Environmental assessment of soil pollution Forumad with heavy metals using sequential extraction

Extraction of mineral resources and mining can be lead to soil contamination by heavy metals. To determination of the origin of the metals in the sediments in Forumad chromite mine, the sediment samples were taken and analyzed using the sequential extraction method. Analysis of soil samples showed that the concentration of chromium and nickel in sediment is higher than that of global shale. Chromium and nickel in soil distribution map of the region shows that the highest concentration of chromium and nickel in samples from inside the mine tailings deposits of chromite Forumad been harvested according to the average concentration of chromium and nickel in the global shale, the top the amount of chromium in the sediment was attributable to mining activities. Our study shows that Nickel and Chromium with more than 45% concentration are interchangeable phase, which indicating anthropogenic source. Mining activity plays an important role in increasing the concentration of these elements as interchangeable phase. Cd, Pb, Zn and Fe with more than 30% concentration in residual phase, are related to lithogenic source. The results of the sequential extraction method are compatible with the pollution index in the area.