中国设施土壤重金属累积特征与污染阻控技术研究进展

    Accumulation characteristics and control technologies of heavy metal contamination in facility soil of China: A review

    • 摘要: 长期集约化耕作导致中国设施土壤重金属累积和面源污染风险增加的状况已引起广泛关注。该研究总结了中国设施土壤重金属累积状况及其来源,发现长期盲目投入肥料及农药是引发设施菜田土壤重金属累积问题的主要原因。目前,设施土壤重金属累积呈现出广泛性和中轻度污染特征,其中镉是主要的污染元素。遵循面源污染治理中“源头预控-过程阻断-末端修复”原则,基于国内外文献综述,该文总结归纳出适用于设施土壤重金属累积特征与污染的联合阻控技术及作用机制。首先在灌溉和肥药投入等源头环节减少重金属输入;其次在作物种植过程中,通过选用重金属低积累特性的蔬菜种类或品种,结合水肥一体化施用大分子有机水溶性肥料或叶面喷施具有阻控重金属作用的营养型阻控剂,抑制作物吸收重金属;最后在末端修复环节,利用具有多元功能的土壤改良剂或微生物菌剂进行土壤钝化修复,或采用具有超重金属富集能力且能提高设施土壤生物多样性的植物作为填闲作物,实现生物修复的目标。该联合阻控技术的原则在于协同考虑污染防治、土壤改良、减肥增效等农学和环境目标,集成土壤修复与改良、水肥一体化、填闲作物栽培等技术,并兼顾设施土壤重金属污染修复工程所面临的投入品成本较高、经济效益不明显、缺失可持续改良导致效果不稳定等问题,优推能够钝化重金属并改良土壤的多功能土壤改良剂以及具有阻控重金属吸收、提高作物抗逆性的多功能有机水溶性肥料。上述措施能解决设施土壤普遍存在的重金属累积问题,提升土壤的安全生产能力,可为设施农业可持续发展提供更有效的技术支撑。

       

      Abstract: This review aims to evaluate the prevalence and severity of heavy metal contamination in facility soil across China. Through a systematic analysis of 46 articles published between 2018 and 2023, data were extracted pertaining to 128 facility farming sites spanning 31 provincial administrative regions. The findings reveal that these reported locales are severely impacted by heavy metal contamination, with most facility soil exhibiting mild to moderate levels of pollution. Specifically, cadmium (Cd) is identified as a major concern, posing significant risks to soil health and agricultural yield. In addition, other heavy metals such as lead (Pb), chromium (Cr), arsenic (As), mercury (Hg), and copper (Cu) also contribute to the overall contamination, albeit to varying degrees. Agricultural practices, primarily the utilization of chemical fertilizers, manure, and pesticides, have been pinpointed as the principal pathway for heavy metal infiltration into soil, accounting for a substantial share ranging from 69.7% to 86.7% of the total input. There is an urgent need for more sustainable agricultural practices to minimize the influx of heavy metals into the soil environment. Nature-based Solutions (NbS) offer a promising approach for sustainable production in facility soil by utilizing natural resources alongside organic waste. A technical system can be devised to mitigate heavy metal pollution in these soils. Therefore, a risk mitigation strategy has been proposed which includes preemptive source control, process blocking, and terminal remediation measures. The preemptive control at the source aims to reduce contaminant inputs of heavy metals at the origin of the soil environment, particularly focusing on agricultural inputs such as fertilizers, pesticides, and irrigation water. Process blocking utilizes innovative techniques to hinder the mobilization and bioavailability of heavy metals in the soil, thereby minimizing their toxicity during plant uptake. Plant species or varieties with lower heavy metal accumulation potential and the use of water-soluble fertilizers are also encouraged. Terminal remediation strategies primarily involve various functional amendments to immobilize heavy metals in the soil. Additionally, crops with specific tolerance, accumulation, or detoxification capabilities for heavy metals are selected for bioremediation purposes. Furthermore, sustainable practices should be prioritized to mitigate risks while optimizing agricultural productivity. These strategies emphasize waste management, soil health maintenance, and improved practices, especially for the secure and effective utilization of contaminated soil. However, there is a scarcity of research on integrated controlling technologies for soil heavy metal contamination in China's facility agriculture. Nevertheless, case studies have validated the effectiveness of integrated approaches compared to single-technology solutions, highlighting their practicality and broad applicability. In summary, a conceptual framework was formulated to tackle heavy metal contamination in facility soil. The findings provide valuable insights to guide future research and practical strategies. These efforts are imperative in mitigating the hazards posed by heavy metal contamination in facility soil, thereby advancing sustainable agricultural practices.

       

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