Mercury Isotope Investigations of Pre-and Post-Industrial Atmospheric Deposition

来自地球上相距甚远的地区的报告显示，环境中汞的积累即使不是全球的，也是半球的。虽然大气沉积显然起着主要作用，而且每年释放到大气中的汞中可能有多达一半是人为来源的，但汞循环和通量的重要细节尚不确定。某些物理、化学和生化过程会产生这些同位素的轻微分离(分馏)。因此，环境汞的同位素组成可能会对汞循环和通量模型提供关键限制。由于大气汞凝聚等过程中的同位素分馏程度与温度有关，记录在泥炭岩心等测年材料中的汞的同位素组成也可能提供有关古气候的信息。最近的发展使非常精确地测量汞同位素比率成为可能，这些测量揭示了汞矿石和工业加工汞的同位素组成的差异。该项目旨在测试将汞同位素系统学应用于环境汞的可行性，并开发常规技术(通过改进现有技术)，以便在环境一级进行高精度的同位素比率测量。为了能够论证其可行性，选择了一个泥炭岩芯作为样品材料，该泥炭岩芯保存了经过充分研究的大气汞沉积记录。

ABSTRACTReports from widely separated areas of the Earth have revealed a hemispherical, if not global, accumulation of mercury in the environment. While it is clear that atmospheric deposition plays a major role, and that perhaps as much as half of the annual release of mercury into the atmosphere is anthropogenic in origin, important details of the mercury cycle and fluxes are uncertain.There are six naturally occurring isotopes of mercury. Certain physical, chemical and biochemical processes produce slight separations (fractionation) of these isotopes. As a consequence, the isotopic composition of environmental mercury can potentially provide key constraints to models of mercury cycling and fluxes. Since the degree of isotope fractionation during a process like condensation of atmospheric mercury is temperature dependent, the isotopic composition of mercury recorded in well-dated material such as peat cores might also provide information on paleoclimate.Recent developments make it possible to make very precise measurement of mercury isotope ratios and these measurements have revealed differences in the isotopic composition of mercury ores and industrially processed mercury. This project is designed to test the feasibility of applying mercury isotope systematics to environmental mercury and to develop routine techniques (by improving existing techniques) for high-precision, isotope-ratio measurements at environmental levels. In order to be able to demonstrate the feasibility, a peat core that archives a well-studied record of atmospheric mercury deposition is selected as sample material.