Mercury - information sheet

Updated July 3, 2020

Mercury is a toxic substance under the Canadian Environmental Protection Act, 1999 (CEPA 1999) and has been subject to many federal risk management activities over the past fifty years. In 2010, the Federal Government published the Risk Management Strategy for Mercury which outlined its preventive actions toward the reduction of risks posed by mercury. Subsequent to this, the Government conducted an assessment of whether the risk management actions taken for mercury were effective in meeting this objective, and in 2020, summarized the results in the Evaluation of the Effectiveness of Risk Management Measures for Mercury. This information sheet provides background information associated with mercury and communicates progress outlined in the performance report.

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  • Mercury was one of the first substances added to the List of Toxic Substances in Schedule 1 of CEPA 1988, based on the acknowledgement that there was sufficient international evidence of harm to human health and the environment to warrant action to reduce risks associated with this substance. Subsequent to this, in 2012, mercury and its compounds were added to Schedule 1 of CEPA 1999.

About this substance

  • Mercury occurs naturally in the Earth's crust and can enter the environment as a result of natural processes such as volcanic activity and forest fires. It can also be released into the environment through human (anthropogenic) activities such as the burning of coal, the extraction of metals from ore and the use and disposal of products containing mercury. Emissions from human activities account for 40% of mercury deposited in Canada. Once in the environment, mercury cycles between air, water, soil, plants, and animals. Because elemental mercury (mercury in its pure form) evaporates, it can move easily through the air, ending up far from where it was first released; this makes it a global concern. For example, 97% of the mercury from human activities deposited in Canada originates from other countries.

Human and ecological exposures

  • Humans are most often exposed to mercury through their diet. Mercury can be converted into various forms, including methylmercury, a highly toxic compound that accumulates in living organisms. Dietary exposure of humans to methylmercury occurs primarily through eating fish and sea mammals.
  • The accumulation of methylmercury in living organisms results in greater concentrations of methylmercury in animals who are at higher levels of the food chain.
  • Canada's human biomonitoring programs and environmental monitoring and surveillance activities provide essential information to determine trends in the exposure of Canadians' and their environment to mercury.

Key health and ecological effects (hazard)

  • Releases of mercury pose significant risks to Canada's environment and the health of Canadians.
  • In humans, methylmercury affects the central nervous system and is particularly damaging to fetuses, infants, and young children, who are vulnerable due to their developing nervous systems.
  • In animals, mercury exposure is associated with neurological and reproductive effects.

Preventive actions and reducing risk

  • Over many years, the Government of Canada has worked to protect Canadians and the Canadian environment from the harmful effects of mercury. In 2010, the Federal Government published the Risk Management Strategy for Mercury which outlined its preventive actions to reduce risks posed by mercury, followed in 2020 by the Evaluation of the Effectiveness of Risk Management Measures for Mercury. This performance report evaluates the progress made from 2007 onwards toward reducing these risks. It provides the status of emissions and releases of mercury from human activities, outlines trends in environmental monitoring data and human biomonitoring data, and describes the risk management actions and discusses how effective they have been toward risk reduction goals.
  • Specific risk management undertaken by the Government of Canada has involved regulatory and other measures focusing on mining, metal smelting, steel manufacture, cement manufacture, electric power generation, mercury-containing lamps, dental amalgam, waste disposal, and numerous other sources of exposure, including various products used by consumers such as paints, toys, cosmetics, natural health products, drinking water and pesticides.
  • The performance report concludes that these risk management measures have contributed to the overall objectives of protecting Canadians and their environment from mercury. Specifically:
    • Releases of mercury to air and water have declined by over 50% since 2007. Mercury levels in air and animals have declined or are stable in most areas in Canada, with the exception of some Arctic species where levels were found to be increasing.
    • Progress has also been made to reduce Canadians' exposure to mercury. Levels of mercury in the general Canadian population are low and stable. Levels have also been decreasing over time in Northern Inuit populations, although remain higher than those of the general population.
  • The Government of Canada also recognizes that the majority of mercury that is deposited in Canada is from human activities in other countries, and therefore continues to work with its international partners to mitigate this occurrence.

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