Abstract
Increasing attention has come to be focused on the protection of the environment, i.e., non-human biota and ecosystems, from ionizing radiation, over the last decade. For example, the International Commission on Radiological Protection (ICRP) established a new committee for the environmental protection in 2005, and introduced a new chapter entitled "Protection of the Environment" in the ICRP recommendation in 2007. Although a lot of efforts have also been put on the collection of available scientific information mainly in European countries, the relevant data sets are still extremely limited. This paper summarizes recent progress of research activities in National Institute of Radiological Sciences (NIRS) for evaluation of the radiation effects on selected terrestrial and aquatic organisms as well as the ecosystems. Among organisms, conifers, earthworms, collembolans, algae, Medaka, etc. are presently selected to study. Transfers of radionuclides and related elements from medium to organisms are evaluated, for the estimation of possible radiation dose. Dose-effect relationships of acute gamma radiation on the survival, growth, and reproduction of selected organisms have been studied. Information of genome- and metagenome-wide gene expression has been collected. Studies on the effect of chronic gamma radiation at low dose rate were also started. In order to evaluate ecological effects of radiation, study methods by using three-species microcosm were established, and an index for the holistic evaluation of effects on various ecological parameters was proposed. Developments of more complicated and practical model ecosystems have been started. The Denaturant Gradient Gel Electrophoresis (DGGE) has been applied on soil bacterial community for evaluation of the radiation effects on soil ecosystems.
