http://www.radiationdefense.jp/en/investigation
As our first work of our Nationwide Soil Testing Project, we tested soil samples from 150 areas in the Tokyo metropolitan area. This project is the first unified investigation on the diffusion of radioactive particles in the metropolitan area including Tokyo, Chiba, Saitama, Kanagawa, and Ibaraki prefectures, whereas the national and local governments are separately performing their investigations.