Cobalt

Cobalt is "a naturally occurring element found in rocks, soil, water, plants, and animals."

Uses
Cobalt is used in alloys used in the manufacture of aircraft engines, magnets, grinding and cutting tools, artificial hip and knee joints. They are also used to color glass, ceramics and paints, and used as a drier for porcelain enamel and paints.

"Radioactive cobalt is used for commercial and medical purposes. 60Co (read as cobalt sixty) is used for sterilizing medical equipment and consumer products, radiation therapy for treating cancer patients, manufacturing plastics, and irradiating food. 57Co is used in medical and scientific research. It takes about 5.27 years for half of 60Co to give off its radiation and about 272 days for 57Co; this is called the half-life."

In the Environment
Cobalt can enter the environment from natural sources and from human sources (the burning of coal or oil or the production of cobalt alloys). Once released in the air, cobalt settles to the ground within a few days. Cobalt released in the water or soil will stick to particles. Some cobalt compounds can dissolve in water.

In Sewage Sludge
Cobalt can also enter the environment if it is present in sewage sludge that is spread on land. In the Targeted National Sewage Sludge Survey, a 2009 test of 84 samples of sewage sludge from around the U.S., the EPA found cobalt in every sample in concentrations ranging from 0.87 to 290 parts per million.

Human Exposure and Health Effects
Humans are typically exposed to low levels of cobalt from air, food, and water. People who work in industries that make or use cutting and grinding tools; mine, smelt, refine, or process cobalt metal or ores; or that produce cobalt alloys or use cobalt may also be exposed to cobalt on the job. Most people are only rarely exposed to radioactive cobalt, unless one is undergoing radiation therapy. However, occupational exposure may occur at nuclear facilities, irradiation facilities, or nuclear waste storage sites.

Cobalt can affect human health both positively and negatively. Cobalt is beneficial for humans as it is part of vitamin B12.

"Exposure to high levels of cobalt can result in lung and heart effects and dermatitis. Liver and kidney effects have also been observed in animals exposed to high levels of cobalt."

"Exposure to large amounts of radiation from radioactive cobalt can damage cells in your body from the radiation. You might also experience acute radiation syndrome that includes nausea, vomiting, diarrhea, bleeding, coma, and even death. This would be a rare event."

Cobalt and cobalt compounds are possibly carcinogenic to humans.

Related SourceWatch articles

 * Biosolids
 * Sewage sludge
 * Food Rights Network

External resources

 * Agency for Toxic Substances & Disease Registry, ToxFAQs for Cobalt