<unk><unk>  poisoning is the toxic accumulation of<unk><unk> s in the soft tissues of the body.<unk><unk> s are chemical elements that have a specific gravity (a measure of density) at least five times that of water. The<unk><unk> s most often implicated in accidental human poisoning are lead, mercury, arsenic, and cadmium. More recently, thallium has gained some attention in the media as the poison used in several murder cases in the 1990s. Some<unk><unk> s, such as zinc, copper, chromium, iron, and manganese, are required by the body in small amounts, but these same elements can be toxic in larger quantities.
Heavy metal ingestion
Zinc deficiency
Lead poisoning
Mercury poisoning
Copper deficiency
Manganese deficiency 
Chromium deficiency
Gold poisoning