外源铜锌在我国典型土壤中的老化特征  

Aging Characteristics of Copper and Zinc Added to Typical Soils of China

作　　者：徐明岗[1] 王宝奇[1,2] 周世伟[1,3] 李淑芹[2] 陈苗苗[1] 段改莲[1,4] 

机构地区：[1]中国农业科学院农业资源与农业区划研究所,农业部植物营养与养分循环重点开放实验室,北京100081 [2]东北农业大学资源与环境学院,哈尔滨150030 [3]中国科学院烟台海岸带可持续发展研究所,烟台264003 [4]北京市昌平区土肥站,北京102200

出　　处：《环境科学》2008年第11期3213-3218,共6页Environmental Science

基　　金：国家重点基础研究发展规划(973)项目(2002CB410809)

摘　　要：采用室内培养的方法,研究了我国3种典型土壤——红壤、水稻土和褐土,在铜、锌单一污染和复合污染下的老化过程.结果表明,有效态铜、锌（0.01 mol.L^-1CaCl2提取的金属）随时间先是快速下降,然后缓慢降低,大约90 d是转折点.无论是在单一污染还是在复合污染土壤中,铜和锌的老化都没有显著差异,预示着这2个金属有相似的化学行为.铜、锌在红壤、水稻土和褐土中的老化最适合二级动力学方程（R2为0.9940-0.9999,p〈0.0001）,而抛物线扩散方程拟合程度较差,说明金属有效形态向无效形态的转化过程（老化）并不完全取决于扩散作用,它是表面聚合/沉淀作用、有机质包裹作用、扩散作用等交互的结果.铜锌在土壤中的老化显著受pH影响,在低pH土壤（红壤）,金属有效形态比例高,老化速率慢,速率常数k2为4.36×10^-3-7.05×10^-3kg.（mg.d）^-1;高pH土壤（褐土）中,金属有效形态比例低,老化速率快,k2为1.095×10^-2-1.377×10^-2kg.（mg.d）^-1.也就是说,随土壤pH升高,金属的老化速率加快.The aging processes of copper and zinc in single and combined metal-contaminated typical soils of China, red soil, paddy soil and cinnamon soil, were studied. The results showed that available copper and zinc （metals extracted by 0.01 mol· L^-1 CaCl2 ） decreased rapidly at initial stages, and then reduced slowly, where the turning point occurred at about 90 d. The difference in aging of copper and zinc was insignificant whether in single metal-contaminated soils or in combined metal-contaminated soils, suggested there were similar chemical behaviors between copper and zinc. The aging processes of copper and zinc in red soil, paddy soil and cinnamon soil fitted best a second-order equation （R^2 = 0.9940-0.9999, p 〈 0.000 1）, whereas parabolic diffusion equation has less goodness of fit. It indicated that the transformationfrom availability to unavailability of metals, i.e. aging, was not completely controlled by diffusion, but controlled by the interactions from surface nucleation/precipitation, occlusion by organic matter, and diffusion, etc. The aging of copper and zinc in soils was significantly affected by pH. In soils with low pH such as red soil, the ratio of available metals was higher and the aging rate was slower [constant of rate, k2 4.36 × 10^-3-7.05 × 10^-3 kg· （mg·d）^ -1 ] ; whereas in soils with high pH, for example in cinnamon soil, the ratio of available metals was lower and the aging rate was faster [ k2 1.095× 10^- 2.1. 377× 10^- 2 kg· （mg·d）^ - 1 ]. That is, the aging rate of metals in soils increased obviously with increasing pH.

关 键 词：老化 铜 锌 有效性 红壤 褐土 

分 类 号：X53[环境科学与工程—环境工程]