Migration of 137Cs extracted from contaminated tea in sandy clay soil

Abstract

The migration behavior of 137Cs extracted from the contaminated tea at Chernobyl accident in sandy clay soil has been studied by batch and column experiments. Time dependent sorption behavior of 137Cs extracted from the tea reaches equilibrium slower by 6.5 times than 137Cs+ ions. However, the distribution coefficient of 137Cs extracted from the tea for the sandy clay soil was higher than that of 137Cs+ ions. These results indicate that the sorption of the 137Cs attached to the organic materials dissolved from the tea on the sandy clay soil is slower than that of 137Cs+ ions, and the 137Cs attached to the organic materials have more affinity to the sandy clay soil than 137Cs+ ions. In the column experiments, most part of 137Cs were adsorbed on the top of soil layer 0–10 cm in depth and small amounts of 137Cs were flowed out from the soil layer. The concentration profile at the top of soil layer of 0–10 cm is in agreement with that estimated by the dispersion- transport equation considered ion-exchange reaction indicating that the migration of 137Cs extracted from the contaminated tea at the portion of high concentration is dominated by ion-exchange reaction. However, the concentration profile at deeper depth than 10 cm is not fitted by estimation by such equation. Therefore, the mechanism other than ion-exchange dominates the migration of 137Cs in the portion of low concentration. © 1995 Taylor & Francis Group, LLC.