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

Depth distribution of atmospheric 210Pb and 7Be and 90Sr and 137Cs 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 210Pb, 7Be and 137Cs show that these radionuclides have been diffused as solid soil particles in surface soil layers. In aeolian soil layers, about 50% of 90Sr were diffused in surface soil layer and the remaining 50% had penetrated to deeper layers. The half of the fission particles containing 90Sr were shown to have decomposed over the past 35 years. (author)