Use of Chiral Tracers to Determine Cycling of POPs in Stream Ecosystems

使用手性示踪剂确定河流生态系统中持久性有机污染物的循环

• 批准号: 0828699
• 负责人: Cindy Lee
• 金额: $ 35.64万
• 依托单位: Clemson University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-15 至 2012-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0828699&HistoricalAwards=false
• 关键词: Use; Chiral; Tracers; Determine; Cycling

CBET- 0828699Lee, Cindy M.Clemson UniversityUse of Chiral Tracers to Determine Cycling of POPs in Stream EcosystemsAlthough the manufacture and use of many persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) have been banned for decades, many US aquatic systems have fish advisories due to continuing body burdens considered dangerous to human health. Environmental scientists and engineers have proposed and investigated various hypotheses such as continuing inputs or ineffective remediation methods, yet there is still an inadequate understanding of the cycling of POPs in ecosystems, especially the role of biota. Using POPs that are chiral offers an innovative technique for the studying food webs. There are 19 chiral PCBs congeners due to restricted rotation around the biphenyl bond that makes them asymmetric. The resulting atropisomers or enantiomers have the same chemical and physical properties such as solubility and volatility but can have different reaction rates in asymmetric environments. Therefore, biotransformation can result in one enantiomer enriched over the other. The enrichment can be measured as the enantiomeric fraction (EF) by chromatography due to recent developments in technology. We propose to exploit chiral analysis of PCBs to improve understanding of their movement through food webs in a stream ecosystem. The combination of chiral, congener specific and stable isotope analyses will elucidate important questions such as the transfer from contaminated sediment to basal resources such as periphyton (biofilm) and decaying leaves, which serve as food sources for invertebrates, which in turn are prey for fish. We present preliminary data that shows the utility of chiral analysis. To test the working hypothesis that chiral analysis provides significant insight we will conduct field work in a river contaminated with polychlorinated biphenyls (PCBs) and a laboratory study over a three year period. The field study (initiated in Year 1) consists of achiral and chiral analysis of extracts from samples collected over two years (2003-2004) and the targeted collection of a comprehensive set of sediment samples. The laboratory study (initiated in Year 2) will be a controlled feeding study based on the field results.The results can be applied to other POPS which are chiral (eg. DDT, chlordane, toxaphene) as well as many pesticides and pharmaceuticals that are of emerging concern. Our understanding is largely incomplete of the various pathways for POPs as they move from contaminated sediment to fish, which are a major pathway for human exposure to POPs. Risk reduction strategies would benefit from the fundamental knowledge gained from this work. The knowledge will also advance fundamental concepts in ecology through improved understanding of complex food webs. Two graduate students will be supported by the project. They will benefit from the collaboration between Clemson University and the EPA that will expand their perspective of research opportunities. Clemson has a reputation for recruiting and retaining students from under-represented groups. Outreach will include presentations to citizen groups involved in the Superfund and NRDA processes for the study site. A middle school teacher will participate in the research through a supplement.

CBET-0828699 Lee，Cindy M.克莱姆森大学使用手性示踪剂确定河流生态系统中持久性有机污染物的循环尽管许多持久性有机污染物（POP）（如多氯联苯（PCB）和二氯二苯三氯乙烷（DDT））的生产和使用已被禁止数十年，但由于持续的身体负担被认为对人类健康有害，许多美国水生系统都有鱼类寄生虫。环境科学家和工程师提出并研究了各种假设，如持续投入或无效的补救方法，但对持久性有机污染物在生态系统中的循环，特别是生物区系的作用仍然认识不足。使用手性持久性有机污染物为研究食物网提供了一种创新技术。有19种手性多氯联苯同系物，由于联苯键周围的旋转受限，使它们不对称。所得阻转异构体或对映异构体具有相同的化学和物理性质，例如溶解度和挥发性，但在不对称环境中可具有不同的反应速率。因此，生物转化可导致一种对映体相对于另一种对映体富集。由于技术的最新发展，富集可以通过色谱法测量为对映体分数（EF）。我们建议利用手性分析的多氯联苯，以提高他们的运动通过食物网在流生态系统的理解。手性、同系物特异性和稳定同位素分析的结合将阐明一些重要问题，如从受污染沉积物向附着生物（生物膜）和腐烂树叶等基底资源的转移，这些资源是无脊椎动物的食物来源，而无脊椎动物又是鱼类的猎物。我们目前的初步数据显示，手性分析的效用。为了验证手性分析提供了重要见解的工作假设，我们将在一条被多氯联苯（PCBs）污染的河流中进行实地工作，并进行为期三年的实验室研究。实地研究（在第一年开始）包括对两年（2003-2004年）收集的样品提取物进行非手性和手性分析，并有针对性地收集一整套沉积物样品。实验室研究（在第二年开始）将是一项基于田间结果的控制饲养研究。滴滴涕、滴滴涕、毒杀芬）以及许多新出现的令人关切的农药和药品。我们对持久性有机污染物从受污染的沉积物转移到鱼类的各种途径的了解基本上是不完整的，这是人类接触持久性有机污染物的主要途径。减少风险战略将受益于从这项工作中获得的基本知识。这些知识还将通过提高对复杂食物网的理解来推进生态学的基本概念。该项目将资助两名研究生。他们将受益于克莱姆森大学和美国环保署之间的合作，这将扩大他们的研究机会的角度。克莱姆森以招收和留住来自代表性不足群体的学生而闻名。外联活动将包括向参与研究中心超级基金和NRDA流程的公民团体进行介绍。一名中学教师将通过补充参与研究。