Trace Metals Analysis in the Sediments of the Southern Caspian Sea

In this study, concentration of 17 elements, including As, Ba, Cd, Co, Cu, Hg, Mn, Ni, Pb, Zn, Ca,Fe, Mg, Na, P, S, Si, as well as methylmercury in 31 surface sediments were assessed. The sampling stations were Gulf of Golestan, Miankale Island, Babolsar, Nowshahr and Anzali, which represented the most important harbors in the Golestan, Mazandaran and Gilan provinces in the southern parts of the Caspian Sea, respectively. Mercury and methylmercury concentrations in the surface sediments ranged from 10 to 44 and from levels below detection limit to 0.41 ng. g-1 d.w, respectively. The fraction of methylmercury accounted from 0.3 to 2.4 % of the total mercury content. Organic carbon contents varied from 0.26 % to 1.50 %. In this study, element concentrations in the sediments did not exceed the sediment quality guidelines and posed no environmental concerns, with the exception of nickel, which was in the moderate pollution range.