大气气溶胶中元素种态研究

应用化学逐级提取流程对国际原子能机构（简称IAEA）气溶胶、室内和室外气溶胶、煤飞灰中元素的组成和种态进行了分析,应用仪器中子活化法测定了各种态中元素的含量,计算出元素在各种态中的分配比例。按照气溶胶中元素不同种态的环境和生物活性以及主要来源来分类,评述了元素在环境和生态系统中的吸收和转化能力,并对气溶胶中元素对环境的影响作出了初步的探讨。实验数据表明,气溶胶中的不同元素在各种态中的分布是有差异的。地壳来源元素中,Sc,Al,Fe和Ti主要分布在不溶物态中,稀土元素主要分布在氧化物态和不溶物态;不溶物态沉降到地表后不易进行迁移和转化,对环境的影响较小;氧化物态性质比较活泼,可以在大气中发生化学反应。Mn在气溶胶中主要分布在水可溶态和氧化物态,环境可交换性要比Al,Fe,Ti等大得多。人为来源元素的环境可交换态的比例都比较高,这说明它们通过干、湿清除过程沉降到地表后,水可溶态可以直接进入水循环;碳酸盐、氧化物和有机物态可以在适当的条件下与环境中的其他物质发生化学反应,生成易溶于水的化合物进入生态环境中,对环境影响较大。

STUDY ON THE ELEMENT SPECIES OF ATMOSPHERE AEROSOL

One five-stage sequential extraction procedure has been applied for element composition and species in coal fly ash, indoor aerosol, outdoor aerosol, and aerosol supplied by International Atomic Energy Agency (IAEA). Analyses were carried out by instrumental neutron activation analysis , and distribution proportions of elements in five phases were calculated. According to the environmental and biologic characters of elements in different species as well as their main sources, their absorbability and alterability in environment and ecosystem were evaluated , and their influences to environment were discussed. Experiment data show that elements have various distribution complexions in different phases. Among the lithosphere source elements, Sc, Al, Fe and Ti mainly enrich in indissoluble phase , rare earth elements mainly enrich in oxide phase and indissoluble phase. Indissoluble phase does not easily react after they deposited, and has little effect to environment, while oxide phase can react with other compounds. Mn mainly enrich in dissoluble phase and oxide phase, therefore has stronger environment mobile ability than Sc, Al, Fe and Ti. Distribution proportions of elements from anthropogenic sources in five phases have also some difference due to various sources. These elements have large proportion of environment mobile phases, that is, when they deposity on the earth ' s surface by dry and wet removal processes, dissoluble phase can directly enter water circulation. In proper condition, carbonate phase, oxide phase and organic phase can react with other compound in environment to enter ecosystem as water dissoluble compound, thus have strong influences to environment.