Anthropogenic mercury loading

Mercury is a relatively rare chemical element. In the lithosphere it occurs mainly as sulfides, HgS. Mercury sulfide comes in two forms cinnibar, which is black, and vermillion. In some places mercury exists in a small proportion as free chemical species. 

Mercury refining involves heating the metal sulfide in air in accordance with the following reaction  

Gaseous mercury is condensed in a water-cooled condenser and redistilled for sale. 

At present industrial mercury uses are connected with electric batteries, electric tungsten bulb, pulp bleaching and agrochemical production. 

Mercury batteries are used widely in everyday life, in applications such as cameras and hearing aids. About 30% of U.S. production of mercury is used in this way, the reason being the constancy of the voltage in the mercury battery, almost to the point of complete discharge. 

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Mercury emission from electric utilities is the largest uncontrolled source of mercury release into the atmosphere, and globally it accounts for up to 59% of the total annual atmospheric loading of mercury from both natural and anthropogenic sources. Coal-fired power plants are now considered the greatest source of environmental mercury in the U.S., and the only significant source that continues... 

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