Guo Chao-Chen, Lei Kun, Li Xiao-Guang, Zhou Bo, Lü Xu-Bo
Institute of Water Ecology and Environment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
Huan Jing Ke Xue. 2023 Aug 8;44(8):4279-4291. doi: 10.13227/j.hjkx.202209245.
Based on the monitoring data of various pollutants at important water system points in the Yangtze River Basin from 2017 to 2020, research on the flux change law of the main and tributary water systems in the Yangtze River Basin was carried out at the spatiotemporal scale, and the spatial change response, interannual change trend, and flux correlation analysis were analyzed from the aspects of water quantity, quality, and flux so as to reveal the spatial-temporal contribution characteristics of pollutant flux in the upper, middle, and lower reaches of the Yangtze River Basin. The results showed that over the past four years, the concentration of major pollutants in the Yangtze River Basin showed an overall downward trend. The concentration of total phosphorus (TP) and ammonia (NH-N) decreased significantly. The concentration of total nitrogen (TN) and total phosphorus (TP) in the main stream gradually increased from west to east. The annual concentration of permanganate index in the upper, middle, and lower reaches decreased by 18.5%, 16.0%, and 14.0%, respectively, from 2017 to 2020, with the highest decline in the upper reaches. The four-year average value of the spatial distribution of runoff significantly increased from 466×10 m to 9923×10 m. The two lake basins in the tributary river lake water system had the largest contribution to the water volume. The fluxes of permanganate index, total phosphorus (TP), and total nitrogen (TN) among the main pollutants showed an annual increase and then decrease trend. The pollutant fluxes in the Minjiang River, Tuojiang River, Jialing River, and the middle reaches of the two lakes contributed greatly to the river inflow. There were differences in fluxes in different regional water environments. The results of correlation and hierarchical cluster analysis showed that the permanganate index and TP fluxes were highly significantly correlated with water volume, and there was a significant correlation between biochemical oxygen demand (BOD) and total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD). The main pollutants showed strong differences in the flood and non-flood periods and had a significant response in the flood season from July to September. The research results can provide scientific basis and theoretical support for the integrated management and precise prevention and control of the aquatic environment in the Yangtze River Basin.
基于2017—2020年长江流域重要水系点位的各类污染物监测数据，在时空尺度上开展长江流域干流及支流水系通量变化规律研究，从水量、水质、通量等方面进行空间变化响应、年际变化趋势及通量相关性分析，以揭示长江流域上、中、下游污染物通量的时空贡献特征。结果表明，近四年来长江流域主要污染物浓度总体呈下降趋势，总磷（TP）和氨氮（NH-N）浓度显著下降，干流总氮（TN）和总磷（TP）浓度自西向东逐渐升高。2017—2020年，长江上、中、下游高锰酸盐指数年均浓度分别下降18.5%、16.0%、14.0%，上游下降幅度最大。径流量空间分布的四年平均值从466×10 m显著增加到9923×10 m。支流水系中的两湖流域对水量贡献最大。主要污染物中高锰酸盐指数、总磷（TP）和总氮（TN）通量呈先增加后减少的年际变化趋势。岷江、沱江、嘉陵江及两湖中游的污染物通量对入河量贡献较大，不同区域水环境通量存在差异。相关性和层次聚类分析结果表明，高锰酸盐指数和TP通量与水量高度显著相关，生化需氧量（BOD）与总氮（TN）、总磷（TP）和化学需氧量（COD）之间存在显著相关性。主要污染物在汛期和非汛期差异较大，在7—9月汛期有显著响应。研究结果可为长江流域水环境综合管理与精准防控提供科学依据和理论支撑。
