Heavy Metals Pollution and Speciation in Sediments of Southern Part of the Caspian Sea

M. Saeedi; A.R. Karbassi

Heavy Metals Pollution and Speciation in Sediments of Southern Part of the Caspian Sea

2006

M. Saeedi | A.R. Karbassi

In the present investigation seven surficial sediment samples from southern part of the Caspian Sea were subjected to bulk and chemical partitioning studies. Though concentrations of metals (except for Mn and Cd) falls within the ranges of mean crust and mean sediments, but chemical partitioning data is indicative of pollution in the area of study. Proportions of metals that are presented in high risk fraction follows the pattern of Mn (88%)>Pb (71%)>Cd (61%)>Zn (55%)>Cu (53%)>Ni (35%)>Co (33%). Computed geochemical indices clearly reveal that sediments of coastal area of the Caspian Sea are contaminated with Cd, Mn and Pb to various degrees. Cluster analysis shows the affinity of Cu, Pb, Co and Zn with organics. Presence of considerable amount of Mn in reducible phase is suggestive of anoxic conditions that prevail over the sediments. High concentration of Ca (mean = 15.39%) is indicative of higher productivity in spite of presence of many pollutants in the area of study. Results of the present investigation showed that geochemical accumulation index (Igeo) could not be effectively used to sediment pollution assessment in marine environment.

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