Abstract
Over the past several years, increasing attention has been paid on the protection of the environment from ionizing radiation. The ICRP is proposing in their radiation protection recommendations to select reference animals and plants to develop a common approach for the radiological protection of humans and nom-human species. The earthworm (worm) is nominated as one of the reference animals. Earthworms play important roles on ecosystems, and might be a good indicator of soil contamination and its effect on the ecosystem. Elemental composition of earthworm gives useful information on background level and possible accumulation of the metals as well as related radionuclides. In addition, change of the elemental composition itself might be a possible indicator of the effect on the earthworm and/or ecosystem. However, data for the elemental composition of earthworms were limited except for some specific heavy metals such as Cd, Zn, Pb and Cu. In this study, the earthworms and their growth media were analyzed for 37 elements, including radionuclide related elements such as Cs, Sr, Th and U, in order to obtain the basic information on the transfer parameters of the elements. The concentrations and transfer factors of the elements were determined both for laboratory and natural conditions.
