不同钝化剂对猪粪堆肥中重金属形态转化的影响

Effect of passivator on form transformation of heavy metal in composting of pig manure

采用三级四步连续提取法(BCR)研究了磷矿粉、硅藻土和膨润土3种重金属钝化剂对猪粪堆肥过程中重金属As、Pb、Cd含量和形态的影响。结果表明:(1)堆肥处理后,重金属总量会表现出"相对浓缩效应",使其浓度升高。(2)堆肥处理能促进重金属As、Pb、Cd的形态向活性降低的方向转化,从而降低其生物有效性。(3)不同钝化剂对不同重金属钝化效果不同,膨润土和磷矿粉对交换态铅的钝化效果较好;膨润土对交换态砷的钝化效果较好;硅藻土对交换态镉的钝化效果较好。因此,磷矿粉、硅藻土和膨润土处理有利于降低猪粪堆肥施用中的重金属污染风险。

The effect of 3 heavy metal passivators（phosphate rock,diatomite and bentonite）on the concentrations and forms of heavy metals（As、Pb and Cd）during pig manure composting was studied by the BCR sequential extraction method.The results showed that：（1）The total concentrations of heavy metals（As、Pb and Cd）were increased after composting,because of obviouse reflected ＂the relative concentration effect＂.（2）The form of heavy metal was transform from higher activity to lower during composting,therefore,the biological availability of heavy metal also declined.（3）The passivation effectiveness of different passivators on different metals was different,bentonite and phosphate rock could effectively inactivate exchangeable heavy metal Pb;The passivation effectiveness of bentonite on exchangeable heavy metal As,and diatomite on exchangeable heavy metal Cd,was better.Therefore,phosphate rock,diatomite and bentonite could be used to treat pig manure during composting to reduce the risk as heavy metal pollution of using pig manure compost in farmland.