Heavy-metal refers to a metallic chemical element that has a high density and relatively high atomic mass and is toxic or poisonous. Some examples of heavy metals are mercury, cadmium, chromium, copper, iron, nickel, selenium and lead. These elements can damage living things at low concentrations and tend to accumulate in the food chain.
In nature the lowest elements on the food chain is plant life. Specific types of animals are herbivores and eat only plants. These animals can have a build up of heavy-metal in their system, deposited in their muscle mass, from absorption from plants. When these animals are slaughtered and used for food the heavy metal in their system is absorbed by the end user, us.
Doctors have determined that the human body often contains microscopic heavy-metal from environmental toxins and our food sources. Another source of is from the amalgam fillings made for dental appliances. In 1989 the Environmental Protection Agency stated that the use metal fillings were hazardous substances under the Superfund law. When outside of the mouth they must be stored in unbreakable, tightly sealed containers, they are not to be touched and have specific storage requirements. Outside of the mouth they are toxic but when placed in the teeth they are labeled “non-toxic”.