The seasonal and spatial variations of labile copper, iron, manganese, lead and zinc sediment fractions in Lake Naivasha, Kenya

摘要: Lake Naivasha is a freshwater lake with no surface outlet, lying within closed basin of the Kenyan Rift Valley. It perceived to be undergoing anthropogenic stresses. This study intended determine speciation some selected heavy metals in sediments Naivasha, as an indicator potential pollution lake. Sediment and water sampling was conducted March May 2003, during dry wet seasons, respectively. Analyses sediment samples (<63 µm faction) were performed on collected from five sites The results obtained indicated that influent Malewa River not source labile copper (Cu), lead (Pb) or zinc, despite river having highest percentage clay content season (86%). Copper highly distributed residual fraction (average 90%). Among factions, quantity Cu oxidizable phase (3.58 2.30 µg g−1 season, respectively). Carbonate-bound sparingly both ranging between 0.74 1.81 µg g−1. Iron phase, exhibiting concentrations 2.0 6.0 (×103) µg g−1. Relative other metals, manganese lower proportions fraction. High Pb observed most along shore. Zinc largely being at site SS, which located near municipal sewage input deep portion exhibited metals.