Mercury and compounds (as Hg), Hg
Mercury and compounds
At room temperature mercury is a silver coloured liquid. This description refers to mercury and mercury compounds.
In Sweden the use of mercury and mercury-containing products on the Swedish market has been banned since 2009.1 Some exceptions exist that are subject to EU regulations, such as low-energy light bulbs, batteries and vehicles. Time limited exceptions or exemptions from the Swedish ban may be issued, for example regarding measurement equipment, chemicals used for analysis and certain uses of amalgam.
Sources and transportation pathways
A large part of mercury emissions originates from combustion of fossil fuels (coal, oil, natural gas).2 Mercury also occurs naturally in the environment and is spread during volcanic eruptions or forest fires. Other emission sources are crematories, landfills and industrial emissions. Sludge from wastewater treatment plants also contribute to emissions. The main source of mercury in Sweden today is atmospheric deposition from long-range transport.3 Emissions from Swedish point sources to air and water are of a similar magnitude.
Since the 1990’s, mercury emissions have decreased substantially, both in Sweden and within the EU. The concentration of mercury in moss follow the decreasing emission trend in Europe.4 Despite mercury being phased out there are still traceable amounts in the ground, in water and in sediment. This is because mercury does not degrade in the environment. It binds very strongly in the ground, but some of the stored mercury reaches surrounding rivers and lakes by leaching.5 6 7 8 On its way some of the mercury may react to form methyl mercury that is easily absorbed by biota.
Effects on environment and health
Mercury is a very potent poison and pose a risk both to humans and the environment. In areas with elevated mercury levels, the microbial activity in the soil may be inhibited, and therefore the soil fertility.9 10 Mercury is spread through the food chain from plants to animals and is accumulated over time. Methyl mercury is biomagnified through the food chain and in species at the top of the food chain, the reproductive ability may be affected and behavioural disorders may arise.11
In Sweden, humans are primarily exposed to methyl mercury by eating fish. Humans are also exposed to mercury fumes from dental amalgam.12 Methyl mercury may harm the brain, the central nervous system and increase the risk of heart attacks. Foetuses and children are especially susceptible.13
International agreements and regulations
Mercury is regulated by the UN Convention on Long-range Transboundary Air Pollution (CLRTAP) and the Minamata Convention, as well as by the EU Air Quality Directive (2008/50/EC), the EU Water Framework Directive (2000/60/EC), the EU Groundwater Directive (2006/118/EC), the EU Drinking Water Directive (98/83/EC), the EU Sewage Sludge Directive (86/278/EEC) and the EU Regulation on setting maximum levels for certain contaminants in foodstuffs (EC 1881/2006). Limit values for mercury in drinking water is also regulated in the provision of the Swedish National Food Agency. 14 In addition, the presence of mercury in products is regulated in different EU directives and regulations, such as REACH. The UN Protocol on PRTRs and the EU E-PRTR regulation regulate how data on mercury emissions is made available.
1 http://www.kemi.se/hitta-direkt/lagar-och-regler/ytterligare-eu-regler/kvicksilver/mer-om-kvicksilver 2 http://www.kemi.se/hitta-direkt/lagar-och-regler/ytterligare-eu-regler/kvicksilver/mer-om-kvicksilver3 http://emep.int/publ/helcom/2016/Chapter5_mercury.pdf4 http://www.ivl.se/download/18.76c6e08e1573302315f20e/1474381195136/C204.pdf5 Ravichandran M. Interactions between mercury and dissolved organic matter—a review. Chemosphere. 2004;55:319–330.6 Skyllberg U. Bloom, P. R., Qian, J., Lin, C-M. och Bleam, W.F. 2006. Complexation of mercury (II) in soil organic matter: EXAFS evidence for linear two-coordination with reduced sulfur groups. Environmental Science & Technology, 40:4174–4180.7Hintelmann, H., Harris, R., Heyes, A., Hurley, J.P, Kelly, C.A, Krabbenhoft, D.P., Lindberg, S., Rudd, J.W.M., et al. Reactivity and mobility of new and old mercury deposition in a boreal forest ecosystem during the first year of the METAALICUS study. Environmental Science and Technology, 2002; 36:5034–5040.8Lee, Y.H., Bishop, K.H. och Munthe, J. 2000. Do concepts about catchment cycling of methylmercury and mercury in boreal catchments stand the test of time? Six years of atmospheric inputs and runoff export at Svartberget, northern Sweden. Science of the Total Environment, 260:11–19.9Bringmark, L. & Bringmark, E. 2001. Lowest effect levels of lead and mercury on decomposition of mor layer samples in a long-term experiment. Water Air Soil Pollution: Focus. 1: 425-437.10Bringmark, L. & Bringmark, E. 2001. Soil Respiration in relation to small-scale patterns of lead and mercury in mor layers of southern Swedish forest sites. Water Air Soil Pollution: Focus. 1: 395-408.11Driscoll, C. T., Han, Y-H., Chen, C. Y. Evers, D. C., Fallon Lambert, K., Holsen, T. M., Kamman, N. C. and Munson, R. K. Mercury Contamination in Forest and Freshwater Ecosystems in the Northeastern United States. BioScience, 57(1): 17-2812 http://ki.se/imm/kvicksilver13 Mergler, D., Anderson, H.A., Chan, L.H.M., Mahaffey, K.R., Murray, M., Sakamoto, M. and Stern, A.H. 2007. Methylmercury exposure and health effects in humans: a worldwide concern. Ambio 36, 3–11.14 https://www.livsmedelsverket.se/globalassets/om-oss/lagstiftning/dricksvatten---naturl-mineralv---kallv/slvfs-2001-30-kons-2015-3-webb.pdf