Heavy metal mobility and pollution characterization in agricultural soil caused by steel industrial activities in Central Jordan

Abstract

Industry is the main source of soil pollution in Jordan, where higher concentrations of heavy and toxic elements were found in soil around industrial estates. This study deals with an industrial pollution hot spot that is a steel factory in central Jordan, which emits various ashes and gases. This area is populated and its soils were increasingly utilized in agricultural activities. High Fe, Cr and V content were recorded in soil around this factory. Therefore, this study aims to investigate the mobility and oxidation state of these elements. For this purpose, two core samples (up to 50 cm in depth) at sites with higher heavy metal concentrations were sampled. Soil samples were collected at 10 cm intervals and analyzed for Fe, Mn, Cr, V, Zn and Pb by using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Moreover, Fe was analyzed using X-ray Absorption Near-Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) to find the changes in oxidation states and structural parameters with depth. The Fe-EXAFS are associated mainly with (O), which indicates the anthropogenic Fe source. The Fe-XANES are in Fe(II) and Fe(III) forms, which indicate that Fe is usually formed during high thermal processes. In addition, XANES of Cr, Mn and V are found in high oxidation states Cr(VI), V(V), Mn(IV), which might be a result of steel manufacturing under oxygenated environment.