Investigating Biogeochemical Controls on Metal Mixture Toxicity Using Stable Isot

描述（由申请人提供）：评估特定场所的生物利用度是确定和有效解决金属污染废物场所造成的危害的重要考虑因素。该应用程序满足NIEHS超级基金研究计划对基础研究的需求，以提高对生物地球化学相互作用对污染物生物利用度的影响的理解。由于金属以混合物的形式出现，而不是在许多污染地点作为单一污染物出现，因此准确评估金属暴露及其对人类和生态系统的影响必须考虑到混合效应，这种混合效应可能是可加性的，小于可加性的，或大于可加性的。然而，目前的水质法规和管理做法通常针对单个金属，因为还没有足够的工具来预测金属混合物的生物利用度和毒性。我们的长期目标是检测、表征和评估污染金属混合物带来的风险。为了实现这一目标，我们需要开发和/或改进用于检测、评估和评价金属生物利用度的先进技术。这些技术将包括环境分子诊断和稳定同位素测定。在拟议的研究中，我们在受控条件下开发的方法将在科罗拉多州中部北福克Clear Creek超级基金遗址的一条金属污染的溪流中“实地验证”。为该场址开发的方法和工具将提供适用于其他元污染场址的物理和智力决策基础设施。在这个项目中，结合了生物和社区层面的反应研究（项目1）；生物体对多种金属暴露反应的基因组生物测定（项目2）；以及生物可利用水柱金属和组织金属残留物的测量（项目3）将得到发展和应用。我们将了解生物/化学/地质界面之间的通量，因为它与生物利用度和修复有效性有关。此外，我们将阐明影响生物吸收的地球化学因素（例如，进入食物链的运输）。我们还将在受金属污染的河流中进行一项“自然实验”，在安装降低金属浓度的水处理系统之前、期间和之后，我们将检查人们的反应。使用在项目头两年开发和测试的方法，我们将能够在项目的后几年对修复工作的有效性进行建模和观察。最后，我们描述了一个“研究翻译”计划，包括在整个资助期间吸引最终用户（例如，监管机构，金属行业代表和毒性建模者）。虽然拟议研究的重点是一个单一的超级基金站点，但其方法和结果将适用于许多接收水中的金属混合物，无论污染源如何。

DESCRIPTION (provided by applicant): Assessing site-specific bioavailability is an important consideration in determining and affectively addressing hazards posed by metals-contaminated waste sites. This application addresses the NIEHS Superfund Research Program's needs for fundamental research that improves the understanding of the effects of biogeochemical interactions on contaminant bioavailability. Because metals occur in mixtures rather than as single contaminants at many contaminated sites, accurate assessment of metal exposure and effects to humans and ecosystems must account for mixture effects, which could be additive, less than additive, or more than additive. However, current water quality regulations and management practices usually address individual metals, because adequate tools are not yet available for predicting bioavailability and toxicity of metal mixtures. Our long-term objective isto detect, characterize, and assess the risks posed by contaminant metal mixtures. To accomplish that goal, we need to develop and/or refine advanced techniques for the detection, assessment, and evaluation of metal bioavailability. Those techniques will include environmental molecular diagnostics and stable isotope assays. In the proposed research, the methods we develop under controlled conditions will be "field-truthed" in a metals-contaminated stream at the North Fork Clear Creek Superfund site in central Colorado. The approaches and tools developed for that site will provide a physical and intellectual decision infrastructure applicable to other meta-contaminated sites. In this project a combination of organism- and community-level response studies (Project 1); genomic bioassays of organism response to multiple-metals exposure (Project 2); and measurements of bioavailable water-column metals and tissue-metal residues (Project 3) will be developed and applied. We will gain an understanding of the flux between biological/chemical/geological interfaces as it relates to bioavailability and remediation effectiveness. Furthermore, we will elucidate the geochemical factors affecting biological uptake (e.g., transport into the food chain). We will also conduct a "natural experiment" in the metal-contaminated stream in which we will examine responses before, during, and after installation of a water-treatment system that will decrease concentrations of the metals. Using the methods developed and tested during the first two years of the project, we will be able to model and observe the effectiveness of the remediation efforts during the later years of the project. Finally we have delineated a plan for "research translation", including engaging end-users (e.g., regulatory agencies, metals-industry representatives, and toxicity modelers) throughout the duration of the grant. Although the focus of the proposed research is a single Superfund site, the methodology and results will be applicable to metal mixtures in many receiving waters, regardless of the contamination source.