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

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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 (Igeo), degree of contamination (Cd ), 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 < Igeo < 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 Cd factor (Cd = 13.7), and the PLI (PLI = 1.1), respectively.