The exploitation of iron ore could cause heavy metals pollution in the soils, which threatens the ecosystem and human health. In this study, soil, stream sediment, tailings, rock, and atmospheric deposition samples were collected from an iron mine in Baotou City. The concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb, Zn, Al₂O₃, CaO, K₂O, MgO, Na₂O, SiO₂, and Fe₂O₃, as well as the mineral composition and heavy metal speciation of the samples, were analyzed for pollution assessment and source identification of heavy metals. The results reveal that the concentration of Cu in the soils was significantly higher than the background value, and an unpolluted to moderately polluted state was the main pollution level. By analyzing the relationship between Cu/Al₂O₃ and CaO in different samples, as well as the characteristics of the chemical index of alteration (CIA), mineral composition, and the chemical speciation of Cu in soils and profiles, the results suggest that tailings were the source of Cu pollution in soils. The distribution characteristics of Cu and CaO in stream sediments indicated that hydraulic transport may be one of the main migration pathways. In addition, wind transport may also be a pathway of migration.

Sandy desertification is a major ecological and environmental challenge worldwide, posing a severe threat to ecological security in arid regions. A systematic understanding of the spatial–temporal dynamics of sandy desertification and their driving forces enables effective support for ecological engineering in China. We visually interpreted five Landsat imaging periods (1986–2023) to map sandy desert areas (SDA), which were confirmed by 176 field samples. Driving forces were measured using the Geographical Detector model, and changes in the extent and intensity of SDA were evaluated using intensity analysis and center of gravity migration. The results indicate the following: (1) On the temporal scale, sandy desertification land in Dengkou County experienced a significant reversal over the past 40 years, with a total reduction of 1204.72 km². On the spatial scale, the main areas of reduction were located in the central and southwestern regions. (2) Sandy desertification in Dengkou County underwent a process of initial reversal, followed by expansion, and then another reversal. The periods 1986–1995 and 2004–2023 were reversal phases, while 1995–2004 was a development phase. (3) Livestock density showed the strongest influence among anthropogenic factors (q = 0.224), suggesting a strong correlation with sandy desertification patterns. Among natural factors, geological conditions exert the most significant influence (q = 0.182). Every pair of driving factors, with the exception of slope aspect and soil moisture, showed either additive or synergistic effects, increasing their combined influence on desertification. The results provide a scientific basis for local ecological restoration and desertification control.