Understanding the Half Life of Cesium 137

An element in different form is called an isotope. Cesium-137 is a radioactive isotope which is produced during nuclear fission.   It is different from the Cesium, a non-radioactive element which has atomic mass of 133. Cesium-137 has an atomic mass of 137.

Cesium-137 exists in the environment as a result of a nuclear accident. Nuclear weapons tested in the 1950s and 1960s and the Chernobyl power plant accident in the 1980s resulted in Cesium exposure. Cesium-137 seemed to cling to the soil. Thus, concentration of Cesium can be ingested in different ways.  Japan’s nuclear disaster in Fukushima in 2011 as a result of a powerful earthquake has isolated that region because of the release of harmful radiation which included Cesium-137.

Cesium-137 has a half-life of 30 years. What does this mean? A half-life is the time it takes for a substance to reduce to half its initial size.  Being a radioactive substance, Cesium-137 emits beta and gamma rays.  Thus, this isotope is confined in a lead container to prevent it from being dispersed to the environment.  If Cesium-137 is released, it would take 30 years before half of it decays or disappears.  This means that if there is exposure to Cesium-137 in a particular area; it would take 60 years before that area is clear of radiation.

Cesium-137 can be ingested by the body through contaminated food, water and air.  Cesium-137, when ingested, is distributed to different parts of the body mimicking potassium behavior. Because of its strong radiation properties, exposure to Cesium-137 damages the tissues and increases the possibility of developing into a form of cancer as it tends to be concentrated around large muscles.  Because of its long half-life, its long-term effects can be lethal.

It is important to note that Cesium-137 was only produced in the last 70 years. It did not exist prior to 1950s. Whatever amount of Cesium 137 exposure then, it would have been gone by now if the Fukushima crisis had not occurred. While it is commonly used in small doses in hospitals for treating cancer and in the calibration of different radiotherapy units, the exposure Cesium- 137 in the environment is in small doses.  However, people who work in scrap yards trying to salvage metals should be aware of the dangers of Cesium. There are reported incidents where people accidentally opened a canister of unknown origin; thus, putting their health at risk.