Water and Sediment

  • Temporal Changes in Toxic Contamination at the Carillon Sampling Station
    Deforestation, urban development, industrial activity and farming have generated heavy loads of toxic substances that have found their way into rivers and lakes over the last century. These inputs have contributed to degrading the water quality in the Ottawa River basin and have attendant impacts on the quality of the water and ecosystem of the St. Lawrence River.
  • Benthic Macroinvertebrate Communities
    An indicator of water quality and aquatic ecosystem health in the St. Lawrence River
  • Phosphorus at the Mouths of Lake Saint-Pierre Tributaries
    Between 2005 and 2014, the average concentrations of phosphorus measured at the mouths of the Saint-François and Nicolet rivers oscillated around values corresponding to a eutrophic environment. However, it was at the mouth of the Yamaska River that the highest concentrations were observed and where conditions were hypereutrophic.
  • Sediment Quality of the St. Lawrence River
    According to studies by Environment Canada, surface sediments in the St. Lawrence River are generally less contaminated than they were 20 years ago as a result of effluent treatment measures. Yet, concentrations of some substances have remained unchanged or are even increasing.
  • Are Urban Effluents Responsible for the Metal Contamination of the St. Lawrence River?
    With the exception of silver, metals do not originate from municipal effluents.
  • Drug Cocktail in the St-Lawrence River Offers No Relief to Aquatic Organisms
    At water quality monitoring stations along the St. Lawrence River, 17 pharmaceutical, and personal care products (PPCPs), and other substances were detected among the 30-odd contaminants analyzed in 2006.
  • Effect of Water Level on Contaminant Transport
    Contaminant concentrations in the St. Lawrence River near Quebec City are influenced by both the quantities released to the aquatic ecosystem and by the origin of the water masses that carry them, including the Great Lakes water mass.
  • Changes in water levels and flows in the St. Lawrence River
    Flows in the St. Lawrence at Sorel vary greatly from year to year, and they depend on interannual variations in water inputs to Lake Ontario, which in turn depend on climatic conditions.
  • Monitoring the Water Quality of the St. Lawrence River
    There are currently ten water quality sampling stations being operated in Quebec by Environment Canada. They serve to assess the level of water contamination by registering seasonal and interannual fluctuations as well as long-term trends in contaminant concentrations.
  • Pesticides are Entering the St-Lawrence River Through it's Tributaries
    A number of pesticides are present in the water of the St. Lawrence River near Quebec City and at the mouths of some tributaries of Lake Saint-Pierre. This is what scientists at Environment Canada have observed since 2003.
  • Sediment Dynamics in the St. Lawrence River
    Based on the characteristics of the hydrodynamic regime, it is possible to define zones of potential erosion, transport of solid matter and sedimentation. These zones change according to seasons, flows, tides, winds and ice. Facts and figures on sediment inputs in the St. Lawrence are shown.
  • The Freshwater Hydra (Hydra attenuata): Useful in Ecotoxicology
    Thanks to the work of Environment Canada research scientists, the freshwater hydra test is now widely used across the Americas and in Africa, Asia and Europe to assess potential toxicity in water samples.
  • The Use of Algae for Assessment of Sediment Quality
    Research scientists at Environment Canada have developed the algal solid-phase assay for diagnosing toxicity in sediment contaminated by various classes of chemicals, including hydrocarbons. ASPA has certain advantages over conventional bioassays.
  • Tracking Polybrominated Diphenyl Ethers (PBDE): New Chemical Contaminants in the Environment
    Polybrominated diphenyl ethers, or PBDEs, are widely used in industry due to their flame-retardant properties.Although they are useful, these substances accumulate in the environment, including the St. Lawrence River, and questions are being raised about their potential impacts.
  • Wastewater as a Food Source in the Ecosystem
    When we think of urban wastewater, its negative environmental impacts generally spring to mind. For example, the enrichment of the aquatic environment by certain nutrients contained in wastewater can lead to a proliferation of algae and, ultimately, the eutrophication of the site. Yet, according to the results of a study conducted by Environment Canada in collaboration with research scientists at McGill University, urban wastewater can also be a food source for aquatic organisms.
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