Characteristics and Sources of Soil Contamination in a Lead–Zinc Mining Region in Gansu Province, China

Mineral extraction profoundly impacts the environment and human health. This research concentrated on the soil ecosystem surrounding a lead-zinc mine in Gansu Province. We quantified the quantities of eight heavy metals: arsenic, mercury, cadmium, chromium, copper, lead, zinc, and nickel, in the soil. The average on-site heavy metal concentrations in Gansu Province exceeded the background levels by factors of 4.27, 29.50, 19.08, 0.01, 1.43, 24.07, 19.08, and 1.05, respectively. The Geo-accumulation index rated the soil as mildly polluted by As and severely polluted by Cd, Zn, and Hg. The Nemerow index rated the on -site soil as severely polluted overall. The Potential Ecological Risk Index indicates that Hg and Cr have extremely high ecological dangers, whereas Pb presents moderate ecological risks. The primary ecological risk factor in the study area was mercury (Hg), accounting for 60.60% of the contribution rate. Soil heavy metal pollution originates from lead – zinc mining, transportation, nature, agriculture, and mixed sources. These sources comprised 20.81%, 12.38%, 30.73%, 18.80%, and 17.28% of the total, respectively. This study provided data to support the control of soil pollution in mining areas.