Collaborative Research: The Direct and Indirect Photolytic Fate of Persistent Organic Pollutants in Arctic Surface Waters

合作研究：北极地表水中持久性有机污染物的直接和间接光解归宿

• 批准号: 0097182
• 负责人: Diane McKnight
• 金额: $ 15.85万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2004-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0097182&HistoricalAwards=false
• 关键词: Collaborative; Research; Direct; Indirect; Photolytic

Abstract:Persistent organic pollutants (POPs) are capable of being transported to the Arctic by long-range processes (i.e., global distillation), and from locally contaminated areas by sea ice and runoff. The effect of these persistent pollutants on arctic ecosystems is poorly understood, but evidence shows that bioaccumulation occurs for some contaminants, and in particular may pose a threat to organisms at the highest trophic levels and indigenous people. Dissolved organic matter (DOM) is ubiquitous to all surface waters in the Arctic, and may play an important role in the fate of POPs. DOM is capable of acting as a "quasi-sorbent" thereby altering the speciation of POPs in the water column. DOM is also highly photoreactive and is able of forming chemical transients that can transform POPs to other substances. Given the high degree of photon flux that occurs during the boreal summer, photolytic processes may play an important role in POP fate in arctic surface waters. This research is exploring processes that control the fate of POPs in the presence of DOM from surface waters at a freshwater (Toolik Lake) and a marine site (Barter Island) in the Arctic. Specific objectives include:1. identify and quantify the level of POP contamination in the surface waters at the two sites;2. collect, isolate, and elucidate the structural and photolytic properties of DOM at these two sites;3. measure the degree to which direct and indirect photolysis occurs for POPs using solar simulators in the lab and at the Toolik Lake field site;4. identify and quantify the types and amounts of transient species formed by the photolysis of DOM; and5. study the reaction kinetics and mechanisms for the direct and indirect photolysis of POPs and their daughter products.The project is a collaborative effort between investigators at Ohio State University/BPRC (Chin) and the University of Colorado/INSTAAR (McKnight). Heptachlor, hexachlorobenzene, cis-chlordane, lindane, and two PCB congeners have been selected for study because they represent contaminants commonly detected in arctic surface waters, fauna, and the aboriginal people, and because they possess a wide range of physicochemical and photochemical properties. State-of-the-art methods for isolating and quantifying photosensitizers will be used. These include tangential-flow ultrafiltration unit and reverse-phase columns for concentrating DOM from the two sites. DOM isolates present at environmentally realistic levels will be used in both lab and outdoor photolysis experiments to determine the efficacy of these photosensitizers at transforming POPs. The reactions will be followed closely to quantify changes in both the parent compound and their photoderivatives. Other aspects of the project will attempt to "trap" phototransients using "probes" in an effort to elucidate important photolytic pathways. The proposed project will provide the basis for future research into the processes that control POP fate in the Arctic. Finally, information accrued will aid those parties responsible for the stewardship of these ecosystems.

摘要：持续的有机污染物（POPS）能够通过长期过程（即全球蒸馏）和海冰和径流从当地污染的地区运输到北极。这些持续污染物对北极生态系统的影响知之甚少，但有证据表明，某些污染物发生生物蓄积，尤其可能会威胁到最高营养水平和土著人民的生物体。溶解的有机物（DOM）无处不在北极的所有地表水，并且可能在流行的命运中起重要作用。 DOM能够充当“准吸收”，从而改变水柱中的弹出声。 DOM也具有高度的光反应性，并且能够形成可以将POP转化为其他物质的化学瞬变。鉴于在北方夏季期间发生的高度光子通量，光解过程可能在北极地表水中的流行命运中起重要作用。这项研究正在探索在淡水（工具湖）的地表水和北极的海洋地点（易货岛）存在的DOM存在下控制POP的命运的过程。具体目标包括：1。识别并量化两个位点地表水中的POP污染水平； 2。在这两个地点收集，分离和阐明DOM的结构和光解释特性； 3。测量使用实验室和Toolik Lake Field位置中的太阳能模拟器对POP进行直接和间接光解的程度； 4。识别并量化由DOM光解形成的瞬时物种的类型和量；和5。研究了Pops及其女儿产品的直接和间接光解的反应动力学和机制。该项目是俄亥俄州立大学/BPRC（CHIN）（CHIN）和科罗拉多大学/Instaar大学（MCKNIGHT）的研究人员之间的合作努力。选择了七氯，六氯苯，顺式智商，Lindane和两名PCB同源物进行研究，因为它们代表了在北极地表水，动物群，动物群和原住民中常见的污染物，并且因为它们具有广泛的物理化学和光化学特性。将使用用于隔离和量化光敏剂的最新方法。其中包括用于从两个位点浓缩DOM的切向流量超滤单元和逆相柱。在环境现实水平上存在的DOM分离物将在实验室和室外光解实验中使用，以确定这些光敏剂在变换POPS上的功效。这些反应将紧随其后，以量化母体化合物及其光脱发的变化。该项目的其他方面将尝试使用“探针”来“捕获”光传递，以阐明重要的光解通路。拟议的项目将为未来对控制北极流行命运的过程进行研究的基础。最后，累积信息将有助于那些负责这些生态系统管理的各方。