Geochemical baseline of trace elements in the sediment in Dexing area,South China

A baseline might be used as a point of reference to monitor change from some specific data without concern for whether the baseline determination is natural or has been changed by human activity. We selected 326 sediment samples from Dexing area, South China, and analyzed for 17 chemical elements. The geochemical baseline was predicted with the method of the normalization procedure combined with the relative cumulative frequency curve. The results indicate Al was the best reference element for the normalization procedure among four potential reference elements (Al, Fe, Ti, and Mn). The baseline value range obtained from the normalization procedure method included both the regional geochemical background of the sediment and the median value of the measured contents. The median value of baselines obtained from relative cumulative frequency method was lower than that obtained from normalization procedure method. In contrast to the geochemical patterns of heavy metals in 1987, the spatial distribution of anomalies sprawled in 2004 in study area, especially for Cu, Pb, Zn, Cd, As, Fe, and Cr.     

江苏土壤地球化学分区

土壤地球化学分区的实质就是依据不同地区土壤中元素含量等差异及其分布规律,划分地球化学特征一致或相似的土壤分布范围。以江苏1:25万区域生态地球化学调查新获得的大量土壤样品元素含量等测试数据为基础,从全省土壤元素含量等分布不均匀的现状出发,根据土壤中的元素组合、特殊元素含量差异、酸碱度差异等,并结合各地第四纪地质作用特点等要素,将江苏土壤划分为3个地球化学区、24个地球化学亚区,指出了部分土壤地球化学亚区的特殊用途,为江苏土地资源保护与利用提供了新的线索。     

Application of a normalization procedure in determining regional geochemical baselines

 The regional variability of some geochemical parameters in the Gulf of Trieste is considered in terms of their relationship with Al, used as a normalization factor. Baselines calculated from these relationships are used to determine a simple enrichment factor for each element, defined as the ratio between the actual and predicted baseline value. The normalization procedure permits a new non dimensional reference baseline to be obtained that could help to assess the size of possible anomalies and to provide information on the diffusion and dispersion patterns of pollutants inside the monitored area. Received: 24 August 1995 · Accepted: 15 October 1995     

基于元素含量和空间变异系数的化探异常信息识别

化探异常信息识别是化探数据分析最重要的任务之一, 也是化探数据在资源勘查领域受到广泛关注的最重要原因, 前人对化探异常信息识别做过大量研究, 这些研究中的大多数主要关注化探示踪元素的含量, 近而根据含量指标计算异常阈值, 而对示踪元素在空间中的分布特征关注较少。本文选择 1: 20万比例尺的克拉玛依幅为研究区, 根据区内金矿的矿床地球化学特征选择Ag、As、Au和Sb等4种元素为本区内金矿的示踪元素, 以地球化学元素分散晕形成理论为依据, 使用GIS技术和Matlab软件绘制研究区内4种金矿示踪元素的综合地球化学异常图。结果表明, 与传统阈值方法得到的化探异常图相比, 本文得到的化探异常图能够更好地指示研究区内已知金矿。     

Soil and plant composition in the Noun river catchment basin,Western Cameroon: a contribution to the development of a biogeochemical baseline

Soils and selected edible plants of the Noun river catchment basin of western Cameroon were sampled to investigate the distribution of trace elements, based on the preliminary idea of unusual anomalies. Analytical techniques for trace elements included ICP-AES, GF-AAS, and ICP-MS. Further soil analyses comprised the mineralogy and contents of the biogenic elements carbon, nitrogen and sulphur (CNS). The trace element concentrations in the soils reflect those of the lithogeochemical background of the pluto-volcanic rocks of the region. This is consistent with the results from the mineralogical analyses and physicochemical parameters such as pH, taken in the field, which also do not suggest any geochemical anomaly. Most trace elements analyzed in the plants showed concentrations that reflect those of the soils (Al, Fe, Ti, and Rb). However, some trace elements were enriched in the plants as compared to the soils, such as Zn, Cu, Cd, Mo (excluding yam), Ni (peanut), Ba (peanut), Sr (peanut, bean), and B. Trace elements such as As, Cr, V, and Se were not bioavailable for all the analyzed plants. Besides, trace elements such as Cu, Zn, Mo, Fe, Al, Ni, B, Ti, Rb, Cs, and Ba were in the range of phytotoxicity and reached or exceeded human food tolerance level (Cu). The plants with seeds showed a higher absorption of trace elements compared to plants with tubercles.     

A geochemical survey of trace elements in agricultural and non-agricultural topsoil in Dexing area,China

In China, soil pollution is very serious, which has jeopardized the ecology, food safety, the people's health, and even the sustainable development of agriculture. In order to investigate the soil pollution situation, a total of 874 agricultural and non-agricultural topsoil samples were collected from Dexing area, northeast of Jiangxi Province, China. The total elemental concentrations of 17 elements (As, Hg, Mo, Cd, Cr, Zn, Cu, Mn, Ti, Pb, Fe, Ca, K, Si, Al, Mg, and Na) were determined. The geochemical background and threshold was predicted with the method of the median ± median absolute deviation (MAD). The agricultural soil median concentration of trace elements was similar to that of the non-agricultural soil. In contrast to Jiangxi soil background of trace elements, the geochemical background of the study area was obviously higher. The maps of the pollution indices for As, Cd, Cr, Cu, Hg, Mn, Mo, Pb, Ti and Zn of non-agricultural soil and agricultural soils in the study area, showed that the highest level of pollution is distributed near and along the Lean River, especially in the neighboring and surrounding Dexing and Leping mining area.     

Soil and stream sediment based geochemical mapping: A case study in Goa

Geochemical mapping has been carried out in Goa using soil/laterite and stream sediment as media. The geochemical maps for U, Th, Nb and Ta show a conspicuous pattern in the NW part of Goa. The anomaly axis shows a NE-SW trend which is across the formational trend. The nickel and copper distribution around Usgaon area, east of Ponda, have indicated anomalous signature in the northern continuation of the Usgaon ultramafic complex.     

滁州地区土壤地球化学基准值与背景值研究

基于滁州地区多目标区域地球化学调查数据资料,统计获得了表、深层土壤地球化学基准值、背景值及相关的地球化学参数。研究表明：成土母质类型对土壤元素地球化学基准值影响显著,表层土壤元素含量相对于深层土壤既有继承性,又有差异性。在不同的土壤层的一些元素含量明显不同。土壤的形成过程和人类活动已经对土壤中元素含量的分布有显著的影响。因此,土壤地球化学基准值与背景值研究中应多考虑地质背景、物质来源等因素的影响,     

Background levels and baseline values of available heavy metals in Mediterranean greenhouse soils (Spain)

This study determines extractable levels of Cd, Cu, Pb, Zn, Ni and Co in western Almería (Spain) greenhouse surface soil horizons using EDTA solution, which is identified as the fraction available for organisms and plants. It also establishes background levels, geochemical baseline concentration and reference values (RV), and investigates the possible relationships between soil properties and elemental concentrations. The results show that the soil concentration of these extractable heavy metals was high as those reported by other authors for Spanish agricultural soils. The available RV concentrations obtained (mg kg⁻¹) were: Cd 0.17, Cu 1.6, Pb 13.8, Zn 5.0 Ni 1.7 and Co 2.9. Using the upper baseline criterion, 95% of greenhouse soils present a relatively higher content of extractable heavy metals given their Cd and Cu concentration. Significant correlations between total and EDTA-extractable metal levels were found for Zn, Pb, Cu, Cd and Ni. Soil properties also related to heavy metals content, suggesting that Cd, Cu, Pb and Zn are of similar origin and relate to anthropic activities, and implies the same interactions and/or relationships among these metals.     

Selective chemical extraction of heavy metals in tailings and soils contaminated by mining activity: Environmental implications

Total concentrations of chemical elements in soils may not be enough to understand the mobility and bioavailability of the elements. It is important to characterise the degree of association of chemical elements in different physical and chemical phases of soil. Another geochemical characterisation methodology is to apply sequential selective chemical extraction techniques. A seven-step sequential extraction procedure was used to investigate the mobility and retention behaviour of Al, Fe, Mn, Cu, Zn, Pb, Cr, Co, Ni, Mo, Cd, Bi, Sn, W, Ag, As and U in specific physical–chemical and mineral phases in mine tailings and soils in the surroundings of the abandoned Ervedosa mine. The soil geochemical data show anomalies associated with mineralised veins or influenced by mining. Beyond the tailings, the highest recorded concentrations for most elements are in soils situated in mineralised areas or under the influence of tailings. The application of principal components analysis allowed recognition of (a) element associations according to their geochemical behaviour and (b) distinction between samples representing local geochemical background and samples representing contamination. Some metal cations (Mn, Cd, Cu, Zn, Co, Cr, Ni) showed important enrichment in the most mobilisable and bioavailable (i.e., water-soluble and exchangeable) fractions due likely to the acidic conditions in the area. In contrast, oxy-anions such as Mo and As showed lower mobility because of adsorption to Fe oxy-hydroxides. The residual fraction comprised largest proportions of Sn and Al and to a lesser extent Zn, Pb, Ni, Cr, Bi, W, and Ag, which are also present at low concentrations in the bioavailable fractions. The elements in secondary mineral phases (mainly Fe, Mn, Cu, Zn, Cd, Pb, W, Bi, Mo, Cr, Ni, Co, As and U) as well as in organic matter and sulphides are temporarily withheld, suggesting that they may be released to the environment by changes in physico-chemical conditions.     

Trace elements in sub-alpine forest soils on the eastern edge of the Tibetan Plateau,China

Industrial development has increased fast in China during the last decades. This has led to a range of environmental problems. Deposition of trace elements to forest ecosystems via the atmosphere is one potential problem. In this paper, we report the results from a pilot study where the trace element levels of the sub-alpine forest soils on the eastern edge of the Tibetan Plateau have been measured. Possible relationships between soil properties and trace element concentrations have also been investigated. The obtained concentrations (mg kg⁻¹) were boron (B) 48.06–53.70, molybdenum (Mo) 1.53–2.26, zinc (Zn) 68.18–79.53, copper (Cu) 36.81–42.44, selenium (Se) 0.33–0.49, cadmium (Cd) 0.16–0.29, lead (Pb) 25.80–30.71, chromium (Cr) 96.10–110.08, nickel (Ni) 30.16–45.60, mercury (Hg) 0.05–0.11, and arsenic (As) 3.09–4.17. With a few exceptions, the element concentration can be characterized as low in the investigated sub-alpine forest soils. No clear differences in trace element levels were found between topsoil and subsoil samples, indicating that the atmospheric deposition of trace element has been low. The soil parent material plays a key role to determine trace element levels. Soil properties, including pH_w, organic carbon (OC), clay fraction, cation-exchange capacity (CEC), total iron (Fe), and total aluminum (Al) concentrations were related to trace element concentration using correlation analysis. Total Fe and Al showed the strongest relationships with concentrations of most trace elements in the sub-alpine forest soils. PCA analyses indicated that a significant increase in the number of cars with the fast development of local tourism may result in higher Pb concentration in the future.     

成都经济区近地表大气尘地球化学基线

成都经济区近地表大气尘中重金属元素含量空间分布显示,经济区中东部高于西部,北部高于中南部,重工业城市高于综合性城市和旅游城市,工矿影响区元素含量总体偏高,人口密集的平原区高于山区。通过标准极限方法确定了近地表大气尘中元素的“极限浓度”,以低于“极限浓度”值统计确定了地球化学基线值：As为28.6mg/kg 、Hg 0.63mg/kg 、Cd 2.94mg/kg、Cr 110mg/kg、Pb 281mg/kg、Ni 32mg/kg、Zn 535mg/kg。近地表大气尘中元素地球化学基线与区域地质背景和矿产开发有关,矿业活动、工业活动及居民生活是造成近地表大气尘中人为扰动元素含量偏高的主要原因。     

成都经济区近地表大气尘地球化学基线

成都经济区近地表大气尘中重金属元素含量空间分布显示,经济区中东部高于西部,北部高于中南部,重工业城市高于综合性城市和旅游城市,工矿影响区元素含量总体偏高,人口密集的平原区高于山区。通过标准极限方法确定了近地表大气尘中元素的“极限浓度”,以低于“极限浓度”值统计确定了地球化学基线值：As为28.6mg/kg 、Hg 0.63mg/kg 、Cd 2.94mg/kg、Cr 110mg/kg、Pb 281mg/kg、Ni 32mg/kg、Zn 535mg/kg。近地表大气尘中元素地球化学基线与区域地质背景和矿产开发有关,矿业活动、工业活动及居民生活是造成近地表大气尘中人为扰动元素含量偏高的主要原因。     

金红石中锆含量温度计及其微量元素地球化学特征

Zack et al.(2004a)、Watson et al.(2006)以及Tomkins et al.(2007)(在2GPa条件下)的金红石中锆含量温度计计算结果显示,徐淮地区中生代侵入杂岩所含榴辉岩类包体所经历的榴辉岩相变质的温度范围分别为776～1099℃(平均898℃)、663～923℃(平均750℃)和714～981℃(平均804℃),这些温度结果可能并非榴辉岩相峰期变质温度;其角闪岩相退变质作用过程中保存的温度范围分别为555～777℃(平均697℃)、541～663℃(平均6170C)和588～714℃(平均667℃),这些结果不能代表角闪岩相退变质再平衡后的温度,而只能代表角闪岩相退变质作用过程中某-阶段的温度.微量元素地球化学特征研究表明,榴辉岩类包体所含金红石中的某些微量元素(如Nb、Ta、Cr、Fe、V等)含量与其原岩有继承和对应关系,其原岩主要为镁铁质岩石;榴辉岩类包体与其寄主岩石中部分高价态/高场强元素(HFSE)呈相互消长的关系.榴辉岩的形成与扬子地块和华北地块之间的俯冲,碰撞作用有关.     

Use of geochemical modeling to evaluate the hydraulic connection of aquifers: a case study from Chianan Plain, Taiwan

Aquifers are generally composed of highly permeable layers that can conduct a considerable amount of groundwater. Traditionally, aquifer units are correlated through the concept of lithostratigraphy. For low-permeable aquifers, it is difficult to define the spatial distribution of hydrogeological units, and this study attempts to use geochemical modeling to identify the groundwater flow paths in an area of Taiwan. Multiple geochemical analyses, including groundwater chemistry; stable isotopic compositions of hydrogen, oxygen and carbon; and radiocarbon contents were performed. Using these parameters as the constraints of geochemical models, the hydraulic connection was examined between pairs of possibly interlinked wells along four selected cross sections, and the conceptual groundwater model was accordingly established. The resultant model suggests that the hydraulic connection between aquifers should be correlated with the concept of chronological stratigraphy, especially for low-permeable, unconsolidated aquifers. Using Darcy’s law, the hydraulic conductivities of the fine-sand aquifers were estimated to be between 3.14 × 10⁻⁵ and 1.80 × 10⁻⁴ m/s, which are roughly one order of magnitude higher than those derived by in situ pumping tests. The substantial extraction of groundwater over a long period in the studied area could accelerate groundwater flow, leading to an overestimation of the aquifer permeability.

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Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.

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Résumé En règle générale, les aquifères sont constitués de couches très perméables capables de conduire des quantités d’eau considérables. Les unités aquifères sont traditionnellement corrélées d’un point de vue lithostratigraphique. Dans le cas des aquifères à faible perméabilité, il s’avère difficile de définir une distribution spatiale des unités hydrogéologiques, et cette étude tente d’utiliser la modélisation géochimique pour identifier les cheminements des eaux souterraines dans un secteur de Taiwan. Plusieurs analyses géochimiques ont été réalisées ; elles incluent la chimie des eaux souterraines, les isotopes stables de l’hydrogène, de l’oxygène et du carbone et l’abondance en carbone 14. En utilisant ces paramètres comme contraintes pour les modèles géochimiques, les liaisons hydrauliques entre les puits potentiellement interconnectés ont été étudiées deux par deux, le long de quatre coupes présélectionnées, et le modèle conceptuel a été établi en conséquence. Ce modèle résultant suggère que les connexions hydrauliques inter-aquifères devraient être corrélées avec les concepts stratigraphiques, surtout pour les aquifères non consolidés à faible perméabilité. Les perméabilités dans les aquifères de sables fins ont été estimées par la loi de Darcy entre 3.14 × 10⁻⁵ et 1.80 × 10⁻⁴ m/s, soit environ un ordre de grandeur au-dessus de celles issues des tests de pompage sur site. L’exploitation substantielle des eaux souterraines sur une longue période dans la zone d’étude peut accélérer les écoulements souterrains, menant à une surestimation de la perméabilité de l’aquifère.

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Resumen Los acuíferos están generalmente compuestos de capas muy permeables que pueden conducir una cantidad considerable de agua subterránea. Tradicionalmente, se ponen en correlación las unidades acuíferas a través del concepto de litoestratigrafía. Para los acuíferos de baja-permeabilidad, es difícil de definir la distribución espacial de unidades hidrogeológicas y este estudio intenta usar modelamiento geoquímico para identificar las direcciones del flujo de agua subterránea en un área de Taiwán. Se realizó el análisis geoquímico múltiple, incluyendo la química del agua subterránea, la composición de isótopos estables de hidrógeno, oxígeno y carbono, y el contenido de radiocarbono. Usando estos parámetros como limitantes de modelos geoquímicos, la conexión hidráulica se examinó entre pares de pozos posiblemente interrelacionados, a lo largo de cuatro cortes transversales seleccionados y de acuerdo con esto se estableció el modelo conceptual del agua subterránea. El modelo resultante sugiere que la conexión hidráulica entre los acuíferos deba interrelacionarse con el concepto de estratigrafía cronológica, sobre todo para los acuíferos sin consolidar de baja permeabilidad. Usando la ley de Darcy, se estimaron las conductividades hidráulicas de los acuíferos de arena fina obteniendo valores entre 3.14 × 10⁻⁵ y 1.80 × 10⁻⁴ m/s, las cuales son aproximadamente un orden de magnitud mayor, que aquéllos obtenidos in situ por las pruebas de bombeo. La extracción considerable de agua subterránea durante un periodo largo en el área estudiada, podría acelerar el flujo de agua subterránea, llevando a una sobrestimación de la permeabilidad en los acuíferos.

     

Trace element contents and correlation in surface soils in China's eastern alluvial plains

 A study investigating the contents of 13 trace elements and the correlations between these trace elements and soil parameters of the surface soils in the eastern alluvial plains of China is summarized and discussed in this paper. The results show that the contents of some elements studied differ from region to region. Close relations have been noted between all the trace element contents in the soils of the eastern alluvial plains and the relevant surface materials of erosion regions, which demonstrate the effects of parent materials, while climatic conditions and human interventions are also found to be important factors. Close relations were found between the transition elements of the Quaternary period and the chalcophile elements (except Cu). The chemical and geochemical properties of these elements are identified as beeing important inherent characteristics that affect the relations of these elements in the soils. Received: 5 June 1997 · Accepted: 2 March 1998     

重要的地球化学"信息库"

金红石是各种岩石特别是地壳组成岩石中重要的副矿物,它在成岩、风化和各种不同程度的变质过程中均能保持极大的稳定性。同时,除主要成分TiO₂外,金红石还含有为数众多的其它微量元素(例如: Nb, Ta, Zr, Hf, Sn, Mo, Sb, Cr, V, W, U和Pb等),这些微量元素的变化特征,对于包含金红石的主体岩石所经历的地质过程具有非常重要的指示意义。近二十年特别是近十年来,金红石已成为地球化学研究领域的一个热点。对各种元素和同位素在金红石中变化特征的调查,被广泛地应用于对各种地质过程的了解,其研究应用的范围涉及到了整体地球的元素平衡、大陆地壳的形成机制、含金红石岩石的形成源区、变质岩石的温压条件和形成时代的研究等多个方面,同时其所包含的各种同位素体系也被广泛用于各种地质过程的示踪。本文综合近年来金红石研究的最新进展,系统表述了金红石作为一个近年来发展起来的重要地质信息储库,在地球化学研究中各个方面的应用。     

Study of the distribution of Trace elements in soils in and around Mysore city,Karnataka

Soil samples collected from various places in and around Mysore were analyzed for the total trace elements such as Fe, Mn, Cu, Zn, Pb, and Cd. The results of the analysis indicate that the concentration of lead and cadmium in soils is below 2.5 g ml^–1 and 0.2 g ml^–1, respectively, which are the minimum detection levels, whereas the concentration of iron, manganese, copper, and zinc in most of the samples is within the global average ranges of 3%, 500–1000 g g^–1, 15–40 g g^–1, and 50–100 g g^–1, respectively. The investigated area has the presence of gneisses and schists, in which partly there are igneous intrusions and pegmatitic intrusions. There are amphibolite enclaves in gneisses that account for the higher concentration of trace elements. The lower concentration may be attributed to the presence of silicic type of rock.     

Petrological, organic geochemical and geochemical characteristics of coal from the Soko mine, Serbia

A petrological, organic geochemical and geochemical study was performed on coal samples from the Soko Mine, Soko Banja basin, Serbia. Ten coal and two carbonaceous clay samples were collected from fresh, working faces in the underground brown coal mine from different parts of the main coal seam. The Lower Miocene, low-rank coal of the Soko Mine is a typical humic coal with huminite concentrations of up to 76.2 vol.%, liptinite less than 14 vol.% and inertinite less than 11 vol.%. Ulminite is the most abundant maceral with variable amounts of densinite and clay minerals. Sporinite and resinite are the most common macerals of the liptinite group. Inertodetrinite is the most abundant maceral of the inertinite group. The mineral-bituminous groundmass identified in some coal samples, and carbonaceous marly clay, indicate sub-aquatic origin and strong bacterial decomposition. The mean random huminite reflectance (ulminite B) for the main coal seam is 0.40 ± 0.05% Rr, which is typical for an immature to early mature stage of organic matter.The extract yields from the coal of the Soko Banja basin ranges from 9413 to 14,096 ppm, in which alkanes constituted 1.0–20.1%, aromatics 1.3–14.7%, asphaltenes 28.1–76.2% and resins 20.2–43.5%. The saturated hydrocarbon fractions included n-C₁₅ to n-C₃₂, with an odd carbon number that predominate in almost all the samples. The contents of n-C₂₇ and n-C₂₉ alkanes are extremely high in some samples, as a contribution of epicuticular waxes from higher plants. Acyclic isoprenoid hydrocarbons are minor constituents in the aliphatic fraction, and the pristane/phytane (Pr/Ph) ratio varies between 0.56 and 3.13, which implies anaerobic to oxic conditions during sedimentation. The most abundant diterpanes were abietane, dehydroabietane and 16α(H)-phyllocladane. In samples from the upper part of the coal seam, diterpanes are the dominant constituents of the alkane fraction. Polycyclic alkanes of the triterpane type are important constituents of alkane fractions. The occurrence of ββ- and αβ-type hopanes from C₂₇ to C₃₁, but without C₂₈, is typical for the Soko Banja coals.The major and trace elements in the coal were analysed using X-ray fluorescence (XRF), and inductively coupled plasma-mass spectrometry (ICP-MS). In comparison with world lignites, using the geometric mean value, the coal from the Soko Banja Basin has a high content of strontium (306.953 mg/kg). Higher values than the world lignites were obtained for Mo (3.614 mg/kg), Ni (8.119 mg/kg), Se (0.884 mg/kg), U (2.642 mg/kg) and W (0.148 mg/kg). Correlation analysis shows inorganic affinity for almost all the major and trace elements, except for S, which has an organic affinity.     

陕西商洛马角寺钼矿区土壤地球化学特征及找矿前景——地球化学找矿的典型实例

陕西商洛马角寺钼矿位于小秦岭多金属成矿带西部,矿区出露元古界至新生界地层,区内褶皱和断裂较为发育。1∶50 000水系沉积物测量在本区圈出Mo、Pb、Zn等元素异常,指示有多金属找矿前景。在区内开展1∶10 000土壤测量工作,并对取得的大量数据进行统计分析,研究总结矿区土壤地球化学特征,显示本区Mo、(Au)为成矿元素,Ag、Pb、Zn等为指示元素;同时,在区内再次圈出Mo、Ag、Pb、Zn等元素异常,异常再现性较好。运用1∶2 000地球化学剖面对土壤异常进行查证,发现一条含钼矿化构造带(Q1),从中圈出Mo矿体多条。综合研究1∶10 000地球化学特征显示,本区仍有Mo、(Au)矿床的找矿前景。