【作者】 陈雪；

【导师】 郎春燕；

【作者基本信息】 成都理工大学 ， 分析化学， 2008， 硕士

【摘要】 硒具有重要的环境及生理学意义。硒在土壤中的化学行为和生物可利用性取决于它在土壤中的形态,而硒形态又受到土壤理化性质和其他因素的制约。本文针对国内外城市绿地系统硒的形态分布及其影响因素研究相对缺乏,且相关研究多数未区分不同功能区及土层的现状,以成都市绿地土壤为对象,着重分析和研究了不同绿地功能区土壤的理化性质、总硒和硒形态的含量、分布特点以及各形态之间、各形态与土壤理化性质之间的相关关系,得出如下结论:(1)建立的总硒及硒的形态分析方法具有分析成本低、线性范围宽、准确度高、实用性强的特点。(2)成都市市区绿地(公共绿地、交通干道绿地、生活绿地)土壤呈碱性(pH＞7.7),而市郊绿地(生产绿地)呈酸性(PH=5.5):上层绿地土壤的有机质含量及总硫含量高于下层;市区绿地上层土壤的总硫含量接近且远高于市郊绿地:上、下层有机质含量的平均值在生产绿地最大。(3)成都市绿地系统各功能区中,生产绿地总硒含量平均值在上、下层均为最大:上、下层土壤总硒含量均与土壤总硫含量呈显著正相关。(4)容易被植物吸收利用的硒形态(水溶态+可交换态)在市区绿地所占比例最高且非常接近(40%-43%);而市郊绿地残渣态的比例最高,水溶态和可交换态的比例之和最小,不利于植物的吸收利用,但可有效防止对硒的过度吸收。(5)成都市绿地系统上、下层土壤中,残渣态硒与pH呈负相关、而与总硫呈显著正相关,酸溶态硒、有机结合态硒与总硒呈显著正相关;下层土壤中,有机结合态硒与总硫呈显著正相关。上述结论对于揭示硒在成都市绿地环境中的迁移、转化规律有重要意义,这将为开展城市环境评价与硒的综合治理提供有力支持。更多还原

【Abstract】 Selenium is of great significance in environmental and physiological study. The chemical behavior and bioavailability of selenium depend on its speciation in soil. The species of selenium in soils are controlled by physico-chemical properties and other factors in soils. However, there are few researches concerning the distribution of selenium species and its affecting factors based on soil zone and layer depth in urban greenbelt system.The present paper focuses on the contents and distribution of total selenium, selenium species as well as corresponding physico-chemical properties in each soil zone and layer. Besides, the relationships between total selenium, selenium species and physico-chemical parameters were systematically investigated and assessed by calculating Pearson correlation factors. From this paper, it was concluded as follows:(1) A low-cost and wide-linear range procedure was developed for the determination of total selenium and selenium speciation with good accuracy and practicability.(2) Urban greenbelt soil in Chengdu is alkaline while suburb greenbelt soil is acidic; the contents of organic matter and total sulfur in surface are higher than that in sub-surface; the total sulfur contents in surface urban greenbelt soil are close and much higher than that in suburb greenbelt. The average content of organic matter of surface and sub-surface reached maximum in agricultural greenbelt.(3) The maximum means for total selenium in both surface and sub-surface were obtained in agricultural zone. There are significant positive correlations between total selenium and total sulfur in both layers of all greenbelt zones of Chengdu.(4) The proportion of Se species which could be absorbed easily by vegetation (water soluble and exchangeable Se) is highest and very close (40 - 43%) in each urban greenbelt zone. While maximum proportion of residue Se and minimum sum of proportion of water soluble and exchangeable Se were obtained in suburb greenbelt, which is not good for utilization by plants but can efficiently prevent vegetation from over-absorption.(5) In both surface and sub-surface of greenbelt zone of Chengdu, residue Se has a negative relationship with pH and a significant positive correlation with total sulfur; both HCl soluble Se and Se bound to organic matter have a clear positive relationship with total selenium. In sub-surface soils, there is a significant positive correlation between Se bound to organic matter and total sulfur.The conclusion described above is of important significance for study on the mobility and transformation of selenium in urban greenbelt, which is good for environmental evaluation and remediation for selenium contamination.更多还原