Alkali metal from the Chernobyl accident. Caesium-137 undergoes high-energy beta decay and eventually becomes stable barium-137. It is a strong emitter of gamma radiation. Caesium-137 has a very low rate of neutron capture and cannot be feasibly disposed of in this way, but must be allowed to decay. Caesium-137 has been used as a tracer in hydrologic studies, analogous to the use of tritium. Small amounts of caesium-134 and caesium-137 were released into the environment during nearly all nuclear weapon tests and some nuclear accidents, most notably the Goiânia accident and the Chernobyl disaster. As of 2005, caesium-137 is the principal source
Radiation effects from the Fukushima Daiichi nuclear disaster Even into July radioactive beef was found on sale in eleven prefectures, as far away as Kōchi and Hokkaido. Authorities explained that until that point testing had been performed on the skin and exterior of livestock. Animal feed and meat cuts had not been checked for radioactivity previously. Hay and straw were found contaminated with caesium from the reactors and outside the evacuation zone. The news of the contamination of foods with radioactive substances leaking from the Fukushima nuclear reactors damaged the mutual trust between local food producers, including farmers, and consumers. The source of caesium was found to be