PerspectiveEnvironmental Science

Cracking the Mercury Methylation Code

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Science  15 Mar 2013:
Vol. 339, Issue 6125, pp. 1280-1281
DOI: 10.1126/science.1235591

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Summary

Mercury (Hg) is a global pollutant that is transported over long distances. Although it occurs naturally, its concentration in the biosphere has increased dramatically over the past 200 years as a result of industrial activities. Mercury enters the environment in its inorganic form, but its bioaccumulation in organisms, biomagnification in food webs, and toxicity to humans depend on microbial methylmercury (MeHg) synthesis (see the figure). The use of stable isotopes of mercury has improved scientists' ability to trace and measure mercury in the environment (1, 2), but methods to predict methylmercury synthesis in the environment remain scarce. On page 1332 of this issue, Parks et al. (3) identify two genes required for mercury methylation. This discovery will be helpful for developing tools to study the synthesis and accumulation of methylmercury and to improve the management of contaminated environments.