Modelling of biota dose effects. Report of working group 6 biota dose effects modelling of EMRAS II topical heading reference approaches for biota dose assessment. Environmental modelling for radiation safety (EMRAS II) programme
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Date
2014
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International Atomic Energy Agency
Abstract
Radiological protection of the environment is advancing from the old paradigm which stated that if humans are protected then by default all other components of the environment are protected as well [1]. Indeed, humans are among the most sensitive organisms to radiation and their protection does ensure protection of much of the environment. However, a more satisfying approach for many stakeholders, and one that is in-line with protection strategies implemented for other types of environmental contaminants, is to explicitly show that the environment is protected. Therefore, the International Commission on Radiological Protection (ICRP) now recommends explicit consideration of the environment and new approaches are being developed to demonstrate such protection. Appropriately, the new developments strive to protect populations or higher organizational levels (e.g. communities, ecosystems [2]), rather than focusing on the protection of individuals. The protection of higher levels of biological organization was not originally addressed [3], but is now being considered further [4]. During the last 10 years, considerable progress has been made in deriving screening ecological benchmarks and in developing a tiered Ecological Risk Assessment (ERA) approach for radioecology [5–7]. While the ERA-type approach is a substantial advancement in radioecology, a lack of sufficient data prevents current ERA analyses from fully accounting for the realistic environmental conditions to which organisms are exposed. Data are insufficient to predict effects from chronic, low doses; variable dose rate regimes; multicontaminant scenarios or multi-generational exposures; ecosystem level effects; or the influence of variable life-history traits [8]. Additionally, most measurements of effects are assayed on individuals within a population. Extrapolation is required to estimate population level effects from the individual-based measurements, or to account for the knowledge gaps mentioned above. The extrapolation uses assessment factors (or safety factors) that add conservatism and substantially increase uncertainties in risk assessments. Large uncertainties do little to promote confidence with the stakeholders of radioecology. Improvements are therefore needed.
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Keywords
Accidents, Control, Doses, Environment, Forecasting, Human populations, Radiation protection, Radioactive wastes, Radioisotopes, Simulation
Citation
Johansen, M. P. [Contributor] (2014). Modelling of biota dose effects. Report of working group 6 biota dose effects modelling of EMRAS II topical heading reference approaches for biota dose assessment. Environmental modelling for radiation safety (EMRAS II) programme. (IAEA-TECDOC-1737). Vienna, Austria: International Atomic Energy Agency.