Release of Toxic Substances to Water

Toxic substances, when released to the environment, are known to have harmful effects on human health, biological diversity and 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. 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 the National Pollutant Release Inventory (NPRI).

In Canada, the amount of these substances released to water was lower in 2010 than in 2003. In 2010, the amount released was reduced from 2003 levels by 29% or 112 kilograms (kg) for mercury, by 22% or 5 453 kg for lead, and by 46% or 2 275 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.