Evolution of soil contamination in the abandoned Lakan Lead and Zinc mine by heavy metals, Iran

Soil contamination in the vicinity of the abandoned Lakan Lead and Zinc Mine was studied. The results showed that over the past decades, the environmental pollution was caused by Lead, Zinc tailings dam and acid mine drainage. The average of Lead, Zinc, Cadmium, Copper and Nickel is 1295, 4273, 27, 185 and 92 mg/kg, respectively in the soils of tailings dam. These metals were continuously dispersed downstream from the tailings dam. Geoaccumulation index (Igeo), enrichment factor (EF) and contamination degree (Cd) indicate moderate to high contamination of Lead, Zinc, Cadmium, Copper, Nickel and Cobalt and low contamination of Mercury in soils. Factor and cluster analysis indicate that Cadmium, Lead and Zinc were mainly derived from an anthropogenic source (such as mining and smelting of metal ores), but Cobalt and Mercury were controlled by natural source. Copper and Nickel appeared to be sourced both anthropogenically and naturally.