Temporal And Spatial Distribution Characteristics Of Phosphorus And Management Strategy In Dalinoer Lake

Nowadays,Dalinoer Lake is suffering from unprecedented lake water reduction,water pollution and eutrophication.In view of this,this thesis carries out a case study of the Dalinoer Lake basin,explores the spatial and temporal distribution characteristics of phosphorus in its water body,the distribution characteristics of phosphorus forms in its sediments and the calculation of its endogenous phosphorus release flux,and identifies the spatial and temporal distribution characteristics of its phosphorus,with a view to providing data support and theoretical basis for phosphorus pollution prevention and control in the Dalinoer Lake basin.The main research findings are as follows:（1）The average contents of TP in the water body of Dalinoer Lake throughout the year were 2.11 mg·L^-1,respectively,which TP exceeded the limit of Class V（≤0.2 mg·L-1）of GB3838-2002 Standard for Surface Water Environmental Quality.In winter,the water showed a spatial distribution of high around and low in the middle,and the phosphorus concentration increased in the frozen lake area.（2）The average TP concentration of the four inflow streams of Dalinoer Lake,i.e.the Haolai River,the Liangzi River,the Shali River and the Gongger River,were 0.109 mg·L^-1,0.129 mg·L^-1,0.229 mg·L^-1 and 0.076 mg·L^-1,respectively.Of the four inflow streams,PP was the main phosphorus content in the River.Water bodies of the four streams differed greatly in the spatial and temporal distribution of phosphorus,and significantly received hydroclimatic influences.This indicates that although the inflow streams are the main source of phosphorus input to the lake,controlling water quality only by controlling the source of phosphorus in the stream is unlikely to bring the concentration of TP in the lake to the Class III water quality standard.（3）The average TP content in the sediments of Dalinoer Lake was 714.17 mg·kg^-1,with a spatial distribution of high in the south bank and the center and low around the lake.Inorganic phosphorus and organic phosphorus content in the sediment accounted for 39.35%and 60.26%of the total phosphorus.The surface sediments were mostly organic phosphorus.The correlation between the forms of inorganic phosphorus in sediments and the concentration of interstitial water DTP and DIP were higher than that of organic phosphorus.The inorganic phosphorus forms WA-Pi and Fe/Al-Pi had the highest correlation with interstitial water,and the organic phosphorus MA-Po had the lowest,with little effect on phosphorus in the water body.（4）With exogenous pollution under control,endogenous sources remained the main influencing factor of phosphorus in the water.Through analysis of the release flux of endogenous phosphorus in sediments,there was a greater risk of endogenous release affecting water quality.According to the calculation,the sum of endogenous phosphorus load in the sediments of the lake was 47.0 t/a,while the exogenous phosphorus load in the inflow streams was estimated to be 6.036 t/a by the data of the same period.Of these,endogenous sediments in the sediments had a greater impact on phosphorus in the lake water.Therefore,in the treatment of Dalinoer Lake,the reasons for phosphorus pollution from different sources should be identified first,and the treatment should be combined with endogenous control,ecological restoration and other comprehensive treatment.