Mobility of Metallic Trace Elements in Surface Waters and Sediments: Case of the Nil Wadi (Jijel, North-East Algeria)

The Metallic Trace Elements (MTEs) occur in the waters and sediments of wadis with low concentrations. Their mobility is controlled by several physico-chemical parameters (Eh, pH and dissolved oxygen). To determine the effect of these factors on the concentration and mobility of metallic trace elements (Cd, Cr, Cu, Fe, Pb and Zn), bimonthly monitoring of physico-chemical parameters was conducted during the period from November 2013 to January 2015. The results obtained show that the MTEs are very influenced by the variations of the pH and Eh. Under natural conditions, neutral to basic pH and oxidizing medium, only lead is present in waters with high values, indicating its solubility in water and its release of sediments. Other MTEs have high concentrations in sediments, indicating their adsorption and/or chemical precipitation trapping qualities. The spatial monitoring of these MTEs shows the effect of the confluence of the wadi with its tributaries on the variation of its concentrations.