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 at the two main inlets to the St. Lawrence River, the Ottawa River at Carillon (Quebec) and Lake Ontario at Kingston (Ontario), as well as at the river outlet at Lévis (Quebec).

Water Quality Reference Stations

Three reference stations have been set up on the St. Lawrence to assess the water quality by recording seasonal and interannual fluctuations in contaminant concentrations as well as long-term trends. Three main water masses are being monitored: the Great Lakes (green) waters, the Ottawa River (brown) waters, and the mixed waters downstream of Portneuf. To know more: St. Lawrence Water Masses. A team of research scientists from Environment Canada is working to determine if the water quality is getting better or deteriorating.

Concentrations and temporal trends in toxic substances in the water
at the Carillon, Wolfe Island and Quebec City stations

Ottawa River at Carillon

Water Sampling

Four classes of contaminants are analysed: metals, PCBs, PAHs and pesticides. Samples are taken following a rigorous protocol based on the type of parameters to be analysed.

The Lévis reference station

Sampling is conducted in wells located upstream of the pumping station at the Lévis water treatment plant.

Water samples are pumped and transported using Teflon-coated implements. Teflon being impervious to gas, acid washes and organic solvents, these apparatus can be used to draw water samples for analysis of inorganic (metals, mercury) and organic (pesticides, PAHs) contaminants alike.

Schematic diagram of the sampling system for analysing metals and organic contaminants at trace and ultra-trace levels in natural waters

The pump is liberally rinsed with surface water before samples are extracted. Contaminants are analysed in both the particulate and dissolved phases. The pumped water is then line-filtered on site and the filtrate (dissolved phase) stored in stainless steel containers. The filter is set aside for analysis of the contaminants in suspended matter (the particulate phase).

In the Lab

Samples taken from filters are analysed in a “clean room,” so named for its positive pressurization, which repels outside contaminants. The air is filtered and strict rules govern the movements and practices of clean-room personnel to prevent sample contamination.

Working in the clean room

A clean environment is essential to detecting substances at trace and ultra-trace levels. Contamination must be avoided at all costs, so samples must be handled with great care. A critical eye is cast on all laboratory material during every step of the sampling, processing and analysis stages.

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.

Water and Sediments, under "St. Lawrence Info"

Literature

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.

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, 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.