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现代地质 ›› 2021, Vol. 35 ›› Issue (03): 625-636.DOI: 10.19657/j.geoscience.1000-8527.2021.03.04

• 地球化学 • 上一篇    下一篇

广西南流江流域土壤-水稻系统Cd生物有效性及影响因素

邵玉祥1,2(), 杨忠芳1(), 王磊3, 卓小雄3, 张起钻3   

  1. 1.中国地质大学(北京) 地球科学与资源学院,北京 100083
    2.中国地质调查局 应用地质研究中心,四川 成都 610036
    3.广西壮族自治区地质矿产勘查开发局,广西 南宁 530023
  • 收稿日期:2020-05-22 修回日期:2020-06-20 出版日期:2021-06-23 发布日期:2021-06-24
  • 通讯作者: 杨忠芳
  • 作者简介:杨忠芳,女,教授,1961年出生,地球化学专业,主要从事环境地球化学教学和科研工作。Email: yangzf@cugb.edu.cn
    邵玉祥,男,硕士研究生,1993 年出生,地球化学专业,主要从事环境地球化学研究。Email: 127961917@139.com
  • 基金资助:
    广西壮族自治区国土资源厅项目“广西土壤Se、Ge、Cd等元素异常成因与生态效应研究”(桂国土资函[2017]2686号)

Cadmium Bioavailability and Influencing Factors of Soil-rice System in Nanliujiang Catchment of Guangxi

SHAO Yuxiang1,2(), YANG Zhongfang1(), WANG Lei3, ZHUO Xiaoxiong3, ZHANG Qizuan3   

  1. 1. School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083,China
    2. Geological Research Center of China Geological Survey,Chengdu,Sichuan 610036,China
    3. Guangxi Bureau of Geology and Mineral Prospecting and Exploitation,Nanning,Guangxi 530023,China
  • Received:2020-05-22 Revised:2020-06-20 Online:2021-06-23 Published:2021-06-24
  • Contact: YANG Zhongfang

摘要:

广西南流江流域第四系发育形成的土壤中Cd等重金属含量较低,但水稻籽实Cd超标率很高。为了查清Cd在南流江流域土壤-水稻系统中的分布和迁移规律及其生物有效性的影响因素,按照不同成土母质物源分区,系统采集了水稻及其对应的根系土样品,测试了水稻籽实Cd、土壤Cd、pH、Corg、N、S、Mn及氧化物等指标,部分土壤样品进行了七步顺序提取法实验。结果表明,不同母质根系土Cd总量大小顺序为碳酸盐岩区>水系上游第四系区>水系中游第四系区>水系下游第四系区>碎屑岩区,而水稻籽实中Cd含量顺序却基本相反,两者之间不具有明显相关性(r=-0.030,p=0.84 )。形态数据显示,水溶态Cd与籽实Cd相关性较好,能够较好指示研究区Cd的生物有效性,同时,土壤水溶态Cd占比受土壤pH、土壤CaO、Mn、有机碳(Corg)等土壤指标的控制。

关键词: 南流江流域, 土壤-水稻系统, 镉, 生物有效性

Abstract:

The alluvium soil in the Nanliujiang Catchment had the characteristics with low Cd contents in soils but high Cd contents in the rice seeds grown in there. In order to understand the distribution and transfer of Cd in the soil-rice system of the Nanliujiang Catchment, We collected rice and soil samples from different parent material in this region and analyzed the rice Cd and soil Cd, pH, Corg, N, S, Mn and oxides. Meanwhile, seven-step sequential extraction experiments were performed on some of the soil samples to find the representative bioavailability of Cd in soil-rice system. The results showed that compared with different parent soils, the Cd contents of the soils in order for the limestone soils>the upstream alluvium soils>the midstream alluvium soils>the downstream alluvium soils>the clasolite-produced soils, which was contrary to the order of Cd contents in rice seeds grown in these areas, and no significant correlation was observed between Cd contents in rice seeds and in cultivated soils (r=-0.030,p=0.84). It was revealed that total soil Cd content cannot represent bioavailable Cd content absorbed by rice. Water-soluble Cd in the soil was thought to be the main species in Cd translocation from soil to seed, according to its significant correlations between them. With the increase of soil pH, CaO, Mn, and soil organic carbon (Corg), the proportion of water-soluble Cd decreased significantly(r=0.12-0.45). This information may be of great significance for proposing effective measures to reduce the Cd contents of rice in the Nanliujiang Catchment.

Key words: Nanliujiang Catchment, soil-rice system, cadmium, bioavailability

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