From wiki…
Living organisms require trace amounts of some heavy metals, including iron, cobalt, copper, manganese, molybdenum, vanadium, strontium, and zinc, but excessive levels can be detrimental to the organism. Other heavy metals such as mercury, lead and cadmium (with one exception for the latter) have no known vital or beneficial effect on organisms,

Thorium and uranium are more often referred to as “radioactive metals”

Link: http://en.wikipedia.org/wiki/Heavy_metals

Graph showing relative abundance (atom fraction) of the chemical elements in Earth’s upper continental crust as a function of atomic number: http://en.wikipedia.org/wiki/Image:Relative_abundance_of_elements.png