Impact of river sediments on contamination of shallow marine deposits in the South part Caspian Sea, Iran

The study area is the Southern Caspian Sea. Three rivers, Chalous, Sardabroud and Namak Abroud, are effective in this area. Sediment loads carried by these three rivers are the source of environmental pollution in this area's seabed sediments. To identify environmental pollution in this research, a total amount of 80 samples were collected from sediment of the sea and the rivers. By measuring the amount of As, Cd, Co, Cr, Cu, Ni, Pb and Zn in these sediments, one can determine the pollution pattern in this area by calculating environmental indicators such as: Geoaccumulation Index, Enrichment Factor, Contamination Factor and Pollution Load Index. Granulometry experiments show that sedimentary facies are divided into two main groups: sand and mud. The amount of Geoaccumulation Index is unpolluted. Enrichment Factor of river and shallow water sediments, the amount of As, Cd, Pb, Zn is in the high to medium category and the amount of Co, Cr, Cu and Ni is in the low category. Contamination Factor shows that river and shallow water sediments are very high to low ranking. Pollution Load Index is showing heavy metal contamination in the river and shallow water sediments. Statistical studies reveal the relationship between the pollution indicators and the amount of elements more effectively. The concentration of heavy metals in river sediments is more than in marine sediments due to the use of pesticides and chemical fertilizers in agricultural lands. The results of contamination indicate their anthropogenic origin and the lithological does not in the production of environmental pollution.

Automated summary

The study in the Southern Caspian Sea indicates that the environmental pollution in the area is mainly caused by the sediment loads carried by the Chalous, Sardabroud and Namak Abroud rivers. Heavy metal contamination is concentrated in river and shallow water sediments, which may be due to the use of pesticides and chemical fertilizers in agricultural lands.