PARENT SESSION

1L - Exposure Modelling
Poster Hall
8:30 AM - Wednesday, 30 April 2003
Chair: Lammel, G.¹, ¹
Co-chair: Dachs, J.², ²

(WEP/83) Selection of Aggregated Concentration Factor Values for ERA, considering the fish life.

GARNIER-LAPLACE, JACQUELINE ¹, BEAUGELIN-SEILLER, KARINE², ¹ IRSN/DPRE/SERLAB/LRE, Saint Paul les Durance, France, France² IRSN/DPRE/SERLAB/LMODE, Saint Paul les Durance, France, France

ABSTRACT- For radioecological assessment purpose applied to freshwaters receiving radioactive liquid effluents from nuclear installations, the current challenge is to improve accuracy of transfer models working under environmentally realistic scenarii and site-specific values. Within this framework, the transfer of radionuclides from water to omnivorous fish, through a 3 levels food chain, has been mechanistically and dynamically modelled. Mathematical expressions of aggregated concentration factors (ACF) from water to fish were deduced from transfer kinetics, under equilibrium conditions. ACF, expressed as the radionuclide concentration ratio between the organism and the water, referred to steady state and to all possible transfer pathways. As ACF are dependent on the mode of life, the feeding behaviour and the growth of fish, the effect of these physiological parameters on the variability of the obtained values was assessed. The ACF values were calculated for several radionuclides, taking into account average and extreme physiological parameters relevant to the life cycle of the fish. The mode of life, the diets, the feeding and growth rates of one of the dominant fish species within the Rhone river, i.e. the chub (Leuciscus cephalus) were characterized all along its life. The corresponding ACF values for the ¹³⁷Cs vary from 2 to 23 m³.kg^-1 w.w., when for example conventional model recommends values between 3 10^-2 and 3 m³.kg^-1 w.w.. The same approach was applied to other radionuclides (^54Mn, ⁶⁰Co, ¹⁰⁶RuRh, ^110mAg, ²⁴¹Am) underlying the relevancy of the proposed approach to select the most appropriate value for ACF among the wide range (several orders of magnitude) that was evidenced by this sensitivity analysis.

Key words: food, radionuclides, growth, fish