| 抚仙湖子流域尺度氮排放清单构建及关键源解析 |
| 摘要点击 495 全文点击 76 投稿时间：2023-05-05 修订日期：2023-07-17 |
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| 中文关键词 总氮（TN） 排放清单 子流域 关键源 高原深水湖泊 |
| 英文关键词 total nitrogen （TN） emission inventory sub-watershed key source plateau deep water lake |
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| 中文摘要 |
| 对高原湖泊流域总氮（TN）污染的精准调控是预防湖泊水体富营养化的重要环节.但过去基于全流域尺度具体时点建立的流域TN排放清单,因忽略TN污染的时空异质性,导致关键因子识别不清,控源减排措施针对性不强等问题.以典型高原深水湖泊抚仙湖为例,通过资料收集和现场调查,根据上中下游子流域特征,建立子流域尺度TN污染负荷模型；结合GIS空间分析功能,构建抚仙湖流域1990~2020年25个子流域的TN排放清单,分析TN污染负荷时空分布特征及关键污染来源.结果表明：①1990、1995、2000、2005、2010、2015和2020年的抚仙湖流域TN污染负荷分别为933.43、1 012.90、1 090.25、1 096.93、1 075.69、996.27和514.80 t,点源污染负荷逐年递增,但面源污染负荷仍是其主要来源.TN面源污染负荷主要来自化肥施用,点源污染负荷主要来自于农村生活；②TN污染负荷在空间上呈放射状递减的特点,流域整体单位面积负荷为65~6 877 kg·km-2,下游子流域单位面积TN污染负荷（1 009~6 877 kg·km-2）远远高于上中游子流域（65~1 167 kg·km-2）；③污染源在子流域上存在较强的空间异质性,其中化肥施用、农业面源和农村生活污染主要来自于北岸河外直沟、抚澄河和山涧河子流域；畜禽散养污染主要来自于东岸大提坎箐河、大箐河和石股箐河子流域.研究结果可为抚仙湖流域TN控源减排措施的实施、子流域差异化管理措施的制定和湖泊水质恶化预警提供一定的科学依据及技术支撑. |
| 英文摘要 |
| It is essential to control lake eutrophication to reduce total nitrogen （TN） emission from lake watersheds. However, owing to the lack of a TN emission list at the sub-basin scale and over a long period, the key factor of water degradation cannot be identified, and effective measures cannot be taken. Thus, in our study, taking Fuxian Lake, a typical deep lake, as an example and based on the characteristics of the sub-basins, a TN emission list at the sub-basin scale was constructed through the GIS platform to quantify the temporal-spatial distribution of TN pollution loading, and the main source of TN from 25 sub-basins during the period 1990-2020 was identified. The results showed： ① the TN pollution loading in 1990, 1995, 2000, 2005, 2010, 2015, and 2020 was 933.43, 1 012.90, 1 090.25, 1 096.93, 1 075.69, 996.27, and 514.80 t, respectively. Non-point source pollution was the dominant source, which mainly came from synthetic fertilizer. Point pollution increased over time, and rural residential pollution was an important source. ② The overall TN pollution that manifested in this basin decreased radially, with the highest load per unit area mainly found between 65 and 6 877 kg·km-2. Additionally, the downstream sun-basin （1 009-6 877 kg·km-2） had a much higher TN pollution load per unit area than the upstream （65-1 167 kg·km-2） sub-basin. ③ The pollution sources showed clear spatial heterogeneity among sub-basins. Fertilizer application and rural residential pollution mainly came from the Zhigou River, Fucheng River, and Shanjihe River sub-basins located in the northern watershed. On the other hand, TN pollution in the Datikanjing River, Dajing River, and Shigujing River sub-basins in the eastern watershed came from animal manure applied to crop land. This study can provide scientific evidence and technical support for the implementation of TN source control and emission reduction measures, formulate differentiated sub-basin management measures, and improve water quality at the Fuxian Lake watershed. |
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