Dynamic modelling for the assessment of radiation impacts on biota, and related extensions of the ERICA assessment methodology

A biokinetic modelling approach, able to simulate dynamically the uptake and turnover of radionuclides by biota, was applied to the eastern Irish Sea coast case study which has recently been assessed using the non-dynamic, concentration factor (CF)-based ERICA methodology (Hosseini et al., 2007). An additional case study of short-term pulsed discharges has also been used to demonstrate the usefulness of the model in situations where water concentrations are fluctuating. The differences incurred when using a dynamic versus equilibrium-based approach, in respect of absorbed dose rates to biota, are illustrated in detail in this paper. A comparison was also carried out between doses to biota and doses to humans arising from the ingestion of marine organisms by critical groups of consumers, using ICRP 72 human dose factors incorporated in the dynamic assessment tool for the purposes of this study. The results were compared with the standard CF-based approach currently used in regulatory assessments.