不同模拟条件下太湖沉积物-水界面磷行为的研究

随着大量的磷输入水体,太湖富营养化已经成为一个严重的环境问题。沉积物内源磷的释放是湖泊上覆水体磷浓度升高的重要因素之一。文章针对太湖特征,模拟影响沉积物内源磷释放过程因素中的扰动、溶解氧和pH条件研究表层沉积物的内源磷行为。结果表明,在厌氧环境下有利于磷的释放,且没有扰动条件要比有扰动的释放量大,达到0.297 mg/L;好氧条件不利于磷的释放,经过好氧培养的沉积物中有机磷平均减少了约50%,好氧-厌氧交替使得铁结合态磷提高了0.001 8 mg/g。pH 8.2~8.6有助于沉积物磷的释放,且不同pH值下沉积物磷的最大释放时间不同,pH 9.0沉积物磷在1 d时最大释放量达到0.162 mg/L;沉积物中磷在不同pH下的形态会发生不同程度的转变,其中铁结合态磷(Fe-P)的转变最大。可见扰动、溶解氧、pH对沉积物内源磷的释放有着显著影响。

Behavior of Phosphorus in Interface of Sediment-overlying Water in Taihu Lake under Different Simulative Conditions

Phosphorus releases of lake sediment to the overlying water in general give rise to increases of phosphorus content in lake water,which is known as one of the major factors causing eutrophication of Taihu Lake.A bench scale experiment was conducted to simulate the effects such as disturbance of overlying water,DO and pH on the internal phosphorus release from sediment of Taihu Lake.Experimental results showed the conditions conducive to phosphorus release from sediment to water were anaerobic,pH range of 8.2~8.6,and disturbance of overlying water;in addition,the time phosphorus release reached maximum value depended on pH,and it took one day to get the maximum release of phosphorus at pH 9.0 with the concentration of 0.162 mg/L in the overlying water.