In Canada, the largest anthropogenic source of mercury until the 1980s was the chloralkali industry. Although mercury is still employed in this industry to manufacture chlorine and sodium hydroxide, emissions have now declined due to antipollution measures, conversion to non-mercury processes and plant closures. In the 1970s, Canada reported 15 chlor-alkali plants in operation; however, only one Canadian facility remains in operation in New Brunswick.
Between 1990 and 1995, Canadian anthropogenic mercury emissions dropped from approximately 35 to 11 tonnes primarily as a result of process improvements in the base metal mining and smelting industry. In 1995, this industry was the largest source of mercury into the atmosphere, contributing approximately 40% of total emissions. From 1995 to 2003, Canadian anthropogenic mercury emissions dropped to a total of just under 7 tonnes. Three sectors, electricity generation, non-ferrous mining & smelting and incineration were responsible for 71% of mercury emissions into the atmosphere, accounting for 35%, 19% and 17% of Canadian emissions respectively.
The pie chart below illustrates Canadian atmospheric mercury emissions from various sectors for the year 2003. The "Miscellaneous" category includes emissions from sources like residential and commercial fuel combustion, the asphalt paving industry, crematoria, the chemicals industry and landfill sites. For a more detailed inventory of mercury emissions, search Environment Canada's National Pollutant Release Inventory which is a database of information on annual releases to air, water, land and disposal or recycling from all sectors.
Pie chart of canadian atmospheric emissions in 2003. The emissions sources are: electricity generation with 34%, incineration with 20%, non-ferrous mining and smelting with 19%, cement and concrete industry with 6%, iron and steel industries with 6%, other industrial sources with 11% and miscellaneous with 4%, for a total of 6949 kg of mercury.
Environment Canada and other federal Departments have responded to the need for mercury management by developing many diverse policy and program initiatives. Canada is also a signatory to several international and continental agreements that contain commitments to reduce anthropogenic emissions of mercury. A comprehensive list of Canadian mercury management tools can be found on this site. Canada's commitment to the continuing reduction of atmospheric mercury emissions is borne out by the fact that domestic emissions were reduced by around 90% between 1970 and 2003.
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