Assessment of contamination levels of heavy metals in the agricultural soils using ICP-OES

ABSTRACT

This work was carried out to monitor contamination levels of twelve heavy metals (HMs) in the agricultural soils of Kafr El-Zayat city in Egypt. The concentrations of Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, and Pb were determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). Contamination levels were estimated based on various geochemical parameters such as contamination factor (CF), enrichment factor (EF), geo-accumulation index (I_geo), degree of contamination (C_d), and pollution load index (PLI). The results showed that the majority of investigated soil samples were moderately contaminated (1 ≤ CF < 3) with V, Cr, Co, Cu, Zn, and Sr and had low contamination levels (CF <1) with Mg, Mn, Fe, Ni, and Pb. All investigated elements had geo-accumulation indices smaller than zero indicating uncontaminated soil samples except for V which showed (0 < I_geo < 1) indicating uncontaminated to moderate pollution levels. All soil samples were found to have deficient to minimal enrichment for all investigated HMs based on the average values of EF (EF < 2). Cluster analysis (CA) and principal component analysis (PCA) revealed that HMs were clustered into three groups compromising As and V; Ni, Cr, Mn, Co, Fe, and Mn; and Pb, Cu, Sr, and Zn, which suggests the presence of different sources of pollution. The contribution of anthropogenic sources to V, Cr, Co, Cu, Zn, As, and Sr was estimated to be 45, 30, 26, 11, 23, 27, and 13% of the total metal content, respectively. In general, the investigated agricultural soil samples could be classified as moderately contaminated and polluted based on the C_d factor (C_d = 13.7), and the PLI (PLI = 1.1), respectively.

KEYWORDS:

• Pollution
• soils
• ICP-OES
• heavy metals
• Kafr El-Zayat
• contamination levels

Acknowledgments

This work was partially funded by the Ministry of Higher Education and Scientific Research, Cultural Affairs and Missions Sector, and Tanta University, Egypt . Chemical laboratory analysis was supported by NSERC Discovery Grant to Joel Gagnon and Brian J Fryer, and CFI to Joel E Gagnon, University of Windsor, Canada. The authors would like to thank JC Barrette at GLIER, University of Windsor, Canada for help with the ICP-OES analysis. We are thankful to Drs O Hemeda, A Heneish, A Farouk, and H El-Ghrabawy, Physics Department, Faculty of Sciences, Tanta University, Egypt for their help with sample preparation.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Authors’ contributions

MES carried out the experimental work, wrote, and interpreted the results in the manuscript. WT and FEM reviewed the manuscript, AFM Collected the soil samples. BJF and JEG funded the chemical analyses.

Data availability statement

The datasets are available on reasonable request.

Additional information

Funding

Tanta University, Ministry of Higher Education and Scientific Research, Cultural Affairs and Missions Sector, Egypt. NSERC Discovery Grant to BJ Fryer and JE Gagnon, and CFI to JE Gagnon, University of Windsor, Canada;Ministry of Higher Education and Scientific Research, Cultural Affairs and Missions Sector, and Tanta University, Egypt;NSERC Discovery Grant to Joel Gagnon and Brian J Fryer, and CFI to Joel E Gagnon, University of Windsor, Canada;