Spacial And Temporal Variation And Transport Of Contaminants Within Water And Up-layer Sediments In Lake Wuliangsuhai

Due to the natural evolution and human activities, the composition and status of water environment has undergone fundamentally changes. As a result of this, wetland ecosystems have been affacted by means of contamination from both outer and inner sources.As the lake Wulangshuhai has been seriously entroficated, the spatial and temporal distribution of contaminants within its water body and uper-layer sediments were analyzed. Especially the interactions between the water body and uper-layer sediments by means of contaminant transport were modeled. The results showed that:(1) Combining with the geostatistics theory and GIS, the temporal and spatial distribution of the contaminants were analyzed, including eutrophication indexes, organic matter, and nutrient salts etc. The results showed that the contaminants represented different distribution characteristics and the lake Wuliangsu is at the status of eutrophication, salinity, and organic contamination.(2) The content and the spatial distribution of nutrient salts in the sediments indicated that the total nitrogen and total phosphorus have similar spatial distribution characteristics with a decrease in content with the flow direction. Organic carbon content in the mainly depends on the distribution and density of aquatic plants. Content of heavy metals like Cu, Cd, Pb, Zn, Hg, Cr in the sediments varied spatially, being higher in the northern and southern parts and lower in the center area. The average content of Cd is exceeded to Gradeâ…¡of the national soil quality standards.(3) The field site monitoring and the lab experiment results showed that nutrient salts could release faster from the sediments into the water body at alkaline and higher temperature status, higher dissolved oxygen content and redox potential could reduce the release rate of nutrient salts; and higher organic matter content in the sediments could led to higher concentration of total nitrogen, ammonia nitrogen and total phosphorus in the water body. In one word, the total nitrogen and phosphorus within the sediments the water body were exchanged especially in the summer time.(4) WASP model represented the processes of contaminants transport between the sediments the water body. The results showed that the accuracy is greater than 83.33% between the modeled and measured results.