摘要
为探讨外源离子态镉(Cd)进入红壤后随时间的变化特征,在农田土壤中添加不同含量的Cd(0、 0.3、 2.0、 5.0、 10、 30、 60和100 mg·kg^(-1)),分别于第3、 7、 14、 28、 42、 56、 70和84 d时取样,采用BCR分级提取法分析农田土壤Cd的赋存形态,使用3种动力学模型模拟农田土壤Cd的稳定化和分布特征.结果表明:①外源Cd进入土壤后,土壤Cd的形态会重新进行分配,趋向于供试土壤Cd原始形态分布特征,Cd与土壤的结合强度会随时间的增加而增加,并且总再分配系数会逐渐趋于1.②红壤中外源Cd的稳定化是一个较为长期的过程.弱酸可提取态会逐渐向其他3种形态转换,最终转换为残渣态.在84d内,可氧化态在0.3 mg·kg^(-1)时,会随时间逐渐减小,其余形态则相反.在84 d内,可还原态在30 mg·kg^(-1)以下时,会随时间逐渐减小,其余形态则相反.③在红壤中,外源Cd的稳定化过程主要是多个反应机制共同控制的扩散过程.当外源Cd添加量越高时,会导致其残渣态的变化速率越高.研究结果可为以外源Cd为基础的相关研究以及重金属污染土壤风险管控与修复提供理论依据.
To investigate the change characteristics of exogenous cadmium(Cd)into red soil over time,different concentrations of Cd(0,0.3,2.0,5.0,10,30,60,and 100 mg·kg^(-1))were added to farmland soil,and samples were taken at the 3rd,7th,14th,28th,42th,56th,70th,and 84th day,respectively.The occurrence of Cd in farmland soil was analyzed using the BCR hierarchical extraction method,and the stabilization and distribution characteristics of Cd in farmland soil were simulated by three dynamical models.The results showed that:①After exogenous Cd entered the soil,the soil Cd form was redistributed,tending to the original soil Cd form distribution characteristics,the binding strength of Cd and soil increased as time increased,and the total redistribution coefficient gradually tended to 1.②Stabilization of exogenous Cd in red soil was a long⁃term process.The extractable state of weak acid gradually transformed to the other three forms and finally to the residue state.Within 84 days,the oxidation state at 0.3 mg·kg^(-1) gradually decreased with time,and the other concentrations showed the opposite.Within 84 days,when the reducible state was below 30 mg·kg^(-1),it gradually decreased with time,and the other concentrations showed the opposite.③The stabilization process of exogenous Cd in red soil was mainly a diffusion process controlled by multiple reaction mechanisms.The higher the concentration of exogenous Cd,the higher the change rate of the residual state.These research results can provide theoretical basis for the related research based on exogenous cadmium and the risk control and remediation of soil contaminated with heavy metals.
作者
周子阳
庞瑞
宋波
ZHOU Zi-yang;PANG Rui;SONG Bo(College of Environmental Science and Engineering,Guilin University of Technology,Guilin 541004,China;Collaborative Innovation Center for Water Pollution Control and Water Safety Guarantee in Karst Area,Guilin University of Technology,Guilin 541004,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2023年第9期5299-5307,共9页
Environmental Science
基金
国家重点研发计划项目(2018YFD0800600)。
关键词
红壤
外源Cd
BCR分级提取法
分布特征
稳定化
red soil
exogenous cadmium
BCR sequential extraction
distribution characteristics
stabilization
