Determination of heavy metals contamination in based on land accumulation and ecological risk potential (Case study: Sediments of Caspian Sea coastal rivers)

Sediments are considered as the most important storage and absorption of metals and other pollutants in aquatic ecosystems and can reflect the quality of aquatic systems. The aim of this study was to estimate the severity of sediment contamination with cadmium, lead, zinc and copper based on ecological hazard potential (RI) and land accumulation (Igeo) indices in surface sediments of rivers in the southeast coast of the Caspian Sea. 

In order to measure and determine the indicators of metal element pollution, sampling of estuarine surface sediments and a distance of 1000 meters from the estuary of some rivers in the southeastern shores of the Caspian Sea, including Gorganrood, Gharasoo, Nekaroud, Tajan, Talar and Babolrood was performed. Samples in the laboratory based on the method of sequential extraction were prepared and then analyzed by atomic absorption apparatus and the results were determined in micrograms per gram of dry matter. 

The results showed that the values ​​of Igeo indexof metallic elements in the sediments of the rivers of the southern shores of the Caspian Sea ranged from -3.41 to 1.08 and the values ​​of RI index ranged from 62.66 to 101.93.  

Although the pollution of these areas with metallic elements is not dangerous at the border, but the continuation of the pollution process will certainly lead to many environmental risks in the long run. Therefore, applying proper management guidelines such as the proper disposal of urban, rural and industrial wastewater and the use of appropriate pesticides can be effective in improving the current situation in the region, and periodic research is necessary, especially for the entry of other pollutants into the environment.