南四湖流域非点源污染TN/TP时空格局及防治分区演变

[目的]探究非点源污染物TN,TP时空演变特征,找出影响流域非点源污染的主要污染物、污染源和影响TN,TP变动的最活跃单元,分析TN,TP污染防治分区演变,为南四湖流域非点源污染治理提供理论依据。[方法]以1990—2013年土地利用为基础数据,结合3S技术,运用输出系数模型和等标污染负荷法模拟非点源污染时空分布。[结果]1990—2013年期间南四湖流域非点源TN和TP污染排放量整体变化趋势是先上升后下降并趋于平稳,其中TN是主要污染物;TN的主要污染源是土地利用,TP的主要污染源是农业生活和畜禽养殖;1990—2013年期间,南四湖流域非点源TN和TP变动最活跃的单元是降水因子。[结论]南四湖流域非点源污染具有地区差异等特点。整体而言,湖西地区比湖东地区污染严重,但在近24a间,地区差异有缩小的趋势;1990—2013年期间,湖西地区非点源污染较为严重,属于重点治理区;北沙河流域、洸府河流域和梁济运河流域污染程度有加重趋势,是优先控制和重点治理区。

Evolution of Spatio-temporal Pattern and Prevention Partition of TN and TP of Non-point Source Pollution in Nansi Lake Basin

[Objective] The objective of the study was to explore the spatio-temporal changes of TN and TP of non-point source pollution, to find the main pollutants, main pollution sources and the most active units affecting TN and TP changes, and to carry out the prevention partition evolution of TN and TP pollution. All these were expected to provide reference for controlling the non-point source pollution of Nansi Lake basin.[Methods] Based on the land use data from 1990 to 2013, combining with 3S technology, the spatio-temporal distribution of non-point source pollution was simulated using the export coefficient model and standard pollution load method.[Results] Firstly, during 1990-2013, pollution emissions of TN and TP decreased after a first increase and tended to be stable afterwards, and TN was the main pollutant. Secondly, land use was the main pollution sources of TN, and the main sources of TP were agricultural life and livestock and poultry breeding. Thirdly, during 1990-2013, the most active element of non-point source TN and TP in Nansi Lake basin was precipitation.[Conclusion] Non-point source pollution of Nansi Lake basin had many characteristics, such as regional differences. The pollution in the west part of the lake was worse than that in the east part of the lake, but regional difference had a tendency to homogenize in the past 24 years. Finally, the west part of the lake was the key management area, owing to the non-point source pollution being more serious. The Beisha River basin, Guangfu River basin and Liangji Canal basin were the priority control and key management areas because their level of non-point source pollution had a tendency to increase.