Tritium dynamics in large fish – a model test

Abstract

Tritium can represent a key radionuclide in the aquatic environment, in some cases, contributing significantly to the doses received by aquatic non-human biota and by humans due to aquatic releases. Recently, the necessity to have a robust assessment of tritium routine and accidental risk emissions for large nuclear installations increased the interest in the topic. In the present study, the recent experiments concerning tritium transfer in adult rainbow trout are described. The updated model concerning the dynamics of tritium transfer in aquatic food chain (AQUATRIT model) developed by the authors is applied and tested for these experimental data. The model predicts the experimental data with a factor of 2 to 3 and the potential improvements of the model are discussed. The present model results emphasize that in the field conditions, the major factors influencing the OBT biological loss rate are the temperature and the prey availability while, the OBT uptake is mainly influenced by the fish growth rates. The main goals of this study are to enhance the robustness of aquatic models for tritium risk assessment and to fulfil a gap for aquatic pathways in environment.