竺山湖主要入湖口水质及富营养状态评价

Water Quality and Eutrophication Evaluation of Main Estuary for Zhushan Lake

[目的]以竺山湖主要入湖口为研究对象,评价其水质及富营养化状况。[方法]对3条入湖口水质开展了连续3年的监测,监测结果参照GB 3838—2002中IV类水质标准,采用单因子评价法、综合污染指数法和综合营养指数法进行评价。[结果]单因子评价结果表明,只有沙塘港入湖口BOD5单项污染指数大于1.00,3条入湖口水质NH4＋-N和BOD5月均值超标范围分别为30.56%~41.67%和25.00%~52.78%,TP均未见超标。综合污染指数评价表明,3条入湖口水质平均综合污染指数均为0.70~1.00。殷村港入湖口和太滆运河入湖口水质优于沙塘港入河口水质。综合营养指数评价结果表明,3条入湖口水质营养状态指数为63.6~64.8,属于中度富营养状态。其中TN、TP和SD营养状态指数较高,Chl-a和CODMn营养状态指数较低。由于3条入湖河流汇集了大量的N、P,从而导致TN和TP的营养状态指数较高,对Chl-a和CODMn浓度控制得相对较好,从而在入湖口表现出这两项指标营养状态指数较低。[结论]造成竺山湖富营养化的主要外源贡献来自于入湖河流的TP和TN输入,应加大对入湖河流N、P污染物的削减治理。

[Objective] Taking the main estuaries of Zhushan Lake as the research object,water quality and eutrophication status were evaluated.[Method] Water quality in three main estuaries was monitored for three consecutive years.Monitoring results referred to the IV water quality standard in Basic Analytical of Environmental Quality for Surface Water in China（GB 3838—2002）.Evaluation was carried out by the single factor evaluation method,comprehensive pollution index method and comprehensive nutritional index method.[Result] Results of single factor evaluation method showed that only the single pollution index of BOD5 in Shatang estuary was higher than 1.00.Sandard-exceeding rates of NH4＋-N and BOD5（monthly average） in three estuaries were in the range of 35.56%-41.67% and 25.00%-52.78%,respectively.All the TP indexes were under the level of the IV water quality standard.Results of comprehensive pollution index method showed that the comprehensive pollution indexes of all the estuaries were within the range of 0.70-1.00,and water quality of Yincungang estuary and Taige estuary was a little better than those of Shatanggang estuary.Result of comprehensive nutrition index showed that the water quality of three estuaries were in the state of moderate eutrophication with the nutrition state indexes ranging from 63.6-64.8.Among them,TN,TP and SD contributed most to the nutrition state index,while Chl-a and CODMncontributed less.Since a large amount of N and P were accumulated in three estuaries,nutritional indexes of TN and TP were relatively high;the Chl-a and CODMnconcentration was controlled well.Thus,the two nutritional indexes in estuaries were relatively low.[Conclusion] The main exogenous contribution causing the eutrophication of Zhushan Lake is the TP and TN input of inflowing rivers.Therefore,we should strengthen the control of N and P contaminants of inflowing rivers.