[3J01-08] Fukushima 1

[3J08] Investigation on distribution of radioactive substances in Fukushima

(8)Effect of preferential flow on the chemical forms of Cs-137 in a cedar forest soil in Minamisoma

*Shunsuke Mishima¹, Junko Takahashi¹, Yuichi Onda¹ (1. Univ. of Tsukuba)

Keywords:FDNPP accident, Preferential flow, chemical forms of Cs-137, downward transfer, dye tracer

Variation in the Cs-137 inventory in forest soils is attributed to preferential flow, but few studies have been conducted. This study aimed to clarify the effects of preferential flow on the spatial distribution and chemical form of Cs-137 by using dye tracer. RhodamineB was applied by an artificial rainfall device at a cedar forest in Minamisoma. Visually dyed and undyed soils and cores were sampled to investigate Cs-137 and RhodamineB concentrations, saturated hydraulic conductivity, and chemical form of Cs-137. Results suggest that preferential flow increases the heterogeneity of Cs-137 concentrations in dyed soils and correlation was observed between hydraulic conductivity and Cs-137 concentrations in 10-15cm. These suggest that preferential flow may affect the spatial distribution of Cs-137.