Assessment of Heavy Metal Accumulation in Urban Soil around Potash Industrial Site in the East of the Dead Sea and their Environmental Risks

Abstract

The aim of this study was to assess the extent and severity of metal contamination of soils in the east of the Dead Sea, southwestern Jordan. This area was affected by a potash plant and intensive agricultural production. The samples were obtained at two depths, 0–10 cm and 10–20 cm, and were analyzed by atomic absorption spectrophotometry for Cu, Fe, Zn, Mn, Pb, Cd, and Cr. Physicochemical parameters that are expected to affect the mobility of metals in the soil such as pH, TOM, CaCO3, CEC, and conductivity were determined. The relatively high concentrations of metals in soils of the studied area were related to anthropogenic sources such as the potash industry, agricultural activities, and traffic emissions. The mean concentrations of the metals were of the order: CFe > CPb > CZn > CCr > CMn > CCu and CCd where C is the concentration of these metals in solution. Heavy metals such as Zn, Cd, and Pb showed higher concentrations in the area that is closer to the potash plant, while Cr concentration was low. These metals were concentrated in the soil surface and decreased in the lower part of soil due to their mobility, movement and physicochemical properties, and alkaline pH. Metals of anthropogenic origin, including Cd, Pb, and Zn, were highly enriched with respect to crustal composition. The non-clay minerals of the sand-sized fraction are composed mainly of quartz and calcite as major minerals, with dolomite and feldspar as minor minerals. Factor analysis revealed three groups of elements that differ in their distribution. The first of these components is unpolluted soil, which was distributed in the study area. The second is the polluted soil, which occurs mostly around the potash plant and Ghore El-Safi area. The third factor represents the physicochemical sources, and is not significant.