重庆市主城区次级河流总氮总磷污染特征分析及富营养化评价

为掌握重庆市主城区次级河流水环境状况,于2013年4月~2014年3月,在重庆市主城区选取6条典型次级河流测定水体理化指标,开展水体总氮(TN)、总磷(TP)污染特征分析及富营养化评价.结果表明:16条河流TN、TP污染较为严重,不同季节TN、TP均超过国际认可的发生水体富营养化临界值;富营养状态指数评价结果表明,各季节所有河流都处于富营养化状态,富营养化程度排序为:盘溪河清水溪跳蹬河花溪河伏牛溪朝阳河.2各次级河流TN、TP季节变化情况较为显著,为春、冬季TN、TP质量浓度高,夏、秋季TN、TP质量浓度低;3河流在各季节TN、TP从上游向下游增加趋势比较明显,污染物沿河流不断聚集,污染物质量浓度递增率最大达到1.25 mg·(L·km)-1.因此,进一步深入研究城市次级河流污染特征对城市水体污染控制具有重要意义.

Characteristics of Total Nitrogen and Total Phosphorus Pollution and Eutrophication Assessment of Secondary River in Urban Chongqing

To understand the secondary river quality in Chongqing urban area, six typical secondary rivers were chosen to investigate the pollution characteristics of total nitrogen and total phosphorus and to evaluate the water eutrophication level according to the monitoring data of water physicochemical characteristics and chlorophyll content from April 2013 to March 2014. The study results showed that: the six rivers mentioned above have been seriously polluted by TN and TP, with the monthly mean values of TN and TP far exceeding the universally accepted threshold values of water eutrophication. Water eutrophicaton appraisal result indicated that all rivers in each season were in a state of eutrophication, and the eutrophication level could be arranged in the order of Panxi River> Qingshui River> Tiaodeng River> Huaxi River> Funiu River> Chaoyang River. The seasonal changes in TN and TP of secondary rivers were significant, with high concentrations of TN and TP in spring and winter, and lower concentrations in summer and autumn. TN and TP of the rivers showed a trend of increasing from the upstream to the downstream in each season. Pollutant concentration accumulated gradually along rivers and the maximum accumulation rate reached 1.25 mg ·(L ·km)^-1. Therefore, further study on urban secondary river pollution characteristics is of great significance to urban water pollution control.