基于人体健康风险精细化评估结果的土壤Hg污染修复策略

Soil mercury pollution remediation strategies: A critical review based on refined human health risk assessment

  • 摘要: 汞(Hg)作为土壤重金属污染中的一个重要元素,对人体健康会造成严重影响. 现行的土壤质量标准主要依据土壤中污染物的总浓度进行管控,未充分考虑污染物在人体暴露过程中实际可吸收量,可能导致健康风险的高估. 本文综述了土壤Hg污染的现状,对人体的毒性效应,应用于Hg健康风险评价的体内外模型和基于人体健康风险精细化评估的土壤Hg污染修复方法. 结果表明,土壤Hg污染严重的地区多集中于工矿业大气Hg排放较大的区域;在低水平下,Hg暴露对健康产生较大的负面影响,Hg对人体健康的影响主要集中在神经系统和肾脏;对于Hg毒性的研究模型多采用小鼠模型进行体内研究,并应用肠道、神经和肾脏细胞研究Hg可能造成的毒性效应;大脑神经类器官模型和肝脏类器官模型应用于重金属的神经毒性和肝毒性研究;基于土壤Hg污染的人体健康风险评估结果,针对性地选择污染修复方法分区域修复,将有效降低修复成本和提高修复效益. 为使评估结果更真实准确,可选取类器官模型对土壤Hg污染的相应毒性进行机制研究,并综合考虑不同暴露途径、个体差异等,建立差异化评估模型,实现人体精准风险评估. 基于精细化的评估结果,多方面的对土壤Hg污染进行阻控、修复和补救,以期有效地降低土壤Hg污染的健康风险.

     

    Abstract: Mercury (Hg), a major contaminant in soil heavy metal pollution, poses serious health risks to humans. Current soil quality standards primarily regulate pollution based on the total concentration of pollutants in the soil, without fully accounting for the actual amount absorbed during human exposure, which may lead to an overestimation of health risks. This article summarizes the current situation of soil Hg pollution, its migration and transformation mechanisms, and its toxic effects on human health, along with their underlying mechanisms. It also reviews the advantages, disadvantages, and applications of in vivo and in vitro models used for Hg health risk assessment, and finally proposes the selection of soil Hg pollution remediation methods based on refined human health risk assessments. The results show that the spatial variation of soil Hg content in China is large, and the soil Hg content in provinces, municipalities, and autonomous regions is closely related to Hg emissions from industrial and mining atmospheres. Regions with high average soil Hg content are distributed in coastal areas with Hg-related industrial activity. After migration and transformation, soil Hg comes into contact with the population, enters the human bloodstream and brain, and poses health risks. Hg exposure has a significant negative impact on health. Cells are prone to death under Hg exposure due to the production of reactive oxygen species, inhibition of antioxidant stress proteins, and increased oxidative stress. At low concentrations, organic Hg induces apoptosis in differentiated human neurons, whereas high concentrations cause cell necrosis, severely impacting the nervous system. Hg exposure during the embryonic and childhood periods leads to nerve damage in later stages of life. Hg exposure disrupts mitochondrial function in kidneys, affecting their metabolism. Many studies on Hg toxicity use in vivo mouse models alongside in vitro cell models of the intestine, nervous system, and kidneys to investigate the potential toxic effects of Hg. Brain nerve and liver cancer organoid models have been applied to study the neurotoxicity and liver cancer toxicity mechanisms of heavy metals. Existing remediation methods for soil Hg pollution include soil replacement, thermal desorption, microbial remediation, phytoremediation, soil fixation and stabilization remediation, soil leaching, and nanomaterial-based remediation technologies. However, the current evaluation system tends to overestimate health risks. Based on the results of the human health risk assessment of soil Hg pollution, selecting targeted remediation methods for specific regions will effectively reduce remediation costs and improve remediation efficiency. To make the assessment results more realistic and accurate, future studies can utilize organoid models to investigate the corresponding toxicity of soil Hg pollution. Additionally, a differentiated assessment model can be established by comprehensively considering different exposure pathways and individual differences for precise human health risk assessment. Based on the refined assessment results, multifaceted control and remediation of soil Hg pollution can be carried out to effectively reduce the health risks of soil Hg pollution.

     

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