Study of the complex formation of copper(II) by humic and fulvic substances

A study of the complexation of copper(II) by fulvic substances, based on ion-selective electrode measurements, is reported. The influences of the copper concentration (10-6 –1O-4 M), fulvic acid concentration (2–100 mg 1-1), pH (3–8) and calcium concentration (10-4–5 × 1O-3 M) are given particular attention. The effects of statistical errors on the measurement of the values of the complex-formation parameters are considered. These parameters are measured for various surface-water samples, aqueous soil extracts, peat water and solutions of organic matter formed by in vitro decomposition of leaves. In general, these parameters vary little with actual source for a particular type of water.