The researchers studied phosphorus in the sediment and water of Xiangxi River. They found that the pH of the water changed with the seasons, affecting phosphorus release. Total phosphorus content in water and sediment varied annually. Different forms of phosphorus were found in decreasing order in the sediment. The environment and pH influenced phosphorus release from sediment into water, increasing eutrophication risk. Phosphorus content in water was linked to sediment. Phosphate diffused from water to sediment. Sediment is an important nutrient source for water.