[en] A long-term transport model for conservative substances in the marine environment is presented. It has been successfully applied to the simulation of salinity, river water discharges and ¹³⁷Cs dispersion in the Irish Sea. The use of salinity data for calibration of advection and diffusion processes has been shown to be a powerful tool for the development of the model. This mechanism can be considered as a universal calibration method for dispersion models. It could be very useful for the development of models which describe marine scenarios for which very little radiological information is available. (author)