『Abstract
　Phosphorus fractions and phosphate adsorption characteristics of 16 sediments from a shallow freshwater lake (Nansi Lake, China) and its inflow estuaries were investigated. In the present study, the sediment phosphorus is fractionated into exchangeable P (exch-P), Al-P, Fe-P, Ca-P, organic P (OP), inorganic P (IP) and total P (TP). The results show that the total phosphorus (TP) content in the sediments ranged from 571.67 to 1,113.55 mg kg^-1, and calcium bound phosphorus (Ca-P) is the main fraction of IP. The biologically available phosphorus (BAP) ranges from 32.02 to 229.67 mg kg^-1 in the Nansi Lake sediments. Phosphate adsorption on the sediments mainly occurs within 10 h and is completed within 48 h. The content of native adsorbed phosphorus (ωNAP) varies greatly from 6.05 to 194.37 mg kg^-1, showing a significant correlation with the total maximal amount of phosphorus adsorbed (TQmax). Adsorption efficiency (m) ranges from 574.79 to 3,220.68 l kg^-1 and zero equilibrium phosphorus concentration (CEPC) ranges from 9.919 to 0.157 mg l^-1. After the South-to-North Water Diversion Project, the inherent phosphorus present in sediments will be a major threat to the diverted water quality and be a predominant factor determining the trophic status of the lake even if the external load is reduced.

Keywords: Inflow rivers; Nansi Lake; Phosphate adsorption; Phosphorus fractions; Sediment

Introduction
Materials and methods
　Study area
　Sediment sampling and analysis
　Phosphorus fractions and analysis
　Phosphate adsorption kinetics experiments
　Phosphate adsorption isotherm experiments
Results and discussion
　Sediment characteristics
　Phosphorus fractions
　Phosphate adsorption kinetics
　Characteristics of adsorption of phosphorus onto the sediment
Conclusions
Acknowledgements
References