Geochemical Baseline and Pre‑Mining Environmental Assessment of Heavy Metals at Iron Exploration Area, Northeastern Aswan, Egypt

With the emphasis that the study area is a highly mineralized area with high potential for future mining projects due to large iron ore reserves, a total of 21 soil surface samples were investigated in terms of toxic heavy metals (Pb, Cr, Ni, Cu, Zn, Co, and As) using ICP-OES to determine the metal concentrations, define the geochemical baseline during pre-mining conditions, decipher metal sources and their interrelationships using multivariate statistical analysis, and evaluate the contamination grade and potential ecological risks using environmental indices. Abundances of Pb, Cr, Ni, Cu, Zn, Co, and As fluctuated from 17.72 to 0.06, 47.12 to 10.86, 47.88 to 9.25, 45.04 to 6.23, 51.93 to 17.82, 10.55 to 1.24, and 7.04 to 1.66 mg/kg, respectively, displaying a declining trend of Zn > Cr > Ni > Cu > As > Co > Pb. Additionally, the mean concentrations of all studied metals were found to be significantly lower than the selected international reference standards. Pearson correlation coefficient, principal component analysis, and cluster analysis revealed two geogenic geochemical associations for the studied toxic elements: (1) Zn-As-Ni-Cr-Cu-Co; and (2) Pb. Negative Igeo values were observed for all metals, which showed that the samples were uncontaminated and can be considered a geochemical baseline for the study area. Moreover, all CF values were lower than or close to 1, suggesting low contamination levels from all studied metals and supporting the association with natural geological processes. Similarly, Er and RI values of all metals were below 40 and 150, respectively, indicating a low-risk environment.