Three-dimensional vortex structures involving obliquely descending eddies (ODE) has been proved to be associated with local sediment suspension in the surf zone. Otsuka et al. (2017) explained the mechanical contributions of the ODEs to enhance local sediment suspension under the breaking waves and modeled the vortex-induced suspension to predict the profile of the equilibrium sediment concentration. In order to predict local behaviors of sediment, however, sediment-turbulence interactions in the transitional turbulence under breaking waves need to be understood. In this study, contributions of the sediment advection and diffusion in the vortex structure to the concentration are computationally investigated.