Boundary absorption intensity can affect the contaminant depletion capacity within rivers, and the process of spatial contaminant cloud expansion is complicated with the consideration of irreversible absorption boundaries at riverbanks. Nonuniformity of concentration distribution appears in spatial concentration distribution, especially in the transverse direction, which is caused by the absorption capacity difference between two riverbanks. A model for illustrating the performance of environmental dispersion with two irreversible absorption banks in 2D space is given in this work. Furthermore, the position of the maximum concentration distributions shifts within the transverse directions with the change of the absorption intensities at two boundaries. The overall absorption capacity would also be affected by the ratio of two absorption intensities at the left and right riverbanks. The residual mass is left with a greater variation …