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1IntroductionLandscapefragmentationanditsimpactsonbiologicaldiversityhavebeenthehighlyconcernedtopicsintherecentyearsbiologi... 相似文献
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Bu Duo Lulu Cui Zhenzhen Wang Rui Li Liwu Zhang Hongbo Fu Jianmin Chen Huifang Zhang A. Qiong 《环境科学学报(英文版)》2018,30(1):28-42
Atmospheric pollutants including SO2, NO2, CO, O3 and inhalable particulate matter (PM2.5 and PM10) were monitored continuously from March 2014 to February 2015 to investigate characteristics of air pollution at Lhasa, Tibetan Plateau. Species exhibited similar seasonal variations except O3, with the peaks in winter but low valleys in summer. The maximum O3 concentration was observed in spring, followed by summer, autumn, and winter. The positive correlation between O3 and PM10 in spring indicated similar sources of them, and was assumed to be turbulent transport. Temperature was the dominant meteorological factor for most species in spring. High temperature accelerates O3 photochemistry, and favors air disturbance which is conductive to dust resuspension in spring. Relative humidity (RH) and atmospheric pressure were the main meteorological factors in summer. RH showed negative correlations with species, while atmospheric pressure posed opposite situation. Wind speed (WS) was the dominant meteorological factor in autumn, the negative correlations between WS and species indicated diffusion by wind. Most species showed non-significant correlations with meteorological factors in winter, indicating the dependence of pollution on source emission rather than restriction by meteorology. Pollution weather character indicated that emissions were from biomass burning and dust suspension, and meteorological factors also played an important role. Air stream injection from the stratosphere was observed during O3 pollution period. Air parcels from Southwest Asia were observed during air pollution period in winter. An enhancement in air pollutants such as O3 would be expected in the future, more attention should be given to countermeasures for prevention of air pollution in the future. 相似文献
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In this study, iron speciation in five standard clay samples was characterized. Iron mobilization from these clays was then measured in acidic media. For comparison, a commercially available Arizona test dust (ATD) was also observed. The results showed that the free-Fe contents of clays were commonly lower than that of dust aerosols. The components of clays were dominant by the structural Fe held in the aluminosilicate lattice. The iron solubility of the clays were in the order of KGa-2?>?SWy-2?>?CCa-2?>?IMt-2?>?NAu-2. Based upon the Mössbauer spectrum and transmission electron microscopy (TEM) analysis, the Fe(II) fraction and the Fe/Si ratio of clay particles changed after dissolution, suggesting the total Fe solubility depended on the Fe atom states existing within the aluminosilicate lattice. The Fe in KGa-2 and SWy-2 was most likely substituted for alkaline elements as the interlayer ions held by ionic bonds in the aluminosilicate, which are more liable to dissolution. However, the Fe in NAu-2 was more likely to be bound by strong covalent bonds in aluminosilicate mineral, which is less soluble. The much highly soluble Fe in ATD was not only linked to the dissolution of an appreciable fraction of Fe(II), but also could be attributed to the fact that the Fe bonds in the clay fraction of ATD were mainly present as ionic bonds. The TEM images showed that reacted clay particles displayed less aggregate particles, with nanoparticle aggregates and the Fe/S-rich tiny particles attached to the remains. 相似文献
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呼伦贝尔草原优良牧草及土壤中有机氯农药残留量调查研究 总被引:4,自引:0,他引:4
本文根据内蒙古地区草原牧草及土壤中有害物质现状调查技术规范,对著名的畜牧业基地──呼伦贝尔草原优良牧草及土壤中有机氯农药(六六六、DDT)残留量进行了调查研究。结果表明,这两种有机氯农药在呼伦贝尔草原牧草及土壤中的残留量低于内蒙古地区的平均水平,更低于国家粮食作物及土壤卫生标准。但其化学性质稳定、脂溶性强,应停止使用。 相似文献
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中国生物质废弃物利用现状分析 总被引:12,自引:0,他引:12
中国是一个能源资源稀缺的国家,而随着中国经济的发展,我们对能源的需求量越来越大.因此,如何充分有效地利用好中国现有能源资源,显得十分重要.生物质能是一种可再生能源,中国的生物质废弃物资源十分丰富,包括森林能源、农作物秸秆、禽畜粪便、生活垃圾等等,这些废弃物资源若能很好的利用,不但能有效的减少环境污染问题,还将会有助于缓解中国的能源危机.中国的生物质废弃物利用技术起步较晚,但也取得了一些比较突出的科研成果,主要有沼气技术、生物质固化成型技术、生物质气化技术、生物柴油技术等. 相似文献
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