. Human Health and Potential Mercury Releases from Thawing Permafrost

Abstract
Permafrost regions have the largest stores of mercury (Hg) on the planet, with an estimated 1656±962 Gg Hg in the top three meters of soil, half of which occurs in permafrost bound to frozen plant organic matter. If permafrost thaws, microbial decay of the organic matter will release Hg back into the environment. We use a model to estimate the potential release of Hg from northern hemisphere permafrost for different scenarios of future warming. We compare simulated Hg concentrations in the Yukon River to maximum allowed limits from the Environmental Protection Agency (EPA). We estimate Hg concentrations in fish in the Yukon River and compare them to maximum safe levels from the EPA and World Health Organization. The results indicate high risks to human health and food supply in the Arctic in the 21st century.