Study On Environmental Geochemistry Of Heavy Metals In Dalinuoer Lake

In recent years, long-term mineral exploit and the rapid development of industry have resulted in some serious heavy metal pollution, and the frequent pollution events has caused increasingly raising concerns. Due to the characteristics of heavy metal, such as long-term persistent existed, accumulated through food chain, covert and irreversible, they have threaten the persistent development of economic and the construction of harmonious society.The lake Dalinuoer, located in Chifeng city, is one of the four largest lakes in Inner Mongolia, and is also an important fishery base in eastern Inner Mongolia. Chifeng city has an excellent metallogenic geological conditions and abundant mineral resources, especially rich in precious(gold, silver), ferrous metal(iron), nonferrous metals resources. Heavy metal with high level background and some of those that generated through erosion of rock or weathering and injected into Dalinuoer Lake in the way of surface runoff and soil loss should not be ignored.Speciation analys is a basis for bio-availability research, it is used to identify potential hazards of heavy metals in sediments. Research about heavy metals speciations on transformation of heavy metal is of great importance for revealing heavy metal pollution mechanism, study about acid-volatile sulfide and heavy metal concentrations in pore water are of propitious to systematically study the heavy metal pollution characteristics.Based on the mechanism and effect of heavy metal pollution in the Dalinuoer Lake, the transition and transformation characteristics of heavy metals in the Dalinuoer Lake are discussed; the relation between speciation, bio-availablility and toxicity of heavy metal in sediments are revealed and identified; the potential hazards of heavy metal contamination in the sediments are evaluated. The paper could provide strategy and scientific basis for the prevention and cure of heavy metal contamination in the Dalinuoer Lake, and could also provide reference for the study about water quality protection and assess of food safety in the Dalinuoer Lake.Based on the theories of Environmental Geochemistry, Biogeochemistry, Soil Science, and Modern Sedimentology, this work is focused on geochemical characteristics and bio-availability of heavy metals. The Cu、Pb、Zn、Cd in overlying water, filtered water, pore water, 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 Dalinuoer, and provide large amounts of basic data for heavy metal pollution prevention and seafood safety evaluation. The conclusion are as follows:1. We first carry out the study on AVS-SEM of sediments under the high salinity-alkalinity from Dalinuoer Lake, provide basic data to study the environmental geochemistry of heavy metal in plateua lake with high salinity-alkalinity.2. The mainly bio-available speciation of heavy metals(Cu、Pb、Zn、Cd) in sediments from Dalinuoer lake are different due to their different geochemical properties. The organic matter, carbonate and higher degree of pH are the key factors in controlling bio-available fractions of Cu, Pb and Cd, Zn.3. Several methods are applied to assess the pollution level and potential ecological toxicity of heavy metals in sediments from the Dalinuoer Lake. Based on those, we firstly establish a new environmental quality criteria-Sediment Quality Criteria(SQC) to assess the ecological risk of Dalinuoer lake.4. The transport behaviors of heavy metal in pore water and filtered water is studied, and the results illustrate that the sediments of the Dalinuoer Lake acted as a sink of Pb, whereas a source of Cu. According to the Water Quality Standard, we preliminary assessed the water quality of the Dalinuoer Lake.