长湖流域水质时空分布特征及影响因子

Analysis of Spatial-Temporal Distribution and Impact Factors of Water Quality in Changhu Lake

利用2009—2014年长湖5个水质监测点数据,采用时间序列法分析了长湖水质的时间变化规律,采用相关性分析法,分析了流域水污染的影响因子。结果表明:在时间上,长湖水污染物质量浓度季节变化明显,COD、TN、NH3-N均为7、9月较低,1、3月较高,丰水期水质好于枯水期。入湖地区TP质量浓度7月达最高值,且7月份入湖地区的桥河口、关沮口的NH3-N、TN含量稍高于5月。空间上,西北部入湖地区水质劣于湖心及东南部出湖地区。工业、生活等点源污水,以耕地为主的农业非点源以及天然降水量和径流量是影响水质的主要因素,入湖排污量、降水量和径流量与长湖水质呈显著相关关系(P<0.05)。

Based on the data of five water quality monitoring spots in Changhu Lake from 2009 to 2014,time series analytic method was adopted to analyze its time variation rule of water pollutants concentration. Then impact factors of water pollution were analyzed by correlation analytic method. The results showed that in terms of temporal distribution,seasonal variation of organic pollutants concentration in Changhu Lake was obvious. COD,TN and NH3-N concentration were low in July and September,while high in January and March,which indicated that rainy seasons were better than dry seasons in respect to water quality. In the meantime,the highest concentration of TP at inlets of the lake occured in July,and the concentration of NH3-N and TN in July were higher than that of May in Qiaohekou and Guanjukou where water inflows. In terms of spatial distribution,higher concentration of pollutants appeared in the northwest and north of Changhu Lake where water inflows,and lower concentration in the center and southeast of the lake where water outflows. Wastewater discharged by point sources including industrial effluent and municipal wastewater,non-point sources,the amount of natural precipitation and runoff were the main factors affecting the variable water quality. Wastewater discharged into the lake,annual average precipitation,runoff were notably correlated（ P〈0. 05） with water quality in Changhu Lake.