In this study, total phosphorus (TP) and the phosphorus (P) fractions in the water and surface sediments of the Baotou Nanhai wetland in China were determined using molybdenum blue/ascorbic acid spectrophotometry and continuous extraction methods. An APCS-MLR receptor model was combined with correlation analysis (CA) and principal component analysis (PCA) to identify and quantify the pollution sources. The results showed ① differences in the pollution level of phosphorus between the surface sediments and water. The contribution of dissolved inorganic phosphorus (DIP) to TP in the water (WTP) was the lowest, while the contribution of calcium-bound phosphorus (HCl-P) to TP in the surface sediments (STP) was the largest in the study area. The surface sediments of the Nanhai Lake (L area) and the wetland plant area (P area) exhibited high bioavailability and the potential for releasing phosphorus into the water, which could result in eutrophication and is therefore of concern. ② The APCS-MLR receptor model indicated that the main pollution sources of phosphorus were industrial wastewater and domestic sewage (29.07%), and pesticides and fertilizers (29.00%). In addition, the degradation of animal and plant residues (18.49%) also contributed to pollution in the study area.
Keywords: Nanhai wetland; bioavailability; phosphorus fraction; quantitative source identification; release risk.