School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, 230601, Anhui, China.
School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei, 230601, Anhui, China.
Environ Pollut. 2023 Oct 15;335:122378. doi: 10.1016/j.envpol.2023.122378. Epub 2023 Aug 14.
The Hg released from coal mining activities can endanger soil ecosystems and pose a risk to human health. Understanding the accumulation characteristics of mercury (Hg) in coal mining soil is important for effectively controlling Hg emissions and developing measures for the prevention and control of Hg contamination. To identify the potential sources of Hg in soils, the Hg concentration and isotopic composition characteristics of raw coal and different topsoil types from the areas surrounding a coal mine were determined in this study. The results showed that Hg in coal mainly exists mainly in the form of inorganic Hg, and Hg has experienced Hg photoreduction prior to incorporating into coal. In addition, the composition of Hg isotopes differed significantly among different topsoil types, and the δHg value of the farmland soil exhibited large negative excursions compared to the coal mining soil. The ternary mixed model further revealed the presence of substantial differences in potential Hg sources among the two regions, with the coal mining soil being greatly disturbed by anthropogenic activity, and the relative contributions of Hg from raw coal, coal gangue, and background soil to coal mining soil being 33.42%, 34.4%, and 32.19%, respectively. However, Hg from raw coal, coal gangue and background soil contributed 17.04%, 21.46%, and 61.51% of the Hg in the farmland soil, indicating that the accumulation of Hg in farmland soil was derived primarily from the background soil. Our study demonstrated that secondary pollution in soil caused by immense accumulation of solid waste (gangue) by mining activities offers a significant challenge to ecological security. These findings provide new insights into controlling soil Hg in mining areas and further highlight the urgency of strict protective measures for contaminated sites.
采煤活动释放的汞会危及土壤生态系统，并对人类健康构成威胁。了解煤矿土壤中汞的积累特征对于有效控制汞排放和制定汞污染防治措施至关重要。为了确定土壤中汞的潜在来源，本研究测定了矿区周围不同表土类型原煤及土壤中汞的浓度及同位素组成特征。结果表明，煤中汞主要以无机汞的形式存在，且在汞进入煤之前经历了汞光还原作用。此外，不同表土类型的汞同位素组成差异显著，农田土壤的 δHg 值与煤矿土壤相比表现出较大的负偏移。三元混合模型进一步揭示了两个区域之间潜在汞源存在显著差异，煤矿土壤受到人为活动的强烈干扰，原煤、煤矸石和背景土壤对煤矿土壤汞的相对贡献分别为 33.42%、34.4%和 32.19%。然而，原煤、煤矸石和背景土壤中汞对农田土壤汞的贡献分别为 17.04%、21.46%和 61.51%，表明农田土壤中汞的积累主要来自背景土壤。本研究表明，采矿活动中大量固体废物（煤矸石）的积累导致土壤的次生污染，对生态安全构成了重大挑战。这些发现为控制矿区土壤汞提供了新的思路，并进一步凸显了污染场地严格保护措施的紧迫性。
