Soil Pollution: A Case Study on the Determination of Toxic Elements in Soil in Jeddah City, Saudi Arabia

Abstract

A considerable increase in the population of Jeddah City and the construction of new residential areas in the last few years has been noticed. Thus, a total of 23 soil samples were collected from three different areas of Sewage Lake, namely, Area A (polluted; the highest concentration of toxic elements), Area B (Southeast), and Area C (Northwest) for the analysis of toxic elements. The soil samples were digested by acid digestion to quantify the As, Co, Cr, Hg, Ni, V, Pb, and Zn using Inductively Coupled Plasma- Optical Emission Spectrometry (ICP-OES). Zn has the highest concentration in all studied areas (4821±10.2 mg/kg for A, 1108.6±9.5 mg/kg for B and 2339.8±8.7 mg/kg for C). On the other hand, Cr concentration was found 872±2.5 mg/kg for A, 1128±5.4 mg/kg for B and 680±3.4 mg/kg for C. These elements were above the level of the quality guidelines (300 mg/kg for Zn and 4.0 mg/kg for Cr). In majority of the area C samples, the concentration of Hg was found below the detection limit. The results indicated that the area A has a significantly higher metal contents as it is an inference polluted area. Hence, it is influencing the level of metal concentrations in area B, and area C might be due to wind spread. The indiscriminate disposal of hazardous waste in the study area causes a significant source of the soil contamination.