Effect of Cl-, SO4(2-), and fulvate anions on Cd2+ free ion concentrations in simulated rhizosphere soil solutions.

The binding between heavy metals and corresponding ligands affects their chemical behavior and toxicity in soil environments. The mechanisms of competitive complexation and/or chelation between Cd(2+) free cations and preferential concentrations of Cl(-), SO(4)(2-), and fulvate anions were investigated in simulated soil solutions at pH 4.00, 5.