[Spatial and Temporal Distributions of Nitrogen and Phosphate in the Chaohu Lake].

In order to determine the concentrations, spatial and temporal distributions of nitrogen ( N) and phosphorus (P) nutrients in Chaohu Lake, the surface water samples were collected systemically in different flood seasons by grid sampling methods. Meanwhile, the predominant pollution factors and priority control area were confirmed. The results showed that the concentrations of TP, TN and NO3- -N in the inflowing rivers were higher than the V class water standard, the concentrations of nutrients in wet season were lower than those in normal season and dry season in Nanfei River and Shiwuli River, while the levels of nutrients in the other selected rivers were higher in wet season. The variations of spatial and temporal of nutrients were observed in the Chaohu Lake. The concentrations of N and P nutrients in the western part of Chaohu Lake were higher than those of the eastern part. The elevated concentrations of TP, TN and NH4+ -N were found in the dry season, while the elevated content of NO3- -N was observed in the wet season. The predominant pollution factors in Chaohu Lake were TN and NH4+ -N, the concentrations of these nutrients were decreasing from the western part of the Chaohu Lake to the eastern part of the Chaohu Lake.