must continue to target a reduction in phosphorous discharges.

  5. Emerging contaminants are a major concern.

Water Quality Monitoring: Toxic Contaminants

Picture of Myriam Rondeau

Myriam Rondeau

Project manager, Water Quality
Water Quality Monitoring and Surveillance
Environment Canada


Myriam Rondeau has a background in geology and holds a master’s degree in geochemistry from the Université du Québec à Montréal. She has been a project manager at Environment Canada since 1990, working on water quality and, in particular, on the presence and movement of contaminants in the St. Lawrence River. Since 2006, she has been the senior specialist in fluvial geochemistry and has been involved in numerous national projects regarding water quality in Canada.


The movement of contaminants in the St. Lawrence has been evaluated by calculating the annual loads between 1995 and 2009 at two of the river’s main entrances -- Wolfe Island for deposits from the Great Lakes, and the Ottawa River -- as well as at the exit of the St. Lawrence towards the estuary at Lévis. The sources vary as to the different contaminants found in the river (nutrients, metals, pesticides and PBDEs). Although only small temporal trends were detected for the various compounds analyzed, we can observe that the year-to-year fluctuations in the river’s water level play a major role in the movement of contaminants. The supply of nutrients to the St. Lawrence comes in large part from Lake Ontario; however, suspended particles and their associated contaminants do not come from the Great Lakes.


In the context of this presentation, it is impossible to address the impact that dredging has on contaminant levels following the resuspension of contaminated sediments. It is also impossible to comment on the water mixing and dispersion patterns update following the installation of rock cribs at Laviolette Bridge. Pharmaceutical products have in fact been detected in the river water.

Sediment Quality in the St. Lawrence – Back to Square One

Picture of Magella Pelletier

Magella Pelletier

Manager, Sediment Quality Monitoring
Water Quality Monitoring and Surveillance – Atlantic Ocean Watershed
Environment Canada


Magella Pelletier holds a master’s degree in environmental geology from Université Laval and INRS University, and has been a sedimentologist at the Water Quality Monitoring and Surveillance Directorate since 2001. He is currently responsible for sediment quality monitoring for the St. Lawrence area and is national sediment supervisor for the Chemicals Management Plan (CMP). He has conducted several studies on the various fluvial lakes of the St. Lawrence River and on emerging substances.


During the 20th century, sediments in the St. Lawrence River and principally those of the fluvial lakes had been contaminated by industrial and municipal waste -- a consequence of North America’s economic boom. Numerous contaminants such as mercury, PCBs, dioxins and furans accumulated on the streambed, creating a harmful environment for numerous benthic and aquatic species. Recently, studies have shown that these contaminants have largely diminished in surface sediment deposits and that clean-up operations and regulations implemented in the last 20 to 30 years have proven effective for recuperating waterways.

However, for about the last dozen years, the St. Lawrence has faced a new wave of contaminants that are more diffuse but just as dangerous to aquatic life. Polybrominated diphenyl ethers (PDBEs), siloxanes and perfluorocarbons (PFCs) are only some of the examples of contaminants resistent to current wastewater treatment practices and that are found to be untreatable in the natural environment. These new contaminants require scientists to go back to the drawing board to create new methods of analysis, to re-evaluate risks to organisms and to establish new sediment evaluation criteria.

This presentation provides an overall view of contaminants in St. Lawrence sediments and the observable trends over the short and medium term for both past substances and those of emerging interest.


This presentation describes the improvement in toxicant concentrations in sediments. There have been significant improvements compared with the 1970s. However, even if the water appears clear, it may still contain toxic contaminants. This positive finding about sediments does not mean that everything is fine. The overall health of the St. Lawrence covers many aspects. Since 1990, major efforts have been made, and a number of indicators confirm the impacts of these efforts. However, monitoring activities must continue so that we can learn how the recent changes detected by the indicators will affect the food chain.

Levels of Polybrominated Diphenyl Ethers (PBDEs) in Fish in the St. Lawrence River (2002–2008)

Monitoring Contaminants in Birds of the St. Lawrence

Picture of Louise Champoux

Louise Champoux

Wildlife Ecotoxicologist
Ecotoxicology and Wildlife Health Division
Environment Canada


Louise Champoux has worked as a wildlife ecotoxicologist at the Ecotoxicology and Wildlife Health Division (formerly part of the Canadian Wildlife Service) since 1990. She received a master’s degree in biological sciences from the Université de Montréal in 1986. At Environment Canada she has conducted studies on the presence of pollutants and their effects on wildlife, and research on the use of biomarkers to assess exposure to contaminants and understand the effects of such contaminants on wildlife health.


Through the State of the St. Lawrence Monitoring Program, the Northern Gannet and Great Blue Heron have been identified as sentinel species for the Gulf of St. Lawrence and St. Lawrence River. The concentrations of major contaminants (mercury, polychlorinated biphenyls (PCBs), organochlorinated pesticides, dioxins and furans, etc.) detected in the eggs of the two species and in young herons have mainly trended downward since the late 1960s. The large number of toxic substances present in the environment and the varying sensitivity displayed by different species make it challenging to interpret cause-and-effect relationships between exposure and impacts on bird health. Contaminant concentrations are generally down or stable in Northern Gannets and Great Blue Herons, but they remain a concern for population maintenance.

Complement to the presentations session

While polybrominated diphenyl ethers (PBDEs) do turn up in the water, approximately 90% are eliminated when this water is treated at the two sampled drinking water treatment plants. Treatment is effective in removing substances that tend to adhere to particles, including PBDEs. It is much less effective and potentially ineffective for persistent soluble substances such as perfluorinated compounds.

The 1999 mass balance factors in the loads from the tributaries (data from Quebec’s Ministère du Développement durable, de l’Environnement, de la Faune et des Parcs). Also available were data on the inputs from industry and wastewater treatment plants. Monthly sampling was conducted in the tributaries for a number of years. Models were developed to calculate annual loads. Suspended loads can double in the spring. Internal erosion was calculated using the differential between the upstream and downstream loads, taking into account the loads from the tributaries. Riverbed erosion is not a significant contaminant source, as marine clays are low in contaminants.

In terms of possible sources of contamination, the case of the Snow Goose stands out. Its population has experienced an explosion in numbers and has adapted to agriculture. Its migratory range has expanded, and the contaminant source can be linked to a multitude of possible causes. Cases where contaminant concentrations are not high are rare. There is also the issue of physical causes, including diseases. There are no test years (year 0) for commercial fishery landings, which could provide other avenues of research.