Reconstruction of land-to-sea radionuclide flux by POSEIDON/RODOS model chain: The Thermaikos Gulf base

¹ OINPE, Studgorodok 1, Kaluga Region, Obninsk 249020, Russia
² NCRS "Demokritos", Greece
³ IPMMS, Ukraine

Abstract

The model chain simulating the radionuclide transport in watersheds, rivers and sea waters, developed in the frame of the EC project POSEIDON, was applied to River Axios watershed and Thermaikos Gulf of Northern Aegean Sea. The model system included coupled deterministic box models for radionuclide transport on watershed (RETRACE-3), complemented by a 3D hydrodynamic model (THREETOX) and a stochastic weather generator. The generic representation of the complex watershed hydrology was used under conditions of important uncertainties in the input data. A Monte-Carlo approach was applied to tune the wash-off model. The simulated results are in reasonable agreement with scarce measurements. The results obtained demonstrate strong seasonal variability of the land-to-sea radionuclide flux and transport in the Thermaikos Gulf. Estimations of the land-to-sea radionuclide flux and the radionuclide concentration in seawater for the next 50 years were obtained using the generated weather parameter's sets. These estimates could be used to assess the radio-ecological doses and risk under worst, average and favourable climatic conditions.