骨炭修复重金属污染土壤和降低基因毒性的研究

采用分级提取的方法研究了施加骨炭对污染土壤重金属的固定效果,结果表明,土壤施加10 mg·kg^-1骨炭后水溶态、交换态、碳酸盐结合态和铁锰氧化物结合态Pb的浓度都显著下降;而加入骨炭后土壤有机结合态Pb的浓度显著上升,表明骨炭可以吸附、固定土壤中的Pb,改变Pb的化学形态,降低Pb的生物可利用性.加入骨炭后土壤中水溶态和交换态Cd的浓度都显著下降,残渣态Cd的浓度明显上升.骨炭处理对土壤中Cu化学形态的影响和Pb相似,表明骨炭可以吸附固定土壤中的Cu.骨炭处理对Zn也有一定的固定效果,降低了土壤中水溶态的Zn.采用植物彗星实验研究了施加骨炭对土壤基因毒性的影响,表明加入骨炭后减轻了污染土壤对洋葱根尖细胞的DNA的损伤,降低了土壤污染对植物的基因毒性.生物评价和化学评价的结果均表明骨炭是重金属污染土壤的有效修复剂,能有效降低污染土壤中重金属的生物有效性和对植物的毒性.

Chemical Fixation of Metals in Soil Using Bone Char and Assessment of the Soil Genotoxicity

We evaluate the effects of soil in situremediation by application of bone char as a soil amendment based on chemical and biological assessment. The application of bone char decreased the Pb in the in the water soluble (WS), exchangeable (EX), carbonate-bound (CAR) and Fe-Mn oxides-Bound (Fe-Mn) fraction but increased the Pb in organic-bound (ORG) fraction indicating the decreased bioavailability of Pb. The application of bone char decreased the Cd, Cu and Zn in water soluble, exchangeable, carbonate-bound fraction by increasing substantial amounts of heavy metals in the ORG fraction or Residual (RES) fraction. The soil genotoxicity was evaluated using plant comet assay of root tip cells of Allium cepa L. and the results indicated that bone char application reduced genotoxcity of heavy metals, decreasing the DNA damages in plants which was consistent with the changes of the chemical forms of Pb, Cd, Cu and Zn indicating the changes of the chemical forms of heavy metals may be one of the reasons for decreased soil genotoxicity.