Arsenic Complexation with Reduced Organosulfur Moieties in Soil Organic Matter: Implications for Arsenic Oxidation via Biotic and Abiotic Pathways

土壤有机质中砷与减少的有机硫部分的络合：对生物和非生物途径砷氧化的影响

• 批准号: 1905175
• 负责人: Matthew Reid
• 金额: $ 35.51万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1905175&HistoricalAwards=false
• 关键词: Arsenic; Complexation; Reduced; Organosulfur; Moieties

Supported by the Environmental Chemical Sciences Program in the Division of Chemistry, Professor Matthew Reid and his students are studying interactions between inorganic arsenic and dissolved organic matter (DOM). DOM is a complex mixture of biomolecules derived from plant residues and microorganisms, and is an important component of all natural environments. DOM binds arsenic to form dissolved complexes with significantly different properties than unbound inorganic arsenic molecules. These reactions influence arsenic concentration in water and uptake into plants, with important implications for human exposure to arsenic, a human carcinogen. However, the functional groups of DOM that react with arsenic are poorly understood. In this project, researchers explore how the structure of DOM affects its reactivity with arsenic, and evaluate how arsenic-DOM binding influences arsenic behavior in soils. Throughout this research, undergraduate and graduate students are trained in experimental methods and characterization techniques to address fundamental problems in environmental chemistry. A graduate student is partnering with outreach staff from the Cayuga Nature Center to develop hands-on activities with a portable X-ray fluorescence instrument. This outreach strengthens the student's science communication skills and engages high school teachers and the public with soil chemistry topics of societal importance. In this project, standard humic substances as well as hydrophobic and hydrophilic DOM fractions isolated from wetland soils with a range of sulfur concentrations are reacted with arsenite (As(III)) in order to explore As(III)-DOM coordination reactions. In the first phase of the research, wet chemical analysis and synchrotron-based XAS are integrated with laboratory dialysis equilibrium experiments to quantify conditional distribution coefficients, characterize sulfur speciation in DOM, and determine the As coordination environment in DOM-bound As. In the second phase of the research, impacts of As(III) binding by DOM on As(III) oxidation kinetics via abiotic and microbial pathways are evaluated using laboratory batch studies. These research activities are designed to test the hypothesis that thiol functional moieties are high-affinity binding sites for As(III), and that As(III) bound with thiol functionalities in DOM will be stabilized in its trivalent oxidation state during oxidizing conditions. Research outcomes are expected to improve geochemical modeling of As speciation in DOM-rich environments and provide new insight into arsenic oxidation reactions in redox dynamic environments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在化学系环境化学科学项目的支持下，Matthew Reid 教授和他的学生正在研究无机砷和溶解有机物 (DOM) 之间的相互作用。 DOM 是源自植物残留物和微生物的生物分子的复杂混合物，是所有自然环境的重要组成部分。 DOM 与砷结合形成溶解的复合物，其性质与未结合的无机砷分子显着不同。这些反应影响水中砷的浓度和植物的吸收，对人类接触砷（一种人类致癌物）具有重要影响。 然而，人们对 DOM 与砷反应的官能团知之甚少。 在这个项目中，研究人员探索了 DOM 的结构如何影响其与砷的反应性，并评估砷-DOM 结合如何影响土壤中砷的行为。 在整个研究过程中，本科生和研究生接受实验方法和表征技术的培训，以解决环境化学的基本问题。 一名研究生正在与卡尤加自然中心的外展工作人员合作，利用便携式 X 射线荧光仪器开展实践活动。 这种外展活动增强了学生的科学沟通技巧，并使高中教师和公众参与具有社会重要性的土壤化学主题。 在该项目中，标准腐殖质以及从湿地土壤中分离出的具有一定硫浓度的疏水性和亲水性 DOM 组分与亚砷酸盐 (As(III)) 反应，以探索 As(III)-DOM 配位反应。 在研究的第一阶段，湿化学分析和基于同步加速器的 XAS 与实验室透析平衡实验相结合，以量化条件分配系数，表征 DOM 中的硫形态，并确定 DOM 结合的 As 中的 As 配位环境。 在研究的第二阶段，通过实验室批量研究评估了 DOM 与 As(III) 结合对通过非生物和微生物途径的 As(III) 氧化动力学的影响。 这些研究活动旨在检验以下假设：硫醇功能部分是 As(III) 的高亲和力结合位点，并且与 DOM 中硫醇功能区结合的 As(III) 在氧化条件下将稳定在其三价氧化态。 研究成果预计将改善富含 DOM 的环境中砷形态的地球化学模型，并为氧化还原动态环境中的砷氧化反应提供新的见解。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优势和评估进行评估，被认为值得支持。更广泛的影响审查标准。

项目成果

Inhibition of methanogenesis leads to accumulation of methylated arsenic species and enhances arsenic volatilization from rice paddy soil

抑制产甲烷作用导致甲基化砷形态的积累并增强稻田土壤中砷的挥发

• DOI: 10.1016/j.scitotenv.2021.151696
• 发表时间: 2022
• 期刊: Science of The Total Environment
• 影响因子: 9.8
• 作者: Zhang, Xuhui;Reid, Matthew C.
• 通讯作者: Reid, Matthew C.

Effects of organic sulfur and arsenite/dissolved organic matter ratios on arsenite complexation with dissolved organic matter

有机硫和亚砷酸盐/溶解有机物比例对亚砷酸盐与溶解有机物络合的影响

• DOI: 10.1016/j.chemosphere.2022.134770
• 发表时间: 2022
• 期刊: Chemosphere
• 影响因子: 8.8
• 作者: Abu-Ali, Lena;Yoon, Hyun;Reid, Matthew C.
• 通讯作者: Reid, Matthew C.

Time-Dependent Biosensor Fluorescence as a Measure of Bacterial Arsenic Uptake Kinetics and Its Inhibition by Dissolved Organic Matter

• DOI: 10.1128/aem.00891-22
• 发表时间: 2022-08-01
• 期刊: APPLIED AND ENVIRONMENTAL MICROBIOLOGY
• 影响因子: 4.4
• 作者: Yoon，Hyun;Giometto，Andrea;Reid，Matthew C.
• 通讯作者: Reid，Matthew C.