崇明岛河流中氮营养盐分布特征

摘要

In order to evaluate the distribution characteristics of nitrogen nutrient of Chongming Island and its polluting situation,the characteristics of temporal and spatial variations of nitrogen nutrient as well as the main reasons of the pollution were studied based on the water quality data of Chongming Island.The results showed that the rivers were badly polluted in Chongming Island and the contents of TN in both wet and drought periods were in the danger range which might lead to eutrophication.The average contents of nitrogen nutrient in different levels of rivers at different precipitation periods varied significantly.The dissolved inorganic nitrogen (DIN) was the major composite of TN in Chongming Island.NO3——N accounted for over 50% of DIN.Additionally,the contents of water nitrogen nutrient at different spatial conditions varied significantly as well.The main sources of nitrogen nutrient include agricultural runoff,industrial and domestic wastewater.%为研究崇明岛河流氮营养盐的分布特征及其污染迁移情况,以不同时空条件下崇明岛河网水质数据为基础,探讨了崇明岛水体氮营养盐的时间和空间变化特征,并分析了岛内河流氮营养盐污染的主要原因.结果表明,崇明岛内河流水质恶化日益严重,不同级别河流的总氮(TN)含量在丰水期和枯水期均处于富营养化发生的风险范围,岛内不同级别河流的氮营养盐均值在不同降水期变化显著.溶解态无机氮(DIN)是崇明岛氮营养盐的主要存在形式,其中以硝态氮为主,平均占到DIN的50%以上.同时,不同空间条件下水体氮营养盐含量变化复杂,氮营养盐的主要来源为农田径流、工业废水和生活污水.