Study On The Release Of Nitrogen And Phosphorus In The Surface Sediments Of LiaoHe River Under Different Environmental Conditions

With the development of social economy and the acceleration of urbanization.A large number of industrial,agricultural and domestic sewage are discharged into Rivers and gradually deposited in River sediments.When external contamination is well controlled,The nitrogen and phosphorus nutrients in the sediments can be released through biological,physical and chemical processes to maintain a high concentration of nitrogen and phosphorus nutrients in water.Therefore,it is of great significance to study the occurrence patterns and release rules of nitrogen and phosphorus in sediments for the prevention and control of eutrophication.In this study,the main occurrence patterns of nitrogen and phosphorus in LiaoHe River surface sediments were analyzed by means of ultrasonic,digestion and STM continuous extraction.In the laboratory static simulation,correlation analysis and regression analysis of nitrogen and phosphorus release patterns and release quantities in LiaoHe River surface sediments were conducted.By controlling the single variable,the nitrogen and phosphorus release characteristics of the surface sediments were analyzed by regression analysis and correlation analysis.The results showed that the order of phosphorus content in different forms was Ex-P>Al-P>Ca-P>Fe-P,which indicated that the phosphorus element in the surface sediments of LiaoHe River was mainly in the form of Ex-P.The content of nitrogen in LiaoHe River sediments is mainly in the form of NO3-N,and the nitrification in sediments is strong.Static simulation of the release characteristics of LiaoHe River sediments,N elements are mainly released in the form of NO3-N;P elements are released mainly in PO43-form.The content of chlorophyll a indicates the strength and time of eutrophication in the water body,and the results show that the eutrophication occurs only after the release of TN,NO3-N and NH4-N.Phosphorus and eutrophication occur at the same time,so the time and intensity of eutrophication can be predicted by predicting the content of nitrogen in River water.The nitrogen and phosphorus content of nitrogen and phosphorus can be predicted in different time.The linear regression equation of chlorophyll a and nitrogen and phosphorus was established.C(a)=-0.0621n(C(TP))-0.1484(R2 = 0.7328),C(a)?0.0039e2.6613C(NO3-N)(R2 ?0.1134).The intensity of eutrophication can be predicted by monitoring the content of nitrogen in water.The results of single factor study show that the regression equation of single factor and nitrogen and phosphorus release can predict the nitrogen and phosphorus release under different environmental conditions.The fitting equations of temperature influencing TN and TP were C(TN)= 0.0454T-0.5573(R2 = 0.4961),C(TP)=0.0682e0.0595T(R2 = 0.9386).The fitting equations of pH influencing TN and TP were C(TN)=-0.0586pH2 + 0.878pH-1.7569(R2 = 0.4847),C(TP)= 0.006pH-0.0096(R2 = 0.9912).By measuring different external environment changes to the change of TP concentration in water to predict risk of eutrophication in water body,the water eutrophication of early warning,provide a scientific basis for management and monitoring...