The Study Of Heavy Metal Pollution Of Water And Sediments In Zhuzhou Section Of Xiangjiang River

The rapid economic development of human society and the improvement of industry make the water pollution more and more serious,especially the heavy metal pollution which was paid attention for.The present paper was based on the surface water and sediments of Zhuzhou section of Xiangjiang river and the pollution of heavy metal was carried out.Four monitoring sections (Feng Xi,Bai Shi,Xia Wan,Ma Jia He ) ,eight sections of sampling surface sediments,three sections of sampling vertical sediments were arranged along the Zhuzhou section. The variation of surface water quality parameters (temperature, pH, COD, BOD₅, NH₃-N, TN, TP) and the heavy metals pollution (Cu, Pb, Zn, Cd, Ni, Cr, Hg, As) in water environment in Zhuzhou section were stuied. The results were as follows:1. The variation of surface water quality parameters in four monitoring sections was evuluated by the third Class of the State, "Surface Water Environmental Quality Standard" (GB3838-2002).The concentrations of BOD₅,TP,NH₃-N and the pH were not attained the state's standard (BOD₅:4mg/L,TP:0.2 mg/L ,NH₃-N:1.0 mg/L)all the year.The average concentration of TN was 2.97mg/l. The variation of concentration of COD was ranged from 7.71mg/L to 24.03mg/L.The concentration of COD of Xia wan and Ma jiahe was the Fouth Class in months which was excessive.2. The total concentrations of heavy metal(Cu,Pb,Zn,Cd) of surface water was determined by AAS and determined the species of heavy metal in August. The total of concentrations of heavy metal was not attained the state's third class standard.The maximum of the concentration of Cd was 0.0041mg/l which was close to the standard limit of 0.005 mg / L.The order of concentrations of dissolved heavy metal was the Cu>Zn>Cd>Pb.3. We collected eight surface sediment sampels(S1～S8) to be drying .We determined the total heavy metal By atomic absorption spectrometry and cold vapor atomic absorption with the way of Mixed acid digestion. The total concentrations of heavy metal (Cu,Pb,Zn,Cd) were respectively 1.71,4.56,4.23,73.52 times than the value of geochemical background,and were respectively 1.73,2.25,1.71,1.96 times than the value of eighties in Xiangjiang river,and were respectively 4.6,6.89,6.85,58.82 times than the background value of Xiangjiang river. The pH of sediments were between 7.59～8.08.4. We collected three vertical sediment samples(A1,A2,A3) and determined the concentrations of heavy metal.The A1 was in the left bank of the pollution belt about 700 meters from the Old Xia wan.The maximum of Cu,Pb,Zn,Cd was respectively 111.69mg/kg, 253.52mg/kg, 886.65mg/ kg,46.10mg/kg which appeared respectively at the depth of 0～50cm.The concentrations of heavy metal decreased as the depth reduced. The maximum concentrations of Ni,Cr,Hg,As was respectivly 46.136mg/kg,78.01 mg/kg,1.65mg/kg,116.01mg/kg.The average heavy metal(Cu,Pb, Zn,Cd,Ni,Cr,Hg,As) content of sampling point A2 was 93.92mg/kg,262.85 mg/kg,697.42 mg/kg,35.94 mg/kg,30.14 mg/kg,28.50 mg/kg,1.87 mg/kg ,99.22 mg/kg. The average heavy metal content of sampling point A3 was 67.24mg/kg,161.49mg/kg,304.86mg/kg,13.65mg/kg,24.67mg/ kg, 58.03mg/kg,0.78mg/kg,71.19mg/kg.5. The level of heavy metal pollution was assessed by means of Geo-accumulation Pollution Index and Potencially Ecological Risk Index.The results showed that the pollution of Cd was the most serios,and the variation of index of potencially ecological risk index ranged from 901.3～2847.15. The levels of pollution was strong-very strong,very strong which was the biggest. The results of two evaluation methods are basically the same...