INTERACTIONS OF LEAD(II) WITH NATURAL RIVER WATER .1. SOLUBLE ORGANICS

A comparative study of dissolved complexants for lead(II) on three different sites along a polluted river was undertaken. Intrinsic and apparent acidity constants were obtained from potentiometric titrations. The difference between the two values in all samples reflects conformational and electrostatic effects during titrations. Complexometric capacities for Pb(II) were estimated and average equilibrium constants were obtained from DPASV voltammetric titration curves. Differential equilibrium functions were defined. At the pH measured in the river, the affinity of metal ions for ligands decreases with increasing metal loading of solutions, due to the heterogeneous effect of the ligands.