Mixing of atmospheric 210Pb and 7Be and 137Cs and 90Sr fission products in four characteristic soil types

Depth distribution of atmospheric Pb-210 and Be-7 and Sr-90 and Cs-137 fission products was measured in two types of aeolian soils (desert dust and volcanic ash), irrigated paddy soil and strongly acidic soil. The depth dependence of Pb-210, Be-7 and Cs-137 show that these radionuclides have been diffused as solid soil particles in surface soil layers. In aeolian soil layers, about 50% of Sr-90 were diffused in surface soil layer and the remaining 50% had penetrated to deeper layers. The half of the fission particles containing Sr-90 were shown to have decomposed over the past 35 years.