Biogeochemical Framework to Evaluate Mercury Methylation Potential During in-situ

原位评估汞甲基化潜力的生物地球化学框架

• 批准号: 9405783
• 负责人: Heileen Hsu-Kim
• 金额: $ 0.74万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-11 至 2018-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9405783
• 关键词: Address; Amendment; Anaerobic Bacteria; Bioavailable; Biological; Biological Availability; Calibration; Carbon; Effectiveness; Equilibrium; Fibrinogen; Food Webs; Fractionation; Gene Cluster; Genes; Genetic; Genetic Fingerprintings; Growth; Guidelines; In Situ; Knowledge; Laboratories; Link; Measurement; Measures; Mercury; Methanobacteria; Methodology; Methods; Methylation; Methylmercury Compounds; Microbe; Microbiology; Molecular; Neurotoxins; Organism; Process; Production; Research; Research Personnel; Series; Site; Sulfhydryl Compounds; Techniques; Testing; Uncertainty; Unspecified or Sulfate Ion Sulfates; Work; base; cinnabar; experimental study; implementation research; improved; microbial; microbial community; microorganism; multidisciplinary; nanoscale; public health relevance; remediation; success; superfund site; tool

DESCRIPTION (provided by applicant): This project will establish biogeochemical indicators for methylmercury production that will be used to improve the effectiveness of in-situ remediation of mercury-contaminated sediments. Methylmercury (MeHg) is a potent neurotoxin that is produced by anaerobic microorganisms and biomagnifies in the aquatic food web. In-situ remediation methods such as sediment amendments have not been widely implemented, mainly because the effects on MeHg production are unknown. Moreover, the processes that control mercury methylation can differ between sites, and this uncertainty is a barrier for effective implementation of in-situ remediation. This project aims to address this knowledge gap by establishing indicators of mercury methylation potential and using them to assess the effectiveness of sediment amendments for remediation. The research will focus on two critical drivers of methylmercury production: the environmental conditions that promote the growth of sediment microorganisms that produce MeHg and the processes that influence the bioavailability of mercury for these microorganisms. The balance between these two drivers will determine the success of in-situ sediment treatments. In this respect, the central hypothesis of this work is that the identification of the primary controls to methylmercury production at the fied site will improve the efficacy of sediment treatments. To test this hypothesis, the research team will apply fundamental knowledge regarding mercury biogeochemistry to improve the determination of mercury methylation potential in sediments and compare in-situ techniques for sediment remediation. Specific aims are to: (1) Develop relationships between the activity of methylating microorganisms and MeHg production in sediments; (2) Refine methods to quantify mercury bioavailability in sediments; (3) Identify factors that control methylation potential and formulate guidelines for characterization of sites; and (4) Determine how sediment amendment techniques influence methylmercury production potential. This work will be implemented with laboratory sediment microcosm experiments that will simulate a range of conditions relevant to mercury-contaminated Superfund sites. A variety of molecular biological and geochemical tools will be used to quantify the activity of methylating microorganisms and the reactivity of mercury as related to biouptake into anaerobic microorganism. The novelty of this work is that the researchers will apply recent discoveries to develop new tools to quantify mercury methylation potential. These discoveries include the genetic basis of mercury methylation in microorganisms and the geochemical processes controlling mercury speciation in sediments. The researchers will work with managers of Superfund sites in the implementation of the research, interpretation of the results, and also in the establishment of a guiding framework for assessments at specific field sites and the selection of remediation strategies.

描述（由申请人提供）：该项目将建立甲基汞生产的生物地球化学指标，该指标将用于提高汞污染沉积物的原位补救的有效性。甲基汞（MEHG）是一种有效的神经毒素，是由厌氧微生物产生的，并且在水生食物网中产生的生物毒素。诸如沉积物修正案之类的原位补救方法尚未广泛实施，主要是因为对MEHG产生的影响尚不清楚。此外，控制汞甲基化的过程之间可能会有所不同，而这种不确定性是有效实施原位修复的障碍。该项目旨在通过建立汞甲基化潜力的指标来解决这一知识差距，并利用它们来评估沉积物修正案修复的有效性。 这项研究将集中于甲基汞生产的两个关键驱动因素：促进产生MEHG的沉积物微生物的生长的环境条件以及影响这些微生物的汞生物利用度的过程。这两个驱动因素之间的平衡将决定现场沉积物治疗的成功。在这方面，这项工作的核心假设是，在FIED地点鉴定主要控制甲基汞生产将提高沉积物处理的疗效。为了检验这一假设，研究小组将采用有关汞生物地球化学的基本知识来提高沉积物中汞甲基化潜力的确定，并比较原位技术中的沉积物修复技术。具体目的是：（1）在沉积物中发展甲基化微生物的活性与MEHG产生之间的关系； （2）量化沉积物中汞生物利用度的方法； （3）确定控制甲基化潜力的因素并制定了表征地点的指南； （4）确定沉积物修订技术如何影响甲基汞生产潜力。这项工作将通过实验室沉积物缩影实验实施，这些实验将模拟与汞污染的超级基金站点相关的一系列条件。各种分子生物学和地球化学工具将用于量化甲基化微生物的活性以及与Biouptake与厌氧微生物相关的汞的反应性。这项工作的新颖性是，研究人员将应用最新的发现来开发新工具来量化汞甲基化潜力。这些发现包括微生物中汞甲基化的遗传基础以及控制沉积物中汞形成的地球化学过程。研究人员将与超级基金站点的经理合作，以实施研究，结果解释以及在特定现场的指导框架建立指导框架以及选择补救策略的选择。