土壤重金属地质高背景成因、风险与管控研究进展

土壤重金属地质高背景是近年来学术界研究的热点之一，涉及地质学、地球化学、土壤学、环境科学等学科。采用文献计量方法分析了土壤重金属地质高背景领域的研究进展与近期热点，介绍了全球和中国土壤重金属地质高背景分布特征、成因与类型，梳理了高背景区土壤重金属的环境风险及管控措施，以期为土壤重金属地质高背景成因机制与风险管控提供理论与技术参考。建议关注高背景区土壤重金属背景值调查、富集特征与形成机制、潜在活化与迁移，开展地质高背景区土壤风险评估、环境基准研究与管控技术研发。

Research Progress on the Causes, Risks, and Control of High Geological Background of Heavy Metals in Soils

The high geological/geochemical background of heavy metals in soil is one of the hot spots in academic research in recent years, involving geology, geochemistry, pedology, environmental science and other disciplines. High concentrations of heavy metal(loid)s in soils including cadmium (Cd), arsenic (As), chromium (Cr), nickel (Ni), etc, pose a threat to environmental quality, food safety, and ecological security. This review uses bibliometric methods to analyze the research progress and recent hotspots in the field of high geological background of soil heavy metal. The distribution characteristics, causes, and types of high geological background of soil heavy metals in the world and China are systematically reviewed. The geological high background area in the world shows diversified distribution characteristics, and the causes of geochemical anomalies are complex. In China, the geological high background is mainly distributed in the southwest (Guangxi, Yunnan, Guizhou, Sichuan, etc.), the east, the Yangtze and the Pearl River basins, and is closely related to long-term weathering and migration and transportation of carbonate rock, basalt, black shale and other rocks. Lithological types, topography and organisms are key factors that affect elemental geochemical processes in the differentiation of heavy metals during soil formation. The total concentrations of heavy metals (especially Cd) in soils of geological high background areas often exceeded the risk screening values of the Chinese Soil Environment Quality Risk Control Standard for Soil Contamination of Agricultural Land (GB 15618-2018). Also, the bioavailability of heavy metals is usually low, especially in carbonate rock areas. The superposition of human activities has intensified the migration, diffusion and enrichment of heavy metals in the soils of geological high background areas, increasing the risk of heavy metal absorption by crops and human health. The screening values for elements such as Cd in the current standards in China are not suitable for ecological risk assessment of geological high background soils, therefore, soil Cd thresholds based on extractability or bioavailability need to be developed. There is still a lack of specialized research on the safe utilization and remediation technology for high geological background areas where the heavy metals concentration in crops exceed the standard. This review aims to provide theoretical and technical references for understanding the mechanism and risk control of high geochemical background soil heavy metal. Future work in high background areas can focus on the investigation of soil heavy metal background values and environmental benchmark values, enrichment and formation mechanisms, potential activation and migration, risk assessment and control technologies.