我国丘陵山区和平原河网区典型流域面源污染规律研究

NON-POINT SOURCE POLLUTIONS IN TYPICAL RIVER BASINS IN HILLY AND MOUNTAINOUS AREAS AND PLAIN RIVER NETWORK AREA IN CHINA

由于城镇化进程的差异,不同区域流域面源污染也存在较大差异,为研究典型流域城镇和非城镇面源污染规律及环境效应,选取长江流域丘陵山区(重庆市永川区)和平原河网区(江苏省常州市金坛区)为研究对象,分析不同地貌下城镇面源污染和非城镇面源污染的时空分布特征,并结合降雨特征探究了降雨与城镇和非城镇面源污染物的相关性。结果表明:在长江流域,丘陵山区和平原河网区城镇面源污染占比均远高于非城镇,在丘陵山区降雨较少的冬季(11月—次年3月)差异更显著。两区域对不同面源污染物指标的月度响应不同,丘陵山区的不同形态氮和磷浓度均略高于平原河网区。丘陵山区城镇不同形态磷浓度最高值出现在12月,而非城镇的最高值则出现在8月,平原河网区不同形态磷浓度最高值均出现在11月。此外,两区域秋冬季节非城镇的COD_(Mn)高于城镇区域。降雨与两区域非城镇大多数面源污染物指标呈正相关,说明降雨是非城镇面源污染的主要影响因子之一,但降雨与不同面源污染物相关性有长期响应和瞬时作用之分,表现在10年内年平均降雨量与两区域大多数非城镇面源污染指标呈正相关,而采样期间降雨量则与多数平原河网区城镇面源污染指标呈正相关。研究结果揭示了城镇面源污染在长江流域丘陵山区和平原河网区的面源污染中占据的较重分量,厘清城镇和非城镇面源污染的时空分布特征和污染规律对科学防控面源污染具有重要意义。

Due to the differences in the process and extent of urbanization,large differences of non-point source pollution appeared in different regions.To study the distribution characteristics and environmental effects of urban and non-urban non-point source pollution in typical river basins,this study selected two typical hilly and mountainous areas of the Yangtze River basin(Yongchuan District,Chongqing)and plain river network area(Jintan District,Changzhou,Jiangsu)as research objects.The spatial and temporal distribution characteristics of urban and non-urban non-point source pollution in different landforms were analyzed.Combined with rainfall characteristics,the correlation between rainfall and urban and non-urban non-point source pollutants was explored.The results showed that the proportion of urban non-point source pollution was much higher than that in non-urban areas in the two regions,especially in winter(from November to March)when there is less rainfall in the hilly and mountainous area.The monthly responses of those two regions to non-point source pollutants were different.Generally,the concentrations of different forms of nitrogen and phosphorus in the hilly and mountainous area were slightly higher than those in plain river network area.In the hilly and mountainous area,the highest nitrogen and phosphorus concentrations of different forms in urban areas appeared in December,while the highest concentrations in non-urban areas appeared in August.However,the highest nitrogen and phosphorus concentrations of different forms in plain river network area appeared in November.In addition,the permanganate index of non-urban areas was higher than that of urban areas in autumn and winter.Rainfall is positively correlated with most non-urban non-point source pollutants in the two regions,indicating that rainfall is one of the main influencing factors of non-urban non-point source pollution.However,the correlation between rainfall and different non-point source pollutants can be divided into long-term response and instantaneous effect.10-year average annual rainfall is positively correlated with most non-urban non-point source pollutants in the two regions,while rainfall during the sampling time is positively correlated with most urban non-point source pollutants in plain river network area.This study reveals the non-negligible role of urban non-point source pollution in the hilly and mountainous area and the plain river network area.Analyzing the spatial and temporal distribution characteristics and emission characteristics of non-point source pollutants from different sources is important for scientific prevention and control of non-point source pollution.