HEAVY-METALS IN THE WATER, SUSPENDED-SOLIDS AND SEDIMENT OF THE RIVER TIGRIS IMPOUNDMENT AT SAMARRA

The concentrations of Cd, Cu, Co, Fe, Zn, Mn, Pb and Ni were determined in water, suspended solids and surficial sediments of the River Tigris at the Samarra impoundment during high (April) and low (July) river discharge months in 1988. The recorded concentrations in water were either significantly lower or within the Iraqi river water standards and the average clean river water of the world. Variations in the concentrations of heavy metals in suspended solids were interpreted to be due to local differences in current velocity and distance from the shore line (from sewage source of the residential sector). The concentrations of most of the examined elements in the surficial sediments (except for Mn and Fe during April) were lower than those in the suspended solids. Results stress the importance of the suspended solids in transportation of heavy metals in the River Tigris. Higher concentrations of Co, Mn and Fe are discussed in relation to sedimentation process and the nature of the river basin.