Multi-index assessment of sea bottom sediments of the Izmir Gulf, Aegean Sea: A study of interrelation between anthropogenic and hydrodynamic effects

This study aimed to investigate the sediment transport pathways and geochemical parameters in the Izmir Gulf to determine the heavily impacted areas by natural and anthropogenic parameters. The grain size trend analysis was used to determine sediment transport patterns and, statistical methods were employed to identify the sources and distribution of chemical elements in sediments. The main factors that were affecting the area were identified as lithogenic, anthropogenic, maritime traffic, biogenic and shipyard activities. The tannery industry (Cr), maritime traffic and shipyard/dock activities (Cu and Zn), road traffic run-offs (Pb and Zn), and untreated domestic waste discharges (TOC and S) were identified as the sources of metals. Contamination rankings based on metal concentrations indicated higher pollution levels in the Inner Gulf compared to the Central Gulf. Zinc and chromium were found to pose significant risks to benthic organisms. The pollutants tended to accumulate in deposition zones, following sediment transport directions. [Display omitted] •A multidisciplinary method was used to determine the anthropogenic and hydrodynamic parameters.•All environmental assessment indices showed low to high pollution existing in the Izmir Gulf.•The pollution migration pathways from Izmir Inner Gulf to Central Gulf were revealed by net sediment transport model.•The main element that poses the most risk for benthic organisms was Zn in the Inner Gulf and Cr in the Central Gulf.•The main sources of pollutants were lithogenic, anthropogenic, maritime traffic/shipyard activities and biogenic in origin.