Impact on the remobilization of trace metals in lake sediments by micro-organisms

Abstract

蓄积在湖泊沉积物中污染物质某些情况下可以成为威胁上覆水体水质安全的二次污染源．根据贵州省阿哈湖季节性缺氧的特性,通过控制氧化还原状况,设计了对该湖沉积物-水柱的原样/抑菌条件的培养实验．实验发现,微生物活动对界面附近氧化还原反应具有控制作用;改变水体的含氧状况可以显著影响上覆水体水质,包括表观性状和水体中污染物含量．聚类分析结果表明,早期成岩过程中Mn,Ga,SO₄^2-,Cu,Cr,Pb和Co,Ni,Fe,Sc,V,Rb两大类分别具有相似的地球化学行为．根据实验结果,计算了厌氧培养过程中,微量元素的最大释放量,发现铁、锰在厌氧过程中可以大量向水体释放．;It is of great concerns on some pollutants cumulated in lake sediments to become the source of pollution, under certain circumstances, causing serious harm on overlying water quality. In this research, experiment was designed based on the fact of seasonal hypoxia near sediment-water interface (SWI) in Lake Aha,Guizhou Province. By means of the control of redox potential, together with microbiological activities, it was found that microbiological activities has significant influences on the redox reactions happened around SWI; and the overlying water quality can be changed remarkably, along with the variation of redox potential, including transparency, odor and poUutant contents. The cluster analysis of experimental data demonstrated that two main groups with similar geochemical behavior during diagenesis process, could be sorted as Mn,Ga, SO₄^2-,Cu,Cr,Pb and Co,Ni,Fe, Sc,V, Rb. Finally, the maximum release of some metals when lake water turned to hypoxia, were calculated, of which plenty of Fe and Mn found can be released into overlying water.