| 城镇河流CO2及CH4排放与市政排水管网污水输入的关联影响 |
| 摘要点击 1208 全文点击 609 投稿时间：2019-12-12 修订日期：2020-01-15 |
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| 中文关键词 城镇河流 CO2 CH4 排放通量 市政排水管网污水 |
| 英文关键词 urban rivers CO2 CH4 emission flux municipal drainage network sewage |
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| 中文摘要 |
| 城镇污染河流日益剧增的碳排放是当前我国许多城市共同面临的环境问题.本研究以上海市市郊城镇河网R1与中心城区河流R2为研究对象，监测了其在旱天与雨天条件下的CO2及CH4排放特征，分析了城镇河流污染程度及类型与碳排放的关联影响，并同时解释了市政排水管网污水输入影响城镇河流CO2及CH4排放的机制过程.结果表明：①旱天时，中心城区河流的CO2与CH4平均排放通量为（2.48±1.02）mmol·（m2·h）-1与（1.21×10-2±0.71×10-2）mmol·（m2·h）-1，市郊城镇河网的CO2与CH4的平均排放通量则为（1.53±0.39）mmol·（m2·h）-1与（9.26×10-3±9.18×10-3）mmol·（m2·h）-1.雨天时，受市政排水管网污水影响，中心城区河流泵站下游的水体的CH4通量大幅增加，可达旱天时的119倍；②本研究与全球其他河流碳排放统计数据进一步表明，城镇河流碳排放与本身污染水平存在关联性，总体上污染程度高的河流碳排放强度也高；③从PCA相关性分析结果来看，河流有机污染是影响碳排放的重要因素，这在中心城区河流与市郊城镇河网中都有体现；河流碳排放与氮污染的相关性随区域下垫面利用类型不同而有所不同；在污染较轻的城镇河流中，水体物理因子也是一个重要的影响因素；④排水管网污水输入对城镇河流碳排放的影响，体现在短期内向河流中输入的大量CH4，以及长期上强化受纳河流碳物质赋存及循环，并进一步提高河流本身的CO2与CH4排放潜势. |
| 英文摘要 |
| The increasing carbon emission of polluted rivers in urban areas is an environmental problem commonly faced by many cities in China, especially the megacities with vast populations. In this study, two typical rivers located in the megacity of Shanghai, including the suburban river network R1 and urban river R2 (in the central city), were investigated for their emission characteristics of CO2 and CH4 in dry and wet weather. We also analyzed the relationship between the state and type of river pollution and CO2 and CH4 emissions, and further explained the mechanisms of CO2 and CH4 emissions in urban rivers impacted by sewage discharged from the municipal drainage network. The results show that:① In dry weather, the average fluxes of CO2 and CH4 emitted from the river in the central city (R2) were (2.48±1.02) mmol·(m2·h)-1 and (1.21×10-2±0.71×10-2) mmol·(m2·h)-1, respectively. The average fluxes of CO2 and CH4 from the suburban river (R1) network were (1.53±0.39) mmol·(m2·h)-1 and (9.26×10-3±9.18×10-3) mmol·(m2·h)-1, respectively. In wet weather, affected by sewage from the municipal drainage network, CH4 flux emitted from the surface water of the R2 river downstream of the pump station P increased by up to 119 times that in dry weather. ② Global carbon emission statistics, involving the data from our study and from other rivers around the world, seemed to imply a relationship between the carbon emission flux and the pollution state of an urban river, i.e., the rivers with high pollution showed significant carbon emission intensity. ③ According to the results of PCA, organic matter can be an essential factor in driving the variation of carbon emissions, and this trend is evident in all the rivers in urban and suburban areas. The relationship between carbon emissions and nitrogen pollution in a river varies with different types of underlying riparian surface. In the less polluted urban rivers, the aquatic physical factor can also be an essential factor. ④ In the short term, with massive quantities of sewage discharged into urban rivers, a large amount of CH4 flux can be emitted. In contrast, in the long run, the carbon cycle can be strengthened when the carbon storage is increased, and thus the emission potential of CO2 and CH4 is improved. |
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