Abstract
El Temsah Lake is one of the most important wetlands in the Suez Canal area and the major source of fish for the area. In this study, the relative role of sediments' geochemical properties and metals geochemical fractionation in determining Cd, Cr, Fe, Mn, Ni, and Pb mobility and toxicity was especially concerned. The results reflected that the increasing order of contamination for the investigated metals according to individual contamination factor (ICF) was: Cr > Mn > Ni > Pb > Cd > Fe. Risk assessment code (RAC) classification showed that the relative amounts of easily dissolved phases of metals in the sediments followed the order of Ni > Cr > Cd > Pb > Fe > Mn. The toxicity as indicated by toxic unit (TU) due to an individual metal followed a descending order of Ni > Cr > Pb > Cd, indicating that Ni and Cr accounted for the majority of the overall sediment toxicity while, Cd contributed the least to the ΣTU. This work constitutes a good basis for further studies about metal fractionation in El Temsah Lake which might help policy makers to take effective decisions for proper management of the lake.
•A five-step sequential extraction technique has been applied to verify the chemical forms of metals.•Cr, Ni, Mn, Cd, and Pb are abundantly found in the Fe/Mn oxides fraction.•The increasing order of contamination followed: Cr > Mn > Ni > Pb > Cd > Fe.•The relative amounts of easily dissolves phase of metals followed the order of Ni > Cr > Cd > Pb > Fe > Mn.•Calculated total risk index of the sediment samples indicated no toxic risks.