Heavy metals in general have no basic function in the body and can be highly toxic. High- concentration exposure is not necessary in order to produce a state of toxicity in the body. Most cases of heavy metal poisoning result from chronic low level exposure to these hazardous environmental toxins. In the last 50 years, human exposure to heavy metals has risen dramatically. This is the result of an exponential increase in the use of heavy metals in industrial processes and products. Today chronic exposure comes from toxic waste dump and burn sites, agriculture, chemical products, mercury amalgam dental fillings, lead-based paint, tap water, and chemical residues in processed foods. Personal care products, such as cosmetics, mouthwash, toothpaste, soap, shampoo, and other hair care goods, are also sources of contamination. In addition to the hazards at home and outdoors, many occupations are subjected to daily heavy metal exposure. More than 50 professions are exposed to mercury on a daily basis. These include physicians, pharmaceutical workers, dentists, dental workers, laboratory workers, hairdressers, painters, printers, welders, metalworkers, cosmetic workers, battery makers, engravers, photographers, visual artists and potters.