Environmental radiological surveillance in the Baltic Sea: offshore wind farms as platforms for early-warning detection systems.

The Baltic Sea is an environmentally sensitive semi-enclosed marine basin characterized by intensive maritime activity, expanding offshore infrastructure, and the presence of nuclear-related facilities. These conditions increase the importance of environmental radiological surveillance capable of supporting the early detection of transboundary contamination events. This study assesses the potential application of offshore wind farm infrastructure as a platform for autonomous radiation monitoring within an expanded regional surveillance network.The study combined a review of regional radiological hazards, assessment of existing monitoring infrastructure, analysis of environmental radiation data from the European Radiological Data Exchange Platform (EURDEP), and analysis of representative meteorological conditions from 2023-2024 using European Centre for Medium-Range Weather Forecasts (ECMWF) data.The results indicate that radiological monitoring in the Baltic region is concentrated predominantly in terrestrial and coastal areas, leaving offshore regions with limited surveillance coverage. Representative atmospheric conditions indicate that airborne contaminants originating near the Gulf of Finland could potentially reach the southern Baltic coast within approximately 24 h under favourable wind conditions. Assessment of offshore infrastructure suggests that offshore wind farms could serve as platforms for autonomous radiation monitoring because they provide existing power supply, communication infrastructure, distributed offshore locations, and maintenance accessibility. Integration of offshore monitoring with terrestrial surveillance networks could improve spatial coverage and strengthen regional early-warning capability.The proposed framework provides a basis for future atmospheric dispersion modelling and optimization of offshore radiological monitoring networks.