Analysis Of Water Quality Characteristics And Nutrient Status In Baiyang Lake In Recent Ten Years

In this paper,the monitoring data of the past ten years are selected to fully reflect the water environment characteristics of Baiyangdian Lake.Through the comprehensive pollution index method,the water quality status of each region in the lake area is evaluated,the pollution sharing rate of the assessment factors in different regions is calculated,and the main pollution factors in different regions are determined.The eutrophication in different areas of the lake area was evaluated by using the comprehensive nutritional state index,and the correlation between water level and eutrophication was analyzed.This paper analyzes the correlation between nutrition factors and other water quality factors,and analyzes the characteristics of water quality factors in different seasons in different regions of the lake area from the perspective of temporal and spatial changes.The main pollution factors in different seasons were determined by principal component analysis.The spatial and temporal classification of different regions and seasons in the lake area is carried out by using the method of systematic cluster analysis.In order to provide basic data for nutrient reduction and ecological restoration of Baiyangdian Lake,the change trend of total phosphorus and total nitrogen and the spatial and temporal distribution characteristics of nitrogen phosphorus ratio were evaluated.Through the systematic analysis of the water quality of Baiyangdian Lake,the following conclusions are obtained:1.The comprehensive pollution index was calculated to evaluate the water quality in the lake area,from good to bad:Zaolinzhuang,Guangdian Zhangzhuang,Caiputai,Quantou,Shaochedian,Wangjiazhai,Duancun and Nanliuzhuang.By calculating the pollution share rate,it is concluded that the characteristics of Nanliuzhuang are TN,TP and other nutrients,and the characteristics of 7 sites in the middle of the lake are TN,TP and other nutrients,COD_Mn,COD_crr and other organic pollutants.2.The eutrophication index Tli???of Nanliuzhuang was 67.35?moderate eutrophication?.The eutrophication index Tli???of Doingt,Wangjiazhai,Quantou,Shaoche Lake and Caiputai in the central Lake region is between 50-60?mild eutrophication?.The eutrophication index of Zaolinzhuang and Guangdian Zhangzhuang in the central area of the lake is between 40-50?middle nutrition?.The total eutrophication index Tli???was53.91?mild eutrophication?.There is a negative correlation between water level and eutrophication.3.In spring,Baiyangdian Lake is mainly characterized by BOD₅?COD_Mn?TN?TP?NH₄⁺-N?NO₃^--N organic pollutants and nutrients.In summer,autumn and winter,TN?TP?NH₄⁺-N?NO₃^--N are the typical eutrophication factors and toxic factors.4.According to the spatial clustering,they can be divided into four categories:Shaoche Dian,Wangjiazhai,Guangdian Zhangzhuang and Caicputai,Quantou and Duancun,Nanliuzhuang and Zaolinzhuang.According to the time clustering,it can be divided into four categories:February,March,April and November,January and December,May and October,June,July,August and September.5.The concentration of chlorophyll a in water is mainly affected by many factors,such as transparency,water temperature,nutrient salt,organic matter and so on.Its concentration was positively correlated with permanganate index,water temperature and total phosphorus,negatively correlated with transparency and weakly correlated with total nitrogen.6.Baiyangdian Lake is a nitrogen polluted lake with the characteristics of phosphorus limitation.The ratio of nitrogen to phosphorus is lower in the West and higher in the East.The ratio of nitrogen to phosphorus in Duancun and Nanliuzhuang is lower than that in other sites.In terms of seasonal variation,the limitation of phosphorus in winter and spring is stronger,while that in summer and autumn is weaker,and the ratio of nitrogen and phosphorus suitable for algal eruption is easier to form.To sum up,while reducing nitrogen emissions,we should pay attention to phosphorus emissions in key regions.Carry out the project of returning farmland to wetland,use wetland to strengthen the barrier of nutrients,establish a long-term water supply mechanism,and ensure that the ecological water volume and water level in the lake area are within a reasonable range.We will strictly control industrial,living and agricultural non-point source pollution,steadily carry out the dredging and regulation of rivers in and into the lake,and reduce internal pollution to solve the problem of pollution in Baiyangdian Lake.