南通市通甲河水体氮磷分布特征及富营养化评价

以南通市典型污染河道——通甲河为研究对象，于2013年夏季采集引水期、引水后与引水前水样．对水体中各种形态氮磷及环境因子与叶绿素浓度的相关性进行分析．并运用综合营养指数法对通甲河3个不同采样点的富营养等级进行评价．结果表明：3个采样点总氮浓度都在引水前达到最大：龙王桥总磷浓度最大值出现在引水前，其余2个采样点（法伦寺桥和通海交汇处）总磷浓度最大值都出现在引水期：3个采样点总氮和总磷浓度都在引水后出现最小值，说明引水可以降低水体中总氮总磷浓度；叶绿素a含量与总氮、硝态氮和化学需氧量具有正相关性；引水期、引水后和引水前，通甲河综合营养指数分别为73．74，71．04，74．91，都属于重度富营养．此外，从龙王桥到法伦寺桥和通海交汇处，综合营养指数有逐渐降低趋势，龙王桥综合营养盐指数最大，水体属于重度富营养级别．法伦寺桥和通海交汇处属于中度富营养级别．

Distribution of Nitrogen and Phosphorus,Assessment of Eutrophication for Water of Tongjia River in Nantong

Water samples were collected from Tongjia River in Nantong during, after and before diversion in 2013 summer. Various forms of nitrogen and phosphorus nutrients and the environmental factors were analyzed and then the comprehensive eutrophication status index was calculated. These results suggested that the maximum values of total nitrogen concentrations were detected before the diversion in all the sampling sites. The maximum values of total phosphorus concentrations were detected in Longwangqiao before the diversion, which was detected in the others two sites （Falunsiqiao and Tonghaijiaohuichu） after the diversion. These results suggested that the concentrations of total nitrogen and phosphorus can be reduced by the diversion. The correlation between chlorophyll a and total nitrogen, nitrate and chemical oxygen demand was significant. The comprehensive eutrophication status index in Tongjia River was 73.74, 71.04 and 74.91 during, after and before the diversion respectively. Moreover, the highest eutrophication status index was detected in Longwangqiao, where the water can be categorized as the heavy eturophication level, and Falunsiqiao and Tonghaijiaohuichu categorized as the medium eutrophication level.