沉积物扰动持续时间对悬浮物中磷形态数量分布的影响

为了探讨沉积物扰动时间(分别扰动10 min和9 h)对悬浮物中形态磷转化的影响,以太湖月亮湾沉积物和上覆水为对象,开展室内模拟试验,分析悬浮物中不同形态磷间的转化过程.结果表明,扰动时间越长,上覆水溶解性总磷(DTP)含量越高.对照试验中,上覆水中DTP含量远高于扰动试验.磷形态分析表明,随着试验时间的延长,扰动作用下(10 min,9 h),铁铝结合态磷(Fe/Al-P)占总磷(Tot-P)的质量分数逐渐降低,第10 d分别降至42.5%(10 min)和38.1%(9 h).试验结束,则有所升高.相反,钙结合态磷(HCl-P)占Tot-P的质量分数则在第10 d分别达到最大(48.9%,10 min)和(53.7%,9 h).这说明沉积物扰动促进了悬浮物中易释放态磷向难释放态磷的转化.

Impacts of Sediment Disturbance Time on the Distribution of Phosphorus Forms in Suspended Solids

To examine the impact of sediment disturbance time (disturbance 10 min and 9h, respectively) on the transformation of phosphorus forms in suspended solids, the microcosm experiment was carried out with sediment and lake water from Yueliang estuary in Taihu Lake. The transformation of phosphorus forms in suspended solids was analyzed. The longer disturbance time, the greater of dissolved total phosphorus (DTP) in the overlying water was observed. However, in the control experiment, the concentration of DTP was higher than that in the disturbance experiment. Sequential fractionations indicted that mass fraction of Fe/Al-P to Tot-P in the suspended solids decreased gradually under disturbance conditions (10 min, 9 h) with increasing the experiment time, and then, the values decreased to 42.5% (10 min) and 38.1% (9 h) at 10 d, respectively. At the end, they increased slightly, compared with the values at 10d. However, mass fraction of HCl-P to Tot-P in the suspended solids increased gradually with time, and then went up to the highest (48.9%, 10 min and 53.7%, 9 h) value at 10 d. It suggested that sediment disturbance promoted the transformation of phosphorus forms in the suspended solids, especially from mobile phosphorus forms to refractory forms.