Comprehensive risk assessment of heavy metals in surface sediments along the Egyptian Red Sea coast

The contamination of heavy metals (Fe, Zn, Mn, Cu, Ni, Pb, Cd, Co, Cr, and Hg) in 16 surface sediment samples collected from the Suez Gulf, Aqaba Gulf and the Red Sea Proper was studied to evaluate their distribution and potential ecological risk. The concentrations of the studied metals decreased in the order of Fe > Mn > Zn > Cr > Ni > Co > Pb > Cu > Cd > Hg (3490.2, 115.77, 28.66, 18.47, 11.40, 9.70, 3.26, 1.94, 6.10, 0.02 μg/g dry weight). Based on the effect-range classification (ERL–ERM, TEL–PEL, LEL–SEL), the studied heavy metals did not pose any environmental risks for all investigated stations except Marsa Alam and El-Quseir stations, which may pose an environmental risk for Cr and Ni. The ecological risk assessment for metals in surface sediments was evaluated using the metal pollution index (MPI), geoaccumulation index (Igeo  ), and potential ecological risk index (ERIERI). Multivariate techniques including Pearson correlation, hierarchical cluster and principal components analysis were used to evaluate the metal sources.