Assessment of coastal radio pollution via simulation experiment

Abstract Radionuclide pollution in coastal areas is of particular concern due to the persistence of radionuclides in the marine environment, their accumulation in sediments, and the potential consequences for human populations and ecosystem health. In this study, the distribution of 137 Cs in coastal beach sands and the associated potential external radiological exposure risks were evaluated for the Eastern Mediterranean following a hypothetical accidental release from the Akkuyu NPP in southern Turkey. A coupled hydrodynamic and particle-tracking modelling framework was applied to simulate radionuclide transport, coastal deposition and beach inventories. The results indicate pronounced spatial variability in coastal contamination, with the highest beach inventories occurring along the southwestern Turkish coastline and parts of the Dodecanese islands. Eight beaches were identified as the most impacted locations, where annual effective doses exceeded the IAEA reference level of 10 mSv/year for emergency exposure situations and reached a maximum of 107.5 mSv/year in the Akyaka region. Elevated contamination persisted for several months following the release, although beach inventories gradually decreased due to coastal circulation and sediment redistribution processes. The proposed methodology provides a complementary framework for linking marine radionuclide dispersion, beach contamination, and external radiological exposure assessment, thereby enabling the identification of vulnerable coastal areas requiring priority monitoring and management following a nuclear accident.