Variation and correlations of selected heavy metals in sediment and aquatic plants in Tasik Chini, Malaysia

This paper aims to determine the correlation between Cd, Cu and Pb concentration in the sediment and in five aquatic plants sampled during wet, normal and dry seasons. Analyses of the sediment showed that concentrations of exchangeable Cd and Cd after acid reduction were higher during the wet season (October) than on other sampling dates with mean values of 0.18 and 0.29 mu g g(-1), respectively. The concentration of Cu in the organic oxidation phase was higher in the normal season (January) than on other sampling dates with a mean value of 11.1 mu g g(-1). The concentrations of exchangeable Pb and that in the residual phase were higher during the wet season than on other sampling dates with mean values of 1.05 and 9.18 mu g g(-1), respectively. Cd and Pb concentrations in the leaves, stems and roots varied between sampling dates with a reduced concentration during dry season (July) and the highest metal concentrations (Cd and Pb) during wet season. There were positive correlations between Cd and Cu concentrations in the plant tissues (leaves, stems and roots) of most aquatic plants in the acid reduction fraction. Conversely, there was no positive correlation between Pb concentration in the plant tissues of all aquatic plants and the acid reduction fraction of the sediment.