乌梁素海湖泊水质演变特征及富营养化评价

Assessment on the Evolution Characteristics and Eutrophication of Water Quality in Wuliangsuhai Lake

利用乌梁素海近6年的水质监测资料,分析了乌梁素海水体的主要营养盐在不同湖区的时空变化规律.结果显示,出湖河口营养盐含量较低,各湖区营养盐含量较高;受河套灌区灌溉退水水量及水质条件的影响,湖区内氨氮,TN,TP等营养盐浓度丰水期>枯水期>平水期.年际之间,湖泊氨氮,TN,TP水质呈现波动变化趋势,COD浓度呈明显下降趋势但其浓度一直高于Ⅳ类水质标准.最后,采用综合营养状态指数法对2011年湖泊营养化水平进行了评价,乌梁素海处于中度富营养水平.

The spatial and temporal variation law of the essential nutrients in Wuliangsuhai Lake in different lake sites was analyzed in the paper by using the passed six years＇ water quality monitoring data.Results showed that the nutrient salt content was lower in the lake outlet while higher in the body of the lake.Influenced by the return water yield and the water quality of Hetao irrigation district,the nutrients concentrations of NH3-N,TN and TP in the wet season were than that in the low water season,while lowest in the normal water season.It also showed a downward trend of the COD concentration over the recent years,but the concentration was still higher than the VI level of lake water quality standard,while the NH3-N,TN and TP concentrations showed the trend of fluctuation during recent years.Finally,by use of aggregative nutrition status index method,the Wuliangsuhai Lake eutrophication assessment result was judged as the middle level in 2011.