In this talk we discuss transport mechanism of small solute molecules across various fluid interfaces, such as an interface between two immiscible liquids and a surfactant-covered liquid-liquid interface. First, we present a detailed discussion of the transport in a model system which consists of an immiscible hexadecane-water interface and a spherical solute. This system is modeled using coarse-grained molecular dynamics simulations. It turns out that the motion of the solute molecules near the interface significantly deviates from the Brownian motion and cannot be described by a Langevin equation typically assumed to be valid for transport of small solutes. Specifically, the correlation time of the random force due to the interactions between the solute and the solvent molecules is strongly dependent on the solute distance from the interface. The correlation times are on the order of 1 ps away from the interface but reach 100 ps within a very narrow (less than 1 nm wide) region of the interface. We demonstrate that the slow fluctuations of the random force in this narrow region are caused by density fluctuation of the two fluids in an area surrounding the solute. Unlike the random collisions of the solute with the solvent molecules in homogeneous fluids, the density fluctuations at the interface change the composition of the fluid surrounding the solute relatively slowly. This in turn leads to the slow force fluctuations. The force correlation time increases in the area of a large gradient of the potential of mean force acting on the solvent, i.e. in the areas of large resistance to the solute transport. Therefore, the long-time force correlations play a significant role in the solute transport. Once the connection between the density fluctuation and the random force is established, we propose a modification of the transition-state theory for the solute transport to account for the long-correlation times of the random force in the areas corresponding to a large resistance to the solute transport. In conclusion, we demonstrate that this phenomenon is also observed for solute transport across surfactant-covered oil-water interfaces, as well as lipid bilayer membranes and discuss implications of this phenomenon on the solute transport in a large class of interfacial systems.