Effect of an attendant anion on the balance of cations in the soil-solution system with an ordinary chernozem as an example

The effect of different anions on the balance of heavy metal cations in the soil-solution system has been assessed under model laboratory conditions. It has been found that the uptake of the Cu, Zn, and Pb cations by an ordinary chernozem from solutions of different salts is accompanied by the displacement of the exchangeable cations to the solution in the following order: Ca²⁺ > Mg²⁺ > Na⁺ > K⁺. The sum of the displaced exchangeable cations in most cases exceeds the amount of the adsorbed heavy metal cations. According to the effect of the anions on the displacing capacity of the metal cations, the following series are formed: for copper, SO ₄ ^2? ? Cl^? > OAc^? > NO ₃ ^? ; for lead, Cl^? ? NO ₃ ^? > OAc^?; and, for zinc, SO ₄ ^2? ? Cl^? ? OAc^? > NO ₃ ^? .