纳米羟基磷灰石对重金属污染土壤Cu/Cd形态分布及土壤酶活性影响

通过室内培养实验,研究了纳米羟基磷灰石对重金属污染土壤Cu/Cd形态分布及土壤酶活性的影响。结果表明,施加纳米羟基磷灰石显著提高了土壤pH,其中3%和5%添加剂量处理60 d后使土壤pH分别提高了1.23个和1.35个单位;纳米羟基磷灰石显著减少了毒性较强的离子交换态Cu/Cd的含量,增加了毒性中等的碳酸盐结合态、铁锰氧化物结合态、有机结合态及毒性最低的残留态Cu/Cd含量,使Cu/Cd由植物可利用态向潜在可利用态转变;纳米羟基磷灰石不同程度地提高了土壤过氧化氢酶、脲酶和酸性磷酸酶活性。3种酶活性与Cu/Cd形态分布的相关性表明,过氧化氢酶和酸性磷酸酶对土壤重金属Cu/Cd活性变化比较敏感,可以作为重金属Cu/Cd污染土壤的评价指标。

The Effects of Nano-scale Hydroxyapatite on the Speciation of Cu and Cd and Enzymatic Activities in Soils

The batch experiments were set up to test the effects of nano-scale hydroxyapatite on the speciation of Cu and Cd and enzymatic activities in soils.The results showed nano-scale hydroxyapatite could increase soil pH,and 1.23 and 1.35 of pH units were improved in the treatments with 3% and 5% nano-scale hydroxyapatite after 60 days incubation.Nano-scale hydroxyapatite significantly decreased the contents of exchange forms Cu and Cd,and increased the contents of carbonate form,Fe-Mn oxides bound form,organic form and residual Cu and Cd,which promoted the transformation of Cu and Cd from the active forms to the inactive ones.Nano-scale hydroxyapatite effectively increased the enzymatic activities of hydrogen peroxidase,urease and acid phosphatase in soils.The high correlativity among soil enzymatic activities and the contents of Cu and Cd with different forms suggested that hydrogen peroxidase and acid phosphatase were sensitive to the changes of available Cu and Cd,and could be served as the evaluation index for Cu and Cd contaminated soil.