Mercury Stable Isotopic Compositions in Coals from Major Coal Producing Fields in China and Their Geochemical and Environmental Implications

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• 作者：Runsheng Yin ; Xinbin Feng ; Jiubin Chen
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：May 20, 2014
• 年：2014
• 卷：48
• 期：10
• 页码：5565-5574
• 全文大小：447K
• 年卷期：v.48,no.10(May 20, 2014)
• ISSN：1520-5851

文摘

Total mercury (Hg) concentrations (THg) and stable mercury isotopic compositions were measured in coal samples (n = 61) from major coal producing fields in China. The THg concentrations in coals ranged from 0.05 to 0.78 渭g g^鈥?, with a geometric mean of 0.22 渭g g^鈥?. Hg isotopic compositions in coals showed large variations both in mass-dependent fractionation (MDF, 未²⁰²Hg: 鈭?.36 to 鈭?.14鈥? and mass-independent fractionation (MIF, 螖¹⁹⁹Hg: 鈭?.44 to +0.38鈥?. The MIF signatures in coals may reveal important information on the coal-forming conditions (e.g., humic and sapropelic). The 螖¹⁹⁹Hg/螖²⁰¹Hg of 1 determined in coals indicated that a portion of Hg has been subjected to photoreduction process prior to being incorporated to coals. On the basis of THg, Hg isotopic signatures, and other geological factors (e.g., total ash content and total sulfur content), the potential sources of Hg in coals from different coal producing regions were estimated. The main source of Hg in coals from southwestern China and eastern part of northern China is likely geogenic Hg, whereas the source of Hg in coals from other parts of northern China is mainly biogenic Hg. Finally, we estimated that Hg emission from coal combustion in China is characterized by diagnostic Hg isotopic signatures (未²⁰²Hg: 鈭?.70鈥?and 螖¹⁹⁹Hg: 鈭?.05鈥?. The present study demonstrates that Hg isotopes can serve as a tool in understanding the sources and transformation of Hg in coals and may also be used as a tracer to quantify Hg emissions from coal combustion.