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

来自地球不同地区的报告揭示了汞在环境中的积累，即使不是全球的，也是半球形的。虽然大气沉积显然起着主要作用，而且每年向大气中释放的汞可能有多达一半是人为的，但汞循环和通量的重要细节尚不确定。汞有六种天然的同位素。某些物理、化学和生化过程对这些同位素产生轻微的分离（分馏）。因此，环境汞的同位素组成可能成为汞循环和通量模型的关键制约因素。由于大气汞凝结过程中同位素分馏的程度取决于温度，因此在泥炭岩心等年代确定的材料中记录的汞的同位素组成也可能提供有关古气候的信息。最近的发展使对汞同位素比率进行非常精确的测量成为可能，这些测量揭示了汞矿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），在环境水平上进行高精度同位素比率测量。为了证明该方法的可行性，我们选择了一个泥炭岩心作为样本材料，该岩心记录了对大气汞沉积的充分研究。

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.