The ecological half-life of 137Cs in undisturbed silt soil

The time necessary to safely cultivate agricultural areas after they have been contaminated by radioactivity (e.g. after the Chernobyl accident) is not determined by the physical half-life of the radioactive isotopes in question but by their (usually much shorter) ecological half-life (Brisbin et al., 2002). This half-life not only depends on the type of soil but also on whether the soil was fertilized or not. Therefore it is not possible to determine an ecological half-life that is universally valid. However, the value for undisturbed, unfertilized soil should provide a general indication for the duration of ecological half-life. In a silt soil in Vienna, Austria, the ecological half-life of Cs-137 was determined to be 0.8 years, which is much shorter than the physical half-life of 30 years. (C) 2012 Elsevier Ltd. All rights reserved.