Environmental radioactivity part of the Chernobyl release was the caesium-137, this isotope is responsible for much of the long term (at least one year after the fire) external exposure which has occurred at the site. The caesium isotopes in the fallout have had an effect on farming. A large amount of caesium was released during the Goiânia accident where a radioactive source (made for medical use) was stolen and then smashed open during an attempt to convert it into scrap metal. The accident could have been stopped at several stages; first, the last legal owners of the source failed to make arrangements
Effects of the Chernobyl disaster advances in these countries' ability to carry out epidemiological studies of all kinds. Immediately after the disaster, the main health concern involved radioactive iodine, with a half-life of eight days. Today, there is concern about contamination of the soil with strontium-90 and caesium-137, which have half-lives of about 30 years. The highest levels of caesium-137 are found in the surface layers of the soil where they are absorbed by plants, insects and mushrooms, entering the local food supply. Some scientists fear that radioactivity will affect the local population for the next several generations. Note that caesium is not mobile in