Studies On Distribution Characters And Correlation Of Nitrogen And Phosphorus In Lake Chaohu Basin,China

Today, a serious environmental problem the world facing is lake eutrophication, which is also an important research topic in the scientific community. Especially, eutrophication of shallow lake is increasingly becoming the country’s major environmental problems. Nutrient biogeochemical cycle in Water-sediment interface is an important factor of influencing lake eutrophication. Biogeochemical cycles of nitrogen and phosphorus nutrients in the lake water and sediments plays an important factor of influencing lake eutrophication.In order to identify the characteristics and the sources of the pollutants in Lake Chaohu Basin, in this study, the Lake Chaohu Basin is selected as the research object. The methods of the field sampling, laboratory analysis combined with the literature data collection are taken, nutrients content and distribution characteristics in Lake Chaohu Basin are studied. Muchmore, there is focusing on distribution characteristics of different forms of organic phosphorus in the sediments of inflow rivers of Lake Chaohu. And the study provides a scientific basis and reference for causes of eutrophication and the migration, transformation of nitrogen, phosphorus nutrients in Lake Chaohu Basin.The results indicate that:(1) The content of TN and DTN in water in west part of Lake Chaohu were obviously higher than that of the east part of Lake Chaohu, which reached the maximum in Nanfei River estuary. Meanwhile, in west part of Lake Chaohu, the content of TP, DTP and TOC in water were slightly higher than that of the east half of the Lake Chaohu.(2) The nutrients content of sediments in west part was significantly higher than that of the east part of Lake Chaohu, and the nutrients content of sediments in the middle part of Lake Chaohu was strikingly low. The nutrients content of Nanfei River sediments was much higher than that of other inflow rivers, and reached its peak down the river which flowed through the Hefei City. Furthermore, it was found that the relationship between TOC and TN, TN and OM (%), TP and IP of sediments were significantly correlated, which indicated that organic nitrogen and inorganic phosphorus were the main fraction of TN and TP respectively, and content of inorganic nitrogen remained relatively constant comparing with organic nitrogen. However, TN was significantly correlated with TP and IP indicating the homology between nitrogen and phosphorus of sediments. The results of sediment particle size analysis also showed that the correlation between sediment particle size and TOC, TN, TP, IP were not significant as the particle size was increasing.(3) the relative order of Po fractions was residual P0> fulvic acid-P0> HC1-P0> humic acid-P0>NaHC03-P0in sediments of soil and water conservation River, with the relative proportion of average:7.5:3.1:1.9’.1.5:1.0. The relative order of Po fractions in sediments of urban pollution and non-point source pollution rivers is nearly identical, and the content of Po fractions in non-point source pollution rivers is lower than urban pollution and soil and water conservation Rivers. The study found that the middle labile Po was significantly correlated with OM、TP、P、P0、TN、 NaHCO3-Pi and NaOH-Pi. Furthermore, nonlabile Po was also significantly correlated with Po and NaOH-Pi. And they reflected that the middle nonlabile Po may easily convert into bioavailable phosphorus and nonlabile Po, while nonlabile Po still has the potential of Bioavailable.