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321.
电厂煤飞灰单个颗粒的化学表征   总被引:5,自引:0,他引:5  
汪安璞  沙因 《环境化学》1996,15(6):496-504
用扫描电镜X射线能谱对电厂煤飞灰单个颗粒进行了形貌,粒度和化学组成的观察与分析,用X射线衍射鉴定了煤飞灰粗细颗粒中元素存在的化学形态(化合物或物相)结果表明,煤飞灰中有较多球形颗粒,还有一些不规则形颗粒,主要含有Si,Al,Ca,Fe,S,K等,不同形貌,大小颗粒中的组分含量差别较大,但大多以硅铝酸盐为基体,其它元素分布在颗粒表层(约1μm)中,粗细颗粒中均有石英和氧化铁,但粗粒中还富含Ca和Fe  相似文献   
322.
The fast changes in chemical and biological properties of many coastal and inland waters in the last decades reflect the pressure of man on the environment. The surface waters of the Antarctic Peninsula, located far from industrial or populated areas, could eventually be used as background lines. Surface water samples were taken from five lagoons of King George Island, Antarctic Peninsula, and from the Kitiesh Lake. Sample pH and electrical conductivity were analysed in situ and in the laboratory, respectively. The dissolved fractions were analysed in 1997 and 1998. Total concentrations only for 1998 were determined in another fraction adjusted to pH 2. Aluminium, Ca, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Sr, Cd, Sn, Sb, Ba, Bi, and Pb were quantified in all samples by means of inductively coupled plasma-mass spectrometry (ICP-MS). Total and dissolved elemental concentrations were discussed considering the composition of particulate material suspended in the waters removed by streams or by water runoff, or from atmospheric aerosols. Concentrations of dissolved elements change from one lagoon to another. Total and dissolved elemental concentrations could be related to water movement by windstorms, to chemical mechanisms in water and/or to natural and anthropogenic atmospheric factors.  相似文献   
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A hygroscopic tandem differential mobility analyser (H-TDMA) was used to observe the size-resolved hygroscopic characteristics of submicron particles in January and April 2018 in urban Beijing. The probability distribution of the hygroscopic growth factor (HGF-PDF) in winter and spring usually showed a bimodal pattern, with more hygroscopic mode (MH) being more dominant. The seasonal variation in particle hygroscopicity was related to the origin of air mass, which received polluted southerly air masses in spring and clean northwesterly air masses in winter. Particles showed stronger hygroscopic behaviour during heavy pollution episodes (HPEs) with elevated concentrations of secondary aerosols, especially higher mass fraction of nitrate, which were indicated using the PM2.5 (particulate matter with diameter below 2.5 µm) mass concentration normalised by CO mass concentration. The hygroscopic parameter (κ) values were calculated using H-TDMA (κhtdma) and chemical composition (κchem). The closure study showed that κchem was overestimated in winter afternoon when compared with κhtdma, because the organic particle hygroscopic parameter (κorg) was overestimated in the calculations. It was influenced by the presence of a high concentration of hydrocarbon-like organic aerosol (HOA) with a weak water uptake ability. A positive relationship was observed between κorg and the ratio of oxygenated organic aerosol (OOA) and HOA, thereby indicating that the strong oxidation state enhanced the hygroscopicity of the particles. This study revealed the effect of local emission sources and secondary aerosol formation processes on particle hygroscopicity, which is of great significance for understanding the pollution formation mechanism in the North China Plain.  相似文献   
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In recent years, China has conducted considerable research focusing on the emission and effects of sulphur (S) on human health and ecosystems. By contrast, there has been little emphasis on anthropogenic nitrogen (N) so far, even though studies conducted abroad indicate that long-range atmospheric transport of N and ecological effects (e.g. acidification of soil and water) may be significant. The Sino-Norwegian project IMPACTS, launched in 1999, has established monitoring sites at five forest ecosystems in the southern part of PR China to collect comprehensive data on air quality, acidification status and ecological effects. Here we present initial results about N dynamics at two of the IMPACTS sites located near Chongqing and Changsha, including estimation of atmospheric deposition fluxes of NOx and NHx and soil N transformations. Nitrogen deposition is high at both sites when compared with values from Europe and North America (25–38 kg ha–1 yr–1). About 70% of the deposited N comes as NH4, probably derived from agriculture. Leaching of N from soils is high and nearly all as NO3 –1. Transformation of N to NO3 –1 in soils results in acidification rates that are high compared to rates found elsewhere. Despite considerable leaching of NO3 –1 from the root zone of the soils, little NO3 –1 appears in streamwater. This indicates that N retention or denitrification, both causing acid neutralization, may be important and probably occur in the groundwater and groundwater discharge zones. The soil flux density of mineral N, which is the sum of N deposition and N mineralization, and which is dominated by the N mineralization flux, may be a good indicator for leaching of NO3 –1 in soils. However, this indicator seems site specific probably due to differences in land-use history and current N requirement.  相似文献   
327.
海峡西岸地区人为源大气污染物排放特征研究   总被引:2,自引:3,他引:2  
黄成 《环境科学学报》2012,32(8):1923-1933
采用以"自下而上"为主的方法建立了2007年海峡西岸地区的人为源大气污染物排放清单.计算结果显示,海西地区人为源SO2、NOx、CO、PM10、PM2.5、VOCs和NH3排放总量分别为69.5×104、96.1×104、413.1×104、93.9×104、40.6×104、85.0×104和28.5×104t.电厂和工业燃烧设施分别占SO2排放的48%和39%,以及NOx排放的51%和25%.水泥、砖瓦等制造过程贡献了约51%的PM10排放和36%的PM2.5排放.秸秆燃烧、加油站和涂料等VOCs面源分别占到其排放总量的27%、15%和4%.NH3的主要排放源为畜禽养殖和氮肥施用等农业部门,占到总排放量的89%.海西地区的单位面积大气污染物排放量仅相当于长三角地区的25%左右,略高于全国平均水平.该地区人为源和天然源VOCs排放比重分别占56%和44%,人为源VOCs排放比重低于全国大部分地区.海西大气污染高排放地区主要集中在沿海一带,以泉州、潮汕、福州和温州等地区为主,建议"十二五"发展过程中,重点关注上述高排放地区,限制重点排放源的发展,开发低耗能、低污染的发展模式.  相似文献   
328.
The ichthyofauna of 20 small ponds in the Udmurt Republic was studied to estimate the dependence of fish species abundance on pond size and anthropogenic load, as well as trends in the succession of dominant species complexes in ponds exposed to the prevailing impact of agricultural activity. Changes in the ecological structure of fish communities in small ponds upon an increase in the anthropogenic load were analyzed. Some specific features of the species composition of ichthyofauna in technogenic pond biocenoses were revealed.  相似文献   
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Experimental ecotoxicological studies on the norm of reaction to anthropogenic acidification were performed with representative hydrobionts from aquatic ecosystems of the northern taiga zone. Interspecific, interpopulation, and age-related differences in tolerance to acidity and the significant dependence of this parameter on water pH in natural habitats of corresponding populations were revealed.  相似文献   
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