Investigation of the distribution of elements of the whole of Japan and their applications

- Geochemical map of land and sea of Japan -

Abstract

A geochemical map of the whole of Japan has been drawn for the first time by surveying the distribution of elements in land and sea throughout Japan. This map revealed the natural background of the elements distribution and allows us to know the continuous flow of elements from land to sea. The samples used in this work are 3024 riverbed sediments and 4905 seabed sediments, and 53 elements including toxic elements of As, Hg, Cd, etc. have been analyzed. In this research, a new survey method has been established for a certain district at first and then it has been applied to the whole of Japan with modification taking realistic operability into consideration, and the object has been extended from land, sea to soil. The geochemical map is also used for evaluating the pollution of soils and marine sediments resulting from human and industrial activities. The results have been made public through publication and website and have had various social impacts. In this paper, the research scenario adopted to compose the geochemical map of Japan is first described, then a series of research processes are described starting from material sampling and treatment chemical analysis, measurement of element concentration, composition of geochemical map to data release.