植物根际影响含磷物质修复铅、镉污染土壤的微界面机制及其环境效应

Lead and Cadmium are considered to be toxic elements for both ecosystems and human health. In situ Pb and Cd stabilization technique using P is a cost-effective way to remediate the Pb and Cd contaminated soils. However, effects of phosphorus uptake by plants in the long term on the mobility and bioavailability of P-stabilized Pb and Cd in soils are poorly studied. In this proposal three different plants (Lolium Perenne, Triticum aestivum, and Sedum alfredii Hance) will be grown in the P-remediated soils. The techniques, such as the diffusive gradients in thin-films (DGT), X-ray absorption spectroscopy and isotopic dilution method will be used in this study. This proposal plans to study distribution and changes of bioavailable Pb and Cd in the rhizosphere after plant growth. The interfacial processes of exudates, bacteria, Pb, Cd and phosphorus in the rhizosphere and molecular mechanism which affect Pb and Cd bioavailability will be investigated. The project will explain the long-term stabilization of P-remediated Pb and Cd contaminated soils and hence provide the theory information for the remediation of Pb, Cd contaminated soils.

土壤中铅、镉污染对生态环境和健康会产生极大的危害，目前常采用经济高效的含磷物质修复法处理铅、镉污染土壤，但是在植物吸收磷情况下（尤其是长期吸收），对固化的铅、镉的迁移性和生物可利用性的研究是一个比较薄弱的环节，这关系到含磷物质修复铅、镉污染土壤的长期稳定性。本项目将以几种含磷物质(过磷酸钙、磷灰石、羟基磷灰石、磷矿粉)所修复后的铅、镉污染土壤为研究对象，应用新型梯度扩散薄膜技术(DGT)、X射线吸收结构光谱和同位素方法等先进技术，研究不同植物(黑麦草、小麦和东南景天)根系对含磷物质修复后土壤中铅、镉形态变化和时、空分布特征的影响，阐明在根际环境中根系分泌物、微生物与铅、镉、磷的微界面反应过程与分子机理，探索微界面反应过程对铅、镉迁移性和生物有效性的影响及其环境效应，以期探明磷修复铅、镉污染土壤的长期稳定性问题，为铅、镉污染土壤的修复提供理论依据。

本项目以含磷物质(过磷酸钙、磷灰石、羟基磷灰石等)所修复后的铅、镉污染土壤为研究对象，利用新型梯度扩散薄膜技术(DGT)等现代技术，研究不同植物(黑麦草、小麦和东南景天)根系对含磷物质修复后土壤中铅、镉有效态的变化和分布特征的影响，探讨在根际环境中根系分泌物、pH与铅、镉、磷的微界面反应过程与分子机理，探索微界面反应过程对铅、镉迁移性和生物有效性的影响，探明磷修复铅、镉污染土壤的长期稳定性问题，为铅、镉污染土壤的修复提供理论依据。