Maritime transport impact on pollution in Saronikos Gulf: modelling, insight and perspectives from two research projects.

This work concisely presents findings and insight on the impact of shipping on pollution of an eastern Mediterranean coastal marine ecosystem - Saronikos Gulf, Greece. Advanced modelling tools (STEAM, SILAM, Delft3D) were employed to assess shipping-related pollution from direct discharges and atmospheric emissions of heavy metals, PAHs and Elemental (black) Carbon (EC). Simulations for 2018 revealed that shipping contributed < 1% to total pollutant loads. Projections for 2050 under various traffic and fuel scenarios indicated that open-loop scrubber discharges could increase concentrations locally. The fate of fine EC particles was also investigated, showing that EC from shipping represents a small fraction of total atmospheric deposition, though some accumulation in marine sediments occurs. High-resolution Delft3D simulations, forced by seasonal EC deposition data accounting for all sources from the WRF-CAMx modelling system, were used to evaluate EC transport and distribution in the Gulf. Results showed increased EC levels in Elefsis Bay for January and July 2019 and decreasing gradients offshore, in agreement with field observations, reflecting source importance and seasonal variation. Findings highlight the limited yet important role of shipping in localized marine pollution.