State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-environmental Science & Technology, Guangdong Academy of Sciences, Guangzhou 510650, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
J Environ Sci (China). 2025 Apr;150:582-593. doi: 10.1016/j.jes.2024.03.002. Epub 2024 Mar 16.
Coal power plants annually generate quantities of byproducts that release environmentally hazardous heavy metals like Cd and Pb. Understanding the behavior and spatiotemporal impacts on soils of these releases is crucial for pollution control. This study investigated the concentrations and isotope ratios of Cd/Pb in combustion byproducts, depositions and soils collected from a coal-fired power plant or its surrounding area. The pulverized fuel ash (PFA) and desulfurized gypsum (DG) exhibited heavier Cd isotopes with ΔCd values of 0.304‰ and 0.269‰, respectively, while bottom ash (BA) showed lighter Cd isotopes (ΔCd = -0.078‰), compared to feed coal. We proposed a two-stage condensation process that governs the distribution of Cd/Pb, including accumulation on PFA and DG within electrostatic precipitators and desulfurization unit, as well as condensation onto fine particles upon release from the stack. Emissions from combustion and large-scale transport make a significant contribution to deposition, while the dispersion of Cd/Pb in deposition is primarily influenced by the prevailing wind patterns. However, the distribution of Cd/Pb in soils not only exhibit predominant wind control but is also potentially influenced by the resuspension of long-term storage byproducts. The power plant significantly contributes to soil in the NW-N-NE directions, even at a considerable distance (66%-79%), demonstrating its pervasive impact on remote regions along these orientations. Additionally, based on the vertical behavior in the profile, we have identified that Cd tends to migrate downward through leaching, while variations in Pb respond to the historical progression of dust removal.
燃煤电厂每年都会产生大量的副产品，这些副产品会释放出镉（Cd）和铅（Pb）等对环境有害的重金属。了解这些释放物在土壤中的行为和时空影响对于污染控制至关重要。本研究调查了从燃煤电厂或其周边地区采集的燃烧副产品、沉积物和土壤中 Cd/Pb 的浓度和同位素比值。煤粉炉飞灰（PFA）和脱硫石膏（DG）中的 Cd 同位素较重，ΔCd 值分别为 0.304‰和 0.269‰，而底灰（BA）中的 Cd 同位素较轻（ΔCd = -0.078‰），与入炉煤相比。我们提出了一个两阶段冷凝过程来控制 Cd/Pb 的分布，包括在静电除尘器和脱硫装置中积累在 PFA 和 DG 上，以及从烟囱中释放出来后凝结在细颗粒上。燃烧和大规模运输产生的排放物对沉积有很大的贡献，而 Cd/Pb 在沉积中的分布主要受盛行风向模式的影响。然而，Cd/Pb 在土壤中的分布不仅表现出主要的风向控制，而且可能受到长期储存副产品的再悬浮的影响。该电厂显著影响 NW-N-NE 方向的土壤，即使在相当远的距离（66%-79%），这表明其对这些方向上的偏远地区有普遍的影响。此外，根据剖面中的垂直行为，我们已经确定 Cd 倾向于通过淋滤向下迁移，而 Pb 的变化则响应于除尘的历史发展。
