He Kaikai, Lan Jianmei, Wang Yantang, Hao Chunming
North China Institute of Science and Technology, Xueyuan Street 467 Sanhe, Yanjiao, Hebei, 065201, People's Republic of China.
Hunan Center of Natural Resources Affairs, Changsha, 410004, Hunan, China.
Environ Monit Assess. 2025 Feb 22;197(3):321. doi: 10.1007/s10661-025-13770-8.
Multi-isotopes can be effectively utilized to offer new insights into heavy-metal oxidation dynamics and variations in redox conditions. Therefore, hydrochemical data and isotopic characteristics (δO, δD, δS, δO, δN, δO, δC and δC) were determined the oxidation mechanism of Sb(III) to Sb(V) in Dx groundwater. The results showed the concentration of Sb in Dx groundwater ranges from 0.005 to 20.700 mg/L, with an average of 2.300 mg/L, and Sb(V) represented the dominant form present within Dx groundwater. The δS、δN values in Dx groundwater ranges from -4.20‰ to 6.30‰, 1.20‰ to 22.70‰, respectively. the δC and δC content in Dx groundwater vary in the ranges of -26.97‰ to -16.70‰ and -17.84‰ to -2.30‰, respectively. Stibnite oxidation significantly influenced the enrichment of Sb(V) and SO, while microbial nitrification notably contributed to elevated NO levels in high-Sb groundwater by converting Sb(III) to Sb(V). The presence of redox-active moieties in DOM facilitated electron transfer for promoting Sb(III) oxidation rate during the stibnite oxidation process. Additionally, microbial oxidative degradation of DOM can promote Sb(V) enrichment, with carbon serving as an energy source for nitrification, facilitated this process and enhances the oxidation rate of Sb(III) to Sb(V). These findings contribute to a more comprehensive understanding of the geochemical behavior of antimony in groundwater and enhance our knowledge regarding Sb(III) oxidation mechanism in oxygenated groundwater.
多种同位素可有效用于深入了解重金属氧化动力学和氧化还原条件的变化。因此，通过水化学数据和同位素特征（δO、δD、δS、δO、δN、δO、δC和δC）确定了Dx地下水中Sb(III)向Sb(V)的氧化机制。结果表明，Dx地下水中Sb的浓度范围为0.005至20.700mg/L，平均为2.300mg/L，且Sb(V)是Dx地下水中的主要存在形式。Dx地下水中的δS、δN值分别在-4.20‰至6.30‰、1.20‰至22.70‰范围内。Dx地下水中的δC和δC含量分别在-26.97‰至-16.70‰和-17.84‰至-2.30‰范围内变化。辉锑矿氧化显著影响了Sb(V)和SO的富集，而微生物硝化作用通过将Sb(III)转化为Sb(V)，显著导致高Sb地下水中NO水平升高。DOM中氧化还原活性部分的存在促进了电子转移，从而在辉锑矿氧化过程中提高了Sb(III)的氧化速率。此外，DOM的微生物氧化降解可促进Sb(V)的富集，碳作为硝化作用的能量来源，促进了这一过程并提高了Sb(III)向Sb(V)的氧化速率。这些发现有助于更全面地了解地下水中锑的地球化学行为，并增强我们对含氧地下水中Sb(III)氧化机制的认识。
