成都平原区水稻土成土剖面Cd形态分布特征及影响因素研究  

Study of distribution of geochemical speciation of cadmium and factors controlling the distribution in paddy soil profiles,Chengdu Plain,Southwest China.

作　　者：侯青叶[1] 杨忠芳[1] 杨晓燕[1] 杨艳[1] 赖木收[1] 

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《地学前缘》2008年第5期36-46,共11页Earth Science Frontiers

基　　金：中国地质调查局国土资源调查项目(GZTR20060201;GZTR20070201;GZTR02-01)

摘　　要：成土过程中不同形态镉（Cd）迁移转化的影响因素研究对于了解Cd的地球化学行为具有非常重要的意义。以四川省成都平原区农田生态系统水稻土剖面中不同形态CA分布特征为例，探讨成土过程中不同形态Cd的迁移转化影响因素及其生态危害性。结果表明：总量Cd、离子交换态Cd和碳酸盐Cd均表现出表层富集，深层含量稳定的特征；岷江流域和沱江流域水稻土Cd含量的背景值分别为0．147，0．215mg·kg^-1。外源输入耕层土壤中Cd主要为活动态，其增加量占Cd总量增加量的60．71％～90．52％，向下垂向迁移能力非常弱。成土过程随着土壤中Cd总量增加，稳定态Cd含量显著增加，而活动态Cd含量明显降低。土壤的pH值主要对碳酸盐态Cd含量有影响，pH值越大，其含量越高；随着土壤成熟度增高，粉粒和粘粒含量增加的同时，残渣态Cd含量显著降低，而有机结合态Cd含量显著增高。耕层土壤中Cd的生物有效性系数高达0．59～O．65，已经严重地影响到农作物安全。For understanding geochemical behaviors of cadmium （CA）, it is essential to study the factors that affect the transport of different geochemical species of cadmium in the pedogenetic process. We focus on the distribution features of cadmium species in paddy soil profiles in Chengdu agro-ecosystems in Sichuan Province, in order to discuss the factors controlling geochemical behaviors of cadmium species, and to assess the ecological safety. It is known that Cd background values of paddy soils in Minjiang River and Tuojiang River catchments are 0. 147 mg·kg^-1 and 0. 215 mg·kg^-1, respectively. The inputs of Cd Ionexchange species and Cd carbonate species into cultivated soils dominate the total CA increments, and these cadmium species have limited ability to transfer along the profiles. The total Cd, pH, total organic carbon （TOC） and clay minerals contents have significant influence on the transferring of Cd species. The bioavailability index of cadmium for cultivated paddy soil is very high; it ranges between 0.59 and 0.65, which suggests that the cultivated soils have posed high risk on plant safety.

关 键 词：农田生态系统 不同形态镉 成土过程 水稻土 成都平原区 

分 类 号：X53[环境科学与工程—环境工程]