Metal Correlations and Mobility in Sediment and Water from the Gwebi River in the Upper Manyame Catchment, Zimbabwe

Intermetallic correlation and the ameliorative effects of metals (Cd, Cr, Cu, Fe, Ni, Pb and Zn) were determined in water and sediments in the Gwebi River, a major tributary to Lake Manyame, which is a source of potable water to the City of Harare. Water and sediment were sampled at four selected sites in the wet (December- March) and dry (April-November) seasons and metal concentrations were analysed by flame atomic absorption spectroscopy (FAAS). Significantly high concentrations of zinc and copper were observed in water in both the wet and dry season. Concentrations of chromium, copper, zinc iron and nickel in water in both the wet and dry seasons surpassed World Health Organization (WHO) thresholds. The significant difference (ANOVA, p < 0.05) in seasonal/temporal variation in metal concentrations in water indicate different pollutant sources within the catchment of the river. Ameliorative effects of metals were also observed seasonally in the Gwebi River, with