Analysis of Eutrophication of Yangtze River Yibin Section

Based on 2009-2010 two years continuous monitoring data of section Jingkou and Guagongshan, temperature of water, pH, DO, transparency (SD), TN, TP, chlorophyll a and CODmn are selected to evaluate water quality of Yangtze River Yibin section. The results show that the Yangtze River Yibin section is at the level of eutrophication. Besides, the impact Nitrogen, phosphorus, water temperature, light and pH take on the eutrophication of the Yangtze River Yibin section is analyzed. It turns out that the mean concentration ratio between total nitrogen (TN) and total phosphorus (TP) of Yangtze River Yibin section in 2009 and 2010 is 4.05:1. Generally considered, when TN / TP <14, nitrogen is the limiting factor of eutrophication. So the nitrogen is the restrictive factor of Phytoplankton growth in Yangtze River Yibin section.