内蒙古自治区呼伦湖水质变化特征及其影响因素

Impact Factors and Characteristics of Water Quality Variation of Hulun Lake in Inner Mongolia Automous Region

[目的]对内蒙古呼伦湖水质变化特征及其影响因素进行分析,为呼伦湖富营养化机理研究提供理论基础。[方法]采用2012—2014年的水质监测数据,对水体中TN,TP和叶绿素a(Chla)浓度的时空分布进行分析,采用综合营养状态指数法对水质进行富营养化评价,并对影响水质变化的因素进行探讨。[结果]在时间上,Chla,TN,TP浓度均表现为:7,8月>9月>1月;在空间上,TN的浓度的范围为1.70~2.31mg/L,均值为1.94mg/L。TP的浓度的范围为0.15~0.25mg/L,均值为0.19mg/L。呼伦湖水质已经达到地表水环境质量Ⅳ,Ⅴ类水体标准,是磷限制性湖泊。叶绿素a与总氮表现为:西南、东北两端>中部,总磷浓度除一个水质观测点较高外,其他各观测点变化不大。呼伦湖水体夏季已经呈现中度富营养化水平,而冬季和秋季呈轻度富营养化水平。[结论]呼伦湖已经处于富营养化状态,丰富的外源输入为非冰封期呼伦湖发生富营养化提供了一定的物质基础。

[Objective] The Characteristics of water quality variation and its impact factors were analyzed in Hulun Lake to provide theoretical basis for the eutrophication mechanism of Hulun Lake. [Method] Monitoring data from 2012--2014 were used to analyze the spatio-temporal distribution of chlorophyll a （Chla）, TN and TP. Integrated nutritional status index method was use to evaluate the eutrophication of Hulun Lake and the main impact factors were discussed. [Results] Temporal concentrations of Chla, TN, TP ranked as.. July, August〉September〉January, and the spatial concentrations of TN and TP ranges were 1.70-2.31, 0.15-0.25 mg/L, with their averaged values of 1.94 and 0. 19 mg/L, respectively. The water quality of Hulun Lake belonged to levels Ⅳ to Ⅴ according to the water standards of surface water, and the lake was phosphorus limited lake. The concentrations of Chla, TN at southeast, northwest corner were greater that at midle part. Except that one sampling point showed a little high concentration of TP, no obvious spatial variation was found for other points. The eutrophication of Hulun Lake was thought moderate in Summer, but light in Autumm and Winter. [Conclusions] The Hulun Lake has been in eutrophication, this is a result of rich exogenous inputs in non-frozen period.