LEVELS OF SELECTED HEAVY METALS (Pb, Cd, Zn AND Fe) IN SEDIMENT AND WATER OF LAKE ADELE, HARAMAYA, ETHIOPIA

Abstract

This study focuses on the determination of heavy metal levels in lake water and sediment of Lake Adele using AAS. The heavy metals considered in this study were cadmium, lead, iron and zinc. The water and sediment samples were collected within 30m distance of (5) sampling point in the Lake using plastic container and were analyzed based on standard methods. The findings indicated that the mean concentrations (mg/L) of metals in the water samples were found to be Fe: 0.981 ± 0.017; Zn: 0.112 ± 0.001; Cd: 0.006 ± 0.001 and Pb : 0.008 ± 0.000 for wet season and Fe :0.976 ± 0.021; Zn : 0.104 ± 0.004; Cd : 0.004± 0.001 and Pb = 0.005 ± 0.002 for the dry season. The concentrations of the heavy metals (mg/L) obtained in the sediment in both wet and dry seasons were: Fe: 1.048±0.016; Zn: 1.222 ± 0.036; Cd: 0.01±0.004 and Pb: 0.007 ± 0. 0.001and Fe: 1.119 ± 0.020; Zn: 1.334 ±0.034; Cd: 0.017±0.003; and Pb: 0.008±0.002; respectively. The obtained concentration of these heavy metals maybe due to agricultural activity performed around the lake, sewages from the rural as well as urban area near the lake or from combustion of leaded petroleum and benzene from automobiles and probably these may have occurred naturally. It is recommended that a detailed study should be carried out to identify and isolate the main sources of heavy metals in the Lake so that appropriate control measures could be developed.