Modéliser la propagation des effets de l'exposition chronique aux rayonnements ionisants des individus aux populations

Titre de la revue : Journal of Environmental Radioactivity Volume : 99 N° : 9 Pagination : 1464-1473 Date de publication : 01/09/2008

This study evaluated the potential effect of ionising radiation on population growth using simple population models and parameter values derived from chronic exposure experiments in two invertebrate species with contrasting life history strategies. In the earthworm Eisenia fetida, models predicted increasing delay in population growth with increasing gamma dose rate (up to 1.8 generation times at 11 mGy h-1). Population extinction was predicted at 43 mGy h-1. Some recovery at 4.1 and 11 mGy h-1 were suggested in the offspring generation. In microcrustacean Daphnia magna, models predicted increasing delay in population growth with increasing alpha dose rate (up to 0.8 generation times at 14.8 mGy h-1), only after two successive generations were exposed. The study examined population effects of changes in different individual endpoints (including survival, number of offspring produced and time to first reproduction). Models showed that the two species did not respond equally to equivalent levels of change, the slow growing earthworms being more susceptible than the fast growing daphnids. This suggested that susceptibility of a population to ionizing radiation cannot be considered independent of its life history.