铀矿区微生物介导土壤多金属稳定与尾砂固化机制

我国存在至少150处以上铀尾矿库，导致周边土壤铀与多金属复合污染严重，因此铀矿区尾砂滩面固化和周边土壤修复十分急迫。铀、砷、铅、镉等金属的价态与形态多样，传统化学法难以突破多污染物同时稳定/固化的瓶颈。本项目创新提出微生物介导铀砷、铅镉等逐类成矿稳定/固化新思路，拟研究：（1）铀/多金属胁迫下砷氧化菌、解磷菌、诱导碳酸盐产生菌的抗性与代谢分子机理；（2）基于成矿的菌群代谢介导铀/多金属形态转化途径及主控因子；(3）铀酰砷酸盐、铀铅镉磷酸盐的成矿过程与矿相转化调控机制；（4）微生物胞外分泌物促进碳酸盐固化尾砂的作用机制，旨在发展铀矿区环境微生物治理基础理论，形成“铀砷自成矿- 铀铅镉等磷酸盐成矿-碳酸盐固化”的土壤修复与尾砂滩面固化治理技术原型。

There are at least 150 uranium(U) tailing ponds in China, which resulting in soil pollution in the vicinity of tailing ponds. Therefore, it is urgent for soil remediation and tailing solidification in mining area. U, As, Cd, Pb are present in various valences and fractions, resulting in the difficulty for simultaneously immobilizatiom/solidification with conventional chemical method. In this proposal, we proposed a strategy of microbial-induced mineralization by classifying elements of arsenic (As), U and lead (Pb), cadmium (Cd). The research focuses on the following aspects: (1) the resistance of As(III)-oxidation strain, phosphate releasing strain and induced-carbonate forming strain to U, As, Pb and Cd stresses, and their metabolic mechanisms; (2) the transformation processes of mineralizable fractions of U, As, Pb and Cd via microbial roles and the key factors; (3) mineral forming process and mineral phase control of uranyl arsenate and U/Pb/Cd phosphate; (4) the mechanism of tailing solidification as enhanced by extracellular polymeric substances. The objectives of this proposal are to develop the theory of microbial remediation in mining area and to establish the microbial technological prototypes of “mutual mineralization of uranyl and arsenate --U/Pb/Cd phosphate mineralization-- carbonate-based solidification” for immobilizing U and heavy metals in soils and solidifying uranium-containing tailing.