Vertical and Lateral Variation of Ecological Risk Index of Heavy Metals in the Euphrates River Sediments between Heet and Fallujah, Iraq.

Abstract

The heavy metals (HMs) contamination of river sediments and their ecological risks is a global environmental problem that has attracted the attention of researchers and those interested in environmental protection. The study aims to investigate the ecological hazards of some HMs in sediments of Euphrates River between the cities of Heet and Fallujah, Iraq and their lateral and vertical variations. At three depths—0-30, 30-60, and 60-90 cm—samples of sediment were collected from five sites. Atomic Absorption Flame Emission Spectrophotometer (ASC.7000) was used to measure concentration of Cd, Cr, Cu, Ni, Pb, and Zn. The ecological risk index (ErI) values of metals in Euphrates River sediment in the study area take the following descending order: Cd > Ni > Cu > Cr > Pb > Zn. The ErI levels were low for Cr, Cu, Ni, Pb and Zn and considerable ecological risk for Cd. The obtained results did not show a common lateral variation pattern of the ecological risk of the measured metals. There is a high level of risk for the measured metals at the downstream sampling sites except for the risk from Cd on the contrary. The potential ecological risk of Cd, Cr, Pb and Zn showed a similar vertical variation pattern which in turn reflects a common source or origin for these metals, while copper and nickel showed a different common distribution pattern.