Cobalt, a natural element present in certain ores of the earth's crust, is essential to life in trace amounts. It exists in the form of various salts. Pure cobalt is an odorless, steel-gray, shiny, hard metal. Everyone is exposed to low levels of cobalt in air, water, and food. An average of 2g/l in drinking water has been estimated. Cobalt has both beneficial and harmful effects on health.
Important natural sources of cobalt in the environment are soil, dust, and seawater. Cobalt is also released to the environment from burning coal and oil, and from exhaust from cars and trucks.
Cobalt and its salts are used in nuclear medicine, enamels and semiconductors, grinding wheels, painting on glass and porcelain, hygrometers and electroplating; as a foam stabilizer in beer, in vitamin B12 manufacture, as a drier for lacquers, varnishes, and paints, and as a catalyst for organic chemical reactions.
Cobalt has been used as a treatment for anemia, because it causes red blood cells to be produced.
Some isotopes of cobalt are radioactive, the most important being cobalt 60. Cobalt 60 is a beta and gamma emitter and is used in radiation therapy, in level gauges and research.
Cobalt is a non-combustible solid. However, powdered cobalt will ignite. The water solubility of cobalt and its salts range from highly soluble to practically insoluble. Cobalt can move from the soil to underground water. Cobalt is taken up by plants from the soil. Cobalt and its salts are highly persistent in water, with a half- life greater than 200 days.
| BENCHMARKS
| |||||||||||||||||||||||||||||||||||||||
Canadian Water Quality Guidelines
| |||||||||||||||||||||||||||||||||||||||
HUMAN HEALTH
Effects on the lungs, including asthma, pneumonia, and wheezing, have been found in workers who breathed high levels of cobalt in the air.
In the 1960s, some breweries added cobalt to beer to stabilize the foam. Some people who drank large quantities of the beer experienced nausea, vomiting, and serious effects on the heart. However, effects on the heart were not seen in people with anemia or pregnant women treated with cobalt.
Exposure can cause a severe allergic lung reaction with coughing, wheezing, chest pain and shortness of breath.
The International Agency for Research on Cancer has determined that cobalt is a possible carcinogen to humans.
Repeated exposure can cause scarring of the lungs (fibrosis) even if no symptoms are noticed. This can be fatal.
Exposure can damage the heart.
Cobalt dust may irritate the skin, causing a rash or burning feeling on contact.
Exposure to the dust and fumes can irritate the eyes, nose, mouth, and throat. High levels can irritate the lungs, causing a build up of fluid (pulmonary edema), a medical emergency.
Cobalt compounds may cause mutations (genetic changes) in living cells.
Exposure to ionizing radiation is associated with an increased risk of developing cancer. Some isotopes of Cobalt do emit ionizing radiation.
Cobalt has been tested and has not been shown to adversely affect reproduction in humans (New Jersey Department of Health).
Cobalt can cause a skin allergy to develop so that very low future exposures can cause itching and a skin rash.
Cobalt may cause an asthma like allergy.
Cobalt can damage the heart, causing heart failure.
Long term exposure may damage the thyroid and liver.
Repeated exposure can cause scarring of the lungs (pulmonary fibrosis) even if no symptoms are noticed. This can be disabling or fatal.
MEDICAL TESTS
Tests are available to measure cobalt levels in the urine and blood. These tests are only accurate for up to a few days after exposure because cobalt leaves the body fairly quickly.
Chest x-ray for lung scarring should be done every two to three years after five or more years of exposure.
If symptoms develop or overexposure is suspected:
Liver, thyroid, and lung function tests;
Evaluation of heart failure;
Evaluation by a qualified allergist to help diagnose skin allergy.
ANIMAL HEALTH
Animal studies have found problems with the development of the fetus in animals exposed to high concentrations of cobalt during pregnancy. However, cobalt is also essential for the growth and development of certain animals.
Studies in animals have shown that cobalt causes cancer when placed directly into the muscle or under the skin. Cobalt did not cause cancer in animals that were exposed to it in the air, in food, or in drinking water.
Cobalt and its salts have high acute and chronic toxicity to aquatic life. Acute toxic effects may include the death of animals, birds, or fish, and death or low growth rate in plants. Chronic toxic effects may include shortened lifespan, reproductive problems, lower fertility, and changes in appearance or behaviour.
The concentration of cobalt and its salts found in fish tissues is expected to be somewhat higher than the average concentration of cobalt in the water from which the fish was taken.
We investigate | We prosecute | You can help | Staff | Index | Email EBI | Links
Home | News | News archive | Log-in