Review on heavy metal pollution ecological risk assessment and remediation technology in the soil of metal mining areas

ObjectiveThe development of the metal mining industry drives rapid economic growth but inevitably leads to the migration and enrichment of hazardous heavy metals in soils, posing severe threats to ecological security and human health in mining areas and adjacent regions. MethodsThis paper, by consulting a large number of relevant literature on mining area soil heavy metal pollution risk assessment, remediation technology and mine pollution prevention and control, systematically summarizes from aspects such as soil total heavy metal content, occurrence state, classification and applicable scope of remediation technology, and pollution prevention and control measures, and reviews the latest research progress on the current status, evaluation method, remediation technology, and pollution source prevention and control of mining area soil heavy metal pollution at home and abroad. ResultsRisk assessment methods for heavy metal contamination in mining area soil primarily include pollution index assessment, human health risk assessment, risk assessment based on heavy metal speciation, and machine learning prediction risk assessment for crop seeds considering the influencing factors of soil heavy metal bioavailability. Commonly used remediation technologies for heavy metal contamination in mining area soil primarily include soil replacement method, immobilization/stabilization technology, phytoremediation technology, and combined remediation technology. The main engineering measures for mine pollution prevention and control include open-pit mine slope treatment and ecological restoration, underground mine filling, and tailings dam stability reinforcement. ConclusionMachine learning models that consider factors influencing soil heavy metal bioavailability can better explain the nonlinear relationship between soil heavy metal bioavailability and its influencing factors. Accurate prediction of crop grain heavy metal content provides a scientific basis for scientific evaluation of the degree of biological risk posed by mining activities and for achieving land resources' accurately classified management. Among common remediation technologies, the soil replacement method can significantly alter mining area soil pollution status in the short term, but it is primarily suitable for rapid remediation of small-area contaminated soil. immobilization/stabilization technology is low-cost and easy to scale-up, but it cannot completely remove heavy metals; long-term surveillance of its stability is required. phytoremediation technology causes minimal ecological disturbance and is suitable for the remediation of large-area composite pollution, but it has issues of a long remediation cycle and low efficiency. combined remediation technology simultaneously possesses the advantages of multiple remediation technologies, showing better application potential in addressing composite pollution in mining areas. Various engineering measures for mine pollution prevention and control can control heavy metal migration and diffusion at the source. Selecting appropriate engineering methods in combination with remediation technology helps to achieve scientific prevention and control of mining area environmental ecological risk and sustainable utilization of regional land resources.