Toxicology of Selenium and Tellurium and Their Compounds

A comprehensive survey of the toxicological properties of selenium and tellurium and their compounds is presented. Although selenium has been used commercially for many years with no long-term systemic effects on industrial workers, selenium has long been regarded as a toxic substance. This belief stems principally from the well-known selenium poisoning of cattle caused by the consumption of seleniferous plants. Although elemental selenium is relatively nontoxic, certain selenium compounds are definitely toxic toward humans, the most seriously toxic being hydrogen selenide. Recent studies have indicated that selenium has an important role in animal nutrition and may be of particular value in the treatment of a number of deficiency diseases. Therefore it is important that reliable data be available on the toxic level of various selenium compounds toward different animal species. Considersbly less is known about the toxicity of tellurium and its compounds than about the toxicity of selenium. In general it appears that tellurium is less toxic than selenium, although there are exceptions to this rule. The recent developments on semiconducting tellurium compounds for thermoelectric applications have greatly increased the interest in the toxicity of tellurium and its compounds. A critical survey of the available data is presented in thismore » review.« less