Source of Heavy Metal Pollutions in the Sediments of the Anzali Wetland in Northern Iran

Anzali wetland in north of Guilan provience is an international important wetland that is recorded in Ramsar convension. Pollution is one of the major problems facing this wetland. In order to investigate the pollution situation, sediment core samples were taken in 7 stations in 4 districts within the wetland, namely Abkenar, Siakishom, Hendekhale and Shijan). Elements were determined in 0,5 10, 20 and 50 cm depths in each core. Major elements including Al, Ca, Fe, K, Mg, Na, Mn, P, Ti and trace element such as Li, Ba, S, Sr, As, Cd, Cr, Co, Cu, Mo, Ni, Pb, V, Zn, Bi concentrations were determained using ICP-MS. Temporal variability showed that most of the heavy metals decreased in concentartions from surface to depth. The statistical correlations among elemental pairs were performed by Pearson correlation. In Abkenar part of the wetland except Cr, Ni, Zn and Co, other heavy metals have anthropogenic source. Elemets such as Bi, Zn, V, and Pb in Siakishom part, Cu and Ni in Hendekhale, V, Cr and Co In the Shijan part have natural source. When comparing heavy metal concentrations in wetland sediments with Caspian Sea sediments and river sediments, it is apparent that the concentrations of heavy metals in wetland sediments are higher. Furthermore, considering the EF (Enrichment Factor) using Al normalization as the best method, the elements such as Zn, in all parts and Pb, Bi, Cd and Ni in most of wetland have low enrichment.