Assessment of Radionuclide Contamination in Foreshore Sands of the Baltic Sea near Juodkrante in Lithuania

This study presents a methodological approach to assess radionuclide contamination in the Baltic Sea near Juodkrante, Lithuania, based on measurements of β- and γ-emissions in seawater, foreshore sand, and dune top sand. Existing assessments often lack sufficient site-specific detail and multicompartment analysis, limiting the understanding of localized contamination and radionuclide behavior in coastal environments. Sampling was carried out between 2019 and 2024 at approximately the same geographical coordinates, along transects orientated normally to the shoreline. Given that the dune top remains unaffected by seawater intrusion, while the foreshore sand is subject to regular inundation, the foreshore environment is considered a natural filter that is capable of accumulating radionuclides from seawater. The proposed methodology supports the hypothesis that radionuclide retention in sandy substrates may persist beyond episodic contamination events in seawater, with retention dynamics influenced by environmental factors such as hydrodynamic conditions and aeolian processes. Simultaneous β- and γ-emission analysis enhances the precision of radionuclide quantification, while comparative evaluation of γ-spectra improves the detection of both natural and anthropogenic radionuclides, providing insight into both contemporary and historical contamination processes. The sustainability of the proposed approach lies in its efficient use of time, resources, and effort to monitor radionuclide contamination. Unlike conventional techniques that require energy-intensive seawater processing, this approach uses foreshore sand, which passively accumulates radionuclides through natural wave-driven deposition.