Assessment of heavy metal contamination in sediments of the Tigris River (Turkey) using pollution indices and multivariate statistical techniques

► All metals showed significant spatial variations. ► Pollution indices indicated the first site was strongly polluted. ► The concentrations of Cr, Cu, Ni and Pb may result in harmful effects on sediment-dwelling organisms. ► PCA/FA and CA suggest As, Cd, Co, Cr, Cu, Mn, Ni and Zn are derived from the anthropogenic sources.