模拟酸雨淋溶对土壤镉迁移的影响

以紫色土和黄壤作为供试土壤进行模拟酸雨淋溶试验.结果表明,酸雨增加了土壤镉的迁移性.随着酸雨pH值的降低,Cd的淋溶量越大,在土壤中的残留量减少,但是不同pH之间淋溶率的差异小,说明酸雨虽然增强了土壤中金属迁移性,但迁移缓慢.同一重金属的迁移性因土壤类型不同有差异.Cd在黄壤中的迁移性大于紫色土.对数方程表明酸雨淋溶量与Cd残留量之间并非简单的线性关系,重金属在土壤中迁移除了受到酸雨pH的影响,同时还受土壤Eh,有机质含量,CEC,土壤胶体,有机和无机配体的数量等因子的影响.

Influence of Simulated Aicd Rain on Transferring of Cadmium in Soils

Purple soil and yellow soil were selected as the sample for simulated acid rain leaching experiment.Results showed that acid rain had evident impact on the transferring of cadmium in soil.Acid rain could significantly enhance the transferring of cadmium in soils.Leaching amount of heavy metals increased with the decrease of pH of acid rain,which caused decreased heavy metal concentration in soils.Transferring of the same heavy metal also varied from different soil typies.Transferring ability of cadmium in yellow soils was higher when compared to that in purple soils.The relationship between amount of acid rain and content of left heavy metals could be described by logarithmic equation: y=aln(x)+b,in which y represneted concentration of heavy metals left in soils(mg·kg~(-1)),and x means leaching amount of simulated acid rain(L).The above logarithmic equation indicated that the relationship between amount of acid rain and content of heavy metals left in soils was not samplely linear relation.Therefore,transferring of heavy metals in soils was influenced by not only pH of acid rain,but some other factors like Eh,OM content,CEC,soil colloid,organic and inorganic ligands.