Key Laboratory for Heavy Metal Pollution Control and Reutilization, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
Bureau of Hydrology, Ministry of Water Resources of China, Beijing, 100053, China.
Environ Geochem Health. 2021 Aug;43(8):3133-3149. doi: 10.1007/s10653-021-00807-3. Epub 2021 Feb 1.
Kashin-Beck disease (KBD) is an endemic disease in China with the highest incidence rate in Tibet region. Promoted generation of oxygen free radicals by semiquinone structure of humic substance (HS) in drinking water was considered to be one of its pathogeneses. Therefore, detailed analysis of HS was performed in water and sediment samples collected from three endemic and three disease-free areas in Changdu Region, Tibet, China. After purification of the HS in the samples, the fractions of HS were characterized using electron paramagnetic resonance, C nuclear magnetic resonance, fluorescence spectroscopy with parallel factor analysis and Fourier transform infrared spectroscopy (FTIR). The organic carbon content of HS did not show a significant difference between endemic and disease-free areas or correlation with KBD-associated morbidity. Except FTIR, all techniques succeeded in characterization of the quinone redox system, indicating their validity and consistency. The quinone redox system in aquatic HS exhibited significantly higher level of the following indexes in endemic areas than disease-free areas: semiquinone radical content of fulvic acid (FA) (p < 0.05), aromaticity of FA (p < 0.05), fluorescence intensity (per gram carbon) of reduced quinone-like component of FA (p < 0.05) and humic acid (HA) (p < 0.1). Semiquinone radical content (r = 0.781, p < 0.1), aromaticity of FA (r = 0.891, p < 0.05), intensity of oxidized quinone-like component (r = 0.875, p < 0.05) and reduced quinone-like component of FA (r = 0.793 p < 0.1) showed medium to strong correlation with KBD-associated morbidity. Generally, the content of reduced quinone and aquatic FA showed stronger differences between endemic and disease-free areas than oxidized quinone and aquatic HA, respectively. The quinone redox system in sediment HS did not show any significant relationship with KBD. The present study is a successful attempt to combine the three indexes, semiquinone radical content, aromaticity and fluorescence intensity, in characterizing quinone redox system in HS, facilitating more comprehensive understanding of the characteristics of HS in KBD-affected regions.
大骨节病是中国的一种地方病，在西藏地区发病率最高。饮用水中腐殖质（HS）的半醌结构促进氧自由基的产生被认为是其发病机制之一。因此，对来自中国西藏昌都地区三个流行区和三个非流行区的水和沉积物样本中的 HS 进行了详细分析。在对样品中的 HS 进行纯化后，使用电子顺磁共振、C 核磁共振、荧光光谱与平行因子分析和傅里叶变换红外光谱（FTIR）对 HS 的各个组分进行了表征。流行区和非流行区 HS 的有机碳含量没有显著差异，也与大骨节病相关发病率无相关性。除了 FTIR 之外，所有技术都成功地对醌类氧化还原体系进行了特征描述，表明它们具有有效性和一致性。水相 HS 中的醌类氧化还原体系在流行区的以下指标显著高于非流行区：富里酸（FA）的半醌自由基含量（p<0.05）、FA 的芳香度（p<0.05）、FA 中还原醌类成分的荧光强度（每克碳）（p<0.05）和腐殖酸（HA）（p<0.1）。半醌自由基含量（r=0.781，p<0.1）、FA 的芳香度（r=0.891，p<0.05）、氧化醌类成分的强度（r=0.875，p<0.05）和 FA 中还原醌类成分的强度（r=0.793，p<0.1）与大骨节病相关发病率呈中到强相关性。一般来说，还原醌和水相 FA 的含量在流行区和非流行区之间的差异大于氧化醌和水相 HA。沉积物 HS 中的醌类氧化还原体系与大骨节病无任何显著关系。本研究成功尝试了将半醌自由基含量、芳香度和荧光强度三个指标结合起来，对 HS 中的醌类氧化还原体系进行了特征描述，有助于更全面地了解大骨节病影响地区 HS 的特性。
