Geochemistry of Bandan River sediments in Sistan Basin (Eastern Iran): implication for provenance and environmental impact on the Hamoun Lake pollution

The catchment basin of Bandan River in Hamoun territory in E-Iran was studied to determine the origin of river sediments and its contaminant potential for the Hamoun Lake pollution. Thirty-four stream bed samples were analyzed for major oxide and trace elements. Geochemical discriminant diagram represents litharenite composition for the river sediments. On the discriminant functional diagram, the samples show oceanic arc setting with sedimentary quartzitic and intermediate volcanic sources, which almost correspond to the current geodynamic condition of the present covenant. The toxic elements Pb, As, Cr, Ni, Co, Zn, Cu, Mn, V, and Se were analyzed in all samples to evaluate the pollution potential using index of geo-accumulation ( I geo ). According to I geo value, soils were uncontaminated to moderately levels with Pb and Ni, while moderately contaminated with Cr, strongly contaminated with As and strongly to extremely contaminated with Mo. Statistical studies concluded high correlation between the examined elements and indicate that the volcanic rocks are common source of the pollutant elements in the studied catchment basin. Chromium and Ni can also be originated from ophiolitic rocks in the region. Therefore, geogenic factors control the contamination of river sediments, which may lead to Hamoun Lake pollution.