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: 0097142
• 负责人: Yu-Ping Chin
• 金额: $ 15.38万
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0097142&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.

翻译后摘要：持久性有机污染物（持久性有机污染物）能够被运到北极的长程过程（即，全球蒸馏），并从当地受海冰和径流污染的地区。人们对这些持久性污染物对北极生态系统的影响知之甚少，但有证据表明，某些污染物发生了生物累积，特别是可能对最高营养级的生物和土著人民构成威胁。溶解有机物（DOM）在北极地区所有的表层沃茨中普遍存在，并可能对持久性有机污染物的归宿起重要作用。DOM能够起到“准吸附剂”的作用，从而改变水体中持久性有机污染物的形态。DOM还具有高度的光反应性，能够形成化学瞬变，将持久性有机污染物转化为其他物质。鉴于北半球夏季发生的高光子通量，光解过程可能在北极表层沃茨水持久性有机污染物的命运中发挥重要作用。这项研究正在探索在北极的淡水（图里克湖）和海洋站点（巴特岛）的地表沃茨中存在DOM的情况下控制持久性有机污染物命运的过程。具体目标包括：1.确定和量化两个地点的地表沃茨中持久性有机污染物的污染程度;2.收集、分离并阐明这两个站点DOM的结构和光解特性;3.在实验室和图利克湖现场使用太阳模拟器测量持久性有机污染物发生直接和间接光解的程度;4.确定和量化由DOM光解形成的瞬时物种的类型和数量;以及5.该项目是俄亥俄州州立大学/BPRC（Chin）和科罗拉多大学/INSTAAR（McKnight）的研究人员之间的一项合作努力。之所以选择七氯、六氯苯、顺式氯苯、亚麻酸和两种多氯联苯同系物进行研究，是因为它们是北极表层沃茨、动物群和土著居民中常见的污染物，而且具有广泛的物理化学和光化学特性。将使用分离和定量光敏剂的最新方法。其中包括切向流超滤装置和反相柱，用于浓缩来自两个站点的DOM。将在实验室和室外光解实验中使用环境现实水平的DOM分离物，以确定这些光敏剂转化持久性有机污染物的功效。将密切跟踪反应，以量化母体化合物及其光衍生物的变化。该项目的其他方面将尝试使用“探针“”捕获”光瞬变，以阐明重要的光解途径。拟议的项目将为今后研究控制持久性有机污染物在北极的最终结果的过程奠定基础。最后，积累的信息将有助于那些负责管理这些生态系统的各方。