Mercury is released anthropogenically to the environment through processes such as coal burning, metals smelting, gold and silver mining, and chlor-alkali production using mercury or mercury compounds. Figure 10: Change in mercury levels in eggs of 3 seabird species from Prince Leopold Island, Nunavut (left: concentration mg g-1 (dry weight)), and in seabird eggs from the Gulf of St. Lawrence (right: concentration mg g-1 (wet weight)). Chapter 6 – Marine Environment. Site 2 is a smaller region that encompasses Flin Flon and crosses the Saskatchewan-Manitoba border. The overall picture shows (from left to right) the natural environment with sunlight, clouds, rain, sea ice, ocean, mountains, sky, rivers, land, wetlands, forests and forest fires. As a result, over their lifetime, they have much higher mercury levels in their system than their prey (biomagnification). Land vegetation (terrestrial) systems receive mercury from the air and export a portion to rivers and lakes. Wet deposition of mercury is a good indicator of changes in the mercury load from the atmosphere to the environment. As an example, the relative size of emission source contributions from 9 continental regions to deposition in 4 selected sub-regions in Canada is shown in Figure 8. (2014) Antecedent moisture conditions control mercury and dissolved organic carbon concentration dynamics during summer storms in a boreal headwater catchment. The top graph shows the mercury levels in lake whitefish and the bottom, mercury levels in northern pike from the four reservoirs. Which activities are having the most significant impact on mercury levels in fish in Canada? The bottom graph, labelled Northern Pike (700 mm), has a range of 0 to 5 mg/kg ww. Figure 4: Map of freshwater locations within Canada showing mercury risks to piscivorous fish. Continued and, in some cases, enhanced monitoring of mercury levels in key environmental compartments will be required to evaluate the contribution of domestic versus global sources of mercury emissions to the Canadian mercury burden and to assess the risk to biota and humans from mercury. Currently, Environment Canada operates 5 wet-deposition monitoring sites: Stephenville, Kejimkujik, Chapais, Egbert, and Saturna (see Figure 13a). The integrated model was applied to 5 lake ecosystems in different regions of Canada. In Canada, methylmercury remains a public health issue for populations who consume significant amounts of predatory fish and certain traditional wildlife food items (country food). For enquiries, contact us. No overall consistent trends were seen, geographically or by trophic position. The model predicted that, in the absence of additional emissions controls above current levels, in the future fish mercury concentrations will rise above current levels in all the lakes modelled. There are aquatic environments in Canada where average mercury levels in biota are high enough to be of concern. This chapter presents the current knowledge of changes over time in mercury concentrations in biota in Canada. Due to the depth of international and Canadian data and analysis on mercury and its compounds presented in the UNEP global assessment and the well-documented hazardous effects and exposure pathways of mercury and mercury compounds, it was decided that a separate Canadian assessment of mercury compounds was not necessary. Thus, this indicator species shows some signs of the recovery of this ecosystem over the past 10 years. However, for the most part, other marine mammal populations studied showed no signs of changes in mercury. In the Great Lakes region declines are reported to range from 10 to 21% and are likely as a result of reductions in North American emissions. Other populations that have shown decreasing or generally stable trends in mercury concentrations in the past have exhibited an increasing trend in recent years (such as porcupine caribou, lake trout from 2 lakes in Yukon, sea-run char from Cambridge Bay and Nain, beluga whales from Hudson Bay and the western Arctic, ringed seals from Arviat, and mussels from the Gulf of St. Lawrence). Changes in temperature are expected to accelerate in the future, and precipitation and moisture levels are expected to increase. Mercury deposited from the air remains in vegetation until it enters upland and wetland soil pools, where it may be stored for long periods of time or methylated and transported downstream. The solid lines represent the levels of mercury predicted in these two lakes when the “best case scenario” for emissions controls is applied to the model starting in 2007. For wildlife, top predators, particularly those associated with aquatic food chains, are at greatest risk from high dietary exposure to mercury because they accumulate mercury from their prey, which can lead to high levels over their lifetimes (biomagnification). In 2010, overall Canadian emissions of mercury were reported to have decreased by 85% in air and by about 50% in water since 1990. It provides an in-depth knowledge baseline against which future changes in mercury levels in the environment can be attributed to changes in mercury emissions and climate. Geographic areas with bedrock and soils with poor buffering capacity (ability to neutralize additions of acid) or with high levels of acidic deposition from air pollution tend to have more acidic lakes and rivers and higher methylmercury concentrations in aquatic food webs. Thanks to our wonderful copy editors, Carolyn Brown and Sheila Bourque, who made everything sound so much better! Mercury goes through a complex cycle in the ecosystem from emission to accumulation in biota. Contributions from each source region are divided into contributions from “anthropogenic” sources (shown as dark colours) and “other terrestrial” (including both natural and re-emission) sources (shown as light colours). The dashed red, green and blue coloured lines branch off from the solid lines from 2007 onwards. In recent decades, inventories have reported a decline in mercury emissions domestically and, until most recently, globally, but not in all geographical regions. Site 1 is a large region in west-central Alberta, stretching from the BC border to east of Edmonton, and (in the north-south direction) from north of Calgary to north of Edmonton. The Canadian Mercury Science Assessment is a comprehensive, peer-reviewed synthesis of the state of scientific knowledge on mercury in Canada that includes information from the NCP report, covering Canada south and north of the Arctic Circle. Anthropogenic and terrestrial emissions from sources in Europe and South Asia contribute equally to deposition across Canada. Based on results from Environment Canada’s Global/Regional Atmospheric Heavy Metals (GRAHM) model, an estimated 95% of the anthropogenic mercury deposited in Canada comes from sources outside of the country. In humans, consumption of contaminated fish is the primary source of methylmercury exposure. Solid lines are linear trends. Using modelling, it is estimated that 40% of the deposition in Canada comes from worldwide anthropogenic emissions and 60% from other terrestrial and oceanic emissions (including geogenic emissions/re-emissions of previously deposited mercury). While many of the direct emissions have decreased, revolatilization of historically deposited mercury can contribute to the continued elevated levels of mercury in the air. Concentrations of methylmercury in fish populations within reservoirs often exceed consumption guidelines, and human exposure to this contaminant through fishing has caused concern in Canada, especially in northern communities. Part of the reason for this discrepancy is that only a portion of the mercury measured in Canada is a result of Canadian emissions. Methylmercury is a potent neurotoxin that can accumulate in the tissues of living organisms (bioaccumulation) and be magnified as organisms higher in the food chain consume mercury-containing prey (biomagnification), posing exposure risks to human consumers and the health of the organisms themselves. Examines the feasibility of the available non-mercury alternatives for mercury and mercury-added products that are commonly used in K-12 classrooms. Figure 8: Relative contributions from emissions from individual source regions to net mercury deposition for the Canadian Arctic, British Columbia, Ontario and New Brunswick, Nova Scotia and Prince Edward Island combined for the year 2005 (as estimated by the Global/Regional Atmospheric Heavy Metals model). Chapter 10: “Mercury in Terrestrial and Aquatic Biota Across Canada: Geographic Variation” and Chapter 11: “Mercury in Terrestrial and Aquatic Biota Across Canada: Temporal Variation” are both shown on the land surface. Each form of mercury has different chemical properties that govern how soluble, reactive, and toxic the mercury is. Canadian Mercury Science Assessment – Summary of Key Results Environmental cycling of mercury is complex and involves many different processes and pathways. Monitoring mercury in biota in Canada should reflect the following overall objectives: (1) monitoring the species that are most likely to show adverse health effects due to mercury exposure; (2) monitoring mercury in species that would reflect changes in atmospheric mercury deposition, and (3) monitoring mercury trends that are important in consumption and exposure. Despite the decrease in domestic anthropogenic emissions of mercury, the concentrations of mercury in air and biota have not declined accordingly. Alberta’s levels have remained the same while Saskatchewan’s levels have increased as a result of a doubling of emissions from coal-fired electricity generation and some small increases in the upstream and downstream petroleum sectors. Interestingly, at a site close to a power plant in Genesee, Alberta there have been neither declining nor increasing trends reported in mercury levels over 7 years. It is the only metal that is liquid at room temperature; it is predominantly found in the Earth’s crust in the form of cinnabar (mercuric sulphide). Central Quebec shows either no trend or increasing trends in the fish mercury levels and no trend in the seabirds. Is mercury a risk to ecosystem and human health in Canada? It is also emitted from incinerators and areas flooded by dams, and through the production, breakage, and disposal of products containing mercury. The model predicts that, without additional emissions controls, fish mercury levels will rise above current levels in all lakes investigated. The “best case scenario”Note de bas de page11 of worldwide controls on anthropogenic emissions resulted in predicted reductions in mercury deposition of 20%-50% among modelled ecosystems. The second species from the bottom is a small sea animal, representing one higher trophic level in the system and higher levels of mercury, as indicated by the orange arrow. Yellow represents low mercury levels, and as the colour changes from orange to brown, the mercury levels in the fish get progressively higher. Model scenarios involving reductions in Canadian anthropogenic emissionsNote de bas de page12 resulted in minimal (1%) reduction in atmospheric deposition (mercury deposited from the air) in remote ecosystems, but up to 70% reductions for ecosystems close to major Canadian mercury emission sources. The main processes that mercury undergoes in the ecosystem. Mercury and its compounds are identified as a toxic substance under the Canadian Environmental Protection Act, 1999. From a long-range transport perspective, what are the major emission source regions contributing to Canada’s mercury burden? These studies also show that emission reductions from foreign sources will further reduce mercury levels in biota in Canada. At each step up in the food chain, predators accumulate mercury from their prey. The intent of the program was to determine key indicators of environmental quality and risk to human health relevant to atmospheric emissions of mercury. Previous reports have stated a decrease of 90% since the 1970s (a longer time period than that reported here). UNEP, AMAP, 2013. Mercury levels in stream and lake sediments vary across Canada by region and from one location to another. Several species of marine mammals, such as beluga whales, ringed seal, and polar bear, have higher mercury levels in the western and high Arctic (such as the Beaufort Sea) than in the eastern and southern Arctic. Over the 40 years in Canada, mercury levels in wildlife and fish have shown increasing, stable, or decreasing trends, with variation among monitored species and regions (Figure 9). The lines in the top graph decrease to 0.15 to 0.2 mg/kg ww by the 25- or 30-year point, all ending within the shaded region. More acidic (lower pH) aquatic conditions generally lead to higher methylmercury levels in biota. The lower map shows all sites active from 1995 to 2014 and further identifies precipitation and TGM sites run by the Canadian Air and Precipitation Monitoring Network (CAPMoN), which uses the yellow and orange colours from the upper map, speciation sites operated under CARA (green) and other sites, which are shown as pink for precipitation, purple for TGM and brown for speciation. This assessment reflects the research undertaken in Canada within the past 20 years related to the following: There are several overarching gaps identified in this science assessment, including gaps in knowledge of the impacts of climate change on the mercury cycle, in capabilities to predict future mercury levels, in knowledge of the impacts of mercury on the Arctic ecosystem and its vulnerability to mercury as well as on human health, and in information on mercury levels in the environment at sites across the country. The two graphs are shown with y (vertical) axes labelled “THg (mg/kg ww)” which describes the concentration of total mercury (THg) in milligrams per kilogram of wet weight of the fish. The main land-use changes that affect mercury dynamics are logging activities and reservoirNote de bas de page6impoundments. Current predictive capabilities are limited by a lack of understanding of regional differences in the biogeochemistry of ecosystems and of emission sources other than those currently reported. However, in areas close to point sources (such as coal-burning power plants and metal smelters) of mercury emissions, the local contribution of domestic emissions to mercury deposition can be much higher. This analysis is particularly relevant in the context of recent changes to Health Canada’s blood Hg guidance values. Water Resources Research DOI: 10.1002/2013WR014736 The study examining which mercury species could be responsible for the Minamata poisoning was published Feb. 12th in the journal Environmental Science & Technology. In Canada, methylmercury remains a potential public health issue for populations who rely on the consumption of large predatory fish and traditional wildlife items. The last mercury cell chlor-alkali plant in Canada closed in 2008. In 2012, NCP published Canadian Arctic Contaminants Report III: Mercury in Canada’s North to provide a comprehensive evaluation of the environmental fate of mercury in the Canadian Arctic. The left pie chart shows the industrial sector contribution to air in Canada in 2010. Fish mercury levels are generally higher in eastern Canada than in central and western Canada; and Ontario, Quebec, and Nova Scotia have relatively high proportions of lakes where mean mercury concentrations in lake trout, northern pike, and walleye exceed an estimated lowest amount of mercury that causes an adverse effectNote de bas de page7on these fish.Note de bas de page8For example, Figure 6 shows the mercury levels in lake trout sampled from numerous lakes across Canada. Over 90% of the fish advisories in Canada are due to mercury, and many fish and fish-eating birds and mammals are at risk from mercury exposure. Risk Management Strategy for Mercury. The Canadian Mercury Science Assessment is the first comprehensive scientific evaluation and synthesis of mercury (Hg) in the Canadian environment. Northern Quebec shows increasing trends in the fish mercury levels on the northeastern coast and decreasing trends in northern inland fish. 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