污泥中镉的形态分析及蚯蚓对镉的富集探讨

Analysis of Cd Forms in Sewage Sludge and Cd Enrichment in Earthworm

利用BCR三步分级提取法研究了污泥中镉的形态,并利用饲养法研究了蚯蚓对污泥中金属镉的富集效应。研究结果表明:各种污泥中Cd的含量并不高,工业污泥中Cd主要以迁移性较强的可还原态和酸溶态形态存在,而市政污泥中Cd主要以残渣态存在。蚯蚓对Cd有较强的富集能力,富集程度随污泥中Cd浓度的增加而增加,富集系数甚至高达16。蚯蚓对金属镉有一定的耐受性,当蚯蚓体内达到一定量的镉浓度后,金属镉会通过粪便排出体外。

In this article,BCR sequential extraction procedure was used to study the form of Cd in sewage sludge,and the rearing method was applied to research the absorption of Cd in sewage sludge by earthworms.The results showed that the Cd content in different kinds of sewage sludge was not high,and Cd existed mainly as reducible and acid extractable forms in industrial sludge,but more as residual form in municipal sludge.Earthworm could absorb and accumulate Cd in the sludge,as the time went by and the Cd content in the sludge increased,the Cd enrichment in the body of earthworm enhanced,and the enrichment coefficient even reached to 16.Cd would be excreted to wormcast when the Cd content in earthworm reached to a certain degree.