[Terrestrial environmental dynamics of radioactive nuclides released by the Fukushima nuclear accident]

Research into environmental dynamics of radioactive nuclides released by the Fukushima nuclear accident, especially radiocesium (137)Cs (half-life, 30.1 years), is highly focused especially on diffusion processes of radiocesium into ecosystems, which is high-priority knowledge. Because of relatively sparse knowledge about the reallocation of radiocesium contained in organic matter in terrestrial ecosystems, the effects of diffused rediocesium into ecosystem cannot be accurately estimated. In this article, the terrestrial environmental dynamics of radiocesium mainly in the processes of plant uptake and the possibility of release from plants will be discussed. Plants uptake minerals from soil and these minerals are likewise ingested by animals that feed on plants, including humans. Therefore one of the main gateways of radiocesium into ecosystem is via plants. From the viewpoint of human dietary consumption, rice contamination with radiocesium has been energetically investigated and useful data are accumulating. Processes of radiocesium uptake mechanisms by plants are being researched using legumes, e.g. soybean. Speculation on the possibility of radiocesium release into forest atmosphere via plant activity will be introduced.