污灌区镉污染土壤钝化修复及其生态效应研究

采用盆栽试验,研究了海泡石对Cd污染污灌区土壤的钝化修复效应及其对土壤环境质量的影响.结果表明,施用海泡石显著地降低了土壤有效态Cd含量(P<0.05),可交换态Cd比例下降了0.8%~3.8%,而残渣态Cd比例增加了0.5%~9.8%.投加海泡石明显地促进菠菜生长,与对照相比,地上部和根部干重分别增加了0.94~2.11倍和1.63~5.21倍.添加海泡石后,土壤过氧化氢酶、脲酶和蔗糖酶的活性分别增加了5.1%~15.4%、14.2%~28.8%和23.5%~34.0%,细菌和真菌的数量分别增加了15.5%~91.7%和45.6%~96.5%.菠菜体内Cd含量、富集系数和转移系数随土壤中海泡石添加量的增加而降低,与对照相比,地上部和根部Cd含量分别降低了19.9%~45.6%和51.2%~70.2%,且在海泡石投加浓度达到5%时,菠菜可食部Cd含量达到国家食品卫生标准的要求.

The immobilization remediation of Cd contaminated soils in wastewater irrigation region and its ecological effects

Pot experiment was conducted to investigate the effects of sepiolite on stabilization remediation of Cd contaminated soils in wastewater irrigation region and soil environmental quality.Results showed that the addition of sepiolite significantly decreased the concentration of TCLP-Cd in soil,the ratio of Cd exchangeable fraction reduced by 0.8%~3.8% when compared with the control,while the percentage of residual form of Cd increased by 0.5%~9.8%.However,the treatments of sepiolite significantly increased the biomass of spinach,resulting in 0.94~2.11 times increase for shoot biomass and 1.63~5.21 times increase for root biomass,respectively,in contrast to the control group.The activities of catalase,urease and invertase after applying sepiolite increased by 5.1%~15.4%,14.2%~28.8% and 23.5%~34.0%.And the amount of bacteria and fungi enhanced by 15.5%~91.7% and 45.6%~96.5%,respectively.The concentration of Cd in the shoots and roots and Cd bioaccumulation and translocation factors of spinach decreased with increasing of sepiolite,suffering by 19.9%~45.6% and 51.2%~70.2% reduction,respectively.when compared to CK.The Cd content in the editable parts of spinach met with the national standard of hygiene quality for vegetable(GB 2762-2005) when the treatment of sepiolite was up to 5%.