Study On Environmental Geochemistry Of Heavy Metals In Daihai Lake

As one of the four largest lakes in Inner Mongolia, DAIHAI is a closed and brackish lake, and is also an important agriculture and fishery base in the Inner Mongolia. But now, its environment is becoming degeneration with reducing the mount of water into the lake and developing of industry and mining. High regional background of heavy metals and industrial and agricultural the input makes DAIHAI heavy metal pollution can not be ignored. The content of heavy metal can grasp the whole of pollution, and analysis of each form of heavy metals can reveal the heavy metal pollution characteristics and the regularity of migration and transformation. Study about acid-volatile sulfide(AVS) can the better for assessing the pollution of heavy metals.Based on the theories of Environmental Geochemistry, Soil Science, Biogeochemistry, this work is focused on geochemical characteristics and bio-availability of heavy metals. The Cu, Pb, Zn, Cd, Hg, As, Co, Ni, AVS-SEM and speciation in sediment are analysised, which is aimed to reveal the mechanisms of transformation of heavy metals in water-sediment system. According to this, give a preliminary evaluation of the potential ecological risk of heavy metals in Lake DaiHai, and provide large amounts of basic data for heavy metal pollution prevention and seafood safety evaluation. The conclusions are as follows:1. We first analysis the content of heavy metals in sediment of DaiHai Lake from the point of view of environmental geochemistry. And display that heavy metals mainly influenced by the soil background of DaiHai basin. The total spatial differentiation affected by the natural background and human pollution.2. In this paper, the methods of different metal element ratios were used to analyze the sedimentary history of the Lake Daihai, and the results showed that the ratios of Sr/Ba and Ni/Co had a sensitively instructive meaning on the sudden changes of environment, and accurately indicated the fluctuation of the latest Little Ice Age3. Different fractions of heavy metals in sediment core were also analyzed, and the results demonstrated that the bio-availabile fractions of Pb, Zn, Hg and Cd had enrichment tendency under warm and humid climate, while Cu and As presented an contrary tendency; Under arid and frigid conditions (Ni/Co<2.5), the bio-availabile fractions of Pb and Cd presented a decreasing trend but Cu, Hg and As increasing. Heavy metals combined organic sulfide were greatly affected by the environment conditions, presenting enrichment in humid and loss in frigid.4. We first carry out the study on AVS-SEM of sediments from DaiHai Lake, and provide basic data to study the environmental geochemistry of heavy metal in DaiHai Lake. The high value of AVS in southern of DaiHai was attributed by the grown of Reeds and Iris and the disposaled a lot of S2-by the DaiHai Power Plan. he AVS in the core has an obvious peak, but the depth of the peak was conditioned by the organic matter content and water depth.6. Using a variety of water quality assessment, DH-1, DH-2, DH-5polluted heavier and should be given adequate attention.