Cobalt is rather a rare element in earth’s crust which is usually produced as a by-product during the extraction of other metals such as copper. Its involvement in the synthesis of Vitamin B. This is required for the production of red blood cells and prevention of pernicious anemia, makes it an essentail element for animals. About 0.043 µg of cobalt is present per microgram of; Vitamin B12.

Cobalt is used in high temperature alloys, permanent magnets, paints, pigments anddyes. It serves as a catalyst in the manufacture of ammonia, alcohols and a number of other organic compounds. It is a useful therapeutic agent in the treatment of anaemia and cyanide poisoning.

Salts of cobalt are absorbed well from the gastro-intestinal tract. However, increased levels of cobalt in food and water do not tend to accumulate within the human body as about 80% of the ingested cobalt is excreted out in urine while about 15% is excreted in faeces. It is also excreted through milk and sweat. Polycythemia is the usual response of most of the mammals including man to large intakes of cobalt.

It induces vomiting, diarrhoea, and a sensation of warmth. Intravenous injections lead to flushed face, rise in blood pressure, slow respiration, giddiness and deafness due to damaged nerves (Browning, 1969). Incidence of goitre is higher in regions with higher levels of cobalt in water and soil (Wills, 1966). Irritations, damage to pulmonary tract and allergic dermatitis may occur in persons occupationally exposed to cobalt aerosols. There is little evidence of carcinogenic properties of cobalt respired in or taken orally.