Coefficients of association and activity of cadmium and lead ions in soil solutions

摘要

The thermodynamic calculations were made for the contents of Pb and Cd compounds in soil solutions and water extracts of the meadow-steppe and meadow solonetzes (Rostov oblast) based on their prescribed analytic concentrations of 3 and 5 mu g/l, respectively. The solonetzes studied are characterized by their high carbonate content and high alkalinity. The activity of Pb2+ and Cd2+ was shown to be many times lower than their total concentration in the solution due to the association of these metals with carbonate and other anions and the formation of hydroxocomplexes CdOH+ and PbOH+. This fact is one of the reasons for the low input of Pb2+ and Cd2+ to plants growing on calcareous soils.