Phosphorus Speciation and Distribution in the Sediments of Xinfeng River Reservoir
Xinfeng River reservoir is one of the largest oligotrophic water bodies in South China and the largest deep-water reservoir in Guangdong Province and it serves as an important drinking water source for the Pearl River Delta.In this study,we investigated the total phosphorus(TP)content and phosphorus speciation in the surface sediment of Xinfeng River reservoir.Further,we explored the relationships among the different forms of phosphorus,and revealed their sources and response to the aquatic environ-ment.Our aim was to provide a theoretical basis and data support for scientific management of the reservoir.In January 2021,sediment and water samples were collected at 12 sampling sites in the reser-voir for determination of total phosphorus,the content of different phosphorus forms,and water physio-chemical properties.Results show that the content of TP in the surface sediment of Xinfeng River reser-voir was in the range of 346.3-1 243.8 mg/kg,with an average value of(707.0±265)mg/kg.Inorganic phosphorus(IP)was the primary form of sediment TP,with an average content of(504.9±223.6)mg/kg,and the contents and proportions of different IP forms were in the following order:autogenous calcium-bound phosphorus(Ca-P)(239.9±113.3 mg/kg,47.1％)＞detrital phosphorus(De-P)(143.2±57.7 mg/kg,28.9％)＞exchangeable phosphorus(Ads-P)(61.6±16.1 mg/kg,13.5％)＞Fe-bound phosphorus(Fe-P)(60.2±43.5 mg/kg,10.5％).The content of organic phosphorus(OP)ranged from 122.6 to 284.2 mg/kg,and the average content was(203.5±50.4)mg/kg,accounting for 30.4％of TP.The content of bioavailable phosphorus(BAP)ranged from 139.5 to 379.5 mg/kg,and the average content was(243.9±83.1)mg/kg,accounting for 36.2％of TP.Spatially,TP content decreased significantly from upstream to downstream,and the distribution of OP,Fe-P,De-P and TP was similar,reflecting that exogenous input of phosphorus was the primary source of TP in reservoir sediment.Correlation analysis shows that there was a strong re-lation between sediment TP and the different forms of phosphorus,and their sources were similar.The correlation between BAP and Fe-P was the highest,and Fe-P was probably the most important source of sediment BAP.There were significant positive correlations between Ca-P,TOM and OP,and all were in-fluenced primarily by exogenous inputs,followed by endogenous organisms,and there is a risk of phos-phorus release from sediments.In conclusion,extending the study on mechanisms of endogenous phos-phorus release from reservoir sediments and possible control measures is crucial for scientifically manag-ing water source reservoirs.
万方数据
维普
