Mercury is a naturally occurring metal that is liquid at room temperature. This heavy metal is toxic to humans. It is silver in color, and its high surface tension causes it to form into round drops on surfaces. Mercury is more volatile than any other metal and forms a colorless, odorless gas.
Mercury is very dense, weighing 13.5 times a similar volume of water. It forms amalgams with other common metals, with the exception of iron.
The primary source of mercury is the mineral cinnabar. Refiners heat the mineral in a stream of hot air and condense the vapor. As of 2014, the toxicity of mercury has eliminated many of its former uses, although it was once common in switches, lighting and thermometers. Mercury amalgams formed many dental fillings, and mercury compounds served as pesticides on seed corn.
Mercury is a cumulative toxin. It is absorbed through the skin, digestive system and respiratory system. Because it is an element, it does not break down in the human body. Mercury poisoning damages brain function and disrupts the nervous system. It results in damage to the DNA and chromosomes, leading to birth defects and miscarriages. It accumulates in some mushrooms and fish, affecting other organisms within their food chains.