城市小型景观水体水环境质量评价

Water Quality Assessment for Small Urban Waterscape

城市小型景观水体因其水体特征、水文条件及污染来源与大型天然水体存在较大差异,面临的水体富营养化问题及水华风险更为突出。文章以典型城市小型景观水体——张家港市马家泾为研究对象,运用综合营养状态指数法和营养状态指数法进行水体富营养化评价及水环境因子相关性研究,探讨水质变化规律及富营养化程度,分析叶绿素a与各水环境因子的相关性,识别富营养化和水华风险发生的关键因子。结果显示:水体中总氮、总磷等营养物质含量随季节性变化明显,呈现夏季含量最高,南区、北区水体均存在富营养化现象,其中,南区为重度富营养化,北区为中度富营养化,总氮、总磷对水体富营养化贡献程度最高,并与叶绿素a含量具有正相关性,是导致马家泾水体富营养化的主要营养物质。

Due to the tangible difference from large natural water body in characteristics,hydrological conditions and pollution sources,small urban waterscape is more challenged by the problem of water eutrophication and water bloom risk.Taking Majiajing in Zhangjiagang City,a typical small urban waterscape,as the case,this paper evaluates the water eutrophication and studies the correlations among water body related environmental factors using the methods of comprehensive trophic state index and trophic state index.It discusses the change of water quality and the degree of eutrophication,and analyzes the correlation between chlorophyll a and various water body related environmental factors,so as to identify the key factors to eutrophication and water bloom risk.The results show that the contents of total nitrogen,total phosphorus and other nutrients change significantly with seasons,but reach the highest in summer.Eutrophication is found in the areas in both the South and the North,while the southern area has severe eutrophication and the north area is moderate in eutrophication.Total nitrogen(TN)and total phosphorus(TP)contribute the most to water eutrophication,and have a positive correlation with chlorophyll a content.They are the main nutrients leading to water eutrophication in Majiajing.