Mobility of Gamma-Emitting Fission Products in Typical Black and Laterite Soils

Studies on the movement of the gamma-emitting fission products ¹⁰⁶Ru, ¹²⁵Sb, ¹²⁷Cs and ¹⁴⁴Ce, surface deposited on columns of the black and laterite soils revealed that the mobility of these nuclides in the two soils depended mainly on the ionic form of the nuclide, soil reaction ond predominant clay mineral type in the soil. Results showed a rapid breakthrough of ¹⁰⁶Ru in the black soil and considerable migration to the lower layers in the laterite soil on leaching with rain water, or moderately high calcium or sodium Irrigation waters. While near complete fixation of ¹⁴⁴Ce and ¹³⁷Cs in the top contaminated layer of both soils was observed, a slight movement of ¹²⁵Sb only in the black soil was noticed. Incorporation of organic matter had no effect on the movement of fission products in both soil types, whereas ethylenediaminetetraacetic acid (EDTA) induced variable movement of the different radionuclides in the two soil types.