2018 Volume 34 Issue 12 Pages 1357-1364
In an effort to elucidate the deposition pathway of Pd in river sediments, we analyzed the amount of Pd in the river water and sediments of the Yukawa and Yazawa rivers, as well as in the sediments of the Shinaki dam-lake of the Kusatsu hot-spring area, which is located northwest in Gunma Prefecture of Japan. The crystal structures and elemental compositions of the river sediment samples differed significantly before and after neutralization. This was attributed to the lime input, which also affected the Pd abundance ratio obtained by the sequential extraction procedure. Additionally, the low leachability of Pd in the sediment suggested possible difficulties in its recovery. Considering the analysis of the Pd variation in the environments, it was concluded that the Pd content in the sediment of the Shinaki dam-lake was mainly supplied by the Yukawa river water inflowing the surrounding tributary rivers and hot-spring waters before neutralization, rather than the lime input.