Canadian Environmental Sustainability Indicators: Freshwater quality

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Freshwater quality

What is the issue?

Water quality in Canada is under pressure from a range of sources including agriculture, industrial activity and human settlement. This new indicator provides a preliminary assessment of surface water quality with respect to protecting aquatic life (e.g., fish, invertebrates and plants). It does not assess the quality of water for human consumption.

What is happening?

Freshwater quality was rated as ‘good’or ‘excellent’ at 44% of the sites, 'fair' at 31% and ‘marginal’ or ‘poor’ at 25%.

Almost all of the 345 selected monitoring sites are located in southern Canada in areas of human activity.

This preliminary indicator will be revised in future reports to reflect improvements in monitoring and analysis.

Status of freshwater quality at selected sites, Canada, 2001 to 2003

Notes: The results are for surface water quality with respect to protecting aquatic life. They do not assess the quality of water for human consumption. Number of sites is 345. Observations for the Great Lakes are not included.

Source: Data assembled by Environment Canada from federal, provincial and joint water quality monitoring programs.

What does it mean?

Water quality degradation can affect both aquatic life and human uses of water. For example, higher concentrations of nutrients (e.g., nitrogen or phosphorus) may result in uncontrolled plant growth. Economic activities such as freshwater fisheries, tourism and agriculture can be undermined by degraded water quality. These initial results should not be interpreted as representing the state of all fresh waters in Canada; they apply to the water quality at the sites selected and are based on data collected from 2001 to 2003.

Why is it happening?

Water quality experts most often identified urban development and agricultural activities as key potential causes of degraded water quality. Pulp and paper facilities, mines (including oil sands), forestry, acid rain, and dams or other diversions were also considered important stressors at some sites. Natural phenomena such as glacial flows, seasonal snow melt and heavy rainfall can also lead to high levels of suspended sediments that are rich in nutrients and metals.