Influence of soil properties and climatic conditions on 137Cs vertical distribution in some Chilean soils

Long-term downward distribution of global fallout 137Cs was studied in different soil types of four Chilean climatic zones, in natural and semi-natural environments. The 137Cs soil content showed an exponential decrease with depth; relaxation depth ranged from 0.9 cm in the polar climate environment up to 6.8 cm in the mesothermal warm summer one. In the Antarctic and Westpatagonic ecosystems the long freezing periods hindered the 137Cs downward movement. In temperate and tropical climate zones, the amount of soil coarse pore volume, and annual rainfall rates appear to be the main factors influencing the radionuclide's distribution in the soil profiles. (author)