| 摘要: |
| 水电开发导致河岸生境破碎化程度加剧和水库沉积物截留问题日益突出，而目前关于河道型水库有机质（OM）溯源及分布特征的研究较少，进而造成OM在水库复杂环境介质中迁移机理尚不清楚。本研究将脂质生物标志物分析方法应用于大渡河瀑布沟水库表层沉积物，经过气相色谱—质谱法对沉积物OM脂质组分进行了分析，将其量化并分为自然、成岩、热源和污水标志物4种来源。结果表明：OM平均含量坝前（10.7%±4.8%）>坝后（7.3%±0.9%）>库中（6.7%±1.8%），说明水库对沉积物OM的截留有显著影响。可提取脂质组分主要来源于自然标志物（45.9%±13.9%），碳偏好指数、陆源/水生比和陆生与水生植物输入比显示OM主要来源于陆生高等植物，占自然定量分子的70.5%±9.1%。此外，坝前汉源城镇下游D6和D7点位人为标志物（44.6%±25.1%）分子明显比自然标志物（24.2%±3.7%）含量高，并进一步通过比例研究强调了污水标志物的贡献率较为突出（31.6%±12.8%），这与该地住宅区生活污水处理设施覆盖率较低相关，表明OM污染源组成变化与水库滞留效应的耦合作用有关。 |
| 关键词: 有机质 水库 脂质生物标志物 来源 分布特征 |
| DOI： |
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| 基金项目:(编号:42007148)、国家环境保护协同控制与水土污染联合修复重点实验室开放性(编号:SGHBK-006)S,四川省自然科学基金(编号:S2023NSFSC0799)联合资助。 |
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| Sedimentary organic matter of channel type reservoirs: input of lipid biomarker for source assessment |
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SU Ning-ren1, Emilie Jarde2, YIN Yue-peng1, Marine Liotaud2, ZHANG Wen1
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1.College of Environment and Ecology,State Environmental Protection Key Laboratory of Synergetic Control and Joint Remediation for Soil and Water Pollution SEKL-SW,State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology;2.CNRS,SUnivSRennes,SGéosciencesSRennes,SUMR ,SRennes ,SFrance
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| Abstract: |
| Hydropower development has exacerbated the degree of fragmentation of riparian habitats and the problem of reservoir sediment trapping, and there is currently limited research on the source and distribution characteristics of organic matter (OM) in river reservoirs. As a result, the migration mechanisms of OM in complex reservoir environments remain unclear. In this study, lipid biomarker analysis method was applied to surface sediments of Pubugou Reservoir in Dadu River, and sediment OM lipid components were analysed by gas chromatography-mass spectrometry (GC-MS), quantified and classified into four sources: natural, petrogenic, pyrogenic and sewage markers. The results showed that the average content of organic matter (OM) in the area upstream of the dam (10.7±4.8%) is higher than that downstream of the dam (7.3±0.9%) and in the reservoir (6.7±1.8%), indicating the impact of reservoir interception on the accumulation of sedimentary OM. The extractable lipid fraction was mainly derived from natural markers（45.9±13.9%）, and the OM was represented by the relative ratio of CPI (Carbon Preference Index), TAR (Terrestrial/Aquatic Ratio) and Paq (Terrestrial/Aquatic Plant Input Ratio). It comes mainly from terrestrial higher plants, accounting for 70.5±9.1% of the natural quantitative molecules. In addition, the number of anthropogenic marker molecules increased significantly (44.6±25.1%) compared to natural markers (24.2±3.7%) at D6 and D7 sites downstream of Hanyuan township before the dam. Further proportion studies emphasised the contribution of sewage markers (31.6±12.8%), which is related to the low coverage of domestic sewage treatment plants in the residential area, provides a certain theoretical basis for the coupling effect between the compositional change of OM pollution sources and the retention effect of the reservoir. |
| Key words: organic matter reservoir lipid biomarkers source apportionment distribution characteristics |
