The processes of transfer and diffusion of contaminants in the Sea of Azov in the case of cyclonic atmospheric pertubations were studied using a threedimensional nonlinear mathematical model. The time of dispersal and the maximal volume of impurity penetration (with constant and variable initial distributions of its concentration) were compared for cyclone and calm water conditions. It is demonstrated that the dispersal of impurity slows down as the gradient of its initial concentration increases.