Geochemistry of the Karkheh River Sediments, Khuzestan Province, Iran: Evidences for Natural Contamination

摘要

Sediment samples were taken along a 60 km segment of the Karkheh River in Khuzestan province, southwest of Iran. The Karkheh River with a catchment area of about 50.000 km2 carries sediments very different from those of neighboring areas. This river drains through metamorphic, igneous and sedimentary rocks from north to south. In order to determine trace elements concentrations, geochemical behavior of these elements and mineralogy in the Karkheh river sediment, seven samples from north to south of the Shoosh city were analyzed using INAA and XRD. Mineralogical studies indicate that heavy minerals such an ilmenite, magnetite, garnet and zircon are major fractions of the Karkheh river sediments. Geochemical data show relatively high concentrations of Fe, Ti, Cu, Ni, Cd, Co, Pb, Zn and As in the sediments when compared to same River sediments in Khuzestan Province. Concentrations and distribution of trace element and REE in the sediments have been influenced by erosion of the distal catchment areas. The results suggest a natural source for sediment pollution (e.g., Pb and As). The results show that in many cases as the Karkheh River, contaminated rock and soil in the catchment area can be a major source for sediment contamination.