Concentration, distribution and assessment of heavy metals in surface sandy sediments of south of the Caspian Sea

Abstract

Caspian Sea, surrounded by the five littoral states of Kazakhstan, Turkmenistan, Russia, Azerbaijan and Iran, is the largest inland body of water in the world. As a closed-environment without on outlet, various pollutants due to effluents from coastal catchments areas and leakage have accumulated in Caspian Sea. Concentrations of three heavy metals (Pb, Zn, and Ni) in surface sandy sediments collected from fourteen sites in South of the Caspian sea during autumn 2008 were studied to evaluate the pollution status of south coast of the Caspian sea. The results showed that heavy metal concentrations (in ug/g dry weight) were 27.13(20.42-36.08);55.9(37.74-91.72);38.77(17.46-72.83 for Pb Zn and Ni,respectively. High concentrations of heavy metals determined in the west and East of the Caspian sea because of Sea currents transport and circulate the entrapped pollutants along the Iranian coast of the Caspian Sea, most high concentration measured in these areas (east and west). The Enrichment Factor,Geo-accumulation Index(1geo) and Pollution Load Index (PLI) for each elements were calculated. High calculated of Enrichment Factor observed in the West of the Caspian sea, whereas pollution Load Index(PLI) was high in the East of the Caspian Sea. Geo-accumulation indices (ge) for Ni and Zn in all stations were categorized as class 0 (Uncontaminated)