Technetium [Tc, 43]

Technetium (Tc) is a silvery-gray radioactive transition metal of group 7 in the periodic table of elements, without any stable isotopes. Nearly all Tc is produced synthetically, and only minute amounts are found in the nature. The source of Tc is mainly global fallout and is released from various nuclear processes. Plant uptake of Tc from soils is relatively low, being lowest by tomato and the highest by spinach. Technetium has no biological role. It does not occur naturally in the biosphere, and thus normally never presents a risk. All Tc compounds should be regarded as highly toxic, largely because of its radiological toxicity. The primary hazard, when working with Tc, is inhalation of dust, resulted in lung contamination, which poses a significant cancer risk. Once in the human body, ⁹⁹Tc concentrates in the thyroid gland and the gastrointestinal tract. The body, however, constantly excretes ⁹⁹Tc, after it is ingested.