The biogeochemical coupling of Cd and Fe cycles in agricultural soils under varying redox and geochemical conditions

不同氧化还原和地球化学条件下农业土壤中镉和铁循环的生物地球化学耦合

• 批准号: 408293668
• 负责人: Professor Dr. Andreas Kappler
• 金额: --
• 依托单位: Arbeitsgruppe Geomikrobiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/408293668?language=en
• 关键词: biogeochemical; coupling; Cd; Fe; cycles

Cadmium (Cd) is present in agricultural soils through the use of Cd-containing phosphate-fertilizers. Consumption of Cd leads to health issues such as renal failure and prostate, liver and kidney cancer. It is therefore important to understand the biogeochemical behavior of Cd, so that the mobility and fate of Cd in agricultural soils can be better predicted and controlled. One way in which this goal can be achieved is by closely examining the coupling of Cd with the iron (Fe) biogeochemical cycle. Fe is the fourth most abundant element in the Earth’s crust, and forms a variety of high-surface area Fe minerals, sorbing and incorporating heavy metals such as Cd. Fe is redox-active, alternating between the Fe(II) and Fe(III) oxidation states. Changes in oxidation state, via microbial metabolism or geochemical reactions, may induce mineral transformation and dissolution, causing the release of Cd that is sorbed to the mineral surface or incorporated in the lattice structure. Previous work from our group has shown that after microbial Fe(III) reduction and dissolution of Cd-bearing abiogenic ferrihydrite, Cd was released into solution and eventually sequestered by secondary minerals. However, crop cultivation methods often lead to redox cycling in agricultural soils (potentially leading also to Fe(II) oxidation and Fe(III) mineral formation). The biogeochemical reactions that occur during redox cycling undoubtedly influence the interaction of Cd with Fe minerals. The influence of redox cycling conditions on the fate of Cd is unknown. Therefore, in the present work we are proposing to rigorously examine the fate of Cd in agricultural soils in relation to microbial Fe metabolism under a variety of redox and geochemical conditions. In addition to redox cycling, the presence of organic matter and phosphate will be varied. Both of these constituents are expected to compete with Cd for sorption sites on Fe mineral surfaces but also have the possibility to form complexes with Cd either in solution or at the mineral surface. By analyzing the mobility of Cd in agricultural soils under many different biogeochemical and redox conditions, the most favorable conditions for forming and maintaining stable Cd-Fe mineral phases will be identified. Additionally, biogeochemical conditions that cause Cd mobilization can be better understood and controlled at Cd-contaminated sites.

镉（Cd）是通过使用含镉磷肥而存在于农业土壤中的。镉的消费导致健康问题，如肾衰竭和前列腺癌，肝癌和肾癌。因此，了解Cd的生态地球化学行为，以便更好地预测和控制Cd在农业土壤中的迁移和归宿是非常重要的。实现这一目标的一种方法是仔细研究镉与铁（Fe）地球化学循环的耦合。铁是地壳中第四丰富的元素，并形成各种高表面积的铁矿物，吸附和结合重金属，如镉。Fe是氧化还原活性的，在Fe（II）和Fe（III）氧化态之间交替。氧化态的变化，通过微生物代谢或地球化学反应，可能会导致矿物转化和溶解，导致镉的释放，吸附到矿物表面或纳入晶格结构。我们小组以前的工作表明，微生物Fe（III）的还原和溶解后，镉的非生物成因的铁铁矿，镉被释放到溶液中，并最终被次生矿物隔离。然而，作物栽培方法往往导致农业土壤中的氧化还原循环（也可能导致Fe（II）氧化和Fe（III）矿物形成）。在氧化还原循环过程中发生的地球化学反应无疑会影响镉与铁矿物的相互作用。氧化还原循环条件对镉的命运的影响是未知的。因此，在目前的工作中，我们建议严格审查镉在农业土壤中的微生物铁代谢的各种氧化还原和地球化学条件下的命运。除了氧化还原循环之外，有机物和磷酸盐的存在也会变化。这两种成分都有望与Cd竞争Fe矿物表面上的吸附位点，但也有可能与Cd在溶液中或矿物表面形成络合物。通过分析Cd在农业土壤中在多种不同的土壤地球化学和氧化还原条件下的迁移性，确定形成和维持稳定的Cd-Fe矿物相的最有利条件。此外，土壤地球化学条件，导致镉动员，可以更好地了解和控制在镉污染的网站。

项目成果

Effect of Natural Organic Matter on the Fate of Cadmium During Microbial Ferrihydrite Reduction.

• DOI: 10.1021/acs.est.0c03062
• 发表时间: 2020-07
• 期刊: Environmental science & technology
• 影响因子: 11.4
• 作者: Zhe Zhou;E. Muehe;E. Tomaszewski;E. Tomaszewski;J. Lezama-Pacheco;A. Kappler;James Byrne;James By

Complexation by cysteine and iron mineral adsorption limit cadmium mobility during metabolic activity of Geobacter sulfurreducens.

• DOI: 10.1039/d0em00244e
• 发表时间: 2020-08
• 期刊: Environmental science. Processes & impacts
• 作者: E. Tomaszewski;E. Tomaszewski;L. Olson;Martin Obst;James Byrne;James Byrne;Andreas Kappler;E. Muehe;E. Muehe