State Key Laboratory of Biogeology and Environmental Geology, Hubei Key Laboratory of Critical Zone Evolution, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China.
College of Resources and Environment, Zunyi Normal University, Zunyi 563006, China.
Sci Total Environ. 2020 Apr 15;713:136320. doi: 10.1016/j.scitotenv.2019.136320. Epub 2020 Jan 11.
Coal fly ash in the atmosphere affects air quality and potentially influences the global climate by promoting oceanic productivity. Although accurately tracing the sources of fly ashes is vital for emission control, it remains a challenging task. Stable lead (Pb) isotope analysis is a useful tool for tracing atmospheric pollution but it fails to accurately address coal combustion emissions due to the broad range of Pb isotopic composition of coal. Environmental magnetic parameters can be used as a rapid and economical proxy for tracing atmospheric pollutants (including coal fly ashes) and have the potential for discriminating emission sources. In this study, we combined magnetic parameters with Pb isotopic signatures in order to better discriminate the sources of coal fly ash. Both magnetic particles and Pb are highly concentrated in the fly ashes compared with the feed coals. Most of the fly ashes exhibit higher Pb/Pb and lower Pb/Pb ratios than those of the feed coals. Furthermore, the Pb isotopic compositions of the fly ashes are highly correlated (p < 0.01) with the concentrations of magnetic particles (especially hematite), suggesting that the variation of Pb isotopes in the fly ashes is controlled by the adsorption of Pb on magnetic minerals. Based on the established relationship between magnetic minerals and Pb isotopes within coal fly ashes, we re-analyzed previously reported magnetic and Pb isotopic data from atmospheric dust and demonstrated the effectiveness of the combined method in discriminating coal fly ash in the atmosphere.
大气中的煤飞灰通过促进海洋生产力来影响空气质量，并有可能影响全球气候。尽管准确追踪飞灰的来源对于排放控制至关重要，但这仍然是一项具有挑战性的任务。稳定的铅（Pb）同位素分析是追踪大气污染的有用工具，但由于煤的 Pb 同位素组成范围广泛，因此无法准确解决煤燃烧排放的问题。环境磁学参数可用作追踪大气污染物（包括煤飞灰）的快速且经济的替代物，并且具有区分排放源的潜力。在这项研究中，我们结合了磁学参数和 Pb 同位素特征，以更好地区分煤飞灰的来源。与入炉煤相比，磁颗粒和 Pb 在飞灰中高度富集。大多数飞灰的 Pb/Pb 和 Pb/Pb 比值均高于入炉煤。此外，飞灰的 Pb 同位素组成与磁性颗粒（尤其是赤铁矿）的浓度高度相关（p < 0.01），表明飞灰中 Pb 同位素的变化受 Pb 在磁性矿物上的吸附控制。基于煤飞灰中磁性矿物和 Pb 同位素之间的关系，我们重新分析了大气粉尘中以前报道的磁性和 Pb 同位素数据，并证明了该组合方法在区分大气中煤飞灰方面的有效性。
