Characterization of individual fly ash particles in surface snow at Urumqi Glacier No. 1, Eastern Tianshan  

作　　者：ZHANG XueLei WU GuangJian YAO TanDong ZHANG ChengLong YUE YaHui 

机构地区：[1]Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China,＂ [2]State Key Laboratory of Cryospheric Science, Chinese Academy of Sciences, Lanzhou 730000, China [3]Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China

出　　处：《Chinese Science Bulletin》2011年第32期3464-3473,共10页

基　　金：supported by the National Natural Science Foundation of China (40871046, 40571038 and 4081019001) ;the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-146)

摘　　要：This research aimed to identify and characterize individual spherical fly ash particles extracted from surface snow at Urumqi Glacier No.1 (UG1), Eastern Tien Shan, central Asia. Characterization of the spherical particles (i.e. morphology, chemical composition and genesis) was obtained by scanning electron microscopy coupled with energy dispersive X-ray spectrometer (SEM-EDX). This method enabled the characterization of submicroscopic spherical particles, which were present in very small quantities. Spherical particles and agglomerates were identified according to their morphology in five snow samples. Prevalent particle types in all samples were granular spherical particles, hollow spherical particles, irregularly shaped carbonaceous particles and agglomerates. The vast majority of spherical particles in our samples had mostly smooth and glossy surfaces, although these particles varied in diameter and elemental composition. The diameter of fly ash particles ranged from 0.76 to 16.7 m, with an average of 3.79 m (median: 3.21 m). Individual particle analyses of elemental composition showed that particles formed in combustion were mainly composed of carbon, silicon, aluminum and trace elements (e.g. Na, K, Ca, Fe). Some spherical fly ash particles contained toxic heavy metals (e.g. Pb, Cr, As, Zn), and indicated that fly ash particles acted as the main possible carriers of toxic heavy metals deposited in snow and ice of glaciers in high altitudes of central Asia. On the basis of chemical information obtained from EDX, the fly ash particles deposited in the snow could be classified into four types. Namely, Si-dominant particles, with average diameters of 3.24 m were formed by industrial coal combustion via high temperature processes in typical coal-fired heating stations and thermal power plants. Moreover, Fe-dominant particles, with average diameters of 3.82 m, and Ti-dominant spherical particles formed by lower temperature processes in foundry and iron or steel plants. In addition, C-dominant particles, with averThis research aimed to identify and characterize individual spherical fly ash particles extracted from surface snow at Urumqi Glacier No. 1 （UG1）, Eastern Tien Shan, central Asia. Characterization of the spherical particles （i.e. morphology, chemical com- position and genesis） was obtained by scanning electron microscopy coupled with energy dispersive X-ray spectrometer （SEM-EDX）. This method enabled the characterization of submicroscopic spherical particles, which were present in very small quantities. Spherical particles and agglomerates were identified according to their morphology in five snow samples. Prevalent particle types in all samples were granular spherical particles, hollow spherical particles, irregularly shaped carbonaceous particles and agglomerates. The vast majority of spherical particles in our samples had mostly smooth and glossy surfaces, although these particles varied in diameter and elemental composition. The diameter of fly ash particles ranged from 0.76 to 16.7 ~tm, with an average of 3.79 ~tm （median： 3.21 ~tm）. Individual particle analyses of elemental composition showed that particles formed in combustion were mainly composed of carbon, silicon, aluminum and trace elements （e.g. Na, K, Ca, Fe）. Some spherical fly ash particles contained toxic heavy metals （e.g. Pb, Cr, As, Zn）, and indicated that fly ash particles acted as the main possible carriers of toxic heavy metals deposited in snow and ice of glaciers in high altitudes of central Asia. On the basis of chemical information obtained from EDX, the fly ash particles deposited in the snow could be classified into four types. Namely, Si-dominant particles, with average diameters of 3.24 ~tm were formed by industrial coal combustion via high temperature processes in typical coal-fired heating stations and thermal power plants. Moreover, Fe-dominant particles, with average diameters of 3.82 ~m, and Ti-dominant spherical particles formed by lower temperature processes in foundry and iron or steel plants. In add

关 键 词：天山1号冰川 球形颗粒 乌鲁木齐 表层雪 表征 粉煤灰颗粒 有毒重金属 平均直径 

分 类 号：X513[环境科学与工程—环境工程]