Soil trace elements contamination in the vicinity of Khatoon Abad copper smelter, Kerman province, Iran

Abstract

Continuous deposition from Khatoon Abad smelter stack particulates has resulted in trace elements contamination in soil. To investigate the regional distribution and fractionation of trace elements in soils, soil samples were collected and examined. The results demonstrate that the highest trace element concentrations in top soil are: >10000 mg Cu kg-1, 2000 mg Mo kg-1, >10000 mg Zn kg-1, 2694.2 mg As kg-1, 2006.2 mg Pb kg-1, 420.4 mg Sb kg-1, and 90.7 mg Cd kg-1. The concentrations of the trace elements are much higher than the normal concentrations in the uncontaminated soil and geochemical background. The most contaminated areas are located in the vicinity of smelter in the prevailing wind directions. Calculated geoaccumulation index and contamination load index indicate surface soil enrichment in potentially toxic metals (Cu, Mo, As, Sb, Cd, Zn, and Pb). Combined multivariate statistical and geostatistical methods successfully separate the contaminant metals (As, Cd, Cu, Pb, Sb, Mo, and Zn) from the uncontaminated ones (Al, Fe, Mn, and Cr). Furthermore, it was found that the As, Cd, Cu, Pb, Sb, Mo, and Zn mainly come from the copper smelter. The modified BCR three-step sequential extraction technique was applied to assess the four fractions (residual, acid, reducible and oxidizable) in smelter dust and surface soil samples. The results demonstrate that a high proportion of Cu, Mo, As, Pb, Sb, and Zn is extracted in the mobile fractions, indicating high mobility and probably hazardous environmental consequences.