Research on phosphorus loads and characteristics of adsorption and release in surface sediments of Nanyang Lake and Weishan Lake in China

The characteristics of phosphate adsorption and the transformation of phosphorus forms in the release process of the sediments in Nanyang Lake and Weishan Lake are researched. Distribution of maximal amount of phosphorus adsorbed (Qmax) is 112.76 and 93.91 mg kg−1, respectively, and the adsorption processes of Nanyang Lake and Weishan Lake reach equilibrium after 48 h. Total maximal amount of phosphorus adsorbed is the amount of Qmax and native adsorbed phosphorus (NAP). The m is the sum of the adsorption efficiency of the sediments adsorbing the phosphorus coming from external sources and the phosphorus desorbed from the sediments. Mutual transformation between phosphorus forms exists in the process of phosphorus release. The contents of NH4Cl-P, BD-P, and HCl-P in the sediments reduced, and the content of NaOH-P increased in the process. But the amount of NaOH-P increased is less than the amount of NH4Cl-P, BD-P, and HCl-P reduced. So other forms of phosphorus transformation relations exist.