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<p>As a region with a naturally high geochemical background, Southwestern China is subjected to intense anthropogenic perturbations from industrial, mining, and agricultural activities, posing significant ecological risks. To identify the characteristics and sources of heavy metal (HM) pollution in this complex environment, this study employed an integrated methodology including geochemical analysis, GIS-based mapping, Pearson correlation matrix (PCM), principal component analysis (PCA), geo-accumulation index (<i>I</i><sub>geo</sub>), potential ecological risk index (<i>RI</i>), <sup>210</sup>Pb dating, and dynamic leaching experiments in a pyrite mining-affected area. Results showed that Cd, Hg, Ni, Cu and Zn concentrations in soils and sediments exceeded Sichuan regional background values, with Cd being the most severe contaminant at up to 12.71- and 14.30-fold background levels, respectively. PCM and PCA revealed that Cd, Hg, Pb and As were primarily from anthropogenic sources. Spatially, Cd, Pb, and Hg were highly enriched in the eastern, central, and middle-lower river areas, while elevated levels of Ni, Cu, Zn and Cr were mainly found in the western area. <i>I</i><sub>geo</sub> and <i>RI</i> assessments identified considerable ecological risk, primarily from Cd and Hg. <sup>210</sup>Pb dating showed relatively low HM levels before 1989, a gradual increase from 1989 to 2009, followed by a fluctuating decline. Dynamic leaching tests demonstrated high Cd mobility in both soils and pyrite tailings, and its release was controlled by interfacial and internal diffusion as well as surface reactions. This integrated approach shows that effective pollution control in high-background regions requires coordinated management of both legacy contamination and ongoing anthropogenic emissions.</p>

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Geochemical signature and genesis of heavy metals in soils and sediments from a typical pyrite mining area in Southwestern China

  • 期刊论文

  • 发表日期：

    2025年12月26日

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  • Kai Zhao,
  • Zeming Shi,
  • Yinghai Zhu,
  • Yixin Li,
  • Qi Liu,
  • Qiuyu Huang,
  • Xiaohan Liu

摘要

As a region with a naturally high geochemical background, Southwestern China is subjected to intense anthropogenic perturbations from industrial, mining, and agricultural activities, posing significant ecological risks. To identify the characteristics and sources of heavy metal (HM) pollution in this complex environment, this study employed an integrated methodology including geochemical analysis, GIS-based mapping, Pearson correlation matrix (PCM), principal component analysis (PCA), geo-accumulation index (Igeo), potential ecological risk index (RI), 210Pb dating, and dynamic leaching experiments in a pyrite mining-affected area. Results showed that Cd, Hg, Ni, Cu and Zn concentrations in soils and sediments exceeded Sichuan regional background values, with Cd being the most severe contaminant at up to 12.71- and 14.30-fold background levels, respectively. PCM and PCA revealed that Cd, Hg, Pb and As were primarily from anthropogenic sources. Spatially, Cd, Pb, and Hg were highly enriched in the eastern, central, and middle-lower river areas, while elevated levels of Ni, Cu, Zn and Cr were mainly found in the western area. Igeo and RI assessments identified considerable ecological risk, primarily from Cd and Hg. 210Pb dating showed relatively low HM levels before 1989, a gradual increase from 1989 to 2009, followed by a fluctuating decline. Dynamic leaching tests demonstrated high Cd mobility in both soils and pyrite tailings, and its release was controlled by interfacial and internal diffusion as well as surface reactions. This integrated approach shows that effective pollution control in high-background regions requires coordinated management of both legacy contamination and ongoing anthropogenic emissions.