Study On Arsenic, Lead, And Chromium Toxic Heavy Metals In Three Gorges Reservoir Region After Impoundment

The influence of the Three Gorges Project to environment is an important problem. After the completion of the Three Gorges Project, the environmental conditions, such as the velocity of flow, the sedimentation rate of bedload and water-level-fluctuating zone, will be changed notably. Then the conformation, distribution and behavior of heavy metal pollutions in water column will be also changed distinctly. So the fate of toxic heavy metals (lead, chromium and arsenic) among compartments in Three Gorges Reservoir Region is highly concerned. The seasonal and spatial distributions of heavy metals in water column of the Three Gorges Reservoir Region were investigated for a two-year survey.Sampling was made in wet season and drought period since Aug. 2004 in the Three Gorges Reservoir Region. Through the determination of the toxic heavy metals arsenic, lead, chromium in water and suspended matter and biology samples (fish), the fate of toxic heavy metal in Reservoir Region is discussed. The results show that:(1) The polluted sources of heavy metals As and Pb from bank are not existent, the scour by rain water to the city in the bank and the soil loss are the main reason. It leads that the municipal waste water and the arseniccontaining and leadcontaining particles pour into water column of the Three Gorges Reservoir Region.(2) And the pollution sources of heavy metal chromium comes from Daxigou in Chongqing.(3) Compared with before-impoundment, after impoundment the pollution of heavy metals in water column seems not to increase as a whole, the water quality in drought period is better than that in wet season.