Assessment of Heavy Metals Content in The Agricultural Soils of Kafr El-Zayat Egypt Using Laser Ablation Inductively Coupled Plasma Mass Spectrometry and Inductively Coupled Plasma Optical Emission Spectroscopy

Recent years have witnessed a tremendous increase in contamination levels of heavy metals in the agricultural soils due to the uncontrolled release of chemicals and toxic substances from various human activities. The transfer of heavy metals to the groundwater and humans through the various food chains may cause serious health problems. Therefore, continuous evaluation of heavy metals content in the agricultural soil is important to control the spread of pollution, to preserve the soil quality, and to protect human health. In this study, we determined the content of heavy metals (V, Cr, Mn, Co, Ni, Cu, Zn, and Pb) in the agricultural soils of Kafr El-Zayat city, Egypt using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and inductively coupled plasma optical emission spectroscopy (ICP-OES). In ICP-OES, the soil samples were digested using a mixture of concentrated nitric and hydrochloric acids at a ratio of 1: 3 and heating on a hot plate at a temperature of 120 ? for few hours. This method of sample preparation was not efficient in extracting the total metal content in the soils and the results had to be corrected for using reference materials. In LA-ICP-MS, the soil samples were prepared in a form of rigid pellets using a hydraulic press. The accuracy of the analyses was examined by analyzing reference materials and comparing the observed results to the published concentration values. The concentrations of heavy metals determined by the ICP-OES were found to be 90.14 ppm for Zn, 57.90 ppm for Cu, 75.3 ppm for Ni, 115.18 ppm for Cr, 32.75 ppm for Co, and 11.49 ppm for Pb. Meanwhile, the concentrations of heavy metals as measured by LA-ICP-MS were found to be 100.60 ppm for Zn, 69.78 ppm for Cu, 90.8 ppm for Ni, 116.42 ppm for Cr, 41.38 ppm for Co, and 18.24 ppm for Pb. The concentrations of V, Cr, and Ni exceeded the concentration levels of the Canadian soil quality guidelines, which indicate the contamination of the examined agricultural soils with these elements.