Study On Morphological Characteristics And Variation Regularity Of Sediments And Suspended Particles In A Typical Shallow Lake

With the rapid growth of the population and economy of China,the growing pollution problem caused the continued deterioration of the water quality,and water environment has become a global environment problem.China is currently in a period of rapid economic growth,and eutrophication is one of the major pollution problems our country faced.In recent years,with the rapid growth of urbanization and population density around Chaohu Lake,a large number of emissions of pollutants result in Chaohu Lake,eutrophication problem is increasingly serious.This article studied the morphological characteristics and biological availability of phosphorus in the sediments of Chaohu Lake by using ³¹P-NMR technology and enzymatic hydrolysis methods.Po in environmental samples were available after hydrolyzed into Pi,so Po measured by enzymatic hydrolysis method can reflect the determination of hydrolysis characteristics and biological effectiveness of the samples.But enzymatic hydrolysis cannot categorize all the Po in the environmental samples,and different hydrolysis ability of hydrolysis enzyme can also cause the error of Po analysis,it will also hinder the method application on the analysis of Po in environmental samples.³¹P-NMR technique is applied to analyse the Po in environmental samples and based on the analysis of ³¹P-NMR,phosphate monoester?Mono-P?,phosphate diester?Lipids-P?,DNA,pyrophosphate?Pyro-P?,polyphosphate?Poly-P?were successfully detected.This method has high extraction efficiency,stable and mapping quality and can determine the content of different biomass phosphorus compounds in sediments.Therefore,this study chooses enzymatic analysis and ³¹P-NMR determining the content of biomass phosphorus in sediments.By using these two methods,this study analyses the morphological characteristics and biological availability of phosphorus of surface sediment and suspended particle of the west lake,east lake in spring,summer,autumn and winter,respectively.Through the system research,this study not only reveals the composition and content characteristics of the phosphorus in Chaohu Lake sediment,and probes into the shallow lakes characteristic of phosphorus,morphological characteristics and the vertical change trend.It provides a theoretical basis on the management of eutrophication of the lake water body in eastern China.The main contents and detail results are as follows:?1?The vertical variation characteristics of phosphorus in Chaohu Lake sediment is significantly and along the vertical sediment,phosphorus content was decreased gradually;the average content of total phosphorus,TN and TC in surface sediment of the west lake is higher than that of the east lake.Surface sediment phosphorus content is higher.The average content of the total phosphorus is 1666.15mg·kg^-1,2413.40mg·kg^-1,2509.92mg·kg^-1,1748.41mg·kg^-1,respectively.Seasonal characteristics is obvious: the phosphorus content of surface sediment in algal blooms outbreak period?spring and summer?is higher,the risk of release is high.?2?By using ³¹P-NMR technology,there are several kinds of phosphorus compounds have been detected.By using ³¹P-NMR technology,there are seven kinds of phosphorus compounds have been detected.Phosphate monoester was the main component of biogenic phosphorus.The other biogenic phosphorus are phosphonate,pyrophosphate,DNA-P,phospholipid,polyphosphate.The average content of biogenic phosphorus of the west lake is that: autumn?13.54%?> winter?10.4%?> summer?6.83%?> spring?5.99%?;that of the east lake is: spring?17.09%?> winter?16.98%?> autumn?15.46%?> summer?14.59%?.?3?The content of biogenic phosphorus by ³¹P-NMR has obvious seasonal characteristics.The biogenic phosphorus in surface sediment is mainly Po and pyrophosphate.The content of Po is that: winter(649.22mg·kg^-1)>spring(564.38mg·kg^-1)> summer(317.36mg·kg^-1)>autumn(241.66mg·kg^-1);the content of pyrophosphate is that:winter(2.92mg·kg^-1)>autnmn(2.78mg·kg^-1)>summer(2.07mg·kg^-1)>spring(0.55mg·k g^-1),and along the direction of sediment depth,Po and pyrophosphate content show a trend of gradual decline.?4?The content of monoester phosphorus by enzymatic hydrolysis is higher and that of diester phosphorus content is low.The content of the three phosphorus compounds by enzymatic hydrolysis is that: phytate-like P > monoester phosphorus > diester phosphorus.The average content of monoester phosphorus is that: summer(47.52mg·kg^-1)> autumn(40.75mg·kg^-1)> winter(39.25mg·kg^-1)> spring(39.07mg·kg^-1);the average content of diester phosphorus is that: summer(74.08mg·kg^-1)> autumn(20.69mg·kg^-1)> winter(18.13mg·kg^-1)> spring(15.71mg·kg^-1).It can be obtained that monoester and diester phosphorus in surface sediments is an important source of phosphate.