Project: Monitoring Water Quality

PROJECT
Monitoring Water Quality

Program: Monitoring the State of the St. Lawrence River

Objective

The purpose of this project is to identify temporal variations in contaminant concentrations and fluxes in the St. Lawrence River and its main tributaries. It is part of a Canadian water quality monitoring program and contributes new data for the Canadian Environmental Sustainability Indicators report, which is published annually by Environment Canada.

Water Quality Sampling Stations

There are currently nine 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.

Location map of the water quality sampling stations operated
by Environment Canada in Quebec

Click on the sampling stations for more information.

Three water quality sampling stations for the St. Lawrence River are located in the fluvial section at Lavaltrie, Bécancour and Lévis. The Lévis sampling station has served as a reference site since 1995 because this is where tidal effects cause the mixing of various water masses and their contaminant inputs. Refer to Monitoring Water Quality at Québec.

The Bécancour station, in operation since 2006, monitors the quality of the water masses from south shore tributaries and the Great Lakes. The Lavaltrie station, also in operation since 2006, serves to monitor the quality of the brown waters of the Ottawa River, downstream from the urban centres of Montréal and Laval. Refer to St. Lawrence Water Masses.

The Saint-Maurice River

A sampling station has served to characterize water quality at the mouth of the Ottawa River at Carillon since 2004. The latest results are published in the Monitoring the State of the St. Lawrence River fact sheet. The Saint-Maurice and Richelieu rivers are the two largest tributaries of the St. Lawrence River after the Ottawa River; they therefore form the river's two main secondary water masses. Sampling stations were set up there in 2006.

Photo: Saint-Fran?ois River sampling site

Saint-François River sampling site

Sampling stations at the mouths of the Yamaska, Saint-François and Nicolet rivers have monitored the water quality of the main tributaries of the rural southern shore of Lake Saint-Pierre since 2003. Refer to Pesticides are Entering the St. Lawrence River through Its Tributaries.

Photo: Agricultural discharge into a stream of the Yamaska River

Environment Canada has operated the Wolfe Island station in Ontario, directly upstream from the Quebec sampling network, since 1976; it provides data on the quality of the green water of the Great Lakes, the primary source of the St. Lawrence River.

Collection and Analysis of Water Samples

Precise sampling and analysis protocols must be followed when doing this work. To this end, Environment Canada scientists produce publications on the application of sampling and analysis principles and practices. Publications pertaining to collection and sampling methods can be found at the St. Lawrence Centre Documentation Centre.

Collection and measurement techniques adapted to the study of trace and ultratrace contaminants were adopted in order to obtain reliable, specific data. Sampling strategies are developed based on water regimes and the anticipated variability in concentrations of the contaminants studied. Sampling frequency therefore varies from weekly to monthly, depending on the sampling station and the contaminant being studied.

Scientists at Environment Canada are continuing their work to expand the water quality monitoring and surveillance network to other drainage basins, and to monitor the presence of new substances such as polybrominated diphenyl ethers (PBDE). Refer to Tracking Polybrominated Diphenyl Ethers (PBDEs), New Chemical Contaminants in the Environment.

To Know More

Rondeau, B. 2005. Water Quality in the Fluvial Section: Contamination by Toxic Substances. 2nd edition. Fact sheet in the “Monitoring the State of the St. Lawrence” series. Environment Canada – Quebec Region and Ministère du Développement durable, de l’Environnement et des Parcs du Québec.

Rondeau, B. 2002. Water Quality in the Fluvial Section – Contamination by Toxic Substances. Fact sheet in the series "Monitoring the State of the St. Lawrence River." Environment Canada – Quebec Region, Environmental Conservation, St. Lawrence Centre.

Rondeau, B. and P. Klawunn. 2005. Water Quality in the Great Lakes–St. Lawrence Basin: Contamination by Toxic Substances. Electronic Fact Sheet in the series “State of the Great Lakes–St. Lawrence Ecosystem.” Environment Canada.

Water and Sediments, under "St. Lawrence Info"

Literature

Cossa, D., B. Rondeau, T.-T. Pham, S. Proulx, and B. Quémerais. 1996. Principes et pratiques d’échantillonnage d’eaux naturelles en vue du dosage de substances et d’éléments présents à l’état de traces et ultra-traces. Environment Canada – Quebec Region, Environmental Conservation, St. Lawrence Centre. 28 pages.

Cossa, D., T.-T. Pham, B. Rondeau, S. Proulx, C. Surette, and B. Quémerais. 1998. Tracking Contaminants in the St. Lawrence River: Summary of the Mass Balance Study of Contaminants in the St. Lawrence River. Environment Canada – Quebec Region, Environmental Conservation, St. Lawrence Centre.

Gilbert, D., D. Chabot, P. Archambault, B. Rondeau, and S. Hébert. 2007. Appauvrissement en oxygène dans les eaux profondes du Saint-Laurent marin : causes possibles et impacts écologiques. Le Naturaliste canadien 131(1): 67–75.

Gobeil, C., B. Rondeau, and L. Beaudin. 2005. Contribution of municipal effluents to metal fluxes in the St. Lawrence River. Environmental Science & Technology 39(2): 456–464.

Pham, T.-T., B. Rondeau, H. Sabik, S. Proulx, and D. Cossa. 2000. Lake Ontario: The predominant source of triazine herbicides in the St. Lawrence River. Canadian Journal of Fisheries and Aquatic Sciences 57(Suppl. 1): 78–85.

Quémerais, B., D. Cossa, B. Rondeau, T.-T. Pham, and B. Fortin. 1998. Mercury distribution in relation to iron and manganese in the waters of the St. Lawrence River. The Science of the Total Environment 213: 193–201.

Quémerais, B., D. Cossa, B. Rondeau, T.-T. Pham, P. Gagnon, and B. Fortin. 1999. Sources and fluxes of mercury in the St. Lawrence River. Environmental Science & Technology 33: 840–849.

Rondeau, B., D. Cossa, P. Gagnon, and L. Bilodeau. 2000. Budget and sources of suspended sediment transported in the St. Lawrence River, Canada. Hydrological Processes 14: 21–36.

Rondeau, B., D. Cossa, P. Gagnon, T.-T. Pham, and C. Surette. 2005. Hydrological and biogeochemical dynamics of the minor and trace elements in the St. Lawrence River. Applied Geochemistry 20(7): 1391–1408.