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- Alonzo, Frederic, et al.
(author)
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Population modelling to compare chronic external radiotoxicity between individual and population endpoints in four taxonomic groups
- 2016
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In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 152, s. 46-59
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Journal article (peer-reviewed)abstract
- In this study, we modelled population responses to chronic external gamma radiation in 12 laboratory species (including aquatic and soil invertebrates, fish and terrestrial mammals). Our aim was to compare radiosensitivity between individual and population endpoints and to examine how internationally proposed benchmarks for environmental radioprotection protected species against various risks at the population level. To do so, we used population matrix models, combining life history and chronic radiotoxicity data (derived from laboratory experiments and described in the literature and the FRED ERICA database) to simulate changes in population endpoints (net reproductive rate R-0, asymptotic population growth rate lambda, equilibrium population size N-eq) for a range of dose rates. Elasticity analyses of models showed that population responses differed depending on the affected individual endpoint (juvenile or adult survival, delay in maturity or reduction in fecundity), the considered population endpoint (R-0, lambda or N-eq) and the life history of the studied species. Among population endpoints, net reproductive rate R-0 showed the lowest EDR10 (effective dose rate inducing 10% effect) in all species, with values ranging from 26 mu Gy h(-1) in the mouse Mus musculus to 38,000 mu Gy h(-1) in the fish Oryzias latipes. For several species, EDR10 for population endpoints were lower than the lowest EDR10 for individual endpoints. Various population level risks, differing in severity for the population, were investigated. Population extinction (predicted when radiation effects caused population growth rate lambda to decrease below 1, indicating that no population growth in the long term) was predicted for dose rates ranging from 2700 mu Gy h(-1) in fish to 12,000 mu Gy h(-1) in soil invertebrates. A milder risk, that population growth rate lambda will be reduced by 10% of the reduction causing extinction, was predicted for dose rates ranging from 24 mu Gy h(-1) in mammals to 1800 mu Gy h(-1) in soil invertebrates. These predictions suggested that proposed reference benchmarks from the literature for different taxonomic groups protected all simulated species against population extinction. A generic reference benchmark of 10 mu Gy h(-1) protected all simulated species against 10% of the effect causing population extinction. Finally, a risk of pseudo-extinction was predicted from 2.0 mu Gy h(-1) in mammals to 970 mu Gy h(-1) in soil invertebrates, representing a slight but statistically significant population decline, the importance of which remains to be evaluated in natural settings.
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- Garnier-Laplace, Jacqueline, et al.
(author)
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Assessing ecological effects of radionuclides : data gaps and extrapolation issues
- 2004
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In: Journal of Radiological Protection. - 0952-4746 .- 1361-6498. ; 24:4A, s. A139-A155
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Journal article (peer-reviewed)abstract
- By inspection of the FASSET database on radiation effects on non-human biota, one of the major difficulties in the implementation of ecological risk assessments for radioactive pollutants is found to be the lack of data for chronic low-level exposure. A critical review is provided of a number of extrapolation issues that arise in undertaking an ecological risk assessment: acute versus chronic exposure regime; radiation quality including relative biological effectiveness and radiation weighting factors; biological effects from an individual to a population level, including radiosensitivity and lifestyle variations throughout the life cycle; single radionuclide versus multi-contaminants. The specificities of the environmental situations of interest (mainly chronic low-level exposure regimes) emphasise the importance of reproductive parameters governing the demography of the population within a given ecosystem and, as a consequence, the structure and functioning of that ecosystem. As an operational conclusion to keep in mind for any site-specific risk assessment, the present state-of-the-art on extrapolation issues allows us to grade the magnitude of the uncertainties as follows: one species to another > acute to chronic = external to internal = mixture of stressors > individual to population > ecosystem structure to function.
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- Vandenhove, Hildegarde, et al.
(author)
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ALLIANCE perspectives on integration of humans and the environment into the system of radiological protection
- 2018
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In: Annals of the ICRP. - : SAGE Publications. - 0146-6453 .- 1872-969X. ; 47:3-4, s. 285-297
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Journal article (peer-reviewed)abstract
- Risks posed by the presence of radionuclides in the environment require an efficient, balanced, and adaptable assessment for protecting exposed humans and wildlife, and managing the associated radiological risk. Exposure of humans and wildlife originate from the same sources releasing radionuclides to the environment. Environmental concentrations of radionuclides serve as inputs to estimate the dose to man, fauna, and flora, with transfer processes being, in essence, similar, which calls for a common use of transport models. Dose estimates are compared with the radiological protection criteria for humans and wildlife, such as those developed by the International Commission on Radiological Protection. This indicates a similarity in the approaches for impact assessment in humans and wildlife, although some elements are different (e.g. the protection endpoint for humans is stochastic effects on individuals, whereas for wildlife, it is deterministic effects on species and ecosystems). Human and environmental assessments are consistent and complementary in terms of how they are conducted and in terms of the underlying databases (where appropriate). Not having an integrated approach may cause difficulties for operators and regulators, for communication to stakeholders, and may even hamper decision making. For optimised risk assessment and management, the impact from non-radiation contaminants and stressors should also be considered. Both in terms of the underlying philosophy and the application via appropriate tools, the European Radioecology Alliance (ALLIANCE) upholds that integration of human and ecological impact and risk assessment is recommended from several perspectives (e.g. chemical/radiological risks).
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