Effect of radioactive cesium-rich microparticles on radioactive cesium concentration and distribution coefficient in rivers flowing through the watersheds with different contaminated condition in Fukushima

福島県の汚染度の異なる流域を流れる河川水中のセシウム濃度,分配係数に対する高濃度に放射性セシウムを含む微粒子の影響

辰野 宇大*; 脇 嘉理*; 角間 海七渡*; 二瓶 直登*; 高瀬 つぎ子* ; 和田 敏裕*; 吉村 和也  ; 中西 貴宏   ; 大手 信人*

Tatsuno, Takahiro*; Waki, Hiromichi*; Kakuma, Minato*; Nihei, Naoto*; Takase, Tsugiko*; Wada, Toshihiro*; Yoshimura, Kazuya; Nakanishi, Takahiro; Ote, Nobuhito*

This study investigated the effect of radioactive cesium-rich microparticles (CsMPs) on the radiocesium (RCs) concentration and distribution coefficient (Kd) in two rivers, Takase River and Kami-Oguni River, flowing in the watersheds with different radioactive contaminated conditions in Fukushima Prefecture. Unlike RCs adsorbed on to the suspended solids (SS), there was no correlation between the RCs concentration derived from CsMPs and the SS concentration in both rivers. Inflow of CsMPs to the targeted rivers was contingent. CsMPs were detected only in some samples during rainfall. Furthermore, the proportion of RCs concentration derived from CsMPs in the average RCs concentrations per unit mass of SS in both rivers during rainfall were not large, which were 10% or less. As a results, CsMPs did not significantly increase particulate RCs concentration and had little effect on Kd in both river water flowing the watershed with different RCs contaminated condition.