The habitability of large icy moons has long been disputed due to the presence of an high-pressure (HP) ice layer located between the core and the internal liquid ocean, preventing a direct contact and facilitated exchanges between both. In our previous study Lebec et al. (2023), we have shown that under certain conditions and considering the phase change at the upper boundary of the HP ice shell, heat and mass transfer can occur and be e cient. Now, the aim of this work is to study the e ects of impurities inside the HP ices on the flow dynamics and the mass transfer e ciency from the core to the ocean. These salts can enter the ice layer either by di usion, which is a very ine cient process, or by partial melting at the bottom of the ice layer, if the temperature is high enough. In that case, the liquid water can interact with the core and get enriched in salts. This salts/water mixture, which can be lighter than high-pressure ices, could rise through the ice shell and refreeze. The resulting salts/ice mixture can be transported into the ocean by convection in the solid state but could also impede it due to its density compared to pure ice. Therefore, the convection e ciency depends on the buoyancy number B salts , which is the ratio of density increase associated with salts compared to the decrease associated to temperature. To explore the impact of salts, we model a flux of salts from the core and the advection of these salts using Lagrangian tracers in order to study the effects of the Rayleigh number, the buoyancy number and K, which is the partition coe cient of the salts between the ocean and the HP ices at the top interface, on the heat and salts transfer e ciency through the HP ice layer, as well as the implications for the evolution of salt concentration in the ocean of large icy moons and ocean worlds. We present a scaling of the bottom temperature and the top radial velocity w top as function of the Rayleigh number Ra q for various values of the buoyancy number and a scaling of the e ective flux of salts across the top interface with the ocean as function of the buoyancy number for various values of the partition coe cient. We perform a numerical application for Ganymede and show that depending on the values of the system parameters, a significant percentage of the salts entering the HP ice layer from the core can e ciently flow into the ocean.