长江流域污染负荷核算及来源分析

为研究长江流域污染物输出的时空变化特征和来源,将长江流域划分为114个排污单元,195个纳污河段,应用污染物“产生-排放-入河-消减-输出”模型,结合长江流域2004—2007年的社会经济、水文监测资料,利用朱坨、寸滩、宜昌、大通4个监测断面2004—2007年逐月的水量和水质数据,通过连续演算核算长江流域各河段的污染物输出过程,进行区间污染物输出平衡分析,估算出姚港断面污染物输出过程. 结果表明,各断面计算数据与实测数据相对误差不超过20%,模型及参数组合的可靠性较好. 点源对COD_Mn输出贡献较大,占56.4%；非点源对TN、TP的贡献大,分别占74.3%和92.1%. 从污染物输出分布来看,江西、四川、湖南、湖北四省占流域污染物输出总量的60%以上,贡献率较大,是流域污染物输出的重要区域. 

Pollutant Accounting and Source Analyses in the Yangtze River Basin

The output process of pollutants in the Yangtze River basin was studied using a model including five processes for the pollutants, generation, emission, pouring into the river, degradation and output. The Yangtze River basin was divided into 114 units and 195 reaches in this study in order to investigate the temporal and special change of the pollutants in this area. According to the data on socio-economic and hydrological conditions of four monthly monitoring sites from 2004 to 2007, the pollutant output process of each reach of the Yangtze River basin was calculated through output balance analysis. The pollutant output process of the section of Yaogang at the Yangtze River estuary, was further estimated. The differences between the estimated and investigated values were less than 20%. Simulation results showed that the COD_Mn flux was mainly impacted by the point source pollution which accounted for 56.4%, and fluxes of the total nitrogen (TN) and the total phosphorus (TP) were mainly impacted by the non-point source pollution which accounted for 74.3% and 92.1% respectively. Four provinces, Jiangxi, Sichuan, Hunan and Hubei were the key areas of pollution control of the river basin, since they contributed more than 60% of the total pollutant output loads of the whole river basin.