Properties of concentration waves of solutes affected by nonlinear sorption, precipitation/dissolution and homogeneous reactions in the mobile and stationary phases are established when the number of phases is constant. These properties essentially depend on the structure of a stoichiometric matrix which describes the chemical interactions. A reduction procedure of the stoichiometric matrix gives the number of waves or peaks together with their propagation velocities, and the retardation factors of species at trace levels. The location of the peaks and their broadening behavior due to the nonlinear equilibria are estimated. The number of waves and the properties of suitable linear combinations of concentrations provide a method for discriminating among rival interaction mechanisms irrespective of the equilibrium constants. This cannot be done using conventional methods based on the comparison between numerical simulations and experimental curves. ¿ American Geophysical Union 1993