Heavy Metals:Heavy metals are chemical elements with a high density and a relatively high atomic number. The term “heavy metal” is used in several different ways, depending on the context. In chemistry, a heavy metal is an element that has a high density and is toxic at low concentrations. In geology, a heavy metal is an element with a high atomic number that is resistant to corrosion and wear. In biology, a heavy metal is an element that interferes with the normal function of enzymes or other proteins.