Release of Toxic Substances to Water

Toxic substances, when released to the environment, are known to have harmful effects on human health, biological diversity or the overall environment. Industrial facilities and wastewater treatment plants are the primary sources of toxic-substance releases to water in Canada.

The following Canadian Environmental Sustainability Indicators (CESI) track the release to water of three toxic substances: mercury, lead and cadmium, and their compounds. They are listed as toxic[1] according to the Canadian Environmental Protection Act, 1999 (CEPA 1999), and therefore their release to the environment is closely monitored. The data used to calculate these indicators are taken from reported facility releases from the National Pollutant Release Inventory (NPRI).

In Canada, the amount of these substances released to water was lower in 2011 than in 2003.[2] In 2011, the amount released was reduced from 2003 levels by 8% or 31 kilograms (kg) for mercury, by 30% or 7312 kg for lead, and by 45% or 2206 kg for cadmium.

Details on release of toxic substances to water by substance

[1] Section 64 of CEPA 1999 defines a substance as toxic if it is entering or may enter the environment in a quantity or concentration or under conditions that a) have or may have an immediate or long-term harmful effect on the environment or its biological diversity, b) constitute or may constitute a danger to the environment on which life depends, or c) constitute or may constitute a danger in Canada to human life or health.

[2] The indicators include only the releases from facilities that reported to the National Pollutant Release Inventory (NPRI) and may not be representative of total releases nationally.