Concentrations of Different Metals in the Caspian Sea Coastal Surface Sediments along the Three Transects of Kapourchal, Bandar-Anzali, and Kiashahr

This study was conducted to determine the origin and distribution of the lead, copper, zinc, nickel, chromium, and vanadium metals in the surface sediments of the southwestern coasts of the Caspian Sea. Surface sediment samples were collected from the three transects of Kapourchal, Bandar-Anzali, and Kiashahr at three different depths of 10, 20, and 50 m. Metal concentrations were determined by ICP-OES. The metals in these areas were identified to originate from such natural sources as rock weathering and soil erosion transported by rivers into the sea. The mean total concentrations of the metals along the three transects showed significant increases with increasing distance from the shore, which might be due to the transportation of sediments as a result of increasing slope along the sampling transects. The same trend was observed in the samples taken from the coastal areas along Bandar-Anzali, which was could be due to the wetlands in the region and the multitude of rivers flowing into this wetland which eventually carried the sediments into the sea. Results revealed that the total metal concentrations in the region were below the SQGs and NOAA standards. Finally, risk assessment code did not show any serious risks, but indicated only a low risk due to lead and copper levels.