Analysis And Control Measures Of The Causes Of Pollution In Shahu Lake

The most important problem is the shortage of freshwater resources in the world.The importance of lakes is more prominent in the arid and semi-arid areas of Western China.In recent years,the water quality of Shahu Lake has shown a downward trend year by year,from class III in 2012 to grade V in 2016,and maintained at class V in2017 and 2018.The main exceeding factors are COD_Mnand fluoride exceeding the standard all year round,petroleum and total nitrogen exceeding the standard seasonally,and the total phosphorus fluctuates in different regions in different seasons.In this paper,through a variety of means to explore the water environment of the Shahu Lake,the temporal and spatial characteristics of the main pollution factors migration and transformation,and the impact of internal and external pollutants on the water quality changes of the Shahu Lake,and analyze the water pollution of the Shahu Lake.In the endogenous aspect,the Shahu Lake is a closed water body,without external drainage,and has large evaporation capacity.A large number of pollutants are concentrated in the Shahu Lake,resulting in the continuous increase of pollutant concentration,the original aquatic ecosystem is damaged,and it is difficult to effectively degrade pollutants;the concentration of pollutants in the sediment of Shahu Lake is high,and various pollutants will be released to the water body under the specific natural environment.In terms of exogenous factors,there are a large number of agricultural non-point source pollution sources around the Shahu Lake,and the pollutants produced by infiltration through various ways have the greatest impact on the water quality of the Shahu Lake;secondly,a large amount of sediment in the Yellow River has not been precipitated or purified before entering the Shahu Lake,resulting in nitrogen,phosphorus and other pollutants in the sediment deposited in the Shahu Lake.In 2018,a series of eco-environmental projects were carried out in Shahu Lake,and the effect was obvious.In 2019,the water quality could be stabilized at class IV or even class III.The main factor exceeding the standard was cod.According to the common characteristics of pollutant simulation release experimental data,the release degree of total P and total N is positively correlated with water temperature.Increasing the amount of water supplement helps to slow down the release process of total P and total N in sediment,and the length of disturbance time has obvious influence on the release process of total P and total N in sediment;fluoride concentration under low temperature condition is higher than that under high temperature condition The concentration of fluoride decreased linearly with time,which indicated that the release rate of fluoride in sediment was a slow linear decreasing trend.