Abstract: The aim of this research is to investigate the phosphorus pollution in the water and sediment of the Shengzhong Lake. We collected water and sediment samples from fifteen sampling sites in the summer (August) of 2019,measured the forms of phosphorus in surface water,interstitial water and sediment,and further analyzed the correlation among various forms of phosphorus. Results revealed that the total phosphorus content in the surface water of Shengzhong Lake ranged from 0.033 mg/L to 0.085 mg/L,and the content of phosphorus in different forms were DTP (61.93%),DOP (40.00%),PP (38.07%),and DIP (21.93%),respectively. The total phosphorus content of interstitial water ranged from 3.49 mg/L to 7.57 mg/L,which is the source of phosphorus in water;however,the orthophosphate accounted for only 1.9%. Total phosphorus content of sediment ranged from 299.04 mg/kg to 1138.69 mg/kg. Five forms of phosphorus in surface sediments were extracted by continuous classification of Psenner,of which Res-P accounted for 44.78% of the total phosphorus content of the surface sediment,followed by NaOH-P occupying 22.92%,and then HCl-P 14.82%,BD-P 13.39%,and NH₄Cl-P 4.09% in sequence. The content of different forms of phosphorus varied in spatial scale. Generally,the total phosphorus content in the northwest of Shengzhong Lake was higher than that in the southeast. The results of correlation analysis showed that the release of phosphorus in sediments was mainly through BD-P,NaOH-P and NH₄Cl-P. No significant correlation was found between orthophosphate in interstitial water and various forms of phosphorus in water body (P > 0.05),and the release potential of phosphorus in sediments was not large in summer.

Key words: water and sediment, phosphorus form, sequential extraction method, correlation analysis, Shengzhong Lake