|
This thesis through the study of the basic data of the Sediment of Dianchi Lake, Dianchi Lake sediment pollution characteristics and potential ecological risk index evaluation and geological and major combined cumulative index method effectively comprehensive evaluation of modern Dianchi Lake sediment pollution levels; Second, BCR sequential extraction method using improved sequential extraction of heavy metals in the sediment of Lake forms and by different forms of analysis to explain the principle of the release of heavy metals; Then, the Dianchi Lake sediment extracted humic acid (HA), experimental by adding different concentrations of HA solution, the analysis the HA release of heavy metals; then, Ray magnetic data acquisition software, similar complexometric titration method, the conductivity of the copper ion selective electrode solution of copper ions Finally, the mechanism of interaction between the analysis of copper ion and HA;, using the same method with the HA and the complexing copper ions, to quickly and easily obtain the data Dianchi sediment for the complexation of Cu. The results show that: (1) heavy metal pollution of Dianchi Lake sediment is calculated in accordance with the evaluation of potential ecological pollution, we can see the potential for environmental contamination of heavy metals in sediment of Lake Cd heaviest and lightest Zn, and the north than in the south easier There is a secondary pollution of heavy metals in the sediment. Heavy metals in sediments of Dianchi Lake is calculated in accordance with the geological cumulative index method can be seen more serious pollution of Pb and Cd. Cu and Zn is less contaminated. The combination of the two methods can be drawn, Dianchi Lake sediment, Cd is a major pollution problem smaller Cu, Zn and Pb in the pollution of Dianchi Lake. (2) heavy metal the BCR species distribution can be seen from the sediment of Lake Dianchi sediment from north to south, gradually reduce the effective state (except outside the residual fraction and other forms), a gradual increase in the residual fraction. Effective state is to play a major role in the sediment, and residue stable states can exist in the sediment, and effective states can be relatively easy in the occurrence of physical, chemical, and biological environment. (3) Experimental studies have shown that the release of HA concentration changes Pb impact the largest, Dianchi sediment organic matter content such external conditions conducive to the release of Dianchi sediments Pb. Cd pollution of Dianchi Lake, the main problem of the heavy metals in sediments. HA concentration changes in binding experiments found the impact of the release of Cd increased HA concentration, strengthen the ability of Cd in sediment release, lower release rate from north to south, Cd, and may be related to sediment characteristics , related to the nature of the HA. (4) HA concentration changes for certain effects of heavy metals. HA concentration increases, the increase in heavy metal release. The same time, the concentration of HA for the release of heavy metals, depending on the study sites vary. (5) The copper ion solution with different concentrations of HA solution when complexation with the increase in HA concentration, will cause increase in the amount of copper ion complexation, copper ions will be stable chelate with the HA. Sediment and copper ion complexation experiments, the amount of organic matter content Caohai Center complexation of copper ions, the higher the organic matter content of the sediment, smaller role in the release of heavy metals. The above findings reflect preliminary Dianchi sediments Cu, Zn, Pb, Cd, the spatial distribution of heavy metals and content distribution, can provide the basis for the assessment of heavy metals in sediments of Dianchi Lake; same time, actual samples of the Dianchi Lake sediment through laboratory conditions, the experimental study of heavy metals in the sediment release mechanism and the main factors, can provide the basis for the treatment of heavy metal contamination in the sediment of Dianchi Lake.
|