Biomethylation of selenium and tellurium: Microorganisms and plants

The biomethylation of selenium and tellurium with the major emphasis on the conversion of inorganic forms of these metalloids to volatile materials by microorganisms and plants is discussed. The similarity of selenium and tellurium encompasses not only their names and positions on the periodic table but to a large degree their chemistry and biochemistry. Results shows that it is possible to have the toxic element tellurium as an essential element, like selenium.