Chemical state of radiocesium in the estuary sediments collected in the marine estuary

Although the pathway of radiocesium in surface water systems has been simply evaluated, the characteristics of the transported minerals in surface water such as the chemical form of the radiocesium associated with those minerals and the geochemical nature are not understood well. The present study investigated estuary sediments near the FNDPP, and evaluated the properties of the transported mineral particles associated with cesium and the chemical state of the radiocesium. In addition, the desorption process of the cesium was experimentally examined by leaching the estuary sediments with a simulated seawater. The mobile clay aggregates associated with radiocesium play a key role on the radiocesium migration in the surface environment and can be a potential source of radiocesium either in the form of soluble or fine colloidal particle. (J.P.N.)