Toxic element contamination from tailings dam failure disrupts seedling emergence dynamics and soil seed bank...

Environmental disasters involving the release of tailings rich in Potentially Toxic Elements (PTEs) pose a significant threat to the ecological integrity and regenerative capacity of riparian ecosystems. This study aimed to evaluate the long-term impacts of a dam failure on the resilience of soil seed banks, with an emphasis on seedling emergence dynamics and their relationship to soil chemical properties. A 202-day seed bank emergence experiment was conducted across sampling sites in both impacted and preserved reference areas. Results demonstrated that sites affected by tailings exhibited a markedly reduced Number of Emerged Seedlings (NES) compared to reference locations. Key indicators such as Emergence Velocity Index (EVI) and Mean Emergence Time (MET) revealed delayed and less synchronized germination in contaminated soils. Geochemical analysis revealed significantly elevated concentrations of specific PTEs (Fe, Sb, Cr, Ni, and Mn) in impacted soils, particularly at points closest to the rupture site. Correlation networks and Principal Component Analysis (PCA) showed strong associations between elevated Fe, Sb, Cr, Ni, and Mn concentrations and impaired seedling emergence, evidenced by higher MET, reduced EVI, and lower NES. These findings highlight the critical role of metal toxicity in delaying germination and constraining seedling establishment. The reduced resilience of soil seed banks in contaminated areas underscores the urgency for targeted remediation strategies and ecosystem-based restoration interventions aimed at reestablishing ecological functionality and ensuring the long-term recovery of riparian biodiversity.