Comparison of the uptake of radiocaesium from soil to grass after nuclear weapons tests and the Chernobyl accident

Abstract

In order to compare the transfer factors of ¹³⁷Cs deposited after the fallout from the Chernobyl accident with ¹³⁷Cs from nuclear weapons testing, soil and vegetation samples have been collected from a semi-natural ecosystem in western Norway. For the ¹³⁷Cs from Chernobyl, 85% is found in the upper 5 cm of soil, whereas most of the nuclear weapons test ¹³⁷Cs is found between 3 and 12 cm in the soil profile. The transfer factors from soil to vegetation are calculated to be 0.41 ± 0.07 m² kg^–1 for the nuclear weapons test ¹³⁷Cs and 0.40 ± 0.22 m² kg^–1 for Chernobyl ¹³⁷Cs. Hence, the results show no significant difference between the two fallouts. The effective ecological half-life of ¹³⁷Cs for this ecosystem is estimated to be between 10 and 20 years. Wash-out and binding effects seem to be of minor importance for the uptake.