In this study, a polymer/zeolite-based composite barrier material was prepared and its performance against 126Sn isotope under varying conditions in radioactive waste repository was investigated. Adsorption isotherms and kinetic and thermodynamic parameters were calculated from the data obtained by examining 126Sn in its interaction with the barrier material under varying parameters such as different initial concentrations, interaction time and temperature. It has been observed that the adsorption of tin ions on the barrier material fitted into the D-R isotherm model. The adsorption of the tin onto the barrier was determined to be endothermic from the thermodynamic parameters. From the kinetic evaluation, it has been seen that the tin adsorption process was compatible with the pseudo second-order model. The risk of migration of 126Sn as a result of an accident in radioactive waste repository was assessed using by GOLDSIM Monte Carlo Simulation Software. Carcinogenic and non-carcinogenic risks and excess lifetime cancer risks of tin were evaluated.