Oceanographic and weather forcing on PAH transport. The case study of mussel farming in the Gulf of Pozzuoli (Southern Tyrrhenian Sea)

This thesis investigates the oceanographic and meteorological mechanisms driving recurrent exceedances of polycyclic aromatic hydrocarbons (PAHs) in mussels farmed at Lucrino, within the Gulf of Pozzuoli (Southern Italy). Despite long-term monitoring, the processes responsible for contaminant transport and accumulation remained poorly understood. Two complementary experimental frameworks were designed to address this issue. A local model-based approach for the year 2016 integrating chemical monitoring, high-frequency physical and dynamical observations along the water column, oceanographic model outputs, and Lagrangian simulations to analyse the contamination episodes. The results revealed that PAH exceedances occur predominantly during late autumn and winter, under persistent southerly winds associated with enhanced wave energy (Wave height > 1.2 m; Wave period > 8 s). This setting induces sediment resuspension and northwestward nearshore advection from the Bagnoli brownfield toward Lucrino farm. An alternative and complementary regional altimetry-based approach used geostrophic velocities, wind datasets, and particle tracking to evaluate basin-scale contamination dynamics for the 2024 contamination events. The analyses identified wind-driven advection of nautical-fuel residues as a possible source of surface contamination, highlighting the combined role of maritime traffic emissions and large-scale circulation. The integration of both approaches provides a comprehensive multi-scale framework linking local sediment dynamics to regional atmospheric and oceanic forcing. The results demonstrate that PAH contamination at Lucrino might arise from two processes that could interact, namely sediment resuspension and wind-driven surface advection — both modulated by seasonal meteorological patterns. The two hypotheses regarding contamination sources, which account for multi-scale processes, form the basis for a forecast-oriented risk management strategy that integrates real-time meteorological data, hydrodynamic models, and satellite observations. Beyond the Gulf of Pozzuoli, the methodology is transferable to other semi-enclosed or industrially impacted coastal systems, supporting operational monitoring, pollution mitigation, and sustainable aquaculture management.