Characteristics of Phosphorus Sorption on Surface Sediments of Hongze Lake

Sorption behavior and adsorption-desorption equilibrium mass concentration of phosphorus on surface sediments samples taken from Hongze Lake at nine sites were determined in laboratory, the correlation between chemical-physical properties of sediments and their phosphorus sorption characteristics were analyzed. Under low mass concentration conditions, the maximum phosphorus sorption capacities were 50.67-85.17 mg/kg, and there was a negative sorption process during phosphate sorption on surface sediments. The zero equilibrium P concentration (EPC0) of the sediments ranged from 0.06 to 0.11 mg/L, less than the level for the overlying water, showing a positive phosphate adsorption on surface sediments. The maximum phosphate adsorption, NAP and the total maximum phosphate adsorption were positively correlated with active iron and active aluminous contents in the sediments, but had poor correlation with total P, organic P, inorganic P and organic matter in the sediments. The zero equilibrium P concentration (EPC0) had poor correlation with chemical-physical parameters of surface sediments.