| 河流不同分子量溶解性有机质对全氟化合物赋存形态的影响 |
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| 引用本文： | 张杰,赵璞君,夏星辉.河流不同分子量溶解性有机质对全氟化合物赋存形态的影响[J].环境科学研究,2022,35(9):2058-2066. |
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| 作者姓名： | 张杰 赵璞君 夏星辉 |
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| 作者单位： | 北京师范大学环境学院，水沙科学教育部重点实验室，水环境模拟国家重点实验室，北京 100875 |
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| 基金项目： | 国家自然科学基金重点项目(No.52039001, 92047303) |
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| 摘 要： | 目前有关水体全氟化合物(PFASs)赋存特征的研究主要集中于总溶解态，对溶解性有机质(DOM)结合态PFASs的研究较为匮乏，尤其忽视了不同分子量DOM对PFASs赋存形态的影响. 为阐明河流上覆水体不同分子量DOM对PFASs赋存形态的影响，本文以长江干支流为例，分析了河流上覆水体11种典型PFASs (C4~C12)的浓度及组成，研究了不同分子量DOM结合态PFASs的赋存特征. 结果表明:①长江上覆水体中PFASs的平均浓度为52.6 ng/L，其中全氟戊酸(PFPeA)和全氟己酸(PFHxA)是最主要的单体污染物；由于受点源污染的影响，武汉段PFASs总溶解浓度及其单体浓度均显著高于其他采样点. ②长江上覆水体中DOM的浓度范围为0.08~3.84 mg/L (以C计)，将水体DOM按分子量分离为<1 kDa、1~3 kDa、3~5 kDa、5~10 kDa和>10 kDa五种组分，各采样点中<1 kDa的溶解性有机碳(DOC)浓度(1.56~3.84 mg/L)显著高于其他分子量的DOC浓度. ③对于所检出的PFASs，<1 kDa DOM结合态PFASs (含自由溶解态)的浓度亦显著高于其他分子量DOM结合态PFASs的浓度，且其占水体总溶解态PFASs的比例均在85%以上，说明水体DOM结合态PFASs具有较高的生物有效性. 研究显示，水体不同分子量DOM结合态PFASs的赋存特征存在差异，因此对水体PFASs进行生态风险评价时需综合考虑不同分子量DOM结合态的含量及其生物有效性.
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| 关 键 词： | 长江 全氟化合物(PFASs) 溶解性有机质(DOM) 分子量 赋存形态 |
| 收稿时间： | 2022-03-15 |
Effects of Different Molecular Weight Dissolved Organic Matter on Occurrence Form of Polyfluoroalkyl Substances in River |
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| Affiliation: | Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China |
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| Abstract: | At present, studies on the distribution of polyfluoroalkyl substances (PFASs) in the aquatic environment mainly focus on their total dissolved concentration, while the studies about PFASs associated with dissolved organic matter (DOM) is scarce, especially there is a lack of research on the effects of DOM with different molecular weights on the occurrence form of PFASs. To clarify the effects of DOM with different molecular weights on the occurrence form of PFASs in overlying water of rivers, the concentrations and composition of eleven PFASs (C4-C12) in overlying water of the Yangtze River were analyzed and the occurrence characteristics of PFASs associated with different molecular weight DOM were explored. The results showed that: (1) The average total dissolved concentration of PFASs in the overlying water of the Yangtze River was 52.6 ng/L, and perfluoropentanoic acid (PFPeA) and perfluorohexanoic acid (PFHxA) were the main monomer pollutants. Due to the influence of point source pollution, the total dissolved concentration and monomer concentration of PFASs in Wuhan were significantly higher than those in other sampling sites. (2) The concentration of DOM in the overlying water of the Yangtze River ranged from 0.08 mg/L to 3.84 mg/L. DOM was separated into <1 kDa, 1-3 kDa, 3-5 kDa, 5-10 kDa and >10 kDa by molecular weight. The concentration (1.56-3.84 mg/L) of dissolved organic carbon (DOC) of <1 kDa was significantly higher than that of other molecular weights. (3) For the detected PFASs, the concentration of PFASs associated with <1 kDa DOM (including freely dissolved PFASs) was significantly higher than that associated with other molecular weights DOM, accounting for more than 85% of the total dissolved PFASs in overlying water, indicating that the PFASs associated with DOM in overlying water had high bioavailability. This study shows that there are differences in the occurrence characteristics of PFASs associated with different molecular weight DOM in overlying water. Therefore, the concentration and bioavailability of PFASs associated with different molecular weight DOM should be considered comprehensively when conducting ecological risk assessment for PFASs in overlying water. |
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