Phosphorus fractions and distribution characteristics in sediments of East Taihu Lake
东太湖沉积物中磷的形态分布特征研究

Various fractions of phosphorus were extracted in sediment samples of East Taihu Lake by using a sequential chemical extraction,and the fractions distribution characteristics of phosphorus fractions in sediments were analyzed.The results indicated that the average concentrations of Ca-bound P(Ca-P),organic P(Or-P),detrital apatite P(De-P) and Fe-bound P(Fe-P) were(188.6±32.5),(73.1±18.6),(45.2±3.3) and(34.3±18.5) μg/g respectively,representing the major existence.While the average concentrations of exchangeable P(Ex-P),occluded P(Oc-P) and Al-bound P(Al-P) were(6.7±2.2),(4.0±1.9) and(1.3±0.4) μg/g respectively.The average concentrations of total phosphorus(TP) were(353.1±46.3)μg/g.Phosphorus of Ca-P,Or-P,De-P and Oc-P,which are not easy to release,accounted for 88%,while the easy release phosphorus of Fe-P,Ex-P and Al-P accounted for 12%.Ca-P content ascended directly with the depth of sediments,Al-P content being no significant variation,whilst contents of other forms of phosphorus declined with the depth of sediments,which presented surface enrichment phenomenon.The results suggested that the internal phosphorus load in sediment was not very serious yet,but it was increasing.