Cesium [Cs, 55]

Cesium (Cs) is an alkali metal of the group 1 in the periodic table of elements. Cesium is relatively active in soils and is thus easily taken up by plants, especially from sandy, acidic soils. Concerns with radiocesium (two radioisotopes ¹³⁴Cs and ¹³⁷Cs) in soils and food chain began since the accident in the Chernobyl nuclear power plant, in 1986. The behavior of ¹³⁷Cs in soils is very similar to those of the stable Cs. Thus, when deposited in soils, it is absorbed by clay fractions and soluble organic matter, and, therefore, migrates slowly. The transfer of Cs isotopes to the fetus has been followed in both humans and animals. The concentrations of ¹³⁷Cs arising from exposure to fall-out from nuclear weapons were measured in nine newborn children, within three days of birth and in their mothers; concentrations were similar.