In nature, it combines with oxygen and carbon or sulfur to form barium compounds. Small amounts of these barium compounds are naturally present in most soils and water.
Physicians often ask patients to swallow a barium sulfite solution before taking stomach X-rays.
Barium compounds are used to manufacture steel, copper, and glass. They are important ingredients in paints and lubricants for oil drilling. Trace amounts of barium are present in coal and oil. When electric utilities burn these fuels at their power plants, barium is released in very small amounts. Most of this barium is carried by particles of ash.