Cobalt Toxicity

Excerpt

Cobalt (Co) metal is a gray, ductile, magnetic element with an atomic number of 27 and an atomic weight of 58.9 Da. In the environment, cobalt is a component of naturally occurring minerals and is found in combination with other elements such as copper, nickel, manganese, arsenic, sulfur, and oxygen.

Due to its ferromagnetic properties, high melting point (1495.05 C), and high boiling point (2927 C), cobalt is widely used in industry to produce hard metals and superalloys. For example, the alloy Alnico is a blend of iron, aluminum, nickel, and cobalt used for its permanent magnetic properties. A common source of chronic cobalt exposure is in the production of tungsten carbide, which is used for its hardness, heat resistance, and strength.

Historically, cobalt chloride (CoCl2) has been used in medicine as a treatment for anemia due to its ability to promote erythropoiesis. However, due to its adverse effects of thyroid dysfunction and the development of goiters, the use of cobalt in treating anemia has fallen out of favor. A biochemically important cobalt compound is cyanocobalamin (vitamin B12) which contains a Co3+-ion.

Vitamin B12 is an essential nutrient naturally found in foods of animal origin, such as dairy, eggs, fish, poultry, and meat. Deficiencies in vitamin B12 may lead to pernicious anemia as well as peripheral neuropathy. The precursor hydroxocobalamin is used as an antidote for cyanide poisoning and may have a role in treating vasoplegic shock.

Potential cobalt exposure can occur via oral, respiratory, and dermal routes.