Geochemical approach for heavy metals in suburban agricultural soils of Sialkot, Pakistan

Abstract

This study was designed to investigate heavy metals concentrations in the suburban agricultural soils with particular emphasis upon their risk assessment. Therefore, a total of 36 collected soil samples were investigated for heavy metals analysis by atomic absorption spectrophotometer. The results showed that the mean concentrations were 126.8 mg kg−1, 83.1 mg kg−1 and 118.5 mg kg−1 for Cr, Ni, and Pb, respectively, higher than the Canadian and European Union permissible limits of metals in agricultural soils; while the concentrations of Co, Cu and Zn were 34.7 mg kg−1, 21.36 mg kg−1 and 92 mg kg−1, respectively, within permissible limits, and were higher than guideline values at some sites. However, enrichment factors showed a substantial anthropogenic input of the studied metals. A significant to very high enrichment was recorded for Pb. Moreover, the geo-accumulation index revealed that these soils were moderately polluted with Pb. In general, pollution load index indicated moderate pollution of soils, which was mainly caused by Pb. The correlation and principal component analyses revealed that traffic emissions, tanneries, municipal waste and automobiles repair workshops were the predominant sources of Pb, Cr, Ni and Co; whereas Cu and Zn are of geogenic origin in agricultural soils of Sialkot.