Heavy Metal Levels and Adsorption Capacity of Nile River Sediments

Abstract

Determination for organic carbon and analyses of Cd, Cu, Mn, Pb and Zn were carried out on extractions (exchangeable and residual phases) of the fraction smaller than 63 μm of Nile sediment samples. Also, the fraction sediment samples were treated by synthetic solutions of metals with different concentrations. According to the index of geoaccumulation, the sediment samples are unpolluted by Mn, Cu and Zn, but they have high accumulation of Cd and Pb. The elevated concentrations of Cd and Pb can be attributed to lithogenic origin and anthropogenic sources (manufactures of metal alloys, batteries, and plastics; fertilizers and pesticides; and corrosion of galvanized materials). The adsorption data suggests that the pH is the important factor in the control of metal ions adsorption onto the bed sediments. Nile sediments exhibited high capacity for sorption of heavy metals, especially Pb and Cd followed by Zn, Cd, and Mn. The adsorption of metal ions on Nile sediments follows the Langmuir and Freundlich isotherm models. Statistical analysis was applied to the results and exhibited good and interesting relationships.

Key Words:

• Heavy metals
• sediment
• pollution
• adsorption
• river Nile