Classification of Dissolved and Particulate Phosphate Components in Xiangxi River, China

These years the water quality deteriorated in Xiangxi River (XXR)---one tributary of Yangtze River in the Three Gorges Project reservoir area. Many components existed in XXR such as nutrients, suspended sediment (SS) and phytoplankton. The nutrients containing phosphorus could be adsorbed to the fine SS, which influenced the water quality components cycling obviously. For calculating the concentrations of different forms of phosphates (mainly the dissolved phosphate and particulate phosphate) more precisely, the formula was deduced based on the Langmuir equation and modified Langmuir equation. Then the field observed data were used to validate the deduced formula, which showed that the deduced formula can calculate the concentrations well. The formula could be applied for the water quality or ecological modeling, and also provide more information for water quality improvement. Keywords: Suspended sediment; Phosphorus; Adsorption-desorption; Xiangxi River