<P> Niobium and its compounds are thought to be slightly toxic, but niobium poisoning is not known to have occurred . Niobium dust can irritate the eyes and skin . </P> <P> Tantalum and its compounds rarely cause injury, and when they do, the injuries are normally rashes . </P> <P> Out of the group 5 elements, only vanadium has been identified as playing a role in the biological chemistry of living systems, but even it plays a very limited role in biology, and is more important in ocean environments than on land . </P> <P> Vanadium, essential to ascidians and tunicates as vanabins, has been known in the blood cells of Ascidiacea (sea squirts) since 1911, in concentrations of vanadium in their blood more than 100 times higher than the concentration of vanadium in the seawater around them . Several species of macrofungi accumulate vanadium (up to 500 mg / kg in dry weight). Vanadium - dependent bromoperoxidase generates organobromine compounds in a number of species of marine algae . </P>

An element in the nitrogen family with a lower atomic number than carbon