阳宗海沉积物中磷的稳定性

Stability of phosphorus in sediments of Lake Yangzonghai

絮凝剂(Fe Cl3)治理阳宗海砷污染的过程中,水体中的磷被大量沉积进入底泥,弄清其是否会在环境条件变化后发生反溶形成二次污染对湖泊富营养化防治具有重要意义。通过模拟实验模拟泥-水界面p H变化、物理扰动和微生物活动的变化,旨在分析这些环境因子变化对沉积物中磷溶出的影响。结果表明,阳宗海水体在目前这种磷浓度下,底泥的磷会随时间的增加而溶出再次造成水体磷污染,当暴露在清洁水条件下时磷的释放率会增加;这种由于絮凝剂吸附沉淀到湖底的磷,在上覆水p H增加0.5时底泥磷解吸附释放速率增加;每年秋季湖泊上下层水的交换活动会造成水体磷浓度的季节性升高,形成不可忽视的磷内源。而夏季水温分层导致湖泊底部厌氧,使厌氧微生物活性增强,这将进一步促进底泥中磷的释放。

A lot of phosphorus was deposited into the sediment during the remedy of arsenic contaminated Lake Yangzonghai by flocculants( Fe Cl3). Whether the released phosphorus can pollute the water secondly or not after the change in the environment plays an important role in protecting the lake. The research was aimed to analyze the effects of these variable factors,such as the bioturbation and the stimulation of p H and microbial activity of mud-water interfacing,in the phosphorus dissolution from the sediments. The results claimed that phosphorus in the sediment will dissolve and cause the water phosphorus pollution again continually under the phosphorus concentrations of Lake Yangzonghai at present,and the phosphorus release rate would increase when it is exposed to the clean water. And the phosphorus,which was absorbed by flocculants and precipitated into the bottom of the lake,would desorb gradually when the p H of overlying water increased 0. 5. Every fall,the internal exchanging in the lake water could cause the seasonally increasing in the phosphorus concentration and form the significant endogenous phosphorus inner source. Furthermore,in summer,phosphorus dissolution would be highly stimulated since the water temperature stratification created the anaerobic environment,which increased the anaerobic microbial activity at the lake’s bottom.