Distribution and pollution level of nickel and vanadium in sediments from south part of the Caspian Sea, Iran

Distribution and pollution level of nickel and vanadium in sediment from south part of the Caspian Sea, north of Iran, were studied. Sediment samples obtained by Van Veen Grab from four stations, including, Turkaman, Amirabad, Fereydunkenar and Noushahr along the south part of the Caspian Sea, during fall of 2015 and april, summer and winter of 2016. The concentrations of metal were ranged from 21.63 mu g/g to 55.45 mu g/g for nickel and from 58.23 mu g/g to 146.27 mu g/g for vanadium in sediments samples collected from all stations. There was significant difference in metals concentration between different stations along the Caspian Sea (P < 0.05), and the highest mean concentration of metals was absorbed in Fereydunkenar estuary, followed by Amirabad, Turkaman and Noushahr, respectively. The results showed that there were significant differences between metals pollution during four seasons (P < 0.05), and the highest concentration of metals were absorbed in dry season (summer) and the lowest concentration in wet season (winter). There was a positive correlation between nickel and vanadium concentration in sediment samples, and the Pearson correlation was (r = 0.67) between nickel and vanadium in sediment samples. The positive correlation between heavy metals can be related to same source of both metals in the environment. Based on our results, anthropogenic activities such as oil industry and agriculture activities are the main sources of pollution in the coasts along south part of Caspian Sea.