title: Population modelling to compare chronic external radiotoxicity between individual and population endpoints in four taxonomic groups.
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 FREDERICA database) to simulate changes in population endpoints (net reproductive rate R0, asymptotic population growth rate λ, equilibrium population size Neq) 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 (R0, λ or Neq) and the life history of the studied species. Among population endpoints, net reproductive rate R0 showed the lowest EDR10 (effective dose rate inducing 10% effect) in all species, with values ranging from 26 μGy h(-1) in the mouse Mus musculus to 38,000 μGy 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 λ to decrease below 1, indicating that no population growth in the long term) was predicted for dose rates ranging from 2700 μGy h(-1) in fish to 12,000 μGy h(-1) in soil invertebrates. A milder risk, that population growth rate λ will be reduced by 10% of the reduction causing extinction, was predicted for dose rates ranging from 24 μGy h(-1) in mammals to 1800 μGy 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 μGy 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 μGy h(-1) in mammals to 970 μGy h(-1) in soil invertebrates, representing a slight but statistically significant population decline, the importance of which remains to be evaluated in natural settings.
authors.affiliation: Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, PRP-ENV/SERIS/L2BT, PRP-ENV/SERIS, Cadarache, Saint-Paul-lez-Durance, 13115, France. Electronic address: frederic.alonzo@irsn.fr.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Alonzo
authors.affiliation: Department of Plant and Environmental Science, The Norwegian University of Life Sciences (NMBU), Box 5003, N-1432, Aas, Norway.
authors.forename: Turid
authors.initials: T
authors.lastname: Hertel-Aas
authors.affiliation: Centro de Investigaciones Energéticas Medio Ambientales y Tecnológicas (CIEMAT), Av. Complutense 40, Madrid, 28040, Spain.
authors.forename: Almudena
authors.initials: A
authors.lastname: Real
authors.affiliation: UMR-I 02 SEBIO, Bat 18, Campus du Moulin de la Housse, BP 1039, 51687, Reims Cedex, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Lance
authors.affiliation: Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, PRP-ENV/SERIS/L2BT, PRP-ENV/SERIS, Cadarache, Saint-Paul-lez-Durance, 13115, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Garcia-Sanchez
authors.affiliation: Department of Ecology, Environment and Plant Sciences, Stockholm University, 10691, Stockholm, Sweden.
authors.forename: Clare
authors.initials: C
authors.lastname: Bradshaw
authors.affiliation: Belgian Nuclear Research Centre (SCK·CEN), Boeretang 200, 2400, Mol, Belgium.
authors.forename: Jordi
authors.initials: J
authors.lastname: Vives I Batlle
authors.affiliation: Department of Plant and Environmental Science, The Norwegian University of Life Sciences (NMBU), Box 5003, N-1432, Aas, Norway.
authors.forename: Deborah H
authors.initials: DH
authors.lastname: Oughton
authors.affiliation: Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, PRP-ENV/SERIS/L2BT, PRP-ENV/SERIS, Cadarache, Saint-Paul-lez-Durance, 13115, France.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Garnier-Laplace
mesh_terms: D000818:Animals; D005260:Female; D005399:Fishes; D005720:Gamma Rays / Q000009:adverse effects*; D007448:Invertebrates / Q000528:radiation effects; D008297:Male; D008322:Mammals; D008962:Models, Theoretical; D000069079:Radiation Exposure; D011834:Radiation Monitoring / Q000379:methods*; D018570:Risk Assessment
keywords: Chronic exposure; Leslie matrix; Life history; Population models; Radiation effects