Recent developments in the modelling of radionuclide uptake, radiation dose and effects in wildlife

Of the ~600 scientific publications on the Fukushima event, more than 80% relate to themes of transport of radionuclides in environmental media, transfer to wildlife and foodstuffs, and dose to environmental receptors. This focus reflects a continued need for development and harmonisation of radiological modelling approaches such as has been underway through recent IAEA and ICRP initiatives (e.g. EMRAS I and II, MODARIA). Key developments in improving the understanding of uptake of radionuclides in wildlife include establishing the Wildlife Transfer Parameter Database and related IAEA handbook on transfer to wildlife. These sources provide access to a comprehensive collection of transfer parameters, including input from Australian sources (www.wildlifetransferdatabase.org). Key improvements were highlighted in a recent Journal of Environmental Radioactivity special issue (Vol. 121). Dose modelling for wildlife continues to be challenged by the high diversity of biotic types (plankton to whales) and the breadth of exposure scenarios in diverse ecosystems. Modelling codes (e.g. ERICA Tool, RESRAD-Biota) are undergoing updates of their transfer parameters, improvement of capabilities such as probabilistic analysis (e.g. Monte Carlo), and harmonization of approaches through IAEA model testing exercises (e.g., Little Forest Burial Ground biota dose modelling assessment). A recent development has been the use of voxel dosimetry approaches which build on the standard simplified ellipsoid approach by modelling the absorbed doses in individual organs. Recent improvements in defining dose effects to environmental receptors have focused on updating the FREDERICA Radiation Effects Database. The more comprehensive data have allowed for the updating/development of new Species Sensitivity Distributions that better support the benchmark values for potential dose effects, and for improving estimation of population effects (rather than individuals) upon which the environmental protection strategies are based.

Keywords

Radioisotopes, Wild animals, Radioactivity, Ecosystems, Receptors, IAEA

Citation

Johansen, M.P., Beresford, N. A., Howard, B.J, Hinton, T.G., Bolhoefer, A., Doering, C., Hirth, G., Grezechnik, G., Ruedig, E., Payne, T. E. & Twining, J.R. (2014). Recent developments in the modelling of radionuclide uptake, radiation dose and effects in wildlife. Paper presented at SPERA 2014, 1-5 September 2014, 13th South Pacific Environmental Radioactivity Association Conference Charles Darwin University, Darwin, Northern Territory, Australia.