Caesium-137

gamma ray emission. The ground state of barium-137 is stable.

Caesium-137 is water-soluble and extremely toxic in minute amounts. Once released into the environment, it remains present for many years as its radiological half-life is 30.23 years. It can cause cancer 10, 20 or 30 years from the time of ingestion, inhalation or absorption providing sufficient material enters the body. ^[1]

The radiography as other isotopes offer higher gamma activities given volume. It can be found in some moisture and density gauges, flow meters, and other sensor equipment.

Biological behavior of Cs-137 is similar to potassium. After entering the organism, all caesium gets more or less uniformly distributed through the body, with higher concentration in muscle tissue and lower in bones. The biological half-life of caesium is short at 70 days ^[2].

Small amounts of Cs-134 and Cs-137 were released into the environment during nuclear weapon tests and some nuclear accidents, most notably the Chernobyl disaster. As of 2005, Cs-137 is the principal source of radiation in the zone of alienation around the Chernobyl power plant. Together with strontium-90, it was among the isotopes with greatest health impact distributed by the reactor explosion.

Improper handling of Cs-137 sources can lead to release of the isotope and radiation contamination and injuries. Perhaps the best known case is the case from 1998, when Recycler Acerinox in Cadiz, Spain accidentally melted a source. Many abandoned sources are scattered over the area of the former Soviet Union.