Geochemical speciation and ecological risk assessment of selected metals in the surface sediments of the northern Persian Gulf

•Geochemical fraction of metals were determined in surface sediments from the northern Persian Gulf.•All metals were predominantly associated with the residual fraction.•Cd and As had moderate to significant enrichment.

The present study aimed to geochemical speciation of metals in the surface sediments of the northern Persian Gulf. Metal contents in the sediment were observed in the order: Al > Fe > Cr > Ni > V > Zn > Cu > Co > As > Pb > Cd. The results of sequential extraction procedure revealed that all metals were predominantly associated with the residual fraction. Among the metals, Cu and As exhibited higher bioavailability. The risk assessment code (RAC) indicated that Cu, As and Cd had medium environmental risk at some sampling sites. Based on enrichment factor (EF), Cd and As had moderate to significant enrichment.