Study On Phosphorus Behavior Between The Sediments And Overlying Water In Dianchi Lake

Lake eutrophication is one of the most important environmental problems in our country,furthermore,the studies on phosphorus behavior between the sediments and overlying water in Dianchi lake is one of the key elements which helps find the mechanism of eutrophication.Among these,the studies on the exchangeable phosphorus in sediments and the characteristics of phosphorus release and adsorption from sediment and the effects on phosphorus behavior by dissolved organic matter and typical metal ion are crucial aspects that can further reveal the mechanism of phosphorus action between the sediment and overlying water and supply direction and theoretical grounds to treatment and management of eutrophic city shallow lakes in our country.Dianchi lake is the famous plateau fresh water lake in China,the water pollution of Dianchi lake is very serious,the water body is serious in eutrophication.For this reason,the pollution control of Dianchi lake was listed as one of the key national "three rivers and three lakes" control projects.This article based on anciently deficiently or blank research at home and abroad of eutrophic lakes,especially plateau lake,and selected sediment samples and Dianchi water,and adopted the field sampling and laboratory simulation,and biological effective states and orthophosphate as perpetual object which is the most universal existence,and preliminary study on Phosphorus Behavior between the Sediments and Overlying Water in Dianchi Lake.The main results of this study could be summed as follows:1.The study on potential exchangeable phosphorus from sediments of Dianchi showed that, the potential exchangeable phosphorus determined by IDE-P and NH4Cl-P indicate that the contents of both are higher in the sediments which areseriously polluted and lower in those of slightly polluted.The contents of IDE-P are higher than that of NH4Cl-P in the sediments of Dianchi.The potential exchangeable phosphorus and availability phosphorus were higher with the higher contents of organic matter in sediments.In addition,The ratio of NH4Cl-P and IDE-P from different sediments,the release ability of exchangeable phosphrus of different sediments during the reversible exchange stage were difference.2.Through the laboratory simulation,the characteristics of phosphorus release and adsorption from sediments was performed compared analysis,it's processes are all the complicated dynamic course,and resulte from comprehensive factors.At the beginning reaction stage from 0 to 0.5 hours,the rate of adsorption and release,and the capacity of adsorption and releasing are the maximum.After 4 hours,the reaction started to slow moving,and were basiclly in the state of dynamic balance after 24h.3.Phosphorus behavior between different sediments and overlying water in Dianchi lak have the bigger difference,but there exist simultaneously the phenomena of adsorption and desorption.The absorpted capacities and rates of Caohai sediments are better than the Waihai,but the binding capability of Caohai sediments with phosphorus are weaker than the Waihai.4.The test results of effect for DOM on phosphorus behavior between the sediments and overlying water,while DHA added is 1ml(concentration is 8.56mg/L),phosphorus absorption are the evident.But the overlying water is from Dianchi,phosphorus adsorption quantity of Waihai is the maximum,and DHA is 2ml.While DHA is 1ml,the quantity is the minimum.In addition,phosphorus discharged capability of Caohai are better than Waihai while DHA is between 0 to 2ml,but it's just on the contrary while DHA is larger than 5ml or equal to 5ml.5.In this study,sediments of were taken as research subject,the effects for three metallic ions Ca²⁺,Al³⁺and Fe³⁺for phosphate behavior between sediments of Waihai and overlying water were study.The experimental results indicate that:above three metallic irons can preferably promote phosphorus absorption from overlying water by sediment,and change tendency were quite similar.In comparison,FeCl₃ has a prominent impact on phosphorus absorption,and the dose is the least,and save cost.The control of lake eutrophication is an urgent task that is very important and complicated. The sediment has an important effect on eutrophication process of lake as the interior load source of nutriment of lake.Therefore,control of interior pollution should be paid attention while strengthening the control of outer pollution.