The discovery of cobalt can be traced back to the Egyptians, being used primarily as a pigment for glazes and ceramics and later to colour glass. 'Cobalt', derived from the German 'kobalt' meaning 'goblin', was a superstitious name given by the miners of that time due to Cobalt ore always being found in a combined form containing arsenic, the smelting of which releases the highly toxic arsenic oxide leading to a notoriety surrounding the metal.
The use of cobalt as a pigment continued into the 20th century, but due to its highly toxic nature cobalt-free alternatives were beginning to become available. It is now more commonly known as one of the raw materials used in manufacturing batteries.
It also has many medical applications as a gamma ray source for radiotherapy, as well as sterilization of medical equipment and waste. Due to its relatively short 5-year half-life, cobalt radiotherapy has largely been replaced by modern machines.
Swallowing a large enough amount of cobalt to pose a health risk is very rare, however absorbing a large amount over a long period could lead to serious health problems. Cobalt is only within the body as part of Vitamin B-12 which is essential for making red blood cells and for maintaining the nervous system. A symptom of higher cobalt concentration in the body is an increase in red blood cell count (polycythaemia). Delayed treatment can cause congestive heart failure or heart muscle disease due to its toxicity.
High exposure is even able to cause damage to genetic material within the cells which could result in the development of cancers. For this reason, cobalt has been identified as a possible carcinogen.
Cobalt occurs naturally in the Earth's crust and can enter drinking water in concentrations that are not harmful to health over even prolonged periods, and it has not been identified as a risk in water in the UK.
In locations where it has been detected it is likely to be associated with industrial pollution contaminating ground water where other contaminants would be at much more significant concentrations than cobalt.
Cobalt in your drinking water can be detected by the following tests.
Cobalt can be reduced or removed from your drinking water using the following methods.
