水源水库沉积物磷的赋存形态及其与间隙水磷的关系

Phosphorus fractions in sediment and its relationship with phosphorus in interstitial water of a source water reservoir

为了探明水源水库沉积物磷的赋存形态及其对水体磷的影响,采用连续提取方法,研究了周村水库沉积物中磷的赋存形态分布特征,并探讨了沉积物各形态磷与总磷、烧失量及间隙水中磷的相关性。结果表明,周村水库内源磷负荷较高,沉积物中TP表现出表层富集的现象,表层沉积物中TP空间分布存在较大差异,上游浅水区为554~563 mg·kg^(-1),库心附近为424~1 161 mg·kg^(-1),而坝前深水区高达812~2 969 mg·kg^(-1)。无机磷(IP)是总磷(TP)的主要成分,占TP的79.26%~89.12%,IP主要由铝/铁磷(Al/Fe-P)构成。沉积物中的Al/Fe-P含量很高,具有很大的磷释放潜能。沉积物中各形态磷的浓度垂向分布随深度增加而逐渐降低,其中B、C两点变化最为明显。相关性分析结果表明,间隙水PO3-4-P与Fe-P存在较好的相关性,说明Fe-P对周村水库沉积物间隙水中PO3-4-P浓度分布有着重要的影响,周村水库水体季节性分层导致恒温层厌氧情况的发生,Fe-P在厌氧还原条件下释放进入间隙水并向上覆水扩散,进而可能对水体水质产生影响。

The main purpose of this paper is to illustrate the influence of sediment phosphorus fractions on phosphorus concentration in the interstitial water of a source water reservoir. Sediments were sampled from Zhoucun reservoir in March 2015,and three representative core samples were used to study the profile distribution of phosphorus fractions,and their correlation with phosphorus in interstitial water. The phosphorus burden in Zhoucun reservoir is high,and shows enrichment of TP in the surface sediment. The sediments of Zhoucun reservoir have high TP content,with 554 to 563 mg·kg^-1in the sediments of an upstream shallow water region,424 to1 161 mg·kg^-1in the center of the reservoir,and 812 to 2 969 mg·kg^-1at the site near the dam. IP is the major part of TP（ about 79. 26% to 89. 12% of TP）,and Al/Fe-P is the main part of IP. The content of Al/FeP in sediment is high,implying a high diffusion trend for sediment phosphorus in Zhoucun reservoir. Phosphorus decreases with depth,especially in the sediments of sampling locations B and C. Regression analysis showed that the concentration of PO3-4-P in the interstitial water is positively correlated with Fe-P. The result suggested that Fe-P would be the dominant factor influencing the distribution of TP in the overlying water. Seasonal stratification in Zhoucun reservoir leads to anaerobic conditions in the hypolimnion,and the Fe-P released under the reducing conditions have an important influence on water quality in Zhoucun reservoir.