水生植被重建对沉积物Pb·Fe迁移转化的影响

Effect of Aquatic Vegetation Reconstruction on Migration and Transformation of Pb and Fe in Sediments

采用修正后的BCR法对经过水生植被重建恢复的2条城市河道（丽娃河、曹杨环浜）进行研究,分析沉积物中0~10 cm层及10~20 cm层的Pb、Fe及总有机碳（TOC）含量。结果表明,经过植被重建后,2条城市河道沉积物Pb总量有所降低,但Pb主要以可还原态存在,占总量的70%~80%,说明Pb的活性很高,对环境仍然存在危害性。沉积物中可还原态的Pb、Fe含量存在相关性,说明根系泌氧形成的铁锰氧化物对Pb的迁移转化有较大影响,各形态Pb、Fe与总有机碳的含量也存在相关性。

Sediments of two urban rivers（Liwa River,Caoyang River） after aquatic vegetation reconstruction are studied using modified BCR sequential extraction procedure.The concentrations of Pb,Fe and TOC in 0-10 cm layer and 10-20 cm layer are analyzed.The results show that total Pb in sediments is reduced after revegetation,however,Pb has identical distribution in iron and manganese oxides fractions,which accounted for 70%-80% of total amount in this study.That means Pb has higher activities and is still harmful to environment.The Pb and Fe associated with iron and manganese oxides have good correlations with each other,that shows the iron and manganese oxides formed by root radial oxygen have a greater impact on migration of Pb.Different fractions of Pb and Fe have good correlation with TOC,too.