Impact of Microbial Activity on Uranyl Mobility in the subsurface

0001923莱基这项研究的目的是阐明控制土壤和地下水环境中重金属去向的主导过程。这项研究将特别关注一个由螯合剂(柠檬酸)、矿物表面(针铁矿)、纯微生物培养物(荧光假单胞菌)、作为铀酰离子的重金属铀(VI)(UO22)和二氧化碳组成的受控良好的模型生物地球化学系统。首先，将进行四个子系统的实验，以密切评估可能对铀酰命运起作用的机制。这些子系统包括：(1)无细菌的铀酰-柠檬酸盐-土硫酸盐体系，以确定柠檬酸对铀酰在土硫石上吸附的影响；(2)无固相的铀酰-柠檬酸盐-微生物体系，以确定微生物与系统组成的相互作用；(3)铀酰-土硫酸盐-微生物体系，以确定在没有柠檬酸盐的情况下的行为；(4)无铀离子的体系，以确定柠檬酸盐吸附对其生物降解的影响。在第二阶段，将对整个生物地球化学系统进行调查，以确定影响铀酰整体分配的机制。***

0001923 Leckie The objective of this research is to elucidate the dominant processes governing the fate of heavy metals in soil and groundwater environments. This research will focus specifically on a well-controlled model biogeochemical system consisting of a chelator (citric acid), a mineral surface (goethite), a pure microbial culture (Pseudomonas fluorescens), the heavy metal uranium U(VI) as the uranyl ion (UO22+), and CO2. First, experiments with four sub-systems will be performed to closely evaluate the mechanisms which may play a role in the fate of uranyl. These sub-systems include: (1) a system of uranyl-citrate-geothite, without bacteria, to determine the effect of citrate on the sorption of uranyl on geothite, (2) a uranyl-citrate-microbe system, without the solid phase, to determine the microbial interactions with the system components, (3) a uranyl-geothite-microbe system to determine behavior in the absence of citrate, (4) a system without the uranyl ion to determine the effect of citrate sorption on its biodegradation. In the second phase, the overall biogeochemical system will be investigated to determine the mechanisms affecting the overall partitioning of uranyl. ***