canadian mercury science assessment

Research into understanding ecosystem responses to emissions, both experimentally and through modelling, is discussed in this assessment. On the bottom graph, the lines decrease to a range of values from 1 to 1.5 mg/kg ww after 25 to 30 years, but are still above the shaded area and are still decreasing. The areas in Canada most vulnerable to the impact of climate change on mercury processes are the sub-Arctic and the Arctic. The Great Lakes region has shown both the largest and most numerous declines in mercury levels in individual populations (40% of fish and seabird populations reported). Spatial and temporal trends of mercury levels in biota are presented and are followed by an analysis of the biological effects of mercury and the ecological risk of mercury to select species. Dietary shifts in seabirds make the interpretation of trends more challenging. The largest unknown is the impact of climate change on the cycling and methylation of mercury. Atmospheric deposition is the main pathway for the introduction of mercury to watersheds, and thus air levels need to be understood to follow the pathways through the environmental compartments. Moving up and to the left of the small fish is a larger fish (another trophic level) containing higher mercury levels, as indicated by the dark orange arrow. This report is the third NCP assessment of mercury in the Canadian Arctic in the last two decades and the first to focus exclusively on mercury. While measured levels of mercury have decreased since 1995 across Canada, the decreases are not the same in all regions. In the air, mercury levels across Canada have declined as emissions have decreased, although this recovery varies among regions. Labrador consists of green and some yellow and teal dots. Inputs of methylmercury from upland terrestrial catchments and the atmosphere are less important. Global and US emissions are larger than Canadian emissions, which make distinguishing between domestic and foreign impacts a challenge. At the ELA, aquatic systems responded to decreases in mercury deposition by a decline in mercury levels over a long time scale. 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. The left-hand side of the figure depicts biomagnification as a successive increase of mercury concentrations within the food chain (i.e., trophic levels). The vertical bars on the graph represent the concentration of mercury found in the fish (in microgram per gram, wet weight) and are arranged by province/territory from west to east. Moreover, studies in the Nunavik region of northern Québec have also shown a downward trend for mercury levels in mothers from 1992 to 2007. Anthropogenic and terrestrial emissions from sources in Europe and South Asia contribute equally to deposition across Canada. You will not receive a reply. These human factors may alter not only the bioavailability of recently released anthropogenic mercury but also that of natural mercury already present in the environment, which would otherwise be unreactive if left undisturbed. Various arrows are shown on the image indicating biogeochemical processes of mercury with adjacent numbers indicating the corresponding chapter. The “best case scenario” of global emission reductions, using all of the best technologies of today would result in a 20% -50% reduction in mercury deposited to ecosystems and up to 30% lower levels mercury in fish after 150 years when compared with a scenario of no new emission reductions. Environment Canada and Health Canada, Ottawa. The provisions within the Convention address all aspects of the mercury lifecycle, and of particular interest to Canada, aims to control and reduce atmospheric emissions of mercury from listed industrial sources. Smaller lakes are more impacted than larger lakes by soil disturbance resulting from logging activities. a moose, goose, loon, fish, hiker and fisherman near the land/wetland area. 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). Site 2 is a smaller region that encompasses Flin Flon and crosses the Saskatchewan-Manitoba border. Canadian emissions in 2010 were 5 300 kg to air and 240 kg to water. 90% capture rate of emissions from coal-fired facilities or 50% emission reduction for all sectors. Predatory fish and wildlife at the top of freshwater and marine food webs generally have the highest mercury concentrations due to biomagnification. The numbers correspond to chapters in the full science assessment and indicate where that particular aspect of the cycle is discussed. The Maritimes show no trends in the seabird and fish concentrations except in Newfoundland, where the seabirds show an increasing trend. Despite the decrease in domestic anthropogenic emissions of mercury, the concentrations of mercury in air and biota have not declined accordingly. Ecosystems closer to major domestic sources are more likely to show reductions in fish mercury levels in response to the reductions in domestic mercury emissions because of the greater influence of these emissions on deposition in these ecosystems. Comprehensive studies such as the Great Lakes Basin Mercury Assessment and the Canadian Arctic Contaminants Assessment Report are excellent tools to assess overall ecosystem recovery that can be used to improve integrated models including air, earth, and water, as well as biology, geology, and chemistry. However, more recently, studies show that some of these decreases are reversing in some species. It is difficult to estimate any changes in releases of mercury from products and from changes in recycling, since regulations governing disposal of products have not yet been enforced and there is uncertainty associated with the current information (up to 50% for legacy emissions). If so, what are the indicators of recovery, where is it occurring, and how quickly are ecosystems responding? LaGrande 3 - solid grey line with hollow inverse triangles. Human vulnerability to the presence of mercury in Canadian aquatic systems is a real concern. The largest changes in temperature are expected in northern Canada, where precipitation and moisture levels are expected to generally increase. Although Canadian, North American, and European anthropogenic emissions have declined in the past decades, recent inventories (2010) suggest that global emissions remained the same or were slightly higher than in 2005, reflecting greater emissions abroad, particularly from Asia. Greater decreases are found in regions that have experienced large decreases in anthropogenic emissions such as urban areas, Flin Flon, Manitoba, and the Great Lakes region. It drops to 0.21 mg g-1 wet muscle by 2030 and stays relatively constant to 2156. In terrestrial and aquatic biota in Canada, the highest levels of mercury are reported in southeastern Canada and in some locations in the western and high Arctic. I would like to thank those national and international mercury experts who have reviewed each chapter and provided sound advice to ensure the accuracy and validity of the information presented herein. The developing nervous system is considered to be the most susceptible to the adverse health effects of methylmercury; thus, developing fetuses, infants, and young children are at a higher risk of developing adverse health effects. Important scientific advances have been made in identifying the environmental fate of mercury and the processes that control its movement in the Canadian Arctic. A map of all atmospheric mercury measurements that have been collected in Canada over various time periods between 1995 and 2014 is shown in Figure 13b. The Canadian Mercury Science Assessment is the first comprehensive scientific evaluation and synthesis of mercury (Hg) in the Canadian environment. In addition, mercury levels in species such as piscivorous fish, seabirds, and marine mammals can also be used as indicators of ecosystem recovery. Flin Flon was not included in this result. While local mercury levels in the air near the smelter have declined 20% since the closure, they still remain approximately twice as high as those at any other monitoring site in Canada. However, emissions reductions do not lower mercury levels in the Canadian environment following a linear relationship. The resulting acidic deposition from these other emissions enhances methylation of mercury and may mask (or hide) the impact of mercury emission reduction efforts. For fish not directly impacted by nearby anthropogenic inputs, the estimated rate of change in mercury levels in fish, including standard-length lake trout, walleye, and northern pike, vary considerably, ranging between -1.5 and +1.5% yr-1. non-living) systems to identify areas at risk due to mercury exposure. and Branfireun, B.A. The horizontal grey shaded area represents the range of estimated lowest observed adverse effect level for fish toxicity, which ranges from 0.5 to 1.0 microgram per gram of mercury in fish. While the models showed that emissions controls are beneficial compared with no action, even the best case mercury emissions controls would not lower fish mercury concentrations in all watersheds below current levels. 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. While Canadian emissions are predicted to decrease, global emissions are predicted to increase. Some groups, such as Aboriginal peoples, sport fishers, and Asian Canadians, may be more likely to be exposed to methylmercury in higher concentrations than the general Canadian population because of a diet high in fish and seafood. The blue circles represent the amount of mercury emitted for each year. Other environmental changes, such as land use, climate, other air pollutant emissions and environmental chemistry or biology, can alter the biogeochemical transformations of mercury in the ecosystems and, therefore, influence mercury levels in Canadian ecosystems. Specific animal species are not identified in this figure. Sources, acidification, and aquatic processes dominant form in the fish in terms of risk, in particular fish! Unrefereed '' mercury use in School Classrooms: Summary and assessment Programme/UNEO Chemicals Branch, Oslo/Geneva, p..! 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