Non-resistant and Resistant fractions of cadmium in surface sediment of south of the Caspian Sea

Trace metals introduced into the aquatic environments by various anthropogenic activities are ultimately absorbed by deposits and incorporated into sediments. Sediments represent the most concentrated physical pool of metals in aquatic environments (Gerhardt, 1990; Clements, 1991; Everaarts et al., 1993).Heavy metals are a major anthropogenic contaminant of estuarine and coastal waters (Brown and Depledge, 1998).The Caspian Sea, bounded by the five littoral states of Azerbaijan, Federation of Russia, Islamic Republic of Iran, Kazakhstan and Turkmenistan, is the largest inland body of water in the world (Kosarev and Yablonskaya, 1994). As a closed-environment without an outlet, various pollutants due to effluents from coastal catchment areas and leakage from off shore oil production have accumulated in the Caspian Sea (Karpinsky, 1992).The ecology of the Caspian Sea, which depends on the input and diversity of pollutants, is determined by economic development of littoral states and the condition of the Caspian watershed basin. The landlocked nature of the sea and volume of the river flow are the main sources of pollution here (Igor S. Zonn, 2005),(table 1). The main sources of pollution of the Caspian natural environment are transborder atmospheric and water transfer of pollutants from other regions, washoff with river flow, discharge of untreated industrial and agricultural wastewaters, municipaldomestic wastewaters from cities and settlements in the coastal zone due to an insufficient number of treatment facilities, operation of oil and gas wells on land and offshore, oil transportation via sea, navigation over both river and sea, secondary pollution during bottom dredging works, and transborder atmospheric and water transfer of pollutants from other regions(State report (1993, Diarov MD 2002, Kosarev AN et all 1966, Stephen de Mora et al 2004).