Analysis and assessment of nickel and chromium pollution in soils around Baghejar Chromite Mine of Sabzevar Ophiolite Belt, Northeastern Iran

The key objective of this research was to estimate the Ni and Cr contents of soil around the Baghjar Chromite Mine (BCM) of Sabzevar Ophiolite Belt, Northeastern Iran, and assess the degree of soil pollution using the pollution indices. Soil samples (0-20 cm depth) were collected at various distances from the BCM. In the present research, heavy metals (Cr and Ni) in soil samples were analyzed by atomic absorption spectrometry to detect their concentrations and contour maps were produced to explain the metal spatial distribution. Also, the degree of metal pollution was quantified. The results indicate that the soils in the studied area are contaminated by Cr and Ni. The corresponding concentrations for Cr and Ni are (156.19 +/- 24.45) and (321.7 +/- 133.27) mg/kg, respectively, which exceed the corresponding maximum allowable concentrations in soils. The different indices demonstrate that soils around chromite mine are significantly contaminated with Cr and Ni, suggesting several times higher levels of toxic metals than normal ranges. The above results revealed that the heavy metal concentrations increase with increasing the distance from the mine and mining pollutants can be transported to long distances from their sources.