Radioisotopes environmentally significant

Table 13.1 shows the environmentally significant radioisotopes of metals and metalloids considered in this chapter. Figure 13.1 shows some of the fluxes of radioactive nuclides in the environment. 

Cesium (chemical symbol Cs) is a metal that may be stable (nonradioactive) or unstable (radioactive). The most common radioactive form of cesium is cesium-i37. Another fairly common radioisotope is cesium-134. Cesium-137 is much more significant as an environmental contaminant than cesium-134. It is also very useful in industry for its strong radioactivity. 

Half-life defined as the time required for half the atoms in a radioisotope to decay. Half-lives range from tiny fractions of a second to tens of thousands of years. The release of radioisotopes with long half-lives is associated with significant environmental contamination and risk to health. 

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