１．はじめに
２．調査地域の概要と河川堆積物試料
　（１）調査地域の概要
　（２）河川堆積物試料
３．分析方法
４．結果と考察
　（１）重金属元素濃度
　（２）重金属元素の濃度分布
　（３）重金属元素の起源
引用文献

『（Abstract）
　The regional distribution of heavy metal elements (V, Cr, Mn, Co, Ni, Cu, Zn, As, Mo, Cd, Sn, Sb, W, Pb, Bi, etc.) was investigated by using X-ray fluorescent spectrometer and ICP-MS for the stream sediments from the Ashida River system in the eastern part of Hiroshima Prefecture.
　In main stream sediments, systematic change in the concentration of heavy metal elements from upper to lower reaches was not recognized. Local abnormality on the concentration of Sn and W, however, were found in the stream sediments at middle reaches. On the other hand, branch stream sediments are generally rich in Cu, Zn, Cd, As and Pb. Of them, the concentration of Zn, Cd and Pb are much higher. Especially, the concentration of Cd reach about 30 ppm in maximum, which is comparable to that of once reported in the stream sediments of the Jinzu River, Toyama Prefecture, being well-known as Itai-Itai disease. Consequently, it follows that some of branch stream sediments were heavily polluted by heavy metals.
　There exist many Cu, Zn, Pb and W mines in study area, where had once operated. The high concentration of Cd in branch stream sediments seems to be originated by Zn deposits composed mainly of sphalerite with minor amount of Cd. Furthermore, the high concentration of Pb and Cu are likely to be responsible for the metalliferous deposits. As for the local abnormality n concentration of Sn and W in main stream sediments, corresponding mines could not find. Therefore, potential vein-type deposits of Sn and W in surrounding granitic rocks may be their origin.』

• 瀬戸内海の底質土中の元素分布　　http://www.kusa.ac.jp/~tkato/heavym/heavym.html