Barium [Ba, 56]

Barium is an alkaline metal of the group 2 in the periodic table of elements and occurs in the Earth’s crust at levels 550–668 mg/kg. It has a lithophilic affinity and is likely to be concentrated in acidic igneous rocks and argillaceous sediments. Barium contents in soils vary from 10 to 1500 mg/kg, with the lowest in organic soils and the highest in loamy soils. During weathering processes, barium precipitates easily with sulfates and carbonates, and is also strongly adsorbed by clays, oxides, and hydroxides. Barium is primarily distributed to the bone and teeth; it is not known if Barium distributed to these tissues would result in toxicity. However, there are no data correlating Barium levels in tissues and fluids with exposure levels. Toxicity of barium compounds depends on their solubility. In humans, ingestion of high levels of soluble barium compounds may cause gastroenteritis (vomiting, diarrhea, and abdominal pain), hypopotassemia, hypertension, cardiac arrhythmias, and skeletal muscle paralysis.