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1.
Spheroidal carbonaceous particles (SCPs) are produced by the high-temperature combustion of fossil fuels and emitted in to the atmosphere. The distribution and concentration of SCPs in sediments have been used as a proxy for the distribution of pollutants emitted to the atmosphere. However, the effect on the distribution of SCPs due to industrial activity at nearby industrial cities is yet to be quantified. To clarify the origin of SCPs of ~20 μm in size that are preserved in sediments, we evaluated the abundance, surface morphology, and chemical composition of SCPs in sediment core samples recovered from industrial cities in Japan (Tokyo, Osaka, and Nagasaki) and China (Beijing), with the cities being located at least ~500 km away from each other. Vertical profiles of SCP concentration in sediment cores from the Japanese cities and Beijing are different, reflecting the contrasting industrial histories of the two countries. The SCPs from different cities show contrasting morphological and chemical characteristics, suggesting that ~20 μm SCPs in sediments from the industrial cities could represent the local combustion history in detail, as the influx of local SCPs is dominant at such sites.  相似文献   

2.
The property of sphericity is used to identify some anthropogenic particles in a Lake Michigan sediment. Three classes of products from high temperature processes, primarily fossil fuel burning, have been isolated: charcoals, iron oxides and aluminosilicates. The morphologies, structures and surface characteristics are indicative of the combustion process.  相似文献   

3.
The transformation and mobility of charcoal in a fire-impacted watershed   总被引:3,自引:0,他引:3  
The incomplete combustion of fossil fuels and biomass has resulted in the global-scale distribution and accumulation of black carbon (BC) in the environment. Recently, the molecular identity of BC in the dissolved phase has been distinguished from that of natural organic matter. However, many of the processes that control BC cycling remain unidentified. We investigate changes in soil charcoal particle morphology and chemical composition using surface area analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, chemical oxidation, and 13C NMR spectroscopy. A comparison of soil charcoals differing in age by 100 years shows that aged charcoal has lower specific surface areas, higher BC/OC ratios, direct associations with soil minerals and microbial biomass, and a greater abundance of non-aromatic carbon. The water-soluble portion of soil charcoal and dissolved organic matter (DOM) from the watershed were also characterized by electrospray ionization mass spectrometry. Aqueous charcoal extracts are comprised mostly of condensed aromatic ring structures (CARS) which are also present in soil pore, river, and ground water samples. We present indirect evidence and a chemical rationale for a microbial BC dissolution mechanism. Furthermore, the speciation of CARS in the soil solution versus river and ground water provides molecular evidence of reactivity in the dissolved phase. The dissolution and export of soil BC are presently unmeasured fluxes with important implications for the global carbon cycle.  相似文献   

4.
韶关市大气降尘矿物成分和形貌特征研究   总被引:1,自引:2,他引:1  
利用X射线衍射(XRD)仪、扫描电镜X射线能谱(SEM/EDX)仪研究大气降尘矿物成分和颗粒物形貌特征。结果表明,韶关市大气降尘主要矿物成分为伊利石、斜长石、绿泥石、石英、方解石、白云石和无定型非晶质物等,大气颗粒物形貌可分为4种类型:粒状、片状单矿物,链状集合体,圆球状飘珠和不规则粒状集合体。伊利石、绿泥石来源于地面扬尘,方解石、白云石来源于建筑扬尘,无定型非晶质物来源于工业烟尘。粒状、片状单矿物是地面扬尘的标志,链状集合体和圆球形飘珠是工业烟尘的标志,不规则粒状集合体是建筑扬尘的标志。大气降尘矿物成分和形貌特征是判别污染物来源的重要标志。  相似文献   

5.
刘恋  杨帅斌  乔彦松  周鑫  詹涛 《地质学报》2017,91(3):658-667
黑碳是由生物质和化石燃料等燃烧产生的一系列含碳物质,长期广泛分布于土壤、大气等多种载体中,且表现出不同的环境效应。土壤作为一种不可再生的自然资源,是人类生存与发展不可缺少的物质基础,也是支撑城市发展的空间和生态基础。土壤中的黑碳构成土壤有机碳库的重要组分,且影响着土壤肥力、结构、有机污染物等多方面。目前,对黑碳的研究集中在其对环境的影响,我国在这方面的研究开始较晚,特别是对土壤中黑碳的研究还处于起步阶段。本文详细分析了土壤黑碳的可能来源(自然火灾、人类农业活动、化石燃料燃烧以及汽车尾气排放等),概括了常见的土壤黑碳来源辨析方法(黑碳形态特征分析、黑碳/有机碳比值分析、黑碳碳同位素分析),总结了国内外对不同自然环境、不同城市功能区的土壤黑碳研究现状。最后,提出了全球黑碳研究亟待关注和解决的关键问题,以期为将来合理制定控制黑碳排放的相关政策,减缓黑碳对环境质量和人体健康的影响,提供重要的理论依据。  相似文献   

6.
利用气相色谱、气相色谱-质谱分析法从北京市西北城区四个季节大气可吸入颗粒物(PM10)中检测出种类丰富的饱和烃,主要包括正构烷烃、萜烷及甾烷等系列化合物。利用饱和烃的多项参数(如主峰碳数、碳优势指数CPI、藿烷22S/(22S+22R)比值等)对大气PM10中可溶有机物的来源及分布作了探讨。北京市西北城区PM10中正构烷烃的主峰碳数均介于23和27之间,而CPI值介于1和3之间,表明北京市西北城区PM10中的饱和烃均不同程度地受到了高等植物等现代生物和化石燃料(石油、煤等)不完全燃烧产物两种来源的影响,其中在春、夏季以高等植物、花粉、微生物等生物来源占比重较大,而在秋、冬季,尤其在冬季,化石燃料的不完全燃烧造成的污染比较明显。萜烷类物质的检出,表明北京市西北城区四个季节PM10中部分饱和烃来自于石油等化石燃料的不完全燃烧。甾烷类物质的检出,表明北京市西北城区四个季节PM10中部分饱和烃是来自于车辆释放的机油等。  相似文献   

7.
To stabilize the atmospheric concentration of greenhouse gases (GHG), a huge reduction of carbon dioxide (CO2) emissions is required. Although some people believe that this necessitates a considerable reduction in the use of fossil fuels or fuel switching, other options are available that allow the use of fossil fuels and reduce atmospheric emissions of CO2. Sequestration of CO2 from fossil fuel combustion in the subsurface could prevent the CO2 from reaching the surface for millions of years. Geological sequestration of CO2 in deep aquifers or in depleted oil and gas reservoirs is a mature technology. Despite the huge quantities of CO2 that can be sequestered in this way, this approach does not provide any economic benefit. This paper discusses a third option, which consists of injecting CO2 in deep coal seams to sequester the carbon and enhance the recovery of coalbed methane (CBM). Waste CO2 from CBM-fueled power plants could be injected into CBM reservoirs to produce more methane (CH4) for the power plant. The 2:1 coal-sorption selectivity for CO2 over CH4 supports the feasibility of operating fossil-fueled power plants without atmospheric CO2 emissions. Other CO2 sequestration technologies, such as ocean disposal and biofixation, are briefly discussed and the suitability of these approaches is evaluated for use in Alberta, Canada.  相似文献   

8.
The isotopic composition of fossil fuels is an important component of many studies of C sources and sinks based on atmospheric measurements of CO2. In C budget studies, the isotopic composition of crude petroleum and CH4 are often used as a proxy for the isotopic composition of CO2 emissions from combustion. In this study, the C isotope composition (δ13C) of exhaust from the major fossil fuel emission sources in Salt Lake City, USA, was characterized with 159 measurements of vehicle exhaust of various types and eight measurements of residential furnace exhaust. These two sources were found to be isotopically distinct, and differed from global-scale estimates based on average values for crude petroleum and CH4. Vehicle-specific factors such as engine load and operation time had no effect on δ13C of vehicle exhaust. A small difference was found between the mean δ13C of vehicle exhaust collected randomly from different vehicles and the mean δ13C of gasoline collected from multiple fueling stations representing major gasoline distributors in Salt Lake City and the surrounding area. However, a paired comparison of δ13C of exhaust and gasoline for six different vehicles did not show any consistent C isotope fractionation during vehicle combustion. The mean δ13C of crude petroleum processed for local distribution differed slightly from refined gasoline collected at multiple fueling stations, but time lags between processing and transportation cannot be ruled out as an uncontrollable contributing factor. Measured isotope ratios were then combined with fuel consumption statistics to predict the annual cycle of δ13C of fossil fuel emissions for the Salt Lake City metropolitan area. The results showed that the isotopic composition of CO2 emissions from fossil fuel combustion varied by almost 3‰ over the course of the 2002 calendar year. This study illustrates that on a regional scale, the isotopic composition of fossil fuel emissions shows a high degree of both spatial and temporal variability that may influence characterization of C sources and sinks with atmospheric measurements.  相似文献   

9.
Sediment cores from Sagamore Lake and Woods Lake in New York State's Adirondack Park, an area remote from industrial activities, were analyzed for polynuclear aromatic hydrocarbons (PAH) by high resolution gas chromatography/mass spectrometry (GC/MS). Their composition and distribution with depth in the sediment indicate that the parental PAH in the surface sediments are primarily produced by anthropogenic combustion of fossil fuels. Perylene in deep sediments is apparently transformed from natural precursors in the reducing environment, however, the exact precursors remain unknown. The rather even sediment distributions of the non-parental PAH differ from the parental, suggesting biogenic origins. Based on their chemical structures, retene and alkylated and partially hydrogenated phenanthrenes are believed to be biogenically converted from abietic acid; hydrochrysenes and hydropicenes, from pentacyclic triterpenes.  相似文献   

10.
用扫描电镜技术识别广州市大气颗粒物主要种类   总被引:19,自引:2,他引:19  
董树屏  刘涛等 《岩矿测试》2001,20(3):202-207
利用扫描电镜技术对大气颗粒物的来源进行识别,采取手动分析与自动分析两种方法,得出的结果在总趋势上相互一致。手动方法和自动方法各有特点。自动分析在细颗粒,特别是含硫颗粒分析方面有优势,而手动分析在形貌观测和确定有机粗颗粒污染状况方面有独到之处。实验结果表明,大气颗粒物的来源是多样的,治理措施也应是综合性的,既要注意工业点源的污染治理和排放控制,如燃煤飞灰,钙质颗粒富铁颗粒等,也要注意面源排放,如土壤扬尘和碳质颗粒,碳质颗粒的来源复杂,可以是工业过程,燃烧过程,机动车尾气,生物质燃,树木自然排放。  相似文献   

11.
Recent sediment cores of the western Baltic Sea were analyzed for heavy metal and carbon isotope contents. The sedimentation rate was determined from radiocarbon dates to be 1.4 mm/yr. The ‘recent age’ of the sediment was about 850 yr. Within the upper 20 cm of sediment, certain heavy metals became increasingly enriched towards the surface; Cd, Pb, Zn and Cu increased 7-, 4-, 3- and 2-fold, respectively, whereas Fe, Mn, Ni and Co remained unchanged. Simultaneously, the radiocarbon content decreased by about 14 per cent. The enrichment in heavy metals as well as the decrease in the 14C-concentration during the last 130 ± 30yr parallels industrial growth as reflected in European fossil fuel consumption within that same period of time. The near-surface sediments are affected by residues released from fossil fuels at the rate of about 30 g/m2 yr for the past two decades. The residues have a pronounced effect on the heavy metal and carbon isotope composition of the most Recent sediments allowing estimates to be made for sedimentation, erosion and heavy metal pollution.  相似文献   

12.
为掌握太原市冬季灰霾发生期间黑碳气溶胶形貌特征和化学成分变化特点,分别于2011-12-30 T 08:00至2012-01-01 T 04:00和2018-11-25 T 08:00至2018-11-27 T 04:00灰霾发生期间在山西大学环境与资源学院楼顶使用MAY七级冲击式颗粒采样器每隔4 h采集空气动力学直径...  相似文献   

13.
《Atmósfera》2014,27(1):61-76
The Carbon Tracker system will play a major role in understanding CO2 sinks and sources, gas exchange between the atmosphere and oceans, and gas emissions from forest fres and fossil fuels in Latin America and the Caribbean. This paper discusses the trends in carbon fluxes in the biosphere and ocean, as well as emissions from forest fres and fossil fuel use in the above-mentioned region, using the Carbon Tracker (CT) system. From 2000 to 2009, the mean carbon fluxes for the biosphere, fossil fuel use, wildfires and the ocean in Latin America and the Caribbean were −0.03, 0.41, 0.296, −0.061 Pg C/yr, respectively, and −0.02, 0.117, 0.013, −0.003 Pg C/yr, respectively, in Mexico. The mean net carbon flux for Latin America and the Caribbean was 0.645 Pg C/yr, and 0.126 Pg C/yr for Mexico. The terrestrial sinks in Latin America and the Caribbean are dominated by the forest, agricultural, grass and shrub regions, as well as the Andes mountain range and the net surface-atmosphere fluxes including fossil fuel are dominant in regions around large cities in Mexico, Brazil, Chile, and areas undergoing deforestation along the Amazon River. The results confirm that forest fres are an important source of CO2 in Latin America and the Caribbean. In addition, we can confirm that policies encouraging the use of ethanol in light vehicles in Brazil have helped to decrease carbon emissions from fossil fuel, and assume the effects of the Proárbol program on carbon sinks from the biosphere and from fire emissions sources in Mexico. Based on this analysis, we are confident that the CT system will play a major role in Latin America and the Caribbean as a scientific tool to understand the uptake and release of CO2 from terrestrial ecosystems, fossil fuel use and the oceans, and for long-term monitoring of atmospheric CO2 concentrations.  相似文献   

14.
北京市中关村地区大气降尘的来源与垂向分布特征   总被引:1,自引:0,他引:1  
利用光学和电子显微镜、X射线衍射仪以及同步辐射X射线荧光对北京市中关村地区大气降尘的粒度分布、颗粒物微观形貌特征、矿物组成及化学元素组成等方面进行分析研究。粒度分析表明中关村地区大气降尘随着相对高度的增加,粗颗粒物逐渐减少。大气降尘的颗粒物形貌可以分为粒状、柱状单矿物,圆球状飘珠和不规则粒状集合体3种类型。矿物组成及化学元素组成的分析显示中关村地区大气降尘的污染物主要来自自然扬尘、建筑扬尘、燃煤、汽车尾气等污染源。  相似文献   

15.
现代植物植硅体化学组成研究有利于揭示植硅体的化学组成与细胞形态、植物种类及植物生长环境之间的关系,认识植硅体形成机制、植物分类及生态意义。植硅体化学组成测试方法多种多样,主要涉及植硅体化学元素组成及Si、O和C元素同位素组成测定,研究表明植硅体主要含二氧化硅和水,封闭有少量的有机成分及多种矿质元素。在植硅体封闭有机成分存在形式,部分元素的形成、迁移等循环机理,稳定碳同位素组成、分布及其生态指示意义以及^14C测年研究等方面取得一定认识。植物种类、组织部位、细胞微环境以及植物生长的环境因子能够影响植硅体的化学组成。植硅体化学组成研究对植硅体形成机制及碳、硅等元素循环具有重要意义,植硅体部分化学元素、植硅体稳定同位素组成及^14C测年具有较好的古环境及考古研究潜力。现代植物植硅体化学组成及其与环境因子的关系,以及植硅体电子探针微区研究有待于进一步深入开展。  相似文献   

16.
Wilfrid Bach 《GeoJournal》1985,10(4):339-352
Many of the world's most troublesome problems are closely interrelated. A case in point is the acid rain/carbon dioxide threat. Acid rain is the commonly used synonym for the major ingredients in the ongoing regional forest dieback, and carbon dioxide is a major influencing factor in the man-induced global geophysical experiment which is feared to lead to unacceptable climatic changes. Both problems have a major common cause, namely the squanderous use of fossil fuels. For this the most effective short-term preventive control measure is the reduction of fossil fuel combustion through more efficient use which drastically reduces the pollution output by minimizing the need of having to burn fossil fuels in the first place. However, the large differences in the quantity of the emissions involved (some 20 000 million tons of CO2/yr. and about 130 and 50 million tons of SO2 and NOx, respectively) ingredients of acid rain, can be stripped from the gas stream by technical means which are affordable, the sheer quantity of CO2 involved renders its sequestering and disposal technically, logistically and economically unfeasible. Through short-term measures the necessary time is gained for a sensible introduction of pollution-free sustainable resources. The long market penetration times (typically 50–100 years) force us to act now, ifwe do not wish to have upon us in the near future a major CO2/climate problem that is of similar severity as the acid rain/forest dieback problem of today. To my knowledge this is the first attempt to analyse the acid rain/CO2 problems in their genetic and functional context and to present ways which lead to feasible solutions.  相似文献   

17.
Radiocarbon measurements of black carbon in aerosols and ocean sediments   总被引:1,自引:0,他引:1  
Black carbon (BC) is the combustion-altered, solid residue remaining after biomass burning and fossil fuel combustion. Radiocarbon measurements of BC provide information on the residence time of BC in organic carbon pools like soils and sediments, and also provide information on the source of BC by distinguishing between fossil fuel and biomass combustion byproducts. We have optimized dichromate-sulfuric acid oxidation for the measurement of radiocarbon in BC. We also present comparisons of BC 14C measurements on NIST aerosol SRM 1649a with previously published bulk aromatic 14C measurements and individual polycyclic aromatic hydrocarbon (PAH) 14C measurements on the same NIST standard.Dichromate-sulfuric acid oxidation belongs to the chemical class of BC measurement methods, which rely on the resistance of some forms of BC to strong chemical oxidants. Dilute solutions of dichromate-sulfuric acid degrade BC and marine-derived carbon at characteristic rates from which a simple kinetic formula can be used to calculate concentrations of individual components (Wolbach and Anders, 1989). We show that: (1) dichromate-sulfuric acid oxidation allows precise, reproducible 14C BC measurements; (2) kinetics calculations give more precise BC yield information when performed on a % OC basis (vs. a % mass basis); (3) kinetically calculated BC concentrations are similar regardless of whether the oxidation is performed at 23°C or 50°C; and (4) this method yields 14C BC results consistent with previously published aromatic 14C data for an NIST standard.For the purposes of intercomparison, we report % mass and carbon results for two commercially available BC standards. We also report comparative data from a new thermal method applied to SRM 1649a, showing that thermal oxidation of this material also follows the simple kinetic sum of exponentials model, although with different time constants.  相似文献   

18.
High soot contents have been reported in Cretaceous-Paleogene boundary (KPB) clays worldwide. One of the interpretations suggests this material comes from combustion of fossil fuels such as crude oil, coal or oil shales near the Chicxulub impact site. Combustion was triggered by the KPB impactor. In this Note, I show that the estimated mass of crude oil (or fossil hydrocarbons in general) burned (ca. 1017?C1019 g), based on the average amount of soot (0.0022?C0.012 g cm?2) or elemental carbon (0.011 g cm?2) found at the marine KPB sites, contradicts the fossil hydrocarbons hypothesis.  相似文献   

19.
Samples of ascending geogas flow particles were collected on to SiN grids directly in the Quaternary sediments overlying the Dongshengmiao polymetallic pyrite deposit, China. Corresponding soil samples were collected in the surface of Dongshengmiao district at the same time. After pretreatment, these SiN grid samples were analyzed by transmission electron microscopy. The tests focused on the characteristics of particles including size, shape, chemical composition, structure and association. The results show that there are numerous carbon‐bearing particles in particulate samples of the ascending geogas flow. The particles contain organic matter, carbonate or carbonate mixed with other minerals. These carbon‐bearing particles generally contain metallic elements like Fe/Zn/Au/Cu/Pb. However, all of the soil particles do not contain elemental C and only consist of common elements (O, Na, Mg, Al, Si, Ca, Ti) just like the composition of earth crust. Through a comparison between the particles from different sources, the carbon‐bearing particles were found to come only from the deep earth and carried useful information about concealed deposits as they pass through the deep‐seated orebodies. Given the influences of organic matter on mineralization, the carbon‐bearing particle may provide information on the deposit genesis. Combining the use of geogas particle for prospecting with characteristics of large depth, and the carbon‐bearing materials' close spatial and genetic relationship with orebodies, we propose a new prospecting method based on the characteristics of carbon‐bearing particles, including morphology, size, chemical component and ultra‐microstructure. This approach could be applied to the exploration of deposits deep in the earth and abundant in carbon‐bearing matter. This approach can provide efficient and effective deposit exploration.  相似文献   

20.
山东半岛海岸带面临着各类复杂的环境问题,尤其是受到了多环芳烃(PAHs)等持久性有机物的污染,本文研究了整个山东半岛典型海岸带62个站点表层沉积物中PAHs的含量及其分布特征,并对其来源和潜在风险进行解析与评价。研究表明,该地区表层沉积物中16种PAHs总含量为0.06~3191.40 ng/g(平均值262.08 ng/g),与国内外海岸带相比,山东半岛海岸带表层沉积物中PAHs整体污染状况处于较低水平,但个别站点的PAHs含量偏高。运用特征比值法、相关性分析及主成分分析法解析研究区PAHs主要来源为木柴、煤炭、油类的燃烧以及油类泄露的联合作用。采用效应区间低值法(ERL)和中值法(ERM)对PAHs进行生态风险评价,结果表明莱州湾周边所有站点及威海、青岛周边个别站点苊、芴浓度位于ERL值与ERM值之间,但多数站点对生态环境潜在负面效应很小。山东半岛典型海岸带中PAHs对生物的毒副作用尚在安全可控范围内,极少对生态环境产生负面效应。  相似文献   

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