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污染场地土壤地下水的勘查需要同时满足取样和建井需求,中空螺旋半合管具有一定的自攻性,能够在获取低扰动土壤样品的同时建立地下水监测井。本文首先分析了中空螺旋的技术特点,同时基于直推式环境取样装备,提出中空螺旋半合管直推取样建井工艺,并在砂土相对密实度为0.46~0.83（12~16 m）的第四系砂土类地层进行项目试验。试验结果表明,该工艺能够有效解决传统直推取样工艺在土壤密实区域难以到达预定深度的难题,且岩心采取率>90%,是一种值得推广的环境取样技术。 相似文献
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应用单体碳同位素分析技术探析农田土壤中多环芳烃的植物降解过程 总被引：1，自引：0，他引：1
长期以来,研究者在探讨土壤中多环芳烃(PAHs)的降解及修复过程中,缺乏简便有效的手段对化合物的降解动态进行定量研究。前人尝试用投加实验、对比采用降解措施前后污染物的浓度变化、模型计算等方法研究PAHs的降解过程,其结果常互相矛盾,或不能真实反映复杂的实际环境。本文应用单体碳同位素技术对农田土壤中多环芳烃的植物降解过程进行定量表征,采集了某地农田表土作为供试土壤,选择玉米作为供试作物,开展了作物对土壤中PAHs降解及消除过程的研究。气相色谱-质谱分析结果表明,培养所用的玉米原始土及分4批收集的空白土、根际土、非根际土样品中16种PAHs的浓度总和(∑PAHs)平均分别为380.8 ng/g、(281.5±34.7) ng/g、(272.2±11.6) ng/g和(299.8±37.9) ng/g;玉米生长期间,各土壤样品 的∑PAHs均比原始土壤有所下降,但除3环化合物(苊烯、苊、芴、菲、蒽)外,其他化合物并未随玉米的生长表现出显著趋势。与玉米根、叶倾向于富集低环PAHs化合物相对应,可以判断植物对土壤中的低环化合物去除作用最为显著。各采样时期玉米根际土、非根际土和空白土壤样品中多环芳烃单体化合物的碳同位素分馏值(δ13C)在-34.31‰~-23.95‰之间,且除芘外的其他化合物的δ13C值随时间呈现逐步变轻的趋势,波动值位于-0.6‰~-9.0‰之间;本文对于PAHs单体化合物,尤其是4、5环化合物,在玉米降解过程中的碳同位素分馏与浓度变化之间未发现明显关系。考虑3环以下的PAHs化合物更倾向于被降解和清除,且其碳、氢同位素分馏情况更容易被观察到,因此稳定同位素分析更有助于探明该类单体多环芳烃污染物在环境中的迁移、转化规律。 相似文献
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土壤地球化学样品分析测试质量控制目前采用内部质量控制和外部质量控制相结合方法,重点从准确度、精密度、虚拟图等方面确保元素地球化学图成图质量,应用效果良好,不足之处是规范未规定统一的分析方法及评价分析质量等级的参数。分析系数是评价分析结果准确度和精密度的一个综合指标,既适用于实验室内部质量控制,又适用于实验室间质量控制,其评价方法简便易懂、量化直观,但在地矿实验室较少应用,有较好的推广应用价值。文章应用分析系数法评价河南省农业地质调查样品中4个日常监控土壤标准物质中52个项目的分析质量水平。依据多目标区域地球化学调查规范(1∶250000)相关指标计算出分析系数允许限,划分了质量评定等级并进行了实际应用。研究结果显示,4个土壤标准物质共208个分析项目中,其中138个项目达到优秀级,58个项目为良好级,12个项目为及格,总体分析质量好。对分析质量差的Se、Cr、I、Br、Th、C、Pb、Cd等8个项目,应查明原因,采取相应措施,提高这些项目分析的准确度和精密度。 相似文献
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灰化法与微波消解法处理地电化学泡塑样品的分析效果对比研究 总被引：1，自引：1，他引：0
当前普遍使用灰化法对地电化学泡塑样品进行预处理,但可能存在高温下某些元素(如Hg、As)挥发损失的缺点。本文选择了内蒙古洛恪顿热液型铅锌多金属矿床一条地电化学勘查剖面,开展灰化法及微波消解法处理地电化学泡塑样品的勘查效果对比研究,采用原子荧光光谱和高分辨电感耦合等离子体质谱测定其中的主要元素。结果表明:①对于Zn、Cu、Fe、La等十余种元素,两种处理方法取得的异常模式基本一致,可根据实际工作需求任选一种方法进行样品预处理;②对于Au、Pb等元素,微波消解法因为取样量小,可能存在较严重的样品均匀性、代表性及分析检出限等问题,应采用灰化法;③对于Hg,灰化法存在显著的元素损失,更适合采用微波消解法;④对于As,两种方法均存在较大问题,建议参考植物样品尝试使用硝酸及高氯酸直接溶解等方法进行预处理。 相似文献
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本人有幸拜读黎廷宇先生等所著"黔中碳酸盐岩和非碳酸盐岩上覆土壤CO2来源的对比研究"一文[1](原载<中国科学>2001年,第31卷,第9期,777～782页),觉得文中提供了很有价值的数据信息,但对这些数据的分析及得出的结论,深感有讨论的必要. 相似文献
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为解决高基质土壤样品中痕量重金属元素检测前处理操作繁琐、样品易二次污染或损失等问题,本文建立了采用固体直接进样-电热蒸发-车载电感耦合等离子体质谱定量分析环境现场土壤样品中Cr、Cu、Zn、As、Cd、Hg和Pb元素的分析方法。该方法采用高温电热蒸发石墨炉作为原子化器,样品称量后经梯度升温选择性蒸发,再结合双通道伴热传输石英管、两路氩气在线稀释、ICP-MS瞬时扫描、基体匹配外部校正等策略,有效解决了土壤直接进样过程中传输效率低、基体效应大的问题。在优化的仪器条件下,按照实验方法称取20mg土壤标准物质GBW07401、GBW07406、GBW07407、GBW07430和GBW07456建立外部校正曲线,样品中7种元素的标准曲线线性相关系数≥0.999;并按照实验方法测定了杭州市滨江区两处田间土壤样品中Cr、Cu、Zn、As、Cd、Hg和Pb,相对标准偏差(RSD)7%,相对误差5%,检出限为1.2～32.0ng/g,回收率为91.0%～113.0%。该方法是一种有实用价值的现场样品分析技术,适合现场中大批量土壤样品的分析监测。 相似文献
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钼元素是动植物生长必需的微量元素,生命体中的钼元素直接或间接来自土壤.依据内蒙古自治区鄂伦春旗东部主要耕地区1：25万土地质量地球化学调查项目所采集的土壤样品分析数据,对研究区内表层土壤钼含量进行了营养等级评价.鄂伦春旗东部地区土壤钼含量普遍达到丰富级以上.同时分析了地球化学指标、土壤类型、成土母质等对土壤钼含量的影响.认为钼含量在pH值为5～7之间时随pH增大而减小;在有机质含量20×10-3～140×10-3时,随有机质含量增加而减少.认为暗棕壤及其对应的成土母质为本区提供了钼的来源;提出了研究区内土壤钼主要来源于基岩风化的结论. 相似文献
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S. R. Joshi 《Environmental Geology》1989,14(3):203-207
Four possible sources of analytical error in the measurement of unsupported210Pb and/or nuclear fallout radionuclide (such as137Cs) profiles in sediment cores are pointed out. Each of these errors, if present, can significantly alter the true profile of the radionuclide under consideration. It is shown that simple procedural modifications can substantially improve the quality of analytical data that are subsequently used to develop intricate mathematical models to aid the interpretation of observed radionuclide profiles. 相似文献
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Environmental legislation has had significant impact on coal utilization, especially coal combustion for power generation, in limiting emissions of potentially hazardous materials to the environment. For the most part, such emissions derive from the inorganic constituents in coal. However, as such legislation becomes ever more encompassing, it has increased the need to understand better the behavior of the inorganic species in coal processing to ensure, in part, that such legislation is not unduly burdensome. Consequently, it has led to significant development of new models for the behavior of inorganics in coal combustion and a complementary enhancement of many analytical methods for determining inorganics in coal.In this paper, analytical methods for inorganics in coal are reviewed on three fronts: (i) methods for determining elemental concentrations; (ii) methods for determining the mineralogy of coals; and (iii) methods for determining modes of occurrence (speciation) of trace elements in coal. The concept of association with respect to mineral–maceral and mineral–mineral occurrences is also discussed. Where possible, comparison of different analysis methods has been made by reference to data on well-characterized suites of coals, such as the Argonne premium coal samples.Incremental enhancements will continue to be made in analytical methods for elemental concentrations; however, major improvements are needed in the other two areas. There is a great need to verify and corroborate by direct speciation methods, the many inferences made by indirect methods regarding trace element speciation. Also, improvements in the measurement of mineral association and its integration into the coal mineral analysis by means of the computer-controlled scanning electron microscopy (CCSEM) would be a significant advance. Accurate determinations of both association and coal mineralogy would lead to significant and much-needed refinements of models for the behavior of inorganics in both coal cleaning processes and coal combustion. 相似文献
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An analytical and experimental study of zoning in plagioclase 总被引：1，自引：0，他引：1
A detailed electron microprobe study has been conducted on natural and experimentally grown zoned plagioclase feldspars. Discontinuous, sector, and oscillatory chemical zoning are observed superimposed on continuous normal or reverse zoning trends. The relative accuracy of 3 element (Na, Ca, K) microprobe traverses was found statistically to be 2 mole percent. Comparison of microprobe data on natural zoned plagioclase with zoned plagioclase grown in controlled experiments has shown that it may be possible to distinguish zonal development resulting from physio-chemical changes to the bulk magma from zoning related to local kinetic control on the growth of individual crystals. 相似文献
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从桩与承台下地基土共同分担荷载的基本条件出发,提出了一种从单桩荷载沉降曲线入手的桩-土-承台共同作用简化分析方法。在给定单桩荷载水平下,假定承台下桩间土的变形量等于此时单桩沉降量,求解相应的板底应力,从而可以得到任意桩荷载水平下的承台荷载分担量,而不必将桩的受荷水平限制在极限荷载。将基础沉降分为桩间土变形量及桩端下卧土层的整体压缩量两部分进行分析。桩间土变形量等于单桩在给定荷载水平下的沉降量,而桩端下卧土层的整体压缩量则由承台与桩两部分荷载引起,可以相对准确地预测基础沉降量。工程实例分析与实测结果的比较表明该方法是可行的。 相似文献
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Selection of wastewater treatment process based on the analytical hierarchy process and fuzzy analytical hierarchy process methods 总被引：2，自引：1，他引：1
A. R. Karimi N. Mehrdadi Ph.D. S. J. Hashemian G. R. Nabi Bidhendi R. Tavakkoli Moghaddam 《International Journal of Environmental Science and Technology》2011,8(2):267-280
This paper presents an application of the analytical hierarchy process and fuzzy analytical hierarchy process methods for selecting the best wastewater treatment process. The analytical hierarchy process is one of the best ways for deciding among the complex criteria structure in different levels, and the fuzzy analytical hierarchy process is a synthetic extension of the classical method when the fuzziness of the decision makers are considered. After reviewing aerobic treatment processes operated in Iran’s industrial estates and determining the main criteria used for treatment process evaluation, they are arranged in a hierarchy structure. Selection of the best wastewater treatment process is a multi-criteria decision making problem. Conventional methods are inadequate for dealing with the imprecise or vague nature of linguistic assessment. To overcome this difficulty, the fuzzy analytical hierarchy process is proposed for dealing with the vagueness of decision makers’ judgments. The alternatives consist of extended aeration, absorption bio-oxidation, integrated fixed-film activated sludge, sequencing batch reactor, aerated lagoon. Based on the general condition of industrial estate’s wastewater treatment plants, technical/administrative, economic and environmental criteria and their sub-criteria are weighted and then criteria evaluated and priorities of alternatives have been done by analytical hierarchy process and fuzzy analytical hierarchy process methods by the use of triangular fuzzy numbers. Finally, selection of the best process and ranking of these five processes are carried out by these foregoing methods, and some sensitivity analyses are conducted to show the results’ sensitiveness to the changes of the weights of the evaluation criteria. 相似文献
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The enantiomeric excesses determined for eight amino acids and one hydroxy acid of carbonaceous chondrite meteorites represent to date the only case of molecular asymmetry measured outside the biosphere. Because of the chiral homogeneity of life’s structures and functions, the findings have been debated for the possible relevance that a-biotic chiral symmetry-breaking might have had in the origin of terrestrial homochirality. While the many unknowns surrounding the origin of life have inevitably hindered the inquiries raised in this discourse, the hypotheses put forward in regard to the origin of extraterrestrial chiral asymmetry, which is a defined physico-chemical phenomenon, have been approached analytically and their scrutiny has aided the understanding of pre-biotic chemical evolution. We report here on our current knowledge of the asymmetric effects that could have influenced the chiral symmetry breaking of molecules in cosmochemical environments and how they correlate with the data obtained from meteorite analyses. We also address recent proposals that aqueous processes might have influenced the chirality of amino acids in meteorites and show that the crystallization behavior of isovaline, the most abundant non-racemic amino acid in the Murchison meteorite, excludes its attainment of enantiomeric excesses via phase changes such as crystallization or sublimation. 相似文献
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环境介质中铊的分布及其分析测试方法 总被引：23，自引：0，他引：23
铊在水、土壤、矿物岩石、生物及人体等环境介质中的自然分布均较低，但矿山资源的开发利用等人为因素造成了铊对环境的严重污染。污染地区介质中铊含量超出了背景值的几十倍、几百倍，甚至上万倍。为了对环境中铊污染进行监测和治理，必须发展铊的分析测试技术。除了传统的原子吸收光谱法、分光光度法等方法外，建议推广ICP—MS等灵敏度高、测试方法简单的测试方法。 相似文献
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我国规范液化分析方法的发展设想 总被引：1，自引：0，他引：1
通过分析我国地震形势、液化震害潜在威胁以及震害防御工作现状,阐明了我国发展液化分析方法的客观需求,简要评述了我国规范中现有液化判别方法,总结了我国近来两次大地震液化考察经验,提出了与规范修订相关的研究设想。通过我国地震安全性评价工作的发展现状以及我国大陆地震重点监视区与第四纪沉积分布性态分析,说明了我国发展液化分析方法的必要性和紧迫性。根据2003年新疆巴楚地震和2008年汶川大地震中液化震害考察结果,比较我国规范现状,提出了与未来规范的完善和发展相关的10个研究课题,包括：液化对设计谱的影响、 特殊土类液化判定标准、区域性的液化判别标准、场地液化概率评价、基于液化土层PGD的结构物损害估计、液化引起地裂缝的生成条件、基于剪切波速的液化判别方法、VI度区内场地液化及危害性判定、深层土液化判定以及场地液化的现场判定和识别技术 相似文献
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J. L. Fernndez-Turiel M. E. Durn X. Querol A. Lpez-Soler 《Journal of Geochemical Exploration》1992,43(3)
The scheelite dispersion was studied in a drainage system over an area of 150 km2 with stratabound mineralization of scheelite in a Pre-Ordovician volcano-sedimentary Series in the Hercynian Iberian Massif (Zamora province, NW Spain). A density of two samples per square kilometer (approximately 500 m sample spacing along streams), a sample volume of 10 l and sieving at 5 mm ensure that an anomaly source is detected. It was found that the dispersion of scheelite is typically less than 1 km. The methods applied to panned concentrates (mineralometric scheelite study, with or without multifractional grain size basis, and X-ray fluorescence tungsten analysis) give similar anomaly patterns and are efficient in exploration for scheelite mineralization. 相似文献