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1.
《中国地球化学学报》2006,(Z1)
Health risk from various particulates of dust has been of public health concern for many years and scientific observations on dust have been going on for the last 200 years. Diseases resulting from exposure to dust are generally known as pneumoconiosis an… 相似文献
2.
Edward Derbyshire 《中国地球化学学报》2006,25(B08):219-219
Fine atmospheric dust includes mineral particles and aggregates, fibrous minerals and fibrous organic material. Generation, dislodgement and transport （deflation） of natural dust with the finer （〈4 microns） components suspended as silt-size aggregates, is widespread in and adjacent to the world＇s drylands, as well as deriving from volcanic vents. Silica is a highly fibrogenic agent in lung tissue. Long-term inhaling of siliceous dusts can lead to a number of fibrotic lung diseases, including natural （non-occupational） pneumoconioses （notably silicosis, but including asbestosis and others）. Different polymorphs of silica show different levels of toxicity in interaction with lung tissue. Particles with highly active surfaces may release radicals, causing cell damage. Some types of inhaled particulates are degraded by macrophages, but many are highly resistant and persist in the lungs, some stimulating fibroblastic cells to deposit collagen. Silicosis is an inflammation of the lung commonly caused by silicate mineral particles, leading to fibrosis. Three types are recognized： nodular pulmonary fibrosis （simple or chronic silicosis）, acute silicosis, and accelerated silicosis. Generally, finer particulates have greater oxidative capacity than the coarser fractions. They contain more reactive oxygen species, their greater bioreactivity making them more toxic to pulmonary tissue. Nevertheless, inhalation of large dust particles （〉 10μm） may constitute a health risk if the mineralogy is toxic, regardless of where the grains lodge in the respiratory system. Dust may absorb harmful gases, disease-generating bacteria and carcinogenic hydrocarbon compounds. Silica-related respiratory disease may also an exacerbate cardiac problem, and epidemiology suggests a link with tuberculosis. Quantification of dust loading and exposure requires study of spatial and temporal patterns, supported by meteorological analysis, airflow modeling and satellite-borne imagery. Some acute, short-term health impacts have been assessed using atmospheric and health records both before and after a dust storm or by comparison of populations within and outside such events. Analysis of the size, shape, mineralogy and geochemistry of ambient dust particulates provides information on natural dust sources, dust concentrations, and potential particulate toxicity, as well as providing a datum for assessment of human exposure levels. 相似文献
3.
Norboo Tsering 《中国地球化学学报》2006,25(B08):69-69
Background： Radiographic signs of Pneumoconiosis found in farming Ladakhi despite absences of mines and industries were believed to be due to exposure to frequent dust storms and domestic fire pollutions. Seasonal Koilonychia （spoon nail） occurring predominantly in farming women in absences of iron deficiency anaemia was thought to arise from exposure to water made alkaline by weathering of hornblende minerals. The relation of these health conditions to environmental geohydrochemistry is postulated as the source of irrigation water in the affected population originates from glaciers in trans-Himalaya range of sedimentary geology and steep landscape favouring flushing of silica/silicate containing silts. Methods and results： Survey in two central Ladakh villages revealed radiographic evidence of silicosis in all middle aged women and half in middle aged men. In a large-scale study of 3105 subjects aged over 30 years from three villages; 101 （22.5%） of the 449 radiographed showed signs of pneumoconiosis （ILO 1980 criteria） including eggshell calcification of hilar gland and progressive massive fibrosis. Indoor dust analyzed using Philips 400T electron microscope with energy dispersive analysis system attached showed SiO2 levels upto 53.27% with particle size of 0.5 to 5.0 microns and the concentration during cooking period in the worst affected area was 7.495 mg/m^3. Microscopy and histopathology from the subject was characteristic of pneumoconiosis. Analysis of the inorganic dust in the lung showed 40.2% muscovite, 37.3% quartz with the extracted dust wt 147.9 mg/gm of dry tissue. Prevalence of chronic cough with chronic phlegm and percentage of villagers with FEV1/FVC ratio of less than 65% rose with age. Of 70 subjects studied 19 women and 2 men had Koilonychia with incidence being highest in summer. Absence of seasonal Koilonychia in villages fed by water derived from northern mountain range glaciers with mainly igneous geology supports our hypothesis. 相似文献
4.
Ben J. Williamson Claire J. Horwell 《中国地球化学学报》2006,25(B08):224-225
A link between the inhalation of respirable silicas （SiO2） and respiratory diseases such as silicosis is widely recognized. Ash from dome collapse eruptions on Montserrat has been found to contain high levels （〉20%） of silicas in the form of cristobalite, tridymite, quartz and/or amorphous silica. The toxicity of these silica polymorphs varies widely. Cristobalite and quartz （tridymite less well established） are viewed as carcinogenic to humans whereas amorphous silica generally shows a reduced biological response. In assessing the potential health effects of volcanic ash particulates it is vital to determine the types and concentration of silicas as well as their size （respirable fraction）, shape and surface properties. The aim of this study is to develop methods to assess potentially toxic respirable airborne silicas in the dome collapse ash （applicable to a range of ash types） and to develop a model to predict the levels and types of respirable silicas from future eruptions. The model is being developed by comparing dome rock with related ash from a series of previous eruption events. Mineralogical assessment using conventional scanning X-ray diffraction （XRD） was hampered by difficulties in differentiating characteristic peaks for cristobalite and tridymite in complex multi-component ash samples （containing high levels of plagioclase）. These difficulties have been largely overcome using an Enraf-Nonius PDS120 diffractometer with curved （120 degrees 20） position sensitive detector （PSD）. The determination of size, shape and elemental characteristics of ash particulate and dome rock samples has been carried out using automated analytical scanning electron microscopy. The quantification of mineral proportions using PSD-XRD was highly successful with an accuracy of 1 to 2 wt%. However, the determination of phase proportions using automated analytical SEM was problematic due to scattering effects and the multiphase nature of many of the particles. 相似文献
5.
Nurdan S. Duzgoren-Aydin Zhiguang SONG Adnan Aydin Coby C.S. Wong Minggang YOU Xiangdong LI 《中国地球化学学报》2006,25(B08):75-75
Ever-increasing accumulation of trace metals in the environment is a serious health concern. This is a valid apprehension particularly in urban settings where the population and the level of trace metal contamination are increasing rapidly. Hong Kong and Guangzhou are the most populated cities in the region of the Pearl River Delta, the fastest growing economic region in the world. In unconfined urban compartments, particulates deposited on the earth surface such as road dusts and gully sediments are good indicators to assess the level of trace metal contamination. In such locations, however, source partitioning of the pollution, which is essential to assess and then reduce the potential environmental risk, is a difficult task. This is mainly due to the complexity and variability of site-specific natural and anthropogenic conditions. This leads us to focus on the particulates accumulated in relatively confined settings, such as vehicular tunnels. Our recent studies demonstrated that particulates accumulated on the ceiling of tunnels are useful to characterize particulates mainly derived from traffic related activities. With this in mind, Pb isotope ratios and trace metal contents of the ceiling dusts from the Cross-Harbor Tunnel （CHT） in Hong Kong and the Pearl River Tunnel （PRT） in Guangzhou were characterized and compared with each other in order to evaluate the environmental impact of traffic derived inorganic pollutants in the region. The ceiling dusts from both tunnels were dominated by silt-sized particles （〈63 μm） which are significantly freer than those of road dusts, usually larger than （〉200 μm）. In general, Cr, Ni, Pb and especially Cu contents of the ceiling dusts from CHT were noticeably higher than those from PRT. This was partly attributed to longer residence time of particulates in CHT, which has been operating since 1976, while the PRT was open to public in 1996. On the other hand, Co, Fe, Mn and Zn contents of the ceiling dusts from CHT were similar to those from PRT, while Ca and Mg contents were noticeably lower. 相似文献
6.
Muhammad KASHIF CAO Yingchang Nizam Ud DIN Uzair SIDDIQUE XI Kelai Faisal REHMAN Noor AHMED GU Xihao Mohammad Saleh GAGHMAN 《《地质学报》英文版》2022,96(1):248-260
The precipitation of authigenic quartz plays a significant role to reduce the reservoir characteristics and enhance the stiffness of the rock.The Es1 sandstone of Shahejie Formation is acting as a significant hydrocarbon producing rock in the Nanpu Sag.Various methods like thin section petrography,cathodoluminescence(CL),scanning electron microscope(SEM,with EDS),and electron microprobe analysis has been used to reveal the origin of quartz cement as well as to evaluate the effect of quartz cement on reservoir quality.The studied sandstone is classified as immature to mature feldspathic litharenite and lithic arkose and consists of quartz,feldspar,rock fragments and micas.Petrographic studies and SEM analysis shows that the authigenic quartz is acting a significant cement that reduces the reservoir quality.Whereas clay minerals(kaolinite and mixed layer illite to smectite)are dominant in the Es1 sandstone,that can reduce the reservoir quality.SEM,CL and thin section analysis reveal that there are two stages of quartz cement in the studied samples;that are pore filling authigenic cement and quartz overgrowth cement.Fluid inclusion homogenization temperatures shows that stages of quartz cement were developed with continuous process from 70℃ to 130℃.Quartz cements were generally originated from I/S reaction,feldspar dissolution,conversion of rock fragments and pressure solution.Feldspar dissolution(K-feldspar)and kaolinite to illite reaction is an insignificant silica source for the silica cement which is internally precipitated in a close system with diffusion transporting mechanism.Overall,quartz cement significantly enhance the rock strengthen and brittleness effectively as well as it reduce the overall reservoir quality. 相似文献
7.
Mostafa Raghimi Maryam Ramezani Mojaveri 《中国地球化学学报》2006,25(B08):58-59
Background ＆ objective： Medical geology is a discipline of environmental health dealing with the impacts of geological relationship between loess deposits and certain endemic diseases such as esophagus cancer. This article deals with loess deposits with medical geology aspect toward diagnosis and prognosis. Materials ＆ Methods： In this study sampling from loess deposits from East towards West has been done. Collected samples have been undergone X-ray diffraction （XRD）, scanning electron microscopy （SEM） and Energy dispersive X-ray analysis （EDAX） for determination of minerals, surface morphology of minerals and chemical analysis for further studies, respectively. Results： In mineralogical studies dominated minerals are quartz, feldspar and calcite. Clay minerals are illite and chlorite, which are about 9.3%. The amount of quartz is variable from 56.3 to 45.4. The grains sizes are decreasing from northeast to southwest. Chemical analysis showed that loess deposits contain Si, Al, K and Ca, which are related to the presence of quartz, feldspar, calcite, illite and chlorite minerals. Conclusions： According to medical geology evidence, loess deposits of Gloestan Province could be closely related to the incidence of esophagus cancer due to effect of clay minerals on biochemical cycle, direct relation of grain size with the incidence of esophagus cancer and chemical composition of loess deposit for its high silica are also taken into consideration. As the esophagus cancer belt coincides with the loess deposits belt of the world. 相似文献
8.
Shao nan Zhang Knut Bj Φ rlykke 《沉积学报》2000,18(1):119-126
The timing and duration of
quartz cementation in sandstones have been mainly inferred from diagenetic texture,
relationship between pore filling minerals, fluid inclusions and isotopic data. Fluid
inclusion temperatures from North Sea reservoir sandstones indicate that most of the
quartz cement forms at temperature exceeding 90℃ and is continually proceeding after oil
emplacement, based on the fluid inclusion temperatures in quartz overgrowth which is
approaching the bottom-hole temperatures. The duration of quartz cement after oil
emplacement depends upon the saturation of porewater and the distribution of pore water
film and the property of water-wet or oil-wet of the reactants. The leaching of K-feldspar
by meteoric water requires pore water flow to move the released potassium and sodium and
silica out the solution, which suggests the mechanism does not appear to be a major source
of silica for quartz cementation. The quartz cementation coincidence with the compaction
and pressure solution suggests the major source of silica. The alteration of feldspar by
illitization of kaolinite may serve as another important source of silica at deep burial
depth. External sources are not need to call on for illustrating the quartz cementation,
because there is no evidences for large scale convection of pore water flow occurred in
the burial history of reservoir sandstones of middle Jurassic in the North Sea. 相似文献
9.
Huiwen HSIAO Susanne M. Ullrich Trevor W. Tanton 《中国地球化学学报》2006,25(B08):233-233
This research aims to establish the risks of hurnan exposure to modeling approach. The study site was located on the River Nura 1990s, an acetaldehyde production plant located in the industrial high environmental mercury levels, based on a quantitative risk in central Kazakhstan. From the 1950s until its closure in the mid city of Temirtau released mercury-containing wastewater into the river. River sediments are highly contaminated with mercury up to a distance of 25 km and beyond. In addition, a local power station released an estimated 6 million tonnes of fly-ash into the water and the mercury has become quite tightly associated with the ash deposits. River water, fish and agricultural land in the floodplain are also contaminated with mercury, yet the risks posed to the local population have not been evaluated to date. In June and July 2005, we took samples of soil, interior and exterior dust, drinking water, and food from individual households, communal areas and markets. Additionally, water and sediment samples and fish were taken from the river. Interviews were conducted with householders to establish their age and body weight, general living conditions and sources of irrigation and drinking water. A food frequency questionnaire （FFQ） was designed to investigate the frequencies of consumption of several common regional food items, including fish from the fiver and/or local market. Human hair samples were also collected to estimate the mercury bioburden and to enable the validity of the modeling approach to be established. The paper expands on the main pathways of contamination and looks at linkages between exposure pathways and mercury concentrations found in human hair. Uncertainties inherent in risk analysis as well as their influence on the relative importance of different exposure routes are also discussed. 相似文献
10.
Christina A. Kellogg 《中国地球化学学报》2006,25(B08):218-219
Desert winds aerosolize several billion tons of soil-derived dust each year, including concentrated seasonal pulses from Africa and Asia. Huge dust events create an atmospheric bridge over continents and oceans, and eject a large pulse of soil-associated microorganisms into the atmosphere. These dust events might therefore have a role in expanding the biogeographical range of some microorganisms by facilitating rare long-distance dispersal events. The goal of this study is to characterize the microbes associated with African dust events and determine if they pose a risk to humans or downwind ecosystems. Air samples were collected by vacuum filtration in a source region （Mali, West Africa） during dust events and plated on R2A media to culture microorganisms. These organisms were compared to those in similar samples collected in the Caribbean during Saharan/Sahelian dust events. A high-volume liquid impinger is currently being tested in Barbados, collecting aerosol samples during African dust events. Over 100 bacteria and fungi （19 genera of bacteria and three genera of fungi） have been characterized from source region dust events. 相似文献
11.
Quantification of the dry aeolian deposition of dust on horizontal surfaces: an experimental comparison of theory and measurements 总被引：1，自引：1，他引：1
DIRK GOOSSENS 《Sedimentology》2005,52(4):859-873
Eight techniques to quantify the deposition of aeolian dust on horizontal surfaces were tested in a wind tunnel. The tests included three theoretical techniques and five measurement techniques. The theoretical techniques investigated were: the gradient technique, the inferential technique without grain-shape correction, and the inferential technique corrected for grain shape. The measuring techniques included the following surrogate surfaces: a water surface, a glass surface, a metal surface, a vertical array of metal plates, and an inverted frisbee filled with glass marbles. The efficiency of the techniques was investigated for the sediment as a whole (all grain sizes together) as well as for a large number of grain sizes extending from 1 to 104 μm. The surrogate surfaces showed more or less comparable catch efficiencies, although the water surface nearly always caught the highest quantities of dust and the marble-filled frisbee and the vertical array of metal plates the lowest quantities of dust. The dust fluxes calculated by theoretical methods were markedly different from those obtained by direct measurements. The fluxes calculated by the inferential technique approximated those of the direct measurements only for grain sizes between 30 and 40 μm. For smaller and coarser grains, deviations from the measured fluxes were high. The gradient method, in its turn, provided extremely low calculated fluxes for grains in all size classes investigated. The latter technique was not considered very reliable for the dust used in the tests. 相似文献
12.
对2006年春季南京地区一次“泥雨”形式的湿降尘特征进行了系统分析,并在此基础上对泥雨粉尘来源及泥雨降尘形成机制进行了探讨。结果表明： 1)本次泥雨降尘通量为3.77g/m2,在南京全境的降尘总量达到2.49×104t; 2)泥雨粉尘的质量磁化率值为174×10-8m3/kg,略高于黄土磁化率值; 3)泥雨粉尘中<16μm的细粒组分占绝对优势(含量为91.91％),平均粒径6.05μm,众数粒径7.68μm; 粒度参数及分布曲线显示泥雨粉尘具有比黄土和现代干降尘更好的分选性和更对称的峰态; 4)XRD和SEM分析表明,泥雨粉尘以絮状矿物颗粒为主,其中粘土矿物含量最高,占57.7％,其他矿物有石英(15.5％),钠长石(12.0％)和微量的白云石(1.0％); 5)泥雨粉尘的常量元素组成与黄土、现代干降尘以及上陆壳(UCC)大体相似,显示其主要为地壳源; 而微量元素中Zn,Co,Ni,Ba,Cr,V,Cu,Zr,Cd和Pb等重金属元素含量较黄土及UCC偏高,其中Zn,Cu,Cd和Pb等含量显著偏高,显示了地壳源之外的人为污染源的影响; 相比本地的下蜀黄土,南京泥雨粉尘样品的REE组成特征与北方黄土之间的相似程度更高,显示了更为密切的亲缘关系; 6)根据泥雨降尘的特征,结合天气活动过程,可以判定此次南京泥雨降尘并非本地扬尘所致,而主要来源于北方尘暴活动所产生的细粒粉尘; 寒潮冷锋的南侵提供了长距离输送动力,而长江下游海洋性暖湿气流对细粒粉尘的清除过程则最终导致了泥雨的形成; 南京春季泥雨降尘事件实质上是长江下游地区对西北内陆干旱区沙尘暴活动的一种区域响应。 相似文献
13.
海洋硅循环是海洋生物地球化学循环的关键过程之一,对调控全球二氧化碳浓度、海洋酸碱度和多种元素(氮、磷、铁、铝等)的循环具有重要作用。在当今气候变化和人类活动影响日益增强的背景下,硅循环与“生物泵”及碳循环的紧密联系,是其成为地球科学领域研究热点的主要原因。海洋中硅的外部来源主要为河流、地下水、大气沉降、海底玄武岩风化作用和海底热液输送5个途径,在全球气温变暖趋势的影响下,极地冰川融化成为高纬度海域不可忽视的硅源。生物硅在沉积物中的埋藏、硅质海绵和生物硅的反风化作用是重要的海洋硅移除过程。海洋硅循环过程复杂,受生物(生物吸收、降解)、物理(吸附、溶解)和化学(矿化分解和反风化作用)多重因素的影响,针对海洋硅循环关键过程的研究有助于综合评估海洋硅的“源-汇”和收支。本文总结了海洋硅循环的主要过程及海洋硅的收支,根据国际和国内研究现状讨论了当前海洋硅循环研究中面临的主要问题和挑战。现有研究成果显示,海洋硅的外源输入和输出通量比以往的评估分别增加了2.4和2.2倍。在短时间尺度内(<8 ka),全球海洋中硅的收支大致平衡,海洋硅循环基本处于稳定状态。气候变化和人类活动导致河流输送至陆架边缘海的硅通量发生变化,可能影响硅藻等海洋浮游植物种群结构,是未来海洋硅循环研究需要关注的问题之一。陆架边缘海较高沉积速率和强烈的反风化作用提高了该区域生物硅的埋藏效率,准确评估该区域生物硅的埋藏通量仍是亟须解决的难题。目前的研究评估了全球海洋浮游硅藻、硅质海绵以及放射虫生产力,而海洋底栖硅藻生产力的贡献受到忽视,未来需要关注底栖硅藻对生物硅的贡献及其在海洋硅的生物地球化学过程中的作用。 相似文献
14.
高等植物产生的植硅体是古气候和古环境研究的重要手段,也是陆地硅循环中重要的硅的储库;植硅体通过河流的跨区域输送在全球硅的生物地球化学循环中起着重要作用,是区域硅循环研究的重要载体,然而这方面的关注却很少。河流输送的生物硅大致分为自源和异源两种类别。"自源"生物硅主要包括河流水体本身自生浮游植物(主要是淡水硅藻)产生的硅质颗粒;"异源"生物硅主要由流域土壤的侵蚀输出到河流的植硅体所构成。流域地表过程是使得部分土壤中的植硅体进入河流的主要途径,并成为河流生物硅输送中重要的形式,这对河流-河口水循环体系的硅生物地球化学循环过程产生了重要的影响,但人们对河流输送的植硅体在硅循环中的作用的研究还不够。文章着眼于陆海相互作用研究,以河流中水体携带的植硅体为中心,总结了河流植硅体输送在地表水体硅循环系统中贡献的研究进展,分析了长江与黄河植硅体入海通量与河口行为及对近海海洋环境的影响。最后,对未来河流输送的植硅体参与硅循环研究可能需要加强的科学问题提出了建议。 相似文献
15.
沙粒不能“远走高飞”———有关“尘暴”的一条根本原理 总被引：3，自引：0，他引：3
沙与尘虽然都是岩石物理风化的产物, 但在风力作用下, 习性截然不同。拜格诺用严格的物理实验证明, 尘粒能随风远走高飞, 而沙粒却只能在地面附近跳跃前进。从北方侵袭华北平原的所谓沙尘暴, 实质上都是尘暴。对历次重大天气事件沉积物的分析, 也完全证明了这一点。因此, 尘暴物质的源头不是来自有沙, 而是有尘的地方; 从而可以使人们采取正确的治理方法。 相似文献
16.
北京2002年3月20～21日尘暴过程的降尘量与降尘粒度特征 总被引：27，自引：3，他引：24
本文对2002年3月20～21日发生在北京地区的一次尘暴过程进行了降尘量和降尘粒度的研究。通过对分时段监测取得的13组降尘样品进行降尘量和粒度测定,结合风速变化情况,可将本次尘暴分为尘暴前期和尘暴后期两个过程。降尘量和粒度参数值在尘暴前期和后期都呈现不同特征。结论认为,风速是降尘量变化的重要因素。当风速进一步增大时,降尘量反而有所下降。说明北京地区尘暴降尘量除受本地风速影响外,还与粉尘浓度等特征有关。尘暴降尘的粒度基本呈双峰态分布。本次尘暴初始降尘主要为细粒径颗粒,尘暴前期降尘粒径随风速而变化,尘暴后期降尘粒径基本维持在5～6之间 相似文献
17.
This paper investigates the kinetics of biogenic silica dissolution in seawater, through batch dissolution, where the reaction
is observed as the increase in dissolved silicic acid concentration with time. It utilises new data from dissolution of the
marine diatom Cyclotella cryptica, and the freshwater diatom C. meneghiniana, as well as literature results. The sum of exponentials form:
, is hypothesised as the most general rate equation, with the single exponential form occurring in a minority of cases. The
consistency of this behaviour with a near-exponential decay of surface area with time, an appropriate mathematical integration,
and surface heterogeneity, is discussed. (Serious errors in some existing integrations are identified.) The rate of dissolution
at constant surface area is shown to decrease non-linearly as the ambient concentration of silicic acid increases. A fractional
order with respect to silicic acid in the back reaction, close to 0.5, leads to a mechanism in which an intermediate is formed
from the surface and an, as yet, unidentified molecule, probably water. Good preliminary fits are found between the model
and literature results found using entirely different methods. A parallel treatment of hydrogen ion dependency is suggested.
The likely distortion of full reaction curves from exponential behaviour imposed by the back reaction, is considered in detail. 相似文献
18.
Methodologies for amorphous silica analysis 总被引：1，自引：0，他引：1
Different methodologies have been investigated for their ability to extract amorphous silica (ASi) from soils and plant phytoliths. Methodologies typically used in soil science, including oxalate, acetate and citric extractions, were used in addition to an alkaline digestion technique commonly used in the aquatic sciences. Initial results show that the alkaline technique extracts nearly an order of magnitude greater amount of ASi. The alkaline extraction technique was tested on soil samples with and without acid and peroxide pre-cleaning. Samples, which were not pre-cleaned, showed a poor extraction efficiency of amorphous silica and poor reproducibility, while cleaned soil samples gave better reproducibility and an increase in the amount of Si extracted. 相似文献