This paper presents the study and analysis of the bistatic electromagnetic (EM) signature variation of the sea surface contaminated by pollutants. Therefore, we start with the numerical analysis the effect of the presence of the pollutant on the sea surface characteristics. Then, we evaluate the EM scattering coefficients of the clean and polluted sea observed in bistatic configuration by using the rigorous Forward-Backward Method (FBM) and the asymptotic Two Scale Model (TSM). The obtained numerical results of the EM scattering coefficients are studied and given as a function of various parameters: sea state, type of pollutant, incident and observation angles, frequencies and radar polarization.