source of heavy metal pollutions in the sediments of the anzali wetland in northern iran

abstruct 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.