Present study comprises of laboratory scale dissolution experiments and numerical modeling of the transport of dissolved organic contaminants. Dissolution experiments were conducted in both glass and stainless steel tubes with toluene as the non-aqueous phase contaminant. The results showed that the method of developing residual saturation has a profound effect of the uniformity of mass distribution within the porous media. The issue of using a single value of residual saturation has been analyzed for representing a uniform contaminant source. Further, the effect of residual saturation on the non-equilibrium dissolution mass transfer was observed to more critical than other rate-limiting reactions.