Distribution and ecological risk assessment of some heavy metals in coastal surface sediments along the Red Sea, Egypt

The ecological risk assessment for Al, Zn, Cu, Ni, V, Pb, Cd, and Hg in surface sediment collected from the Egyptian Red Sea coast was evaluated using the Geo-accumulation Index (Igeo), Sediment Enrichment Factor (SEF) and Potential Ecological Risk Index (PERI) methods. The predominant heavy metal, aluminum, showed high concentrations along both of Aqaba Gulf (4378.8±2554.1 µg/g) and southern part of the Red Sea (2972.8±1527.5 µg/g), while it recorded the lowest concentration in Suez Gulf (829.7±398.2 µg/g). The determined heavy metal concentrations had the order of Al>Zn>Ni>V>Pb>Cu>Cd>Hg. The statistical analyses showed some correlations among the heavy metals contents. Several international sediment quality guidelines were used to estimate the quality of the collected sediments. Interestingly, the recorded average heavy metals concentrations were lower than those of the permissible contents for sediment quality guidelines. The Geo-accumulation index calculations (Igeo) proved that the investigated region could be classified as an unpolluted area. Sediment Enrichment Factor (KSEF) study showed high values in Suez Gulf region. The single pollution index analysis of heavy metals in the sediments (Cfi) indicated that Al, Zn, V, and Pb were of natural origin, while Ni, Cd and Hg were seriously affected by human activities. Interestingly, amongst, all the determined heavy metals, Cd and Hg gave moderate ecological risk indicators.