Mercury Cycle

The mercury cycle is the biogeochemical cycle, driven by both natural processes and human activity, by which mercury moves through and changes chemical form across the Earth crust, its surface reservoirs, and its atmosphere. Mercury occurs in elemental, inorganic, and organic forms and in three oxidation states, 0 (elemental), I (mercurous) and II (mercuric). It reaches the atmosphere from two kinds of sources: primary sources that release mercury newly out of the lithosphere, and secondary sources that re-emit mercury already cycling among surface reservoirs; together these sources put more than five thousand metric tons of mercury into the atmosphere every year. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/