东太湖沉积物中磷的形态分布特征研究

应用化学连续提取法对东太湖沉积物中不同形态的磷进行提取，并分析了其空间分布特征和垂直分布特征。结果表明，东太湖沉积物中磷形态以碎屑态磷(Ca-P)、有机磷(Or-P)、自生磷(De-P)、铁结合态磷(Fe-P)为主，平均含量分别为188.6±32.5、73.1±18.6、45.2±3.3、34.3±18.5μg/g；弱吸附态磷(Ex-P)、闭蓄态磷(Oc-P)和铝结合态磷(Al-P)含量较低，分别为6.7±2.2、4.0±1.9、1.3±0.4μg/g；总磷（TP）的平均值为353.1±46.3μg/g。Ca-P、Or-P 、De-P 、Oc-P四种不易释放的磷形态占88%，而Fe-P、Ex-P、Al-P三种易释放的磷形态仅占12%。除了Ca-P含量随沉积物深度的增加而增大，Al-P含量较低且随深度增加无明显变化，其他各形态磷含量大致随深度的增加而减少，表现出“表层富集”现象。上述结果表明，东太湖的内源磷负荷较小，但有增加的趋势。

Phosphorus Fractions and Distribution in Sediments of East Taihu Lake

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.