Dongping Heavy Metal Pollutant Distribution Characteristics And Existing Forms Of Research

Heavy metal pollution, owing to the characteristics of permanent ,eco-toxicity and biological enrichment , has long been an important subject in the international environmental science fields . Dongping lake is one of the most important reservoirs in the East-Line Project of South-North Water Transfer. In this paper, the pollution characters of heavy metals (chromium, nickel, copper, zink, arsenic, lead, cadimium and mercury) in overlying water, suspended solids and surfacial sediments from Dongping Lake were studied as a whole. The speciation and the grain-size effect of surfacial sediments are analysed. The environmental quality was assessed synthetically. The primary fruits are as follows.1. The concentration of Hg exceed the â…¢ criterion of environmental quality for surface water, the heavy metals concentration in suspended solids and surfacial sediments from Hunan Location is higher than other locations.The concentrations of heavy metals in overlying water are far lower than its in suspended solids and surfacial sediments, which indicate the enrichment rule of heavy metals from the water phase to the solid phase.2. The analysis of positive relationships among some elements in surficial sediments indicate that the elements between Cr and Ni, Ni and Hg, Zn and Cd have good correlation, the coefficient are 0.97~ 0.99; the correlation is all right between the elements of Cr with Hg, Pb, As , Ni with As, Pb, Pb with Hg, the coefficient are 0.82~0.89, which show this elements have the same source of geochemistry and man-made pollution.3. According to speciation analysis, Cr>Ni> Cu>Zn% AssPb are associated mainly with residual fraction, as a result ,the stability of this elements is high. Apart from the residue fraction, Hg and Cd are associated mainly with the acid extractable fraction; C^ Zn> Cu> Ni% Pb with the oxidizable fraction; As with the reductive fraction. All this indicate Hg and Cd have larger potential endanger and possibility of second pollution than other elements.4. The heavy metal concention of different grain sizes depend mainly on the content of heavy metals in protomineral and different adsorption affected by granularity effect. So when we predict the hazardous impact of different grain sizes, we should think about the percentage ,density and heavy metal content comprehensively.5. Surficial sediment of Dongping Lake has been polluted by heavy metal, the main polluted elements are Cd and Hg, and this should be attached more importance to. It can reflect the degree of pollution precisely and acquire satisfied assessment results using the potential ecological risk index, the ratio of secondary phase and primary phase and Geoaccumulation index methods together.6. The quality of transfer water should be up to the mustard, and we should provide a stable sediment environment for Dongping Lake, then reduce the effect of heavy metal in surficial sediment from Dongping Lake to the water quality in the East-Line Project of South-North Water Transfer farthest.