recent years, there has been increasing recognition that methylmercury affects fish and wildlife health, both in acutely polluted ecosystems and ecosystems with modest methylmercury levels. Two reviews document numerous studies of diminished reproductive success of fish, fish-eating birds, and mammals due to methylmercury contamination in aquatic ecosystems. In public policy Reported methylmercury levels in fish, along with fish consumption advisories, have the potential to disrupt people's eating habits, fishing traditions, and the livelihoods of the people involved in the capture, distribution, and preparation of fish as a foodstuff for humans. Furthermore, proposed limits on mercury emissions have the potential to add costly pollution controls on coal-fired utility boilers. Nevertheless, substantial benefits can be achieved globally by introducing mercury emission reduction measures because they reduce human and wildlife exposure to methyl mercury. About 30% of the distributed mercury depositional input is from current anthropogenic sources, and 70% is from natural sources. The natural sources category includes re-emission of mercury previously deposited from anthropogenic sources. According to one study, based on modeled concentrations, pre-Anthropocene tissue-bound levels in fish may not have differed markedly from current levels. However, based on a comprehensive set of global measurements, the ocean contains about 60,000 to 80,000 tons of mercury from pollution, and mercury levels in the upper ocean have tripled since the beginning of the industrial revolution. Higher mercury levels in shallower ocean waters could increase the amount of the toxicant accumulating in food fish, exposing people to a greater risk of mercury poisoning. See also Canadian Reference Materials include some with methylmercury, e.g. DORM Dimethylmercury, mercury with a second methyl group Ethylmercury, a related cation Mercury poisoning Mercury regulation in the United States References External links ATSDR - ToxFAQs: Mercury ATSDR - Public Health Statement: Mercury ATSDR - ALERT! Patterns of Metallic Mercury Exposure, 6/26/97 ATSDR - MMG: Mercury ATSDR - Toxicological Profile: Mercury National Pollutant Inventory - Mercury and compounds Fact Sheet Methylmercury-in-fish exposure calculator provided by GotMercury.Org, which uses FDA mercury data with the EPA's calculated safe exposure levels. Methylmercury Contamination in Fish and Shellfish nytimes.com, Tuna Fish Stories: The Candidates Spin the Sushi U.S. Environmental Protection Agency's mercury site U.S. Geological Survey's mercury site Environment Canada's mercury site Health Canada's mercury site International Conference on Mercury as a Global Pollutant 2006-Madison, WI USA 2009-Guizhou, China 2011-Halifax, NS Canada Organomercury compounds Toxins Functional groups Methyl complexes Mercury(II) compounds