A dynamical approach for the uptake of radionuclides in marine organisms for the POSEIDON model system

¹ NRG, P.O. Box 9035, ET Arnhem, The Netherlands
² IMMSP, Glushkova Pr. 42, 03187 Kiev, Ukraine
³ SPA "Typhoon", Lenin Str. 82, 249020 Obninsk, Russia

Abstract

The existing POSEIDON compartment model, developed for modelling the dispersion of radionuclides in coastal areas for regular discharges was modified to be applicable in accidental conditions. One of the important modifications was the development of a generic uptake model for marine organisms to deal with short pulses of radionuclides after accidental releases in the coastal environment. A generic foodweb model to be used in the decision support system POSEIDON-R has been developed. Six key organisms represent the different trophic levels with identical physiological properties. To avoid the introduction of different compartments for the several organs in which radionuclides can accumulate, the so-called target tissue approach was followed. It is assumed that each radionuclide accumulates in a single specific tissue, (the key tissue), and that the behaviour of this radionuclide is organ- and not radionuclide-dependent. To test the reliability of this model, validation tests for various regions, and for several radionuclides, are required. Tests for the Baltic Sea and the Black Sea for the period after the Chernobyl accident in 1986 demonstrated a rather good agreement with the measured data on radiocaesium. The model gave in some cases an overestimation, which is not unacceptable for the aim of decision support.