Mercury is toxic, persistent and accumulates in living organisms. It can be transported over long distances through the air and enter the land and water, where it can build up in foods as they are consumed up the food chain. Micro-organisms found in water, wetlands and soil typically convert mercury to methylmercury, a highly toxic form. Humans are primarily exposed to mercury through the consumption of fish and certain wildlife species. In several areas of Canada, including the Arctic, levels of mercury remain high in some wildlife and exposure to mercury through the consumption of fish and certain wildlife may pose health risks to some Canadians.
Mercury pollution is produced or released:
- by natural sources, such as forest fires and volcanic activity
- by human activities such as: waste incineration; coal-fired power generation; metal smelting; cement clinker production and; the production, breakage and disposal of products containing mercury
- in reservoirs created by dams.
Canadian mercury emissions have decreased by over 90 per cent since the 1970s, particularly with significant reductions occurring in the non-ferrous smelting and refining sector when measures were put in place in the 1990s. The graph below shows the annual amount of mercury emissions generated in Canada by source from 1990 to 2015.
Source: Environment and Climate Change Canada. 2017. Air Pollutant Emission Inventory
Despite these reductions, air emissions continue to be a major source of mercury in Canada. Environment and Climate Change Canada (ECCC) estimates that 97 per cent of mercury from human sources deposited in Canada came from other countries. Mercury released into the air can remain there for 6 to 12 months and wind can carry it long distances. ECCC also estimates that Canada contributed 0.2 per cent of global mercury emissions to the atmosphere from human activities. This is the smallest contribution of any region in the world.
The graph below shows the sources of mercury and where in Canada they were deposited in 2015.
Source: Environment and Climate Canada. 2018.
Measures to reduce local and global mercury emissions help improve ecosystems, wildlife, and the health of Canadians. Canadians can take action in their everyday lives to reduce mercury emissions and releases by properly disposing of mercury containing products (e.g., mercury-containing light bulbs, thermometers, etc.). Canadians can also better protect their health by being informed of fish consumption guidelines and advisories.
Federal, provincial and territorial governments continue to do research and collaborate to reduce mercury emissions. Together they have put in place over 50 regulatory and non-regulatory domestic and international measures that directly or indirectly target reductions of mercury emissions.
CCME developed Canada-wide standards for mercury emissions from base-metal smelters, waste incinerators, coal-fired power plants as well as mercury-containing lamps and dental amalgam waste.
Implementation plans which describe the actions taken to implement the Canada-wide Standards and achieve compliance by the target dates can be found on the websites of individual jurisdictions. Because Québec is not a signatory to the Canada-wide Accord on Environmental Harmonization, nor the Canada-wide Standards, Québec is not required to develop an implementation plan.