Factors controlling the vertical and spatial transport of metal-rich particulate matter in seawater at the outfall of bauxitic red mud toxic waste

The spatial and vertical distribution of metal-rich particulate material is studied in the Antkkyra Bay (Gulf of Corinth Greece), where bauxitic red mud is discharged from an alumina processing plant. It is revealed that a significant amount of the metalliferous mud released on the seafloor enters the water column in the form of suspended particulate matter. At least at certain periods of the year suspended particulate matter is trapped at certain water layers due to the water mass stratification. It is demonstrated that the red mud reaches the seasurface, upwelling being a major process responsible for its upward dispersion. In the upper seawater layers the suspended matter is transportedin a NW-SE direction whereas in the deeper layers it is transported in a NE-SW direction.