A metallic element mostly obtained by reduction from cinnabar, one of its ores. It is a heavy, opaque, glistening liquid (commonly called quicksilver), and is used in barometers, thermometers, etc. Specific gravity 13.6. Symbol Hg (Hydrargyrum). Atomic weight 199.8. Mercury has a molecule which consists of only one atom. It was named by the alchemists after the god Mercury, and designated by his symbol, *.
A heavy, toxic and volatile silvery conducting metal, which is liquid at room temperature. Associated by most people with thermometers and barometers, but also used as an industrial chemical in a range of processes (e.g. chlorine production). Much of the mercury in the environment stems from natural sources (e.g. volcanoes, glaciers, oceans and seas).
Mercury is a highly toxic element that is found both naturally and as an introduced contaminant in the environment. Although concentrations in water are very low, mercury accumulates through the aquatic food chain, resulting in high concentrations in fish that can threaten the health of people and wildlife. It is measured in units of nanograms per liter (ng/L) in water and milligrams per kilogram (mg/Kg) in fish. For more information, see About Mercury