Ji Hongjing, Zhang Jian, Zhao Yingli, Huang He, Ma Yuanqing, Liang Dejian, Chen Funing, Huo Hongxing, Wang Shuangfei, Xie Tian
School of Resources, Environment and Materials, Guangxi University, No, 100 Daxue Road, Nanning, 530004, Guangxi, China.
College of Light Industry and Food Engineering, Guangxi University, Daxue Road 100, Nanning, 530004, P.R. China.
Sci Rep. 2025 Apr 28;15(1):14750. doi: 10.1038/s41598-025-98809-z.
This study examines the factors driving heavy metal pollution in karst soils and assesses the associated environmental risks. Using a representative karst depression in Guangxi as a case study, we measured soil concentrations of arsenic (As), cadmium (Cd), lead (Pb), and zinc (Zn). These concentrations were analyzed in relation to soil physicochemical properties, morphology, and geological factors to understand pollution dynamics and migration patterns. The findings highlight As as the dominant contaminant, primarily existing in a highly mobile, reduced form. Further analysis shows that its mobility is strongly influenced by soil pH and available phosphorus (AP), emphasizing the interplay between soil chemistry and pollutant behavior. The study area, dominated by limestone strata, experiences changes in soil oxidative conditions due to rainfall, which significantly influence As accumulation and migration. The presence of abundant iron and manganese oxides further amplifies these effects. According to the Hakanson index, As contamination in surface soils presents a high ecological risk to the surrounding environment. Microbial analysis reveals a positive correlation between Proteobacteria and both the total concentration and chemical forms of As. These bacteria demonstrate resistance to As and contribute to increased residual As content, thereby reducing its toxicity and mobility. Additionally, Proteobacteria thrive in As-contaminated soils with high pH and low nutrient levels, highlighting their potential for bioremediation. This positions Proteobacteria as a promising microbial group for managing As pollution in the region.
本研究考察了喀斯特土壤中重金属污染的驱动因素，并评估了相关的环境风险。以广西一个典型的喀斯特洼地为案例研究，我们测量了土壤中砷（As）、镉（Cd）、铅（Pb）和锌（Zn）的浓度。分析了这些浓度与土壤理化性质、形态和地质因素的关系，以了解污染动态和迁移模式。研究结果突出了砷是主要污染物，主要以高度可移动的还原态存在。进一步分析表明，其迁移性受土壤pH值和有效磷（AP）的强烈影响，强调了土壤化学与污染物行为之间的相互作用。研究区域以石灰岩地层为主，降雨导致土壤氧化条件发生变化，这对砷的积累和迁移有显著影响。大量铁和锰氧化物的存在进一步放大了这些影响。根据哈坎森指数，表层土壤中的砷污染对周围环境呈现出高生态风险。微生物分析显示变形菌门与砷的总浓度和化学形态之间呈正相关。这些细菌对砷具有抗性，并导致砷的残留含量增加，从而降低其毒性和迁移性。此外，变形菌门在高pH值和低营养水平的砷污染土壤中生长旺盛，突出了它们在生物修复方面的潜力。这使得变形菌门成为该地区治理砷污染的一个有前景的微生物类群。
