LD50 is usually expressed as milligrams or grams of material per kilogram of animal weight (mg/kg or g/kg).)Ĭarcinogenicity- International Agency for Research on Cancer (IARC) haslisted cobalt and cobalt compounds within group 2B (agents which are possibly carcinogenic to humans). (LD50 = Lethal dose 50 = Single dose of a substance that causes the death of 50% of an animal population from exposure to the substance by any route other than inhalation. Exposure to cobalt may cause weight loss, dermatitis, and respiratory hypersensitivity. These patients also suffer from hair loss, diarrhea and vomiting.Ĭobalt dust may cause an asthma-like disease with symptoms ranging from cough, shortness of breath and dyspnea to decreased pulmonary function, nodular fibrosis, permanent disability, and death. This radiation is sometimes used with cancer-patients to destroy tumors. This can cause sterility, hair loss, vomiting, bleeding, diarrhoea, coma and even death. Health effects may also be caused by radiation of radioactive cobalt isotopes. Health effects that are a result of the uptake of high concentrations of cobalt are: Soils near mining and melting facilities may contain very high amounts of cobalt, so that the uptake by humans through eating plants can cause health effects. When plants grow on contaminated soils they will accumulate very small particles of cobalt, especially in the parts of the plant we eat, such as fruits and seeds. This mainly occurs with people that work with cobalt. When we breathe in too high concentrations of cobalt through air we experience lung effects, such as asthma and pneumonia. However, too high concentrations of cobalt may damage human health. The total daily intake of cobalt is variable and may be as much as 1 mg, but almost all will pass through the body unadsorbed, except that in vitamine B 12. Cobalt is used to treat anaemia with pregnant women, because it stimulates the production of red blood cells.
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Skin contact with soil or water that contains cobalt may also enhance exposure.Ĭobalt is not often freely available in the environment, but when cobalt particles are not bound to soil or sediment particles the uptake by plants and animals is higher and accumulation in plants and animals may occur.Ĭobalt is beneficial for humans because it is a part of vitamin B 12, which is essential for human health. Health effects of cobaltĪs cobalt is widely dispersed in the environment humans may be exposed to it by breathing air, drinking water and eating food that contains cobalt. World production is 17.000 tonnes per year. It is also found in Finland, Azerbaijan, and Kazakhstan. The world's major producers of cobalt are the Democratic Republic of the Congo, mainland China, Zambia, Russia and Australia. The main ores of cobalt are cobaltite, erythrite, glaucodot, and skutterudite. Cobalt is usually not mined alone, and tends to be produced as a by-product of nickel and copper mining activities.
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Cobalt is not found as a free metal and is generally found in the form of ores. In the marine environment cobalt is needed by blue-green algae (cyanobacteria) and other nitrogen fixing organisms. Cobalt is of relatively low abundance in the Earth's crust and in natural waters, from which it is precipitated as the highly insoluble cobalt sulfine CoS.Īlthough the average level of cobalt in soils is 8 ppm, there are soils with as little as 0.1 ppm and others with as much as 70 ppm. Most of the Earth's cobalt is in its core. The radioactive isotopes, cobalt-60, is used in medical treatment and also to irradiate food, in order to preserve the food and protect the consumer.
Cobalt blue is an important part of artists' palette and is used bu craft workers in porcelain, pottery, stained glass, tiles and enamel jewellery. Cobalt is stable in air and unaffected by water, but is slowly attacked by dilute acids.Ĭobalt is used in many alloys (superalloys for parts in gas turbine aircrafr engines, corrosion resistant alloys, high-speed steels, cemented carbides), in magents and magnetic recording media, as catalysts for the petroleum and chemical industries, as drying agents for paints and inks.
The element is active chemically, forming many compounds. It is similar to iron and nickel in its physical properties. It is a member of group VIII of the periodic table. 0.28 V ( Co 2+/ Co ) +1.84 V ( Co 3+/ Co 2+ )Ĭobalt is a hard ferromagnetic, silver-white, hard, lustrous, brittle element.
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