天津市近岸海域氮、磷入海总量核算初探

污染物入海总量准确测算对于厘清污染源排放对近岸海域环境质量的影响具有重要意义。本研究聚焦天津市陆域和海域两个氮、磷入海通道，系统开展污染源调查和入海总量核算研究。针对陆域氮、磷入海量，研究建立一套基于入海系数的污染物入海通量计算方法，即以实测数据为基础，对土壤流失方程（USLE）模型进行了改进，并通过德尔菲法确定影响因子的权重系数，最终构建一套陆域氮、磷入海系数，在此基础上得到陆域氮、磷污染物入海量。通过与实测值进行分析比较，该方法具有较高的可信度。调查估算结果显示，“十三五”期间，天津市近岸海域总氮年均入海量为14490吨，总磷年均入海量为768吨，陆域氮、磷输入量占绝对优势。天津近岸海域氮、磷污染来源主要集中在永定新河、蓟运河、海河干流、独流减河，主要来自城镇居民和畜禽养殖等方面。

Preliminary study on accounting of nitrogen and phosphorus fluxes into the sea in Tianjin coastal area

Accurate measurement of the total amount of pollutants into the sea is of great significance to clarify the impact of pollution source emissions on the environmental quality of coastal waters. This study focuses on nitrogen and phosphorus channels into the sea in the land and sea area of Tianjin, and systematically carries out the investigation of pollution sources and the accounting of total amount into the sea. Aiming at the large amount of nitrogen and phosphorus entering the sea in the land area, a set of calculation method of pollutant flux into the sea based on the sea entering coefficient is studied and established. Based on the measured data, the soil loss equation (USLE) model is improved, and the weight coefficient of influencing factors is determined by Delphi method. Finally, a set of coefficient for land nitrogen and phosphorus entering the sea is constructed, based on this system the amount of land nitrgen and phosphorus entering sea can be calculated. Compared with the measured values, this method has high reliability. The survey and estimation results show that during the 13th Five Year Plan period, the average annual input of total nitrogen and total phosphorus in the coastal waters of Tianjin is 14490 tons and 768 tons, in which land nitrogen and phsphorus takes main percentage. The sources of nitrogen and phosphorus pollution in the coastal waters of Tianjin are mainly concentrated in Yongdingxin River, Ji canal, the main stream of Haihe River and Duliujian River, and the pollution is mainly produced by urban residents and livestock and poultry breeding.