干旱区绿洲土壤共存重金属元素形态变化及生物有效性实验分析——以Cd、Zn、Ni元素为例

采用盆栽试验,初步研究了干旱区绿洲土壤—胡萝卜系统中镉、锌、镍3种重金属的形态变化特征及其生物有效性问题。结果表明:供试绿洲土壤原状土中,Cd、Zn、Ni均以稳定的残渣态形式存在,而处理土壤中重金属被钝化的量有限,Cd的存在形式主要以碳酸盐态为主,Zn、Ni则主要以铁锰氧化态为主;3种元素的活性大小依次为Cd>Ni>Zn。根据回归分析,元素Zn对胡萝卜块茎和茎叶吸收Zn量贡献最大的分别是Zn的碳酸盐结合态和铁锰氧化态;元素Ni对胡萝卜各部位吸收贡献最大的均为Ni的铁锰氧化态。

Experiments on Speciation and Bioavailability of Selected Heavy Metals in Arid Oasis Soil, Northwest of China

Using the Tessier A method,the three chemical forms of selected heavy metals were determined to investigate the speciation and bioavailability of selected heavy metals in arid oasis soil-plant system.The findings showed that the chemical form contents of metal Cd,Zn,and Ni mainly existed in residual fraction in untreated soils,while in treated oasis soils those about the exotic metal Cd,Zn,and Ni were found predominantly in carbonate forms to element Cd,and Fe-Mn oxides bound forms to metal Zn and Ni.The passivation of these heavy metals in oasis soil fluctuated smoothly and the activity order of selected heavy metals was Cd>Ni>Zn.According to the results of regression analysis,it was found that CAB-Zn and FMO-Zn made the significant contribution to the accumulation of metal Zn in the tuber and stem of Daucus Carota,and FMO-Ni to the accumulation of metal Ni in both tissues.