土壤-蔬菜中重金属生物可利用性及迁移系数

发布时间：2018-03-26 00:24

  本文选题：生物可利用性　切入点：迁移系数　出处：《环境科学与技术》2017年12期

【摘要】：农田土壤重金属污染不利于农产品质量以及人群健康,土壤重金属的生物可利用性揭示了重金属在土壤-农作物间的迁移信息,该文以广东省顺德市农田土壤为研究对象,通过分析土壤-蔬菜系统的重金属含量与化学形态,并利用相关性分析和聚类分析对土壤-蔬菜系统的重金属生物可利用性及迁移系数进行研究。结果表明:研究区As、Cu、Hg、Mn、Ni、Pb的平均含量均大于广东省背景值的2倍,尤其是Hg,86.2%超过国家农田土壤环境质量二级标准,而蔬菜重金属含量大多数低于卫生部颁布的最新食品卫生标准。土壤重金属可利用态含量表现为:MnCuPbHgNiAs,表明Mn、Cu、Pb和Hg具有更强的活性,同时,土壤属性(pH值和OM值)对重金属的生物可利用性和环境毒性具有影响意义。相比于土壤重金属全量,土壤中重金属的生物可利用态与蔬菜中重金属含量之间具有更显著的相关性,表明土壤重金属可利用态较全量更适合表征重金属对环境的毒性效应。基于重金属可利用态的土壤-蔬菜迁移系数(TF_(avail))表现为:HgAsNi≥Mn≥Cu≥Pb,表明可利用态Hg、As和Ni更容易被蔬菜吸收,并且随着土壤重金属可利用态含量的升高,重金属的迁移富集程度呈幂函数式降低,这可能是缘于植物生理学自我保护机制,使蔬菜对重金属的吸收富集量保持在可控制范围内。
[Abstract]:Heavy metal pollution in farmland soil is harmful to the quality of agricultural products and the health of the population. The bioavailability of heavy metals in the soil reveals the information of heavy metal migration between soil and crops. This paper takes the farmland soil of Shunde City, Guangdong Province as the research object. The contents and chemical forms of heavy metals in soil-vegetable system were analyzed. Correlation analysis and cluster analysis were used to study the bioavailability and migration coefficient of heavy metals in soil-vegetable system. The results showed that the average content of Pb in the study area was 2 times higher than the background value of Guangdong Province. In particular, 86.2% of HgN exceeded the second grade standard of soil environmental quality in farmland, and most of the heavy metals in vegetables were lower than the latest food hygiene standards issued by the Ministry of Health. The available state contents of heavy metals in soil were: MnCuPbHgNiAs. the results showed that MnCuCu Pb and Hg had stronger activities. At the same time, the soil properties (pH and OM) have significant influence on the bioavailability and environmental toxicity of heavy metals, compared with the total amount of heavy metals in soil. There was a more significant correlation between the bioavailability of heavy metals in soil and the contents of heavy metals in vegetables. The results show that the available forms of heavy metals in soil are more suitable to characterize the toxic effects of heavy metals on the environment than the total ones, and the soil-vegetable transport coefficient based on the available forms of heavy metals is as follows: HgAsNi 鈮，

本文编号：1665522