"Hydrodynamics and chemical model to evaluate environmental risks in proximity of river mouth"

Pollution of natural river networks is a growing environmental problem, which produces more and more alterations to complex and fragile aquatic ecosystems. This problem is not limited to the river networks but extend all along the coastal area involved with the mouth apparatus. Anthropic emissions of pollutants both as uncontrolled discharge stream and due to accidental sources (i.e. treatment plant failure or chemical disaster in proximity) are the causes of pollution. Integrated numerical models are necessary to evaluate the environmental risk magnitude. These models have to take into account both the natural characteristics of the environment considered and bio-degradation kinetic of the pollutant. In the present paper a numerical unsteady 2D model, able to describe the complex interaction between the hydrodynamic field and biological and chemical processes, has been developed. The model has been applied to the analysis of the mouth of Sarno river (south of Italy) which well represents a case of extensive pollution.