Living organisms require varying amounts of heavy metals, for example, human body requires iron, cobalt, copper, manganese, molybdenum and zinc. Excessive levels can be damaging to the organism. Other heavy metals such as mercury, plutonium and lead are toxic metals and their accumulation overtime in the bodies of animals can cause serious illness. Certain elements that are normally toxic might be beneficial for certain organisms or under certain conditions, of these are vanadium, tungsten and even cadmium [21].