EXISTENCE FORMS OF RADIOACTIVE CS CONSIDERING SOIL PROPERTIES AND VERTICAL DISTRIBUTION IN FOREST SOIL

Abstract

 Most of cesium in soil is strongly fixed, and forest soils may have a lower capacity of Cs fixation because of organic matter. We investigated the vertical distribution of Cs-137 in forest soils and the characteristics of the soils; loss on ignition, CEC, and RIP. Loss on ignition and CEC decreased with depth, and RIP increased. About 90% of the amount of Cs-137 was present within the upper 6cm layer of soil. The concentration of exchangeable Cs decreased with depth, but the ratio of exchangeable Cs to total Cs increased. Most of Cs in forest soils we collected was strongly fixed, however, it is possible that a part of exchangeable Cs remains because organic matter including dissolved organic matter in soil plays a minor role in fixing Cs and also because organic colloides enhance the transfer of Cs.