Large-Scale Mercury Dispersion at Sea: Modelling a Multi-Hazard Case Study from Augusta Bay (Central Mediterranean...

Area of Science:

• Environmental Science
• Marine Chemistry
• Geology

Background:

• Augusta Bay, a seismically active Mediterranean area, suffers from high mercury (Hg) contamination in sediments and seawater due to historical industrial activities.
• The bay's artificial damming system confines a significant reservoir of mercury in sediments and seawater.

Purpose of the Study:

• To model the potential multi-hazard effects of an earthquake on mercury dispersion in Augusta Bay.
• To assess the impact of dam failure on mercury spreading into the open sea.
• To evaluate the effectiveness of coupled hydrodynamic and biogeochemical models in predicting contaminant transport.

Main Methods:

• Utilized a high-resolution 3D hydrodynamic and transport model.
• Incorporated sediment-seawater mercury (Hg) fluxes using the HR3DHG diffusion-reaction model for inorganic and organic Hg species.
• Simulated a scenario involving earthquake-induced damage to the damming system.

Main Results:

• The study simulated enhanced mercury spreading into the open sea following a hypothetical dam collapse.
• The model demonstrated the potential for significant spatial dispersion of mercury contaminants.
• The findings highlight the complex interplay between natural and anthropogenic hazards.

Conclusions:

• A combination of natural (earthquake) and anthropogenic (industrial pollution, dam integrity) multi-hazards poses a significant risk to marine ecosystems.
• Enhanced mercury dispersion following such events could severely impact the marine environment.
• Current risk management strategies in contaminated marine areas require re-evaluation to account for complex multi-hazard scenarios and pollutant biogeochemical dynamics.