Development of a multi-target tissue approach for the prediction of non-uniform accumulation of radioactivity in fish

Abstract

The present work is concerned with the development of a new dynamic modelling approach for the simultaneous calculation of concentration of a specific radionuclide accumulated in different tissues of fish. That is, as an extension of the previous single target tissue approach, the new model considers three-target tissues, flesh (muscle), bones (carcass), organs for each of fishes considered in the marine food web. The dynamic equation of concentration for each type of fish used in the single target tissue approach is then split into three independent equations having different values of assimilation efficiency parameter and biological half-life. The target tissues were chosen based on the large differences in cell renewal time, namely biological half-life. Organs include liver, kidney, stomach, gonads etc. assuming that dynamics of radionuclide accumulation and elimination is roughly similar. Unlike pharmacokinetic models the new model does notconsider the interaction between targets, considering substantial difference in biological half-life between considered tissues. Such simplification then requires much less number of parameters. The assimilation coefficients were basically defined using the experimental ratios between concentration of radionuclide in whole body of marine fish and concentration in specific tissue (Yankovich et al., 2010). An additional requirement was the ratio between concentration of radion