中文摘要：

通过分析1985—2003年长江流域向河口／东海排放的点源营养盐的时空变化规律，建立长江点源营养盐排放模型，并预测2020年长江流域点源氮磷排放情况．模型基于人口密度、国内生产总值、人均氮磷排放量、以及污水处理率等因子，在99％的置信度上，氮磷模型的方差解释量分别达到92．3％及93．2％．基于此模型预测2020年长江流域点源氮排放量将达到（95．9±6．6）×10^4t，点源磷排放量达到（12．3±0．6）×10^4t．此外，研究结果进一步表明，点源营养盐通量仍然是长江输送营养盐总量的主要部分，是影响河口／近海水质的主要因素．

英文摘要：

We estimated the amount of nutrient （mainly referring to nitrogen, N and phosphorus, P） emissions from point sources discharged to surface water for the period 1985 ～ 2003 from the Yangtze River basin. Point sources are primarily associated with sewage effluents, including human emissions and wastewater from industrial activities. Two models were developed to predict the emissions of nutrient in 2020 by using statistical method, and the influence of human activities was discussed in this paper. The approach to assess the nutrient emissions from point sources was based on population densities, gross domestic products （ GDP）, per capita human N emissions and wastewater treatment. The coefficients of determination （ R^2 ） of the models were 92.3 % and 93.2%, respectively, with a confidence interval of 99%. The estimated amounts of N and P from point sources will be （95.9 ± 6.6） ×10^4 ton N and （ 12.3 ± 0.6） ×10^4 ton P in 2020 based on the models. The study demonstrated that nutrient emission from point sources is still the dominant part of nutrient fluxthrough the Yangtze River compared with non - point sources. Therefore, the point source nutrient pollution will be the main pollution factor for the estuary and coastal sea.