Sedimentary Records of Pyrogenic PAH Emissions from Fossil Fuel and Biomass Sources

该提案是根据环境地球化学和生物地球化学（EGB）招标（NSF 96-152）提交的。它由地球科学部、海洋科学部和大气科学部联合资助。本提案的目的是使用一种新开发的分子水平放射性碳分析方法来建立200年来水生沉积物中燃烧衍生（热原）多环芳烃（PAH）输入的记录。放射性碳是区分化石燃料（无限14C年龄）和现代生物质（当代14C年龄）燃烧源的理想参数。利用这些同位素特征，我们试图确定(a)自前工业化时代以来，化石燃料衍生的热源多环芳烃比例的变化程度；(b)哪些多环芳烃是现代和化石燃烧源最有效的示踪剂；选定的来源不确定的多环芳烃（苝）的来源。本研究选择了Siskiwit湖（MI）和Pettaquamscutt河（RI）中具有确定多环芳烃剖面的放射性定年沉积物。由于地处偏远/农村，这些沉积物中的多环芳烃负荷是大气沉积的函数（即完全由燃烧产生的输入）。下核多环芳烃同位素剖面将有两种用途：(I)同位素质量平衡计算将对不同源物质的贡献提供定量约束；（ii）当在属性-属性图中绘制浓度或化合物特定的13C组成时，分子14C数据将用作新的源识别“向量”。这项新研究的成果将是对人类活动对这类重要污染物来源影响的精确评估。所获得的数据也可能对其他燃烧产物（如二氧化碳、“烟尘”或“单质”碳）的来源的时间变化施加限制，这些燃烧产物通过大气输送进入环境，但难以追踪。最后，这项研究将提高源分配能力，并使人们对环境中多环芳烃的分布和命运有前所未有的了解。这个项目涉及环境化学的几个方面；它将汇集沉积物、水生和大气化学家，并将采用新的分子同位素工具。因此，我们相信这项研究对环境地球化学和生物地球化学项目的目标至关重要

9708478 Eglinton This proposal was submitted in response to the Environmental Geochemistry & Biogeochemistry (EGB) solicitation, NSF 96-152. It is being jointly funded by the Divisions of Earth Sciences and Ocean Sciences and Atmospheric Sciences. The objective of this proposal is to use a newly developed method for molecular-level radiocarbon analysis to establish a 200 year record of combustion-derived (pyrogenic) polycyclic aromatic hydrocarbon (PAH) inputs to aquatic sediments. Radiocarbon represents an ideal parameter to distinguish fossil fuel (infinite 14C age)from modern biomass (contemporary 14C age) combustion sources. Exploiting these isotopic characteristics we seek to determine (a) the extent to which the proportion of fossil fuel derived pyrogenic PAH have varied since the pre-industrial age; (b) which PAH represent the most effective tracers of modern and fossil combustion sources; and c the source(s) of selected PAH of uncertain origin (perylene). Radiometrically-dated sediments with established PAH profiles from Lake Siskiwit (MI) and the Pettaquamscutt River (RI) have been selected for this study. By virtue of their remote/rural location the PAH burden in these sediments is a function of atmospheric deposition (i.e. exclusively combustion-derived inputs). Down-core PAH isotopic profiles will be used in two ways: (I)isotopic mass balance calculations will provide quantitative constraints on the contributions from different source materials; (ii) molecular 14C data will be used as a new source discrimination "vector" when plotted against concentration or compound specific 13C composition in property-property plots. The product of this novel study will be a refined assessment of the impact of anthropogenic activity on the provenance of this important class of contaminants. The data obtained may also place constraints upon temporal variations in the source(s) of other combustion products which are introduced into the environment via atmospheric transp ort, but are harder to trace (e.g. CO2, "soot" or "elemental" carbon). Finally, this study will lead to improved source apportionment capabilities and an unprecedented level of understanding of the distribution and fate of PAH in the environment. This project impinges on several aspects of environmental chemistry; it will bring together sediment, aquatic and atmospheric chemists and will employ novel molecular isotopic tools. As such we believe this study is central to the goals of the Environmental Geochemistry and Biogeochemistry program.***