Recent advances in understanding and measurement of Hg in the environment: Surface-atmosphere exchange of gaseous elemental mercury (Hg-0)
Recent advances in understanding and measurement of Hg in the environment: Surface-atmosphere exchange of gaseous elemental mercury (Hg-0)
复制标题
环境中汞的理解和测量的最新进展：气态元素汞 (Hg-0) 的表面-大气交换
DOI：
10.1016/j.scitotenv.2020.137648
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发表时间：
2020
影响因子：
9.8
通讯作者：
Zhu Wei
中科院分区：
文献类型：
--
作者：
Sommar Jonas;Osterwalder Stefan;Zhu Wei
大气是汞在全球分布的主要传输途径。气态元素汞（GEM，以下简称Hg 0）是人为和自然排放的主要形式。对联合国《水俣公约》（UN-MC）规定的减排效果的评估，关键取决于对全球汞循环动态的了解。这些动力学包括例如red-ox反应，甲基化-去甲基化和干-湿沉降，约束不佳的大气-地表Hg 0通量特别限制其全球地球化学循环的时间尺度的可预测性。本文重点介绍了Hg 0通量场的观测研究，即理论，应用，优势和局限性的各种实验方法，适用于衡量交换通量和破译活动的子过程。我们提出了一个深入的审查，一个全面的文献综合，和方法和仪器的进展，陆地和海洋Hg 0通量的研究在最近几年。特别是，我们概述了广泛的测量技术的理论和详细的操作协议。今天，最常用的测量技术，以确定净汞0通量（>95%的已公布的通量数据）是动态通量室的小规模和微气象方法的大规模测量。此外，以汞浓度测量为基础的自上而下的方法已被用作更好地限制汞排放的工具，作为一种独立的方式，例如挑战排放清单。本综述是Sommar等人2013年（DOI：10.1080/10643389.2012.671733）的最新、彻底修订版。在前一份出版物中给出的1988-2009年>100项被引用的通量研究的表格中，我们在这里列出了过去十年中发表的相应研究，只有少数例外（2008-2019年）。在这十年中，汞稳定同位素比的样品参与大气-陆地相互作用是在手，并提供结合浓度和/或通量测量新的限制，定量和定性评估的双向Hg 0通量。最近的努力，在放松涡动积累和涡动协方差Hg 0通量方法的发展承担的潜力，以促进长期的，生态系统规模的通量测量，以减少普遍存在的大不确定性Hg 0通量估计。汞通量测量方法的标准化对于研究土地利用变化和气候变暖如何影响生态系统特定的汞汇源特征以及验证描述区域和全球尺度汞循环的常用模型参数化至关重要。
The atmosphere is the major transport pathway for distribution of mercury (Hg) globally. Gaseous elemental mercury (GEM, hereafter Hg0) is the predominant form in both anthropogenic and natural emissions. Evaluation of the efficacy of reductions in emissions set by the UN's Minamata Convention (UN-MC) is critically dependent on the knowledge of the dynamics of the global Hg cycle. Of these dynamics including e.g. red-ox reactions, methylation-demethylation and dry-wet deposition, poorly constrained atmosphere–surface Hg0fluxes especially limit predictability of the timescales of its global biogeochemical cycle. This review focuses on Hg0flux field observational studies, namely the theory, applications, strengths, and limitations of the various experimental methodologies applied to gauge the exchange flux and decipher active sub-processes. We present an in-depth review, a comprehensive literature synthesis, and methodological and instrumentation advances for terrestrial and marine Hg0flux studies in recent years. In particular, we outline the theory of a wide range of measurement techniques and detail the operational protocols. Today, the most frequently used measurement techniques to determine the net Hg0flux (>95% of the published flux data) are dynamic flux chambers for small-scale and micrometeorological approaches for large-scale measurements. Furthermore, top-down approaches based on Hg0concentration measurements have been applied as tools to better constrain Hg emissions as an independent way to e.g. challenge emission inventories. This review is an up-dated, thoroughly revised edition of Sommar et al. 2013 (DOI: 10.1080/10643389.2012.671733). To the tabulation of >100 cited flux studies 1988–2009 given in the former publication, we have here listed corresponding studies published during the last decade with a few exceptions (2008–2019). During that decade, Hg stable isotope ratios of samples involved in atmosphere-terrestrial interaction is at hand and provide in combination with concentration and/or flux measurements novel constraints to quantitatively and qualitatively assess the bi-directional Hg0flux. Recent efforts in the development of relaxed eddy accumulation and eddy covariance Hg0flux methods bear the potential to facilitate long-term, ecosystem-scale flux measurements to reduce the prevailing large uncertainties in Hg0flux estimates. Standardization of methods for Hg0flux measurements is crucial to investigate how land-use change and how climate warming impact ecosystem-specific Hg0sink-source characteristics and to validate frequently applied model parameterizations describing the regional and global scale Hg cycle.