The determination of the buffer capacity of natural waters and soil allows calculating the pollutant amounts which delivery does not essentially break the natural character of their functioning. This question is the major one in the soil sciences, ecology and wildlife management. The complexity of the soil solution composition containing mineral phases and a large set of involved chemical compounds determine the possibility of simultaneous chemical reactions along with the capacity of solid phases of minerals to maintain relatively constant the aqueous solution composition [1]. Under real conditions, the buffer action of natural heterogeneous aqueous systems is expressed as the consumption of any element from solution, which causes the partial dissolution of solid phases and as a result the chemical composition of the solution is restored.The provision of plants is generally assessed by the potential buffering capacity of soils in relation to the elements of plant nutrition. The smaller the ion activity changes as conditions change, the higher the buffering capacity of the soil, the more stable conditions of plant nutrition [2]. The main focus in this paper is to show how to use the developed buffer theory for assessing and predicting the long-term phenomena of attenuation and natural remediation of ionic pollutants in contaminated aquatic ecosystems, as natural waters and soil solutions. This theory is used for analyzing the way by which metal ions move and transform within the environment, their distribution in ecosystems, their deposition and cycling in the terrestrial environment. The buffer theory is based on the rigorous thermodynamic analysis of complex chemical equilibria under environmental conditions in aquatic ecosystems. It has been established that both homogeneous and heterogeneous systems manifest a buffer action towards all their components. The buffer properties in relation to the solid phase components are amplified with an increase of solubility due to protolytic or complex formation equilibria in aqueous saturated solutions. It has been established, that the buffer capacities of components are mutually proportional, whereas for heterogeneous systems these relationships depend on the stoichiometric composition of solid phases. The use of the developed buffer approach yields extended knowledge and a deeper understanding of the processes that control the concentrations of various components. The obtained results are intended to provide researchers with a tool needed to set reliable limits of ionic pollutant levels in the environment.