土壤微生物-矿物微界面结合Pb的分子机制

Ecological environment contaminated by heavy metals due to mining and smelting is becoming increasingly degenerative. Among the heavy metals, the distribution and fate of Pb in the mine soil has attracted much more attention because of its toxicity and persistence. Soil microbes and minerals are the important solid-phase components on soil-water interfaces and also the main carriers for heavy metals. The mechanisms of heavy metal adsorption on soil micro-interfaces at molecular level and the effects of multi-interface interaction on metal microcosmic speciation are the scientific base for heavy metal pollution control and remediation. The representative microbes and minerals collected from typical lead/zine mine soil in Shaanxi province were employed. Combined simulation in the lab with in-siu study on natural soil, the effects of microbes-minerals interactions on micro-interface characteristic and the speciation and distribution of Pb on micro-interface were investigated based on molecular-scale methods (ITC、μSXRF、μXAFS、XAFS). The proposal aimed to clarify the effects of microbes-minerals interactions on the fate of Pb in natural environment and to provide technologic support for soil remediation and risk assessment in lead/zine mine soil.

矿产资源开发带来的重金属对生态环境的污染日益严重，特别是Pb的污染危害大、持久性强，其在矿区土壤中的分布、转化及迁移倍受关注。土壤微生物和矿物是土-液界面中重要的固相组分和重金属吸附的主要载体。研究重金属在土壤微界面结合的分子机制，探讨多界面交互作用对重金属微观形态的影响，是重金属污染控制和治理的科学基础。本项目拟采集陕西典型铅锌矿区土壤，以其中代表性的微生物和矿物为材料，采用实验室模拟和自然土壤原位研究相结合的方法，综合利用等温滴定微量热（ITC）、微区X射线荧光（μSXRF）和X射线吸收精细结构光谱（μXAFS、XAFS）等多种分析技术，研究微生物-矿物相互作用对微界面吸附特性的影响，明确Pb在微生物-矿物微界面的分布特点和分子形态，阐明微生物、矿物相互作用对土壤中Pb的环境行为和归趋的影响，为铅锌矿区污染土壤的修复和风险评价提供技术支撑。

矿产资源开发带来的重金属对生态环境的污染日益严重。研究重金属在土壤微界面结合的分子机制，探讨多界面交互作用对重金属微观形态的影响，是重金属污染控制和治理的科学基础。本项目拟采集陕西典型铅锌矿区土壤，以其中代表性的微生物和矿物为材料，采用实验室模拟和自然土壤原位研究相结合的方法，综合利用等温滴定微量热（ITC）、微区X射线荧光（µSXRF）和X射线吸收精细结构光谱（µXAFS、XAFS）等多种分析技术，研究微生物-矿物相互作用对微界面吸附特性的影响，明确Pb在微生物-矿物微界面的分布特点和分子形态，阐明微生物、矿物相互作用对土壤中Pb的环境行为和归趋的影响。研究结果明确了重金属铜和铅在土壤单独组分和复合组分上结合的分子机制，建立了铅在细菌-水铁矿复合体系表明的吸附模型，为理解土壤体系中铅的环境行为提供了理论基础。