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

A comparative study of dissolved complexants for lead(II) on three dif ferent sites along a polluted river was undertaken. Intrinsic and appa rent acidity constants were obtained from potentiometric titrations. T he difference between the two values in all samples reflects conformat ional and electrostatic effects during titrations. Complexometric capa cities for Pb(II) were estimated and average equilibrium constants wer e obtained from DPASV voltammetric titration curves. Differential equi librium functions were defined. At the pH measured in the river, the a ffinity of metal ions for ligands decreases with increasing metal load ing of solutions, due to the heterogeneous effect of the ligands.