Perpendicularity Pollution And Distributing Character Of Both Heavy Metal And OCPs Of Sediment In Poyang Lake Drainage Basin

Poyang Lake is the biggest fresh water lake,which takes in and sends out water in large quantities.96.8%of drainage basin acreage is situated in Jiangxi Province churchyard,so it has very strong area characteristic.Based on the innovation of sampling method----adjacent water vertical spile method,and the manufacture of soil sampling implement of pole shape and push pattern,the samples of lake area were collected using low water of Poyang Lake in late October and early November in 2006.From the cut-in point of heavy metal elements and POPs(OCPs)in the sediments,researches were performed on the perpendicularity contamination of them and their annual distribution features based on the aggradations rate of sediments.Also analysis of the transfer disciplinarian,relative influence factors and zoology toxicity of both heavy metal elements and OCPs was made.The scientific evaluations were as follows:Theheavy metal pollution in the sediments of upper and middle reaches of Le'an River had obvious area features and better annual distribution characteristics. The discrepancy of detected results of sediment from different depths was bigger, which was much related to the exploitation and operation of Dexing Copper Mine.The concentrations of Cu and Mn at the depth of 24cm sediment of Dawu River in the Dexing Copper Mine were 727.201mg/kg,256.663 mg/kg respectively,however, the concentrations of Cu and Mn at the surface layer reduced,at the level of 334.714 mg/kg,162.091 mg/kg separately.The contents of Pb and Cr were ascending at the surface layer with the concentrations of 103.431mg/kg,195.713mg/kg respectively. The Ni concentration was not relative to the depth.The content of Pb was increasing year after year from 48.586mg/kg of the founding Mine date to 103.431mg/kg at present stage.The average values of Pb,Ni and Cr of sediments at the section of Wantou town of Le'an River were 4.943mg/kg,30.575mg/kg,66.878mg/kg separately,which were within the first scale standard of Soil Environment Quality.The Cu concentration of grass root sample at Luci town was 932.571mg/kg. Grass root had strong cumulative effect on Cu,but its function on other heavy metal elements was not so obvious The pollution of heavy metal elements at the lake entrance of rivers of the Poyang Lake in 2006 aggravated obviously.The pollution integration exponents at the lake entrances of rivers including Xiushui River,Gan River,Rao River and Hukou(Yangtse River)were 3.829,5.604,6.294,3.619 respectively,and the pollution degree was medium.In the samples of pole sediments at Wantuo Town Section of middle reaches of Le'an River,Ni,Cr,and Zn present mainly as residue speciation(S5),accounting for 88.57%～91.60%.The proportion of exchangeable speciation(S1)of Mn was higher (average value 22.33%).The percentage of Pb(S2)of surface layer sample was 16.273%.Much higher was Cd(S1,53.40%),the chemical modality sum of S1～S3 (Cd)accounting for 79.50%,which was the highest in the seven elements.The 3 kinds of elements(Mn,Pb & Cd)would be latent in their harm to environment.The speciations of heavy metal elements of the Old Way sediments of Fu River were mainly as S1～S3.For the sake of safety,the sediments of Fu River could not be used as fertilizer resource of crops,however,they could be used as the virescence fertilization in cities.The HCHs concentrations of Lake sediments were 0～8.988μg/kg present mainly asα-HCH andγ-HCH isomers.The residue contents of HCHs at the lake entrances of rivers of Poyang Lake in 2006 were 0.163～10.688μg/kg,only 0.10%～7.63%of 1984 and thus within the first scale standard of Soil Environment Quality (50μg/kg).The detected range of DDTs were 19.707～281.610μg/kg,which were within the second scale standard of Soil Environment Quality(50μg/kg).The residue contents of PS at the lake entrances of rivers of Poyang Lake in 2006 were 0.10%～7.63%of 1984.Based on the biology accumulation and zoology toxicity of POPs,the bottomland sediment of Poyang Lake Area could not be used as the production base of green food.The effusion method pouring additional solution to the original sediment post of drainage basin(EMPAS)was used to study the carrying capacity of sediment environment of Poyang Lake from the heavy metal pollution.The result showed as follows:①The sediment had the sorption function to heavy metal;the effect and velocity of sorption were diversity with different elements.②Water was good carrier of heavy metal.In the drainage area,water flowed from upriver to downriver due to potential energy,here the potential energy was bigger than gravitation,so the penetrative depth of elements to sediment was limited.③In the simulation experiment,under the action of water gravitation and potential energy,the penetrative depth of elements to sediment was much bigger than that of drainage area.④Water flowage of drainage area was better method to decrease the perpendicularity contamination of heavy metal.The contents of heavy metal elements of PM10,construction dust and road dust were much higher than that of general sediments of Poyang Lake.Falling dust and earth's surface pathway stream have become the important origin of heavy metal pollution of drainage area.The content of heavy metal of rivers water in Poyang Lake Drainage Basin was reducing,though some elements concentrations fluctuated,but still present lowness level,which was within the first scale water standard of ground water and could satisfy basically the requirements of all kinds of functions in Poyang Lake Area.