The analyzed homogeneous systems manifest buffer actions towards protons, calcium ion and carbonate. The main theoretical characteristics of the buffer properties of studied systems have been derived. It was found that the buffer capacities towards protons, calcium ion and carbonate are mutually proportional. The deduced analytical expressions for buffer capacities in respect to all ions of distributed species are reported. Apparently, the presence of calcium in solution signifi cantly increases the value of the buffer capacity towards proton. This essential conclusion should be considered at the assessment of the buffer action of soils which increases in the presence of metal ions, capable to form even in insignificant quantities the complex particles. The derived expressions could successfully be used to estimate long-term chemical changes in soil and soil water in response to changes in atmospheric deposition.