Small amounts of cobalt naturally occur in food. In addition, vitamin B12 is a cobalt-containing compound that is essential for good health. Some 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 enters the environment from natural sources and from the burning of coal and oil.
Cobalt stays in the air for a few days.
Pure cobalt does not dissolve in water, but some of its compounds do. Cobalt can stay for years in water and soil. It can move from the soil to underground water. Cobalt is taken up by plants from the soil. Everyone is exposed to cobalt at low levels in air, water, and food.