Assessment of the anthropogenic influx of metallic pollutants in the Sefidrud delta, Gilan Province, Iran

Understanding the anthropogenic effects on the Sefidrud delta, the concentration of six metals (Cr, Co, Cu, Ni, Pb and Zn) was measured in two sites included the old Sefidrud delta (Amirabad, 23 samples) and the new Sefidrud delta (Kiashahr, 24 samples). Geoaccumulation Index (Igeo), Enrichment Factor (EF), Contamination Factor (CF) and Pollution Load Index (PLI) were used to determine the metal pollution in all sediment samples. Although the EF, Igeo, CF and PLI results in the old delta indicate no significant pollution, sediment samples in the new delta show a considerable pollution. Since the sediment source and the lithology of the Sefidrud River drainage basin did not change in the past 500 years, the metal pollution in the new delta must be from anthropogenic sources.