Figure 1 is an image to explain the mercury cycle. The image includes the following symbols: volcanoes, smoke stack, land, water, tree, bird, fish, etc. These symbols are connected using arrows, to represent directions of emission, transportation, deposition, oxidation, photodegradation, evasion, bioaccumulation, etc. The essence of the mercury cycle is the evaporation of inorganic mercury from both natural and man-made sources into the atmosphere where it is then oxidized in the upper atmosphere and returned back to earth, most commonly in precipitation, in its inorganic mercury form. Figure 1 shows the following steps to the mercury cycle:
Figure 2: The four types of mercury emissions
Figure 2 is an image to illustrate four types of mercury emissions. This Figure shows mercury emissions in a circle, which is divided into four portions with a landscape image in the middle representing ecosystems. There are pictures in each portion, such as volcanoes, stack emissions, light bulb, and forest fire. There are arrows to connect one portion to the ecosystems or to another portion. There are also arrows within the same portion. The four portions represent the following four types of mercury emissions:
Figure 3: Estimated global anthropogenic emissions of mercury, 2005
Figure 3 is a pie chart to illustrate estimated global anthropogenic emissions of mercury in 2005. Figure 3 shows that total global anthropogenic emissions of mercury in 2005 was approximately 2,000 tonnes, with Canada represents less than 1% of global emissions and China represents approximately 45% of global emissions. Other countries and their representations in global emission include: India (9%), Europe without Russia (9%), South America (7%), Australia and Oceania (7%), Western Asia, Japan and Koreas (7%), USA (6%), Africa (5%), Russia (4%), and Mexico (< 1%).
Figure 4: Estimated anthropogenic mercury deposition in Canada, 2006
Figure 4 is a pie chart to illustrate estimated anthropogenic mercury deposition in Canada in 2006. Figure 4 shows that total anthropogenic mercury deposition in Canada in 2006 was approximately 65 tonnes. Domestic deposition represents approximately 4% while foreign sources account for over 95% of mercury deposition in Canada, with China identified as the largest source at approximately 42%, followed by the United States at approximately 17%. Other countries and their representations in Canadian mercury deposition include: Europe without Russia (8%), Western Asia, Japan and Koreas (7%), India (5%), South America (5%), Australia and Oceania (5%), Russia (4%), Africa (3%), and Mexico (< 1%).
Figure 5: Comparison of Canadian anthropogenic atmospheric mercury emissions profile for 1970 and 2007
There are two pie charts in Figure 5 to compare Canadian anthropogenic atmospheric mercury emissions profile for 1970 and 2007.
The pie chart in the left shows that Canadian atmospheric mercury emission in 1970 was approximately 80 tonnes. Domestic sources and their representations in total Canadian emissions are: mercury cell chlor-alkali (32%), other fossil fuel combustion (24%), non-ferrous smelting and refining (11%), other miscellaneous sources (10%), coal combustion (9%), incineration (6%), wood combustion (4%), pesticides & fungicides (2%), and mercury production (2%).
The pie chart in the right shows that Canadian atmospheric mercury emission in 2007 was approximately 7 tonnes. Domestic sources and their representations in total Canadian emissions are: electric power generation (30%), mercury-containing products (27%), non-ferrous smelting and refining (20%), miscellaneous industrial sources (10%), iron and steel industries (9%), and cement manufacture (4%).
Figure 6: Spatial distribution of Canadian anthropogenic atmospheric mercury emissions, 2007
Figure 6 is a map of Canada to show spatial distribution of Canadian anthropogenic atmospheric mercury emissions in 2007. Figure 6 displays the spatial distribution of mercury emissions across Canada by 10 km grid using highlights of different colours, which represents different concentrations of deposition. There are also four inserts in the Figure. Three of them show enlarged maps of lower mainland BC, Prairies and Windsor Quebec Corridor, where concentrations of mercury deposition are found to be higher than the rest of Canada. The other one shows different concentration levels with different colours.
Figure 7: Canadian mercury emissions trend from 1970 to 2007
Figure 7 is a line chart to illustrate Canadian mercury emissions trend from 1970 to 2007. Figure 7 shows that mercury emissions have been reduced by approximately 90% from 1970 to 2007. This Figure also depicts a wide range of regulatory and non-regulatory initiatives implemented by the Government of Canada over the past several decades. These initiatives are represented in the Figure as letters A to N. There is a section under the Figure to list the years and the titles of these initiatives. There is also a text box in the Figure to explain that mercury emissions from mercury-containing products were added to the NPRI Inventory in 2007.