Mercury and mercury isotopes in the environment

汞（Hg）是一种全球分布的高毒性污染物。虽然汞已被证实对健康构成威胁，但人们对汞的自然循环仍知之甚少，需要新的方法来更好地阐明和量化汞在环境中的来源和转化。B.A. Bergquist博士最近证明，汞的同位素经历了独特的同位素分异，为直接跟踪和了解环境中汞的循环提供了不可磨灭的指纹。这种同位素特征，即质量无关分馏（MIF），是汞在湖泊和海洋中发生重要化学转变时产生的。到目前为止，我们表明保存在鱼类组织中的MIF可以用来了解食物网中汞的来源。此外，天然样品中的MIF可用于估计已解毒并从个别湖泊栖息地释放到大气中的有毒甲基汞的比例。然而，这只是一种令人兴奋的研究汞的新方法的开始。这些发现为追踪汞在环境中的迁移性和毒性铺平了道路，并将有助于确定动物和人类接触汞的来源。这笔拨款将资助必要的设备，以利用汞同位素特征来研究汞在水生生态系统中的循环和生物积累，并了解汞对环境的来源。为了进行这项研究，有必要准确和精确地测量各种样品类型中的汞浓度，包括沉积物、自然水、空气、雪、鱼组织和其他生物样品。所要求的设备，一个汞分析仪系统和微波消解单元，将允许在各种样品类型和浓度的大范围内准确测定汞浓度。

Mercury (Hg) is a globally distributed and highly toxic pollutant.  Although mercury poses proven health risks, much of the natural cycle of mercury is not well understood and new approaches are necessary to better elucidate and quantify Hg sources and transformations in the environment.  Dr. B.A. Bergquist recently demonstrated that the isotopes of Hg undergo a unique isotopic fractionation that provides an indelible fingerprint for directly tracking and understanding Hg cycling in the environment.   This isotopic signature, mass independent fractionation (MIF), is generated when mercury undergoes important chemical transformations in lakes and in the ocean.  Thus far, we show that the MIF preserved in fish tissue can be used to understand sources of Hg in food webs.  Further, MIF in natural samples can be used to estimate the fraction of toxic methylmercury that has been detoxified and released from individual lake habitats to the atmosphere.   However, this is only the beginning of an exciting new approach for studying Hg.  These findings pave the way tracing the mobility and toxicity of the Hg in the environment and will facilitate fingerprinting of the sources of Hg exposure to animals and humans.This grant will fund equipment necessary to utilize Hg isotopic signatures to investigate Hg cycling and bioaccumulation in aquatic ecosystems and to understand Hg sources to the environment.  In order to perform this research, it is necessary to accurately and precisely measure Hg concentrations in a variety of sample types including sediments, natural waters, air, snow, fish tissues, and other biological samples.  The requested equipment, a Hg analyzer system and microwave digestion unit, will allow for the accurate determination of Hg concentrations in a variety of sample types and over a large range in concentrations.