| 引用本文: | 李雅妮,徐华成,江和龙.鄱阳湖水体溶解有机质分子量分布、荧光特征及对重金属分布的影响.湖泊科学,2020,32(4):1029-1040. DOI:10.18307/2020.0412 |
| LI Yani,XU Huacheng,JIANG Helong.Molecular weight distribution, fluorescence characteristics of dissolved organic matter and their effect on the distribution of heavy metals of Lake Poyang. J. Lake Sci.2020,32(4):1029-1040. DOI:10.18307/2020.0412 |
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| 摘要: |
| 溶解有机质（DOM）在环境水体中广泛存在，具有连续的分子量分布特征，并可显著影响水体中污染物的迁移转化和归趋行为.于2019年春季采集鄱阳湖全湖水样，采用超过滤技术将DOM样品分为低分子量（LMW，<1 kDa）和高分子量（HMW，1 kDa~0.45 μm）组分，通过三维荧光光谱结合平行因子分析（EEM-PARAFAC）和ICP-MS分析不同分子量区间有机组分和重金属含量.结果表明，鄱阳湖水体DOM中LMW-DOM占比为43%~55%，HMW-DOM占比为45%~57%.平行因子模型提取出3个相互独立的荧光组分，分别为类富里酸组分C1、C2和类腐殖酸组分C3.60%~73%的C1分布在LMW中，77%~93%的C2分布在HMW中，而C3几乎平均分布在LMW-和HMW-DOM中，可能与C1、C2、C3组分分别含有的传统荧光峰有关.通过对荧光参数FIX（<1.4）、BIX（<0.8）的计算发现鄱阳湖DOM陆源特征显著，且HMW组分具有比LMW组分更高的陆源特征和芳香度.重金属检测结果表明Cr、Mn、Fe、Pb则主要分布在HMW中（63%~94%），As、Cd、Ba、Se、Sb主要分布在LMW中（63%~84%），Cu、Zn、Ni、Co几乎均匀分布在LMW-和HMW-DOM中.重金属与DOM的相关性结果表明大多数金属与C2占比呈负相关，与C3占比呈正相关，说明重金属离子与水体中DOM的络合可能主要通过腐殖类组分C3进行.且重金属含量的分布受HMW-DOM的影响较大，说明人类活动也对鄱阳湖水体的重金属分布有着重要影响. |
| 关键词: 鄱阳湖 溶解有机质 超过滤 三维荧光 重金属 |
| DOI：10.18307/2020.0412 |
| 分类号: |
| 基金项目:国家自然科学基金项目（51839011，51922101）资助. |
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| Molecular weight distribution, fluorescence characteristics of dissolved organic matter and their effect on the distribution of heavy metals of Lake Poyang |
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LI Yani1,2, XU Huacheng1, JIANG Helong1
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1.State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, P. R. China;2.University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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| Abstract: |
| Dissolved organic matter (DOM) is ubiquitous in environmental waters. It has a characteristic of continuous molecular weight distribution and can significantly affect the migration, transformation, and fate of pollutants in natural waters. Water samples of Lake Poyang were collected in the spring of 2019, and DOM samples were divided into low molecular weight (LMW, <1 kDa) and high molecular weight (HMW, 1 kDa-0.45 μm) components through ultrafiltration. Fluorescence parallel factor (PARAFAC) analysis and ICP-MS were used to analyze the spectral and metal properties in different molecular weight solutions. Results showed that 43%-55% of Lake Poyang's DOC was LMW, and 45%-57% HMW. DOM fluorescence samples were identified as two fulvic-like components (C1, C2) and a humic-like component C3, of which 60%-73% of C1 was distributed in LMW, 77%-93% of C2 distributed in HMW, and C3 almost evenly distributed in the LMW- and HMW-DOM, which may be related to the traditional fluorescent peak contained in each fluorescent components. Calculation of fluorescence index (FIX, <1.4) and biological index (BIX, <0.8) indicates that the DOM of Lake Poyang's terrestrial source characteristics were significant, and the HMW-DOM had higher terrigenous characteristics and aromaticity than the LMW-DOM. Heavy metal Cr, Mn, Fe, and Pb were mainly distributed in HMW (63%-94%), As, Cd, Ba, Se, and Sb were mainly distributed in LMW (63%-84%), and Cu, Zn, Ni, and Co were almost evenly distributed in LMW- and HMW-DOM. Most metals had negative correlations with C2 percentage and positive correlation with C3 percentage, indicating that the complexation of heavy metal ions with DOM in water may be mainly through humic-like component C3. The distribution of heavy metal content was greatly affected by HMW-DOM, indicating the important role of anthropogenic activities in Lake Poyang's heavy metal distribution. |
| Key words: Lake Poyang dissolved organic matter ultrafiltration EEM-PARAFAC heavy metal |
