Speciation of heavy metals in water from the Uganda side of Lake Victoria

Abstract

Different forms of copper Cu, zinc Zn, lead Pb and cadmium Cd in water from the Uganda side ofLake Victoria (25°C, pH 6.75–7.18), the second largest inland freshwater lake in the world, havebeen studied using ion-exchange, dialysis and atomic absorption spectrophotometry. The resultsindicate that heavy metals Cu, Zn, Pb and Cd are present mainly in the cationic form (80–83%).Small quantities of anionic (13–22%), non-ionic, dialyzable (4–8%), and non-ionic, non-dialyzable(< 1.3–4.4%) forms were also detected for all metals except Cd. The corresponding concentrationslay in the ranges: cationic, 0.06–0.99; anionic, < 0.001–0.25; non-ionic, dialyzable, < 0.001–0.08;non-ionic, non-dialyzable, < 0.001–0.06 μg ml−1. The existence of the metals in non-ionic and non-dialyzable forms is attributable to metal associations with high relative molecular mass (RMM)organic matters.