[2M01-08] Environmental Radioactivity 2

[2M04] Investigation on distribution of radioactive substances in Fukushima

(10)Evaluation of the spatial heterogeneity of Cs-137 distribution in forest soils using dye tracer

*Junko Takahashi¹, Takuya Sasaki¹, Satoshi Iguchi¹, Yuichi Onda¹ (1. Univ. of Tsukuba)

Keywords:preferential flow, dye tracer, downward migration, vertical distribution of Cs-137

Rainfall infiltration is one of the most important mechanisms of downward migration of Cs-137 in forest soils. Rainwater infiltration in soil can be divided into two types, which are relatively uniform matrix flow and non-uniform preferential flow through coarse pores and root surfaces. This preferential flow would contribute the downward migration of various substances, resulting in that the preferential flow would make a spatial heterogeneity of the vertical distribution of Cs-137 in soil. In the presnt study, we conducted an artificial rainfall experiment using dye trecers in a forest and collected soil samples from dyed and un-dyed areas at different depths in order to quantify the spatial heterogeneity and chemical form of Cs-137.