Ecotoxicological Assessment of Potentially Toxic Elements (as, Cd, Ni and V) Contamination in the Sediments of Southern Part of Caspian Sea, the Case of Khazar Abad, Mazandaran Province, Iran

In this study, the contamination of arsenic, cadmium, nickel and vanadium in the surface sediments of Khazar Abad, in the southern part of the Caspian Sea was analyzed in 2019 using ecotoxicological indices. The geoaccumulation index (Igeo) values showed that the sediment samples of the study area could be classified as ‘unpolluted’ to ‘strongly polluted’, while, the values of toxic units (TUs) with an average value of 0.591 indicated that all samples could be classified as ‘at low toxicity level’. Moreover, the ecotoxic risk level (TRI) in the studied sediments was classified at the level of ‘no toxic risk’ for Cd and ‘considerable toxic risk’ for As and Ni. On the whole, the results showed that the levels of contamination were higher in the areas where industrial, domestic and agricultural wastewater was discharged (i.e. S4, S7, S10, S11 and S12). Finally, to avoid and/or reduce ecotoxicological dangers, periodic monitoring of PTEs in the coastal strip of the southern part of the Caspian Sea is recommended.