Heavy metal concentrations in surficial sediments and benthic macroinvertebrates from Anzali wetland, Iran

Lead, Copper, Zinc and Manganese were measured in surficial sediments, chironomid larvae, tubificid worms and two species of bivalve molluscs (Mytilaster lineatus and Corbicula fluminalis) from the Anzali wetland, Iran.No distinct relationship was observed between heavy metal levels and percentage fine fraction in sediments. The pattern of Mn accumulation was parallel to trends of organic matter variation. There were highly significant differences between sampling sites in contents of heavy metals but no significant differences between seasons. Significant differences were found in bioaccumulation of Lead and Zinc in three size categories of chironomid larvae. Lead was higher in smaller M. lineatus, while the reverse was observed for Copper.