影响镍在新疆荒漠土壤中形态分布因素研究

选择新疆荒漠区某石化污水库周边土壤作为研究对象,采用室内静态吸附和Tessier连续提取技术对影响供试土壤中镍的形态分布和生物有效性因素进行研究。实验结果表明,在100-400 mg/L浓度范围内,随着土壤中加入镍离子量的增加,镍的碳酸盐结合态和铁锰氧化态比例降低,生物有效性系数K呈递减的趋势,当浓度大于250 mg/L时,这种递减趋势趋于平缓;土壤pH值增大,镍的残渣态比例升高,在pH值小于8范围内,生物有效性系数K减小趋势不明显,当pH值大于8时,生物有效性系数K急剧下降;土壤环境离子强度小于0.01 mol/L时,镍的形态分布变化较小,但当离子强度大于0.01 mol/L时,镍向不易被植物吸收的形态转化。

Form Distribution and Bioavailability for Nickel on the Surrounding Soils of a Petrochemical Sewage Reservoir in Xinjiang

Static adsorption experiment and sequential extraction fractionations of Tessier were used to study the form distribution and its bioavailability of nickel in soils from the surrounding of a petrochemical sewage reservoir in Xinjiang. Results showed that the proportion of carbonate-bound fraction and Fe~-Mn oxides-bound fraction significantly decreased when Ni~(2+) concentration was changed from 100 mg/L to 400 mg/L,and bioavailability rate decreased at first then went flatten when Ni~(2+) content was more than 250 mg/L.As pH increased in treated soils,me proportion of residual fraction greatly increased,and bioavailability rate was reduced slowly at first then becoming sharply when pH value was more than 8.The single speciation of nickel in soil was less changed with the elevation of ionic strength.However Ni~(2+) was transformed into the form which was difficultly absorbed for plants when ionic strength was more than 0.01 mol/L.