Emissions of Hexavalent Chromium and its Compounds to Air
Chromium is a naturally occurring metal that is present in small amounts throughout the environment. Chromium occurs at low concentrations in the atmosphere through natural processes (e.g. soil and rock erosion, forest fires, volcanoes). Through human activities, chromium is added to the environment, primarily in particulate form when emitted to air.
In Canada, hexavalent chromium Cr(VI) and its compounds[1] are released to the air as by-products of fossil fuel combustion (e.g. for electricity generation) and various industrial processes (e.g. aerospace products and parts manufacturing, pulp and paper mills).
Hexavalent chromium and its compounds are of interest because they are declared toxic substances[2] under CEPA 1999 and because Cr(VI) is a known carcinogen. Hexavalent chromium and its compounds are also directly subject to federal risk management actions (e.g. regulations for chromium electroplating, anodizing and reverse etching and pollution prevention plan for wood preservation facilities).
Emissions of Cr(VI) in 2010 were 1.0 t, or 15% lower than in 2009. This can be attributed to emission reductions in the aerospace products and parts manufacturing sector and the glass and glass products manufacturing sector.
Hexavalent chromium emissions to air, Canada, 2003 to 2010
Note: The indicator only includes emissions reported in the National Pollutant Release Inventory (NPRI). Emissions come from facilities that are required to report based on the NPRI reporting criteria for Cr(VI). As a result, the Cr(VI) emissions presented here represent only a portion of the atmospheric emissions of this toxic pollutant in Canada.
Source: Environment Canada (2012) National Pollutant Release Inventory Online Data Search.
Emissions of hexavalent chromium in Canada in 2010 were 63% lower than in 2003. Part of this reduction can be explained by a combination of changes in industrial production processes and the introduction of emission-control equipment and pollution-prevention activities in certain facilities.[3] The greatest emission reductions were found in the glass and glass products sector; the fibre, yarn and thread mills sector; the aerospace products and parts manufacturing sector; and the motor vehicle manufacturing sector.
Sources of hexavalent chromium emissions to air
In 2010, 48% (or 0.5 t) of the national emissions of hexavalent chromium Cr(VI) came from electricity generation, transmission and distribution. Emissions of Cr(VI) from pulp, paper and paperboard mills represented 19% (just under 0.2 t) of the national emissions, and steel product manufacturing from purchased steel released 9% (close to 0.1 t) of national emissions.
Hexavalent chromium emissions to air by source, Canada, 2010
Note: The hexavalent chromium emissions indicator includes only emissions reported in the National Pollutant Release Inventory (NPRI). Emissions come from facilities that are required to report based on the NPRI reporting criteria for Cr(VI). As a result, hexavalent chromium emissions presented here represent only a portion of the atmospheric emissions of this toxic pollutant in Canada. “Other Sources” represents a grouping of all other sources with hexavalent chromium emissions that are not individually displayed on this chart.
Source: Environment Canada (2012) National Pollutant Release Inventory Online Data Search.
Regional hexavalent chromium emissions to air
Alberta facilities emitted the highest proportion of hexavalent chromium in 2010, representing 53% (over 0.5 t) of national emissions, mainly from coal-fired electricity generation facilities. Ontario facilities contributed 24% (more than 0.2 t) of national emissions. The biggest source of Cr(VI) in Ontario was the steel products manufacturing from purchased steel sector. The emissions from the pulp, paper and paperboard mills were the most important source of Cr(VI) in British Columbia; this province was the third-highest source, with 14% (over 0.1 t) of national emissions.
Hexavalent chromium emissions to air by province and territory*, Canada, 2010
Note: The hexavalent chromium emissions indicator includes only emissions reported in the National Pollutant Release Inventory (NPRI). Emissions come from facilities that are required to report based on the NPRI reporting criteria for Cr(VI). As a result, the Cr(VI) emissions presented here represent only a portion of the atmospheric emissions of this toxic pollutant in Canada.
* Facility emissions of hexavalent chromium were not reported for the remaining provinces and the territories.
Source: Environment Canada (2012) National Pollutant Release Inventory Online Data Search.
Local hexavalent chromium emissions from facilities
Environment Canada’s National Pollutant Release Inventory (NPRI) provides detailed information on air emissions from industrial facilities. The Canadian Environmental Sustainability Indicators (CESI) provides access to this information through an online interactive map.
With the CESI interactive map, you can drill down to local areas and obtain details on hexavalent chromium emissions from individual industrial facilities.
Source: Environment Canada (2012) National Pollutant Release Inventory: Facility Data.
Related indicators
[1] Hexavalent chromium compounds are substances containing hexavalent chromium.
[2] 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.
[3] The use of new emissions estimation methods by submitting facilities also accounts for some of the decrease.
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