Ecological geochemical assessment and source identification of trace elements in atmospheric deposition of an emerging industrial area: Beibu Gulf economic zone.

Science.gov (United States)

Zhong, Cong; Yang, Zhongfang; Jiang, Wei; Hu, Baoqing; Hou, Qingye; Yu, Tao; Li, Jie

2016-12-15

Industrialization and urbanization have led to a deterioration in air quality and provoked some serious environmental concerns. Fifty-four samples of atmospheric deposition were collected from an emerging industrial area and analyzed to determine the concentrations of 11 trace elements (As, Cd, Cu, Fe, Hg, Mn, Mo, Pb, Se, S and Zn). Multivariate geostatistical analyses were conducted to determine the spatial distribution, possible sources and enrichment degrees of trace elements in atmospheric deposition. Results indicate that As, Fe and Mo mainly originated from soil, their natural parent materials, while the remaining trace elements were strongly influenced by anthropogenic or natural activities, such as coal combustion in coal-fired power plants (Pb, Se and S), manganese ore (Mn, Cd and Hg) and metal smelting (Cu and Zn). The results of ecological geochemical assessment indicate that Cd, Pb and Zn are the elements of priority concern, followed by Mn and Cu, and other heavy metals, which represent little threat to local environment. It was determine that the resuspension of soil particles impacted the behavior of heavy metals by 55.3%; the impact of the coal-fired power plants was 18.9%; and the contribution of the local manganese industry was 9.6%. The comparison of consequences from various statistical methods (principal component analysis (PCA), cluster analysis (CA), enrichment factor (EF) and absolute principle component score (APCS)-multiple linear regression (MLR)) confirmed the credibility of this research. Copyright © 2016 Elsevier B.V. All rights reserved.

Geochemical characteristics of trace and rare earth elements in Xiangyangping uranium deposit of Guangxi

International Nuclear Information System (INIS)

Chen Qi; Xiao Jianjun; Fan Liting; Wen Cheng

2013-01-01

The trace and rare earth elements analysis were performed on two kinds ore-hosting rocks (Xiangcaoping granite and Douzhashan granite), alternated cataclastic granite and uranium ores in Xiangyangping uranium deposit of Guangxi. The results show that both of the two kinds granites display similar maturity features of highly evolved crust with the enrichment of Rb, Th, U, Ta and Pb, the depletion of Ba and Sr, high Rb/Sr and low Nb/Ta ratio, moderately rich light rare earth elements, strong negative Eu anomaly. Moreover, Douzhashan granite have higher Rb/Sr ratio and U content, which indicate it experienced more sufficient magma evolution and have higher potential of uranium source. There are almost no change in the content of trace and rare earth elements and distribution patterns during chloritization, hydromicazation and potash feldspathization of granite, but there occurred uranium enrichment and mineralization and REE remobilization while hematitization was superposed. This suggest that hematitization is most closely correlated with uranium mineralization in the working area. Because Most hematitization cataclastic rocks and uranium ore display similar geochemical characteristics to Douzhashan granite with relative high Rb/Sr and low Nb/Ta, Zr/Hf, ΣREE, LREE/HREE ration, and the trace and rare earth elements content and distribution patterns of some Xiangcaoping hematitization cataclastic rocks are between the two kinds of granite, therefore it can be concluded that the mineralization materials were mainly from Douzhashan granite and partly from Xiangcaoping granite. (authors)

The Acampamento Velho Formation is a succession of rhyolitic basaltic belong to the lower Paleozoic.: Geochemical characterization of the trace elements and strange lands

International Nuclear Information System (INIS)

De Almeida, M.; Zerfass, H.; De Lima, L.

1998-01-01

During at the end of Brazilian orogeny cycle (lower Paleozoic), the Camaqua basin was filled by a thick vulcanic series, named Acampamento Velho Formation , which consists of a recurrence of basaltic episodes (at the base) and the alternance of pyroclastic rocks with a rhyolitic composition TBr and Igr) in the intermediate portion and rhyolitic flows (Dr) at the top. Based on the geochemical results, especially on the trace elements such as Zr, Ti, Nb, Y, YB,Th. Ta and the REE., it is confirmed the stratigraphical succession and the depositation chronological order observed in the field. All the volcanic succession presents a behavior pattern typical of post- collisional orogenic, rocks, originated from the crustal contamination of basaltic magmas generated in an environment of the active continental margin. (author)

Geochemical Indicators of the Carbonate Sedimentation Depositional Environments and Geodynamic Conditions in the East of the Middle Urals in the Kizelovian Time

Directory of Open Access Journals (Sweden)

S. A. Dub

2017-12-01

Full Text Available Geochemical characteristics of the limestones of Kizelovskian substage of the Eastern Urals zone (Rezh River, Middle Urals, such as carbon and oxygen isotopic composition, concentration of minor and trace elements, and redox value indicators, were studied in details. Based on the results of data interpretation and analysis of lithological features, it was assumed that carbonate deposits formed in shallow oxygen-rich environment with high bioproductivity warm water ecosystem, and within the isolated carbonate platform with a steady sinking territory. Some signs indicate that sedimentation during the Kizelovian time occurred in the inner lagoon of a large atoll. The Maldivian archipelago could be a contemporary analogue of the Rezhevskaya carbonate platform.

Impact of geo-chemical environment of subsurface water on the measurement of ultra trace level of uranium in ground water by adsorptive stripping voltammetry

International Nuclear Information System (INIS)

Singhal, R.K.; Preetha, J.; Karpe, Rupali; Ajay Kumar; Hegde, A.G.

2005-01-01

During the present work, impacts of cations (Ca 2+ , Mg 2+ , K + ,), anions (Cl -1 , F -1 , and PO 4 3- ) and DOC (Dissolved Organic Carbon) on the measurement of ultra trace level of uranium (VI) in subsurface water by adsorptive stripping voltammetry (AdSV) is studied. The concentrations of these anions, cations and DOC in subsurface water changes due to change in the geo-chemical environment at different locations. In AdSV, concentration of U was determined by forming an uranium-chloranilic acid complex (2,5-dichloro- 3,6-dihydroxy-1,4-benzoquinone). AdSV measurements were carried out in the differential pulse (DP) mode using a pulse amplitude of -50 mV, a pulse time of 30 ms and a potential step of 4 mV. The detection limit, was calculated to 2+ , Mg 2+ , K + ) and anions (Cl -1 , F -1 , and PO 4 3- ) was carried out by using Ion Chromatography. Ground water samples were spiked with varying degree of cations, anions and DOC (dissolved organic carbon). DOC in ground waters were measured by Total Organic Carbon (TOC) analyzer. Various experiments show that analysis of uranium in the concentration range of 2+ , Mg 2+ , K + , Cl -1 , F -1 , and PO 4 3- . In case of DOC there is no interference observed in the concentration range of 0.02-15 ppm but beyond 15 ppm the concentration of uranium decrease sharply. Further, if DOC exceeded 16 ppm it was not possible to do the analysis of uranium by AdSV without destruction of DOC, as DOC is surface active organic compound and accumulates on Hg electrode preferentially over uranium-chloroanailic complex. (author)

Granite-repository - geochemical environment

International Nuclear Information System (INIS)

1979-04-01

Some geochemical data of importance for a radioactive waste repository in hard rock are reviewed. The ground water composition at depth is assessed. The ground water chemistry in the vicinity of uranium ores is discussed. The redox system in Swedish bedrock is described. Influences of extreme climatic changes and of repository mining and construction are also evaluated

Geochemical tracing and hydrogeochemical modelling of water-rock interactions during salinization of alluvial groundwater (Upper Rhine Valley, France)

Energy Technology Data Exchange (ETDEWEB)

Lucas, Y., E-mail: yann.lucas@eost.u-strasbg.fr [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France); Schmitt, A.D., E-mail: anne-desiree.schmitt@univ-fcomte.fr [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France)] [Universite de Franche-Comte et CNRS-UMR 6249, Chrono-Environnement, 16, Route de Gray, 25030 Besancon Cedex (France); Chabaux, F., E-mail: francois.chabaux@eost.u-strasbg.fr [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France); Clement, A.; Fritz, B. [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France); Elsass, Ph. [BRGM, GEODERIS, 1, rue Claude Chappe, 57070 Metz (France); Durand, S. [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France)

2010-11-15

Research highlights: {yields} Major and trace elements along with strontium and uranium isotopic ratios show that groundwater geochemical characteristics along the saline plumes cannot reflect a conservative mixing. {yields} A coupled hydrogeochemical model demonstrates that cationic exchange between alkalis from polluted waters and alkaline-earth elements from montmorillonite present in the host rock of the aquifer is the primary process. {yields} The model requires only a small amount of montmorillonite. {yields} It is necessary to consider the pollution history to explain the important chloride, sodium and calcium concentration modifications. {yields} The model shows that the rapidity of the cationic exchange reactions insures a reversibility of the cation fixation on clays in the aquifer. - Abstract: In the southern Upper Rhine Valley, groundwater has undergone intensive saline pollution caused by the infiltration of mining brines, a consequence of potash extraction carried out during the 20th century. Major and trace elements along with Sr and U isotopic ratios show that groundwater geochemical characteristics along the saline plumes cannot reflect conservative mixing between saline waters resulting from the dissolution of waste heaps and one or more unpolluted end-members. The results imply the occurrence of interactions between host rocks and polluted waters, and they suggest that cationic exchange mechanisms are the primary controlling process. A coupled hydrogeochemical model has been developed with the numerical code KIRMAT, which demonstrates that cationic exchange between alkalis from polluted waters and alkaline-earth elements from montmorillonite present in the host rock of the aquifer is the primary process controlling the geochemical evolution of the groundwater. The model requires only a small amount of montmorillonite (between 0.75% and 2.25%), which is in agreement with the observed mineralogical composition of the aquifer. The model also proves

Geochemical fixation of carbon dioxide in the environment. Chikyu kagakuteki kenchi kara no tansan'en ni yoru nisanka tanso no kotei

Energy Technology Data Exchange (ETDEWEB)

Ishikawa, M [Mitsubishi Research Institute, Inc., Tokyo (Japan)

1993-06-15

The Mitsubishi Research Institute has investigated and discussed the current situation and the future direction of the studies on geochemical fixation of carbon dioxide by means of carbonates. This paper summarizes the results thereof. The discussion items are listed as follows: The current status of land areas active in carbonate fixation (lake-bottom deposits, sabkha, dry areas, carbonate rock areas); investigation on sea areas active in carbonate fixation (coral reef areas, land shelf areas, open sea areas, and mantle); development of environmental change analyzing technologies (measurement of ancient environments, measurement of fixation ages, development of local area analysis, measurement of diagenetic structures, origin and behavior of trace elements in carbonate substances, and measurement of the current environments); evaluation on fixation ability of carbon sinks (circulation and fixation in coral reef ecosystems, calcification mechanisms in calcareous algae, dissolution processes at ocean bottoms, and inorganic chemical measurement); and investigation on simulation models (solution chemistry equilibrium model and global carbonate circulation model). 4 refs., 1 tab.

Novel Geochemical Techniques Integrated In Exploration for Uranium Deposits at Depth

International Nuclear Information System (INIS)

Kyser, Kurt

2014-01-01

Recent results in the use of geochemistry in detecting deep uranium deposits: (1) Map element distributions in and around deposits to assess the total chemical environment associated with the deposit, (2) Use element tracing with isotopic compositions in surface media to detect specific components from uranium deposits at depth, (3) Capitalize on element mobility across the geosphere-biosphere interface to enhance exploration using select media, (4) Geochemical data from drill core or surface media can enhance target identification when integrated with geophysical data.

Geochemical study for primary dispersion of trace elements in uranium bearing black slates of the Ogcheon Group, Korea

International Nuclear Information System (INIS)

Kim, O.B.

1980-01-01

Total 145 boring core samples of Deogpyongri, Geosan and Mogsori, Geumsan in Ogcheon Group have been collected and analyzed for uranium and trace elements such as lead, zinc, copper, chromium, cadmium, vanadium and mloybdenium. All the data of the elments analyzed have been processed statistically by computer in order to estimate the correlation co-efficient between elements. The vertical distribution pattern of trace elements has been discussed. The results obtained are summarized as follows: Uranium has high correlation co-efficients with vanadium and molybdenium. And the last two can be used as indicator elements for the geochemical prospecting of uranium. The occurrence of uranium is closely related with the carbonaceous material in boring core of Ogcheon Group. Considering the vertical distribution pattern of uranium, it can't be said that the epigenetic uranium absorption to the carbonaceous material is in progress. The uranium minerals in the carbonanceous material must be correctly defined to resolve the genetic problems of uranium deposit in Ogcheon Group. (Author)

Behaviour and fate of nine recycled water trace organics during managed aquifer recharge in an aerobic aquifer

Science.gov (United States)

Patterson, B. M.; Shackleton, M.; Furness, A. J.; Bekele, E.; Pearce, J.; Linge, K. L.; Busetti, F.; Spadek, T.; Toze, S.

2011-03-01

The fate of nine trace organic compounds was evaluated during a 12 month large-scale laboratory column experiment. The columns were packed with aquifer sediment and evaluated under natural aerobic and artificial anaerobic geochemical conditions, to assess the potential for natural attenuation of these compounds during aquifer passage associated with managed aquifer recharge (MAR). The nine trace organic compounds were bisphenol A (BPA), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMOR), carbamazepine, oxazepam, iohexol and iodipamide. In the low organic carbon content Spearwood sediment, all trace organics were non-retarded with retardation coefficients between 1.0 and 1.2, indicating that these compounds would travel at near groundwater velocities within the aquifer. The natural aerobic geochemical conditions provided a suitable environment for the rapid degradation for BPA, E2, iohexol (half life NDMA and NMOR) did not degrade under either aerobic or anaerobic aquifer geochemical conditions (half life > 50 days). Field-based validation experiments with carbamazepine and oxazepam also showed no degradation. If persistent trace organics are present in recycled waters at concentrations in excess of their intended use, natural attenuation during aquifer passage alone may not result in extracted water meeting regulatory requirements. Additional pre treatment of the recycled water would therefore be required.

Behaviour and fate of nine recycled water trace organics during managed aquifer recharge in an aerobic aquifer.

Science.gov (United States)

Patterson, B M; Shackleton, M; Furness, A J; Bekele, E; Pearce, J; Linge, K L; Busetti, F; Spadek, T; Toze, S

2011-03-25

The fate of nine trace organic compounds was evaluated during a 12month large-scale laboratory column experiment. The columns were packed with aquifer sediment and evaluated under natural aerobic and artificial anaerobic geochemical conditions, to assess the potential for natural attenuation of these compounds during aquifer passage associated with managed aquifer recharge (MAR). The nine trace organic compounds were bisphenol A (BPA), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMOR), carbamazepine, oxazepam, iohexol and iodipamide. In the low organic carbon content Spearwood sediment, all trace organics were non-retarded with retardation coefficients between 1.0 and 1.2, indicating that these compounds would travel at near groundwater velocities within the aquifer. The natural aerobic geochemical conditions provided a suitable environment for the rapid degradation for BPA, E2, iohexol (half life aquifer geochemical conditions (half life >50days). Field-based validation experiments with carbamazepine and oxazepam also showed no degradation. If persistent trace organics are present in recycled waters at concentrations in excess of their intended use, natural attenuation during aquifer passage alone may not result in extracted water meeting regulatory requirements. Additional pre treatment of the recycled water would therefore be required. Crown Copyright © 2010. Published by Elsevier B.V. All rights reserved.

Novel geochemical techniques integrated in exploration for uranium deposits at depth

International Nuclear Information System (INIS)

Kyser, K.

2014-01-01

Mineral deposits are in fact geochemical anomalies, and as such their detection and assessment of their impact on the environment should be facilitated using geochemical techniques. Although geochemistry has been used directly in the discovery of uranium deposits and more indirectly in shaping deposit models, the novel applications of geochemistry and integration with other data can be more effective in formulating exploration and remediation strategies. Recent research on the use of geochemistry in detecting uranium deposits at depth include: (1) more effective integration of geochemical with geophysical data to refine targets, (2) revealing element distributions in and around deposits to adequately assess the total chemical environment associated with the deposit, (3) the use of element tracing using elemental concentrations and isotopic compositions in the near surface environment to detect specific components that have migrated to the surface from uranium deposits at depth, (4) understand the effects of both macro- and micro-environments on element mobility across the geosphere-biosphere interface to enhance exploration using select media for uranium at depth. Geophysical data used in exploration can identify areas of conductors where redox contrasts may host mineralization, structures that act to focus fluids during formation of the deposits and act as conduits for element migration to the surface, and contrasts in geology that are required for the deposits. However, precision of these data is greatly diminished with depth, but geochemical data from drill core or surface media can enhance target identification when integrated with geophysical data. Geochemical orientation surveys over known unconformity-related deposits at depth clearly identify mineralization 900m deep. Drill core near the deposit, clay-size fractions separated from soil horizons and vegetation over and far from the deposit record element migration from the deposit as radiogenic He, Rn and Pb

Methodological approaches in estimating anomalous geochemical field structure

International Nuclear Information System (INIS)

Gavrilov, R; Rudmin, M

2015-01-01

Mathematical statistic methods were applied to analyze the core samples from vertical expendable wells in Chertovo Koryto gold ore field. The following methods were used to analyse gold in samples: assay tests and atomic absorption method (AAS), while emission spectrum semiquantative method was applied to identify traces. The analysis of geochemical association distribution in one central profile demonstrated that bulk metasomatic aureoles are characteristic of concentric zonal structure. The distribution of geochemical associations is correlated to the hydrothermal stages of mineral formation identified in this deposit. It was proved that the processed geochemical data by factor and cluster analyses provided additional information on the anomalous geochemical field structure in gold- bearing black-shale strata. Such methods are effective tools in interpretating specific features of geochemical field structures in analogous potential ore-bearing areas

Geochemical distribution of major, trace and rare elements in chromite ores of Neyriz ophiolite

International Nuclear Information System (INIS)

Karimi, M.; Hosseini, S. Z.; Khankahdani, K. N.

2016-01-01

The chromite deposits in the Neyriz area have lenticular and sometimes vein-like shape which are replaced in serpentinized dunite and harzburgite. Chromite and serpentinized olivines are major minerals and hematite and magnetite are minor minerals in the chromitic ores. Except chromite, other minerals have secondary origin that are related to serpentinization procceses. Whereas along with chromite, only a few of minerals such as pentlandite have primary origin. Native copper and sulfides such as chalcopyrite and bornite have been formed secondarily in microfracturs of chromite grains filled by serpentine. The results of the geochemical data from chromite ores are indicated by the type of chromite in alpine. Despite being the most abundant element in LREE relative to HREE, only six elements Dy, Eu, La, Lu, Nd, and Y are the most common among other elements. Finally, chromite ore in the area is economic but the frequency of trace elements is minimal and non-economic.

Role of soil geochemical and microbiological components on selenium behaviour in oxic and anoxic conditions

International Nuclear Information System (INIS)

Darcheville, O.

2008-09-01

Selenium (Se) is naturally present in the environment. Se is essential for living organisms at trace concentrations, but it becomes rapidly toxic with their increases. The 79 Se radioactive isotopes of Se, is found in nuclear wastes that may be buried in deep geological formations. In soil, Se exists in many forms and its mobility is affected by the redox potential and microbial activity. Very few studies have focused on Se behaviour at trace concentration. We have tried to distinguish the major abiotic geochemical and microbiological processes involved in the fate of trace selenite (Se(IV)) in a soil. The study was based on batch incubation in oxic or anoxic conditions of slurry suspension artificially contaminated with Se (IV) to 0.4 mg Se.kg -1 dry soil. The incubation involved sterilized and non-sterile soil samples with or without organic amendment to stimulate microbial activities. For each incubation, we followed the distribution of Se between solid, liquid and gaseous phases as well as the geochemical evolution of the solution, the composition of the atmosphere gas bottles and the soil microflora. The results showed that Se was relatively few mobile in the soil studied. Geochemical processes played a major role in controlling the Se mobility. Over time, some abiotic transformations in the solid phase contributed to increase the Se immobilisation. The microbiological processes contributed to this increase in the solid phase. Moreover, in oxic as in anoxic conditions, some microbial processes were responsible, to a lesser extent, for a dispersion of Se in the atmosphere by the production of volatile compounds. (author)

Review of the use of magnetic concentrates in geochemical exploration

Science.gov (United States)

Overstreet, W.C.; Day, G.W.

1985-01-01

Magnetic concentrates recovered readily by hand magnet from alluvial sediments or panned concentrates have been used successfully in exploration as a geochemical sample medium for Cu, Zn, Co, Cr, Mo, Ni, V, Sn, and Be, particularly in arid environments where alluvial sediments may be contaminated by aeolian debris. Opportunity for this use arose recently as chemical and spectrographic techniques were developed to determine the abundances of a variety of trace elements in Fe-rich media. The use of analytical data from magnetic concentrates was introduced as one of several anomaly-enhancement techniques based on heavy minerals and intended to identify blind ore deposits. An extensive literature, reviewed here, on the relation of the chemical composition of the mineral magnetite, a main component of magnetic concentrates, to geologic conditions of origin, facilitates the interpretation of trace-element data in the context of association with ore deposits.

Geochemical computer codes. A review

International Nuclear Information System (INIS)

Andersson, K.

1987-01-01

In this report a review of available codes is performed and some code intercomparisons are also discussed. The number of codes treating natural waters (groundwater, lake water, sea water) is large. Most geochemical computer codes treat equilibrium conditions, although some codes with kinetic capability are available. A geochemical equilibrium model consists of a computer code, solving a set of equations by some numerical method and a data base, consisting of thermodynamic data required for the calculations. There are some codes which treat coupled geochemical and transport modeling. Some of these codes solve the equilibrium and transport equations simultaneously while other solve the equations separately from each other. The coupled codes require a large computer capacity and have thus as yet limited use. Three code intercomparisons have been found in literature. It may be concluded that there are many codes available for geochemical calculations but most of them require a user that us quite familiar with the code. The user also has to know the geochemical system in order to judge the reliability of the results. A high quality data base is necessary to obtain a reliable result. The best results may be expected for the major species of natural waters. For more complicated problems, including trace elements, precipitation/dissolution, adsorption, etc., the results seem to be less reliable. (With 44 refs.) (author)

Linking Environmental Magnetism to Geochemical Studies and Management of Trace Metals. Examples from Fluvial, Estuarine and Marine Systems

Directory of Open Access Journals (Sweden)

Michael Scoullos

2014-07-01

Full Text Available Among the diverse research fields and wide range of studies encompassed by environmental magnetism, the present work elaborates on critical aspects of the geochemistry of trace metals that emerged through years of original research in a variety of environmental compartments. This review aims at sharing the insights gained on (a tracing metal pollution sources; and (b identifying processes and transport pathways from sources to depositional environments. Case studies on the Elefsis Gulf (Greece and the Gulf of Lions (France demonstrate the potential of combined magnetic measurements and chemical analysis to trace pollution signals resulting from land-based sources and atmospheric deposition. Case studies on estuarine environments, namely the Louros, Acheloos, and Asopos Estuaries (Greece, address modes of trace metal behavior under the influence of different hydrological regimes and elucidate in situ processes within the transitional estuarine zone, that define their ultimate fate. As sources, transport pathways, and processes of trace metals are fundamental in environmental management assessments, the involvement of magnetic measurements in the policy cycle could facilitate the development and implementation of appropriate regulatory measures for the integrated management of river basins, coastal, and marine areas.

Semi-detailed uranium geochemical survey in Northwestern Samar (27 March 1979 - 4 July 1979)

International Nuclear Information System (INIS)

Santos, G. Jr.; Ogena, M.; Tauli, G.

1980-04-01

A uranium geochemical survey was conducted to delineate in detail the uranium prospective area(s) in northwestern Samar. A total of 805 stream sediments and 1.115 water samples were obtained from the target areas from uranium analysis. Geochemical anomalies were indicated in San Isidro and Mauo. Geochemical correlations between uranium and trace elements (Pb, Ag, Ni, Cu, Co, Zn and Mn) were generally poor. (ELC)

Geochemical radioactive investigation of beach sands and stream sediments, using heavy minerals, trace elements and radon measurements, (Qerdaha sheet of the Syrian coast)

International Nuclear Information System (INIS)

Jubeli, Y.; Kattaa, B.; Al-Hilal, M.

2000-05-01

Reconnaissance geochemical radiometric survey of stream sediments resulting from the weathering of outcropped rocks in and around the study area was performed. This survey included heavy mineral sampling, trace and radioelements and radon measurements to evaluate the radioactivity of the source rocks and to understand the nature and distribution of the heavy minerals and trace elements in the study area. Several techniques were used to achieve these objectives. The results of heavy mineral geochemical survey show that the abundant minerals are iron oxides (magnetite, hematite, goehtite and limonite) pyroxene and olivine; less abundant minerals are apatite, ilmenite, garnet, barite, siderite and gloconite, while rare minerals are zircon and rutile. Amphibole is reported as an abundant mineral in sand dunes and is less abundant in samples located in the northern part of the study area. The amphibole seems to be derived from the ophiolitic complex north of the study area. Grain size analysis of heavy minerals revealed that the concentration of economic minerals such as zircon rutile and ilmenite increases with the decrease of the grain size. The microscopic study showed fragments and fossils of foraminifere mostly impregnated with heavy metals such as iron and manganese resulting from diagenetic metasomatism and replacement processes of. Fish teeth (< 2 mm) and oolite of iron were also noticed in most of the samples. The morphology of heavy mineral grains shows that most of the grains are angular to subangular suggesting that they were transported for short distance from their source rocks. Normally, phosphate pellets, gloconite and iron ooids are not considered since their original morphological features show clear roundness that attributed to their sedimentological origin, not to transportation factor. The source rock of most of the heavy mineral assemblage is the basalt. Apatite and gloconite are derived from the phosphorite and phosphatized limestone encountered

Predictive geochemical mapping using environmental correlation

International Nuclear Information System (INIS)

Wilford, John; Caritat, Patrice de; Bui, Elisabeth

2016-01-01

The distribution of chemical elements at and near the Earth's surface, the so-called critical zone, is complex and reflects the geochemistry and mineralogy of the original substrate modified by environmental factors that include physical, chemical and biological processes over time. Geochemical data typically is illustrated in the form of plan view maps or vertical cross-sections, where the composition of regolith, soil, bedrock or any other material is represented. These are primarily point observations that frequently are interpolated to produce rasters of element distributions. Here we propose the application of environmental or covariate regression modelling to predict and better understand the controls on major and trace element geochemistry within the regolith. Available environmental covariate datasets (raster or vector) representing factors influencing regolith or soil composition are intersected with the geochemical point data in a spatial statistical correlation model to develop a system of multiple linear correlations. The spatial resolution of the environmental covariates, which typically is much finer (e.g. ∼90 m pixel) than that of geochemical surveys (e.g. 1 sample per 10-10,000 km 2 ), carries over to the predictions. Therefore the derived predictive models of element concentrations take the form of continuous geochemical landscape representations that are potentially much more informative than geostatistical interpolations. Environmental correlation is applied to the Sir Samuel 1:250,000 scale map sheet in Western Australia to produce distribution models of individual elements describing the geochemical composition of the regolith and exposed bedrock. As an example we model the distribution of two elements – chromium and sodium. We show that the environmental correlation approach generates high resolution predictive maps that are statistically more accurate and effective than ordinary kriging and inverse distance weighting interpolation

Geochemical orientation for mineral exploration in the Hashemite Kingdom of Jordan

Science.gov (United States)

Overstreet, W.C.; Grimes, D.J.; Seitz, J.F.

1982-01-01

This report is a supplement to previous accounts of geochemical exploration conducted in the Hashemite Kingdom of Jordan by the Natural Resources Authority of the Royal Government of Jordan and the U.S. Geological Survey. The field work on which this report is based was sponsored by the U.S. Agency for International Development, U.S. Department of State. Procedures used in collecting various kinds of rocks, ores, slags, eluvial and alluvial sediments, heavy-mineral concentrates, and organic materials for use as geochemical sample media are summarized, as are the laboratory procedures followed for the analysis of these sample materials by semiquantitative spectrographic, atomic absorption, fluorometric, and X-ray diffraction methods. Geochemical evaluations of the possibilities for economic mineral deposits in certain areas are presented. The results of these preliminary investigations open concepts for further use in geochemical exploration in the search for metallic mineral deposits in Jordan. Perhaps the most desirable new activity would be hydrogeochemical exploration for uranium and base metals, accompanied by interpretation of such remote-sensing data as results of airborne radiometric surveys and computer-enhanced LANDSAT imagery. For more conventional approaches to geochemical exploration, however, several fundamental problems regarding proper choice of geochemical sample media for different geologic and geographic parts of the Country must be solved before effective surveys can be made. The present results also show that such common geochemical exploration techniques as the determination of the trace-element contents of soils, plant ash, and slags have direct application also toward the resolution of several archaeological problems in Jordan. These include the relation of trace-elements chemistry of local soils to the composition of botanic remains, the trace-elements composition of slags to the technological development of the extractive metallurgy of

Metrology of trace radionuclides in environment. Standardization and traceability

International Nuclear Information System (INIS)

Calmet, D.

1999-01-01

Widespread concern over radioactive substances in the environment regularly requires environmental and public health assessments. The credibility of an assessment will depend on the quality and reliability on measurement results that often are of paramount significance in the environmental domain. Those man made radionuclides present in the various environmental components of the French territory are however found at trace, even ultra-trace levels. This article gives an overview of standardization work and required reference materials and rules for measuring radionuclides in environmental matrices as well as the international and national systems to manage standardization and traceability. Some achievements as well as the many difficulties that the metrologist must overcome when using nuclear techniques to measure trace quantities of radionuclides are presented. (author)

Use of trace elements as indicators for underground fluid circulations in karstic environment

International Nuclear Information System (INIS)

Pane-Escribe, M.B.

1995-01-01

The geochemical study of the trace element behaviour in karstic groundwaters has been carried out over the experimental site of Lamalou (Herault, France). Routine measurements of the physico-chemical parameters and of the dissolved elements concentrations have been achieved during two hydrological cycles. Radon has been monitored by passive detectors and by automatic electronic probes. Trace elements (Sc, Ti, V, Cr, Ni, Cu, Zn, As Rb, Sr, Mo, Cd, Sb, Cs, Ba, Th, U) were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The first part of this work presents the methodologies employed with in particular the improvement of the analytical performances of ICP-MS for water samples analysis. The detection limit for each considered element has been determined. The short and long term reproducibility for the samples analysis has also been tested. The second part of this study presents the treatment and interpretation of the results. This analysis has pointed our the influence of the aquifer structure on the chemical elements distribution. The trace and major elements concentrations are effectively related to the fracturing state of the reservoir and allow to individualize the high transmissivity zones from zones with a lower transmissivity in this mono-lithological context, trace elements appear to be particularly efficient tracers for determining the water origin and circulation their spatial and temporal behaviour leads to identify three different origins for the water mineralization over the studied area: limestones, clays and external sources (rainfalls and occasional pollutions). (author)

Study on long-term stability of geochemical environments at deep underground

International Nuclear Information System (INIS)

Mizuno, Takashi; Iwatsuki, Teruki

2005-01-01

Observation and fluid inclusion analysis of fracture filling calcites in granite at the Tono area were conducted to assess long-term stability of geochemical environment at deep underground. The result of observation using SEM and luminoscope shows that precipitation processes of calcite can be divided into four phases (1 to 4) based on their occurrence. (1) Phase 1: indistinct morphology and includes the wall rock fragments. (2) Phase 2: rhombohedral and hexagonal form. (3) Phase 3: elongate rhombohedral form, growth over the layer of phase 2 calcite. (4) Phase 4: small rhombohedral form crystals growth from surface of phase 3 calcite. On Phase 1 calcite, it seems to be hydrothermal origin related to fracture activation. Previous study shows the correlation between the salinity of fluid from which calcite precipitated and morphology of calcite. According to previous studies, the groundwater from which phase 3 calcite precipitated would be the highest salinity such as seawater. Phase 2 and 4 calcite may be precipitated from groundwater with low salinity. On the other hand, fluid inclusions were recognized in phase 2 and 3 calcite. All inclusions indicated mono-phase (liquid phase). These suggest that phase 2 and 3 calcites were precipitated in low-temperature condition. Result of salinity analysis indicates that two groundwaters having different chemical properties had existed during phase 2 and 3 calcite precipitation. Based on these results, geochemical environment had changed by input of high salinity groundwater during Phase 2 and 3 calcite precipitation. It is required to identify the origin of each groundwater in consideration of historical geology for further understanding of long-term hydrochemical condition. (author)

Geochemical Characterization of the Upper and Middle Floridan Aquifer System, South Florida

Science.gov (United States)

Mirecki, J.; Richardson, E.; Bennett, M.; Hendel, J.

2008-05-01

Our study focus is to characterize the water quality and geochemical environment of the Floridan Aquifer System (FAS) throughout the regional flowpath. A synoptic survey of 21 wells (n=15, upper FAS; n=6 middle FAS) was supplemented by additional samples (n=11) obtained during exploratory well development at 4 aquifer storage recovery (ASR) pilot sites. Synoptic survey samples were analyzed intensively, yielding a dataset that consists of major and trace dissolved constituents (including metals), stable isotopes (δ18O, δ13C, δD, δ34S in sulfate and sulfide), carbon species (carbonate alkalinity and organic carbon), uranium-series radionuclides, nutrients, and selected microbes and pathogens. The objectives of this study are three-fold: 1) to provide baseline water-quality and geochemical information prior to initiation of ASR activities that are part of the Comprehensive Everglades Restoration Plan; 2) to quantify the major controls on geochemical evolution along upper and middle FAS flowpaths using geochemical modeling methods; and 3) to identify areas where water- quality may limit the feasibility of ASR methods in the FAS. Preliminary interpretations water quality changes along the regional FAS flowpath can be summarized as follows. Concentrations of dissolved constituents increase from north to south along the flow path; generally, the upper FAS has lower total dissolved solids than the middle FAS at locations where well pairs were analyzed. The redox environment changes from oxic to strongly anoxic, very close to the recharge area. Redox measurements, dissolved iron, sulfide, and sulfur isotope data are consistent with sulfate-reducing conditions. Uranium-series isotope concentrations and activities generally are below regulatory criteria, with few exceptions in both the upper and middle FAS. Areas with greater radionuclide activity occur primarily at distal flowpath locations or at the coast.

Application of Neutron Activation Analysis to Geochemical Studies of Mineral Resources

Energy Technology Data Exchange (ETDEWEB)

Winchester, J. W. [Department Of Meteorology and Oceanography, University of Michigan, Ann Arbor, MI (United States); Catoggio, J. A. [Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata (Argentina)

1969-03-15

Sensitive and accurate measurement of closely related trace element concentrations in naturally occurring materials leads to the most useful geochemical information in the study of crystallizing systems. Studies of the rare earth elements have shown regularities that can be related to geological crystallization processes in igneous and sedimentary materials, and it is likely that similar studies of economic mineral deposits will lead to similar information. An analytical method should be chosen with great care to assure adequate sensitivity for the trace elements under investigation. Neutron activation analysis and spark source mass spectrometry both have high sensitivity adequate for many geochemical applications. However, simpler methods, such as atomic absorption, absorption spectrophotometry and electrochemical methods have adequate sensitivity for many elements and are preferred when suitable. (author)

Methods for geochemical analysis

Science.gov (United States)

Baedecker, Philip A.

1987-01-01

The laboratories for analytical chemistry within the Geologic Division of the U.S. Geological Survey are administered by the Office of Mineral Resources. The laboratory analysts provide analytical support to those programs of the Geologic Division that require chemical information and conduct basic research in analytical and geochemical areas vital to the furtherance of Division program goals. Laboratories for research and geochemical analysis are maintained at the three major centers in Reston, Virginia, Denver, Colorado, and Menlo Park, California. The Division has an expertise in a broad spectrum of analytical techniques, and the analytical research is designed to advance the state of the art of existing techniques and to develop new methods of analysis in response to special problems in geochemical analysis. The geochemical research and analytical results are applied to the solution of fundamental geochemical problems relating to the origin of mineral deposits and fossil fuels, as well as to studies relating to the distribution of elements in varied geologic systems, the mechanisms by which they are transported, and their impact on the environment.

Adsorption of trace metals to plastic resin pellets in the marine environment

International Nuclear Information System (INIS)

Holmes, Luke A.; Turner, Andrew; Thompson, Richard C.

2012-01-01

Plastic production pellets collected from beaches of south west England contain variable concentrations of trace metals (Cr, Co, Ni, Cu, Zn, Cd and Pb) that, in some cases, exceed concentrations reported for local estuarine sediments. The rates and mechanisms by which metals associate with virgin and beached polyethylene pellets were studied by adding a cocktail of 5 μg L −1 of trace metals to 10 g L −1 pellet suspensions in filtered seawater. Kinetic profiles were modelled using a pseudo-first-order equation and yielded response times of less than about 100 h and equilibrium partition coefficients of up to about 225 ml g −1 that were consistently higher for beached pellets than virgin pellets. Adsorption isotherms conformed to both the Langmuir and Freundlich equations and adsorption capacities were greater for beached pellets than for virgin pellets. Results suggest that plastics may represent an important vehicle for the transport of metals in the marine environment. - Highlights: ► Beached plastic production pellets contain considerable concentrations of trace metals. ► In laboratory experiments trace metals are shown to adsorb to both virgin and beached pellets. ► Metal adsorption is greater on aged pellets. ► Pellets may represent an important vehicle for metal transport in the marine environment. - Trace metals accumulate on plastic resin pellets in the marine environment through adsorption to the polymer and to chemical and biological attritions thereon.

Geochemical cycling and depositional patterns across the northeast region of the Greenland Ice Sheet as determined from trace element chemistry

Science.gov (United States)

Wong, G. J.; Osterberg, E. C.; Courville, Z.; Hawley, R. L.; Lutz, E.; Overly, T. B.

2012-12-01

The Greenland Ice Sheet is both a repository of climate history and a major driver in Arctic and global climate. Between 1952 and 1955, Carl Benson led a series of traverses of the Greenland Ice Sheet (GIS), and characterized the GIS via mapping of the spatial distribution of annual net accumulation and classifying the diagenetic glacier facies (Benson, 1962). While polar ice sheets represent a unique archive of past atmospheric and climatic conditions, little information exists on large-scale geographical trends in trace element snow chemistry across GIS because of the remote, challenging location. In the spring of 2011, we undertook a 1120 km traverse of the GIS from Thule Air Base to Summit Station. Samples from 11 snow pits and 3 firn cores, dated by stable water isotopes, were analyzed and evaluated in seasonal resolution for their trace element content (23Na, 24Mg, 27Al, 32S, 39K, 44Ca, 47Ti, 51V, 52Cr, 55Mn, 56Fe, 59Co, 63Cu, 66Zn, 75As, 88Sr, 111Cd, 133Cs, 138Ba, 139La, 140Ce, 141Pr, 208Pb, 209Bi, 238U). Here, we present an initial analysis of the spatial gradients of these trace elements and an interpretation of how their depositional patterns characterize the GIS. The seasonal trends coupled with spatial variability of certain trace elements establish the behavior of specific aerosols (e.g. dust, sea salt, pollution), which will be useful in quantifying geochemical cycling across the GIS and comparing characterizations with results from Benson's traverses. Benson, CS. 1962. Stratigraphic studies in the snow and firn of the Greenland Ice Sheet. SIPRE Research Report, 70, 89 pp.

Prioritizing research for trace pollutants and emerging contaminants in the freshwater environment

Energy Technology Data Exchange (ETDEWEB)

Murray, Kyle E., E-mail: Kyle.Murray@utsa.ed [Center for Water Research, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249-0663 (United States); Thomas, Sheeba M [San Antonio River Authority, San Antonio, TX (United States); Bodour, Adria A [Air Force Center for Engineering and the Environment (AFCEE), Brooks City-Base, TX (United States)

2010-12-15

Organic chemicals have been detected at trace concentrations in the freshwater environment for decades. Though the term trace pollutant indicates low concentrations normally in the nanogram or microgram per liter range, many of these pollutants can exceed an acceptable daily intake (ADI) for humans. Trace pollutants referred to as emerging contaminants (ECs) have recently been detected in the freshwater environment and may have adverse human health effects. Analytical techniques continue to improve; therefore, the number and frequency of detections of ECs are increasing. It is difficult for regulators to restrict use of pollutants that are a human health hazard; scientists to improve treatment techniques for higher priority pollutants; and the public to modify consumption patterns due to the vast number of ECs and the breadth of literature on the occurrence, use, and toxicity. Hence, this paper examines literature containing occurrence and toxicity data for three broad classes of trace pollutants and ECs (industrials, pesticides, and pharmaceuticals and personal care products (PPCPs)), and assesses the relevance of 71 individual compounds. The evaluation indicates that widely used industrials (BPF) and PPCPs (AHTN, HHCB, ibuprofen, and estriol) occur frequently in samples from the freshwater environment but toxicity data were not available; thus, it is important to establish their ADI. Other widely used industrials (BDE-47, BDE-99) and pesticides (benomyl, carbendazim, aldrin, endrin, ethion, malathion, biphenthrin, and cypermethrin) have established ADI values but occurrence in the freshwater environment was not well documented. The highest priority pollutants for regulation and treatment should include industrials (PFOA, PFOS and DEHP), pesticides (diazinon, methoxychlor, and dieldrin), and PPCPs (EE2, carbamazepine, {beta}E2, DEET, triclosan, acetaminophen, and E1) because they occur frequently in the freshwater environment and pose a human health hazard at

Prioritizing research for trace pollutants and emerging contaminants in the freshwater environment

International Nuclear Information System (INIS)

Murray, Kyle E.; Thomas, Sheeba M.; Bodour, Adria A.

2010-01-01

Organic chemicals have been detected at trace concentrations in the freshwater environment for decades. Though the term trace pollutant indicates low concentrations normally in the nanogram or microgram per liter range, many of these pollutants can exceed an acceptable daily intake (ADI) for humans. Trace pollutants referred to as emerging contaminants (ECs) have recently been detected in the freshwater environment and may have adverse human health effects. Analytical techniques continue to improve; therefore, the number and frequency of detections of ECs are increasing. It is difficult for regulators to restrict use of pollutants that are a human health hazard; scientists to improve treatment techniques for higher priority pollutants; and the public to modify consumption patterns due to the vast number of ECs and the breadth of literature on the occurrence, use, and toxicity. Hence, this paper examines literature containing occurrence and toxicity data for three broad classes of trace pollutants and ECs (industrials, pesticides, and pharmaceuticals and personal care products (PPCPs)), and assesses the relevance of 71 individual compounds. The evaluation indicates that widely used industrials (BPF) and PPCPs (AHTN, HHCB, ibuprofen, and estriol) occur frequently in samples from the freshwater environment but toxicity data were not available; thus, it is important to establish their ADI. Other widely used industrials (BDE-47, BDE-99) and pesticides (benomyl, carbendazim, aldrin, endrin, ethion, malathion, biphenthrin, and cypermethrin) have established ADI values but occurrence in the freshwater environment was not well documented. The highest priority pollutants for regulation and treatment should include industrials (PFOA, PFOS and DEHP), pesticides (diazinon, methoxychlor, and dieldrin), and PPCPs (EE2, carbamazepine, βE2, DEET, triclosan, acetaminophen, and E1) because they occur frequently in the freshwater environment and pose a human health hazard at

Geochemical typification of kimberlite and related rocks of the North Anabar region, Yakutia

Science.gov (United States)

Kargin, A. V.; Golubeva, Yu. Yu.

2017-11-01

The results of geochemical typification of kimberlites and related rocks (alneites and carbonatites) of the North Anabar region are presented with consideration of the geochemical specification of their source and estimation of their potential for diamonds. The content of representative trace elements indicates the predominant contribution of an asthenospheric component (kimberlites and carbonatites) in their source, with a subordinate contribution of vein metasomatic formations containing Cr-diopside and ilmenite. A significant contribution of water-bearing potassium metasomatic parageneses is not recognized. According to the complex of geochemical data, the studied rocks are not industrially diamondiferous.

Appliance of geochemical engineering in radioactive waste disposal

International Nuclear Information System (INIS)

Li Shuang; Zhang Chengjiang; Ni Shijun; Li Kuanliang

2008-01-01

The basic foundation of applying geochemical engineering to control environment, common engineering models of disposal radioactive waste and the functions of the engineering barriers are introduced in this paper. The authors take the geochemical engineering barrier materiel research of a radioactive waste repository as an example to explain the appliance of geochemical engineering in the disposal of radioactive waste. And the results show that it can enhance the security of the nuclear waste repository if we use geochemical engineering barrier. (authors)

The impact of pre-restoration land-use and disturbance on sediment structure, hydrology and the sediment geochemical environment in restored saltmarshes.

Science.gov (United States)

Spencer, Kate L; Carr, Simon J; Diggens, Lucy M; Tempest, James A; Morris, Michelle A; Harvey, Gemma L

2017-06-01

Saltmarshes are being lost or degraded as a result of human activity resulting in loss of critical ecosystem services including the provision of wild species diversity, water quality regulation and flood regulation. To compensate, saltmarshes are being restored or re-created, usually driven by legislative requirements for increased habitat diversity, flood regulation and sustainable coastal defense. Yet, there is increasing evidence that restoration may not deliver anticipated ecosystem services; this is frequently attributed to poor drainage and sediment anoxia. However, physical sediment characteristics, hydrology and the sediment geochemical environment are rarely examined in restoration schemes, despite such factors being critical for plant succession. This study presents the novel integration of 3D-computed X-ray microtomography to quantify sediment structure and porosity, with water level and geochemical data to understand the impact of pre-restoration land use and disturbance on the structure and functioning of restored saltmarshes. The study combines a broad-scale investigation of physical sediment characteristics in nine de-embanked saltmarshes across SE England, with an intensive study at one site examining water levels, sediment structure and the sediment geochemical environment. De-embankment does not restore the hydrological regime, or the physical/chemical framework in the saltmarshes and evidence of disturbance includes a reduction in microporosity, pore connectivity and water storage capacity, a lack of connectivity between the sub-surface environment and overlying floodwaters, and impeded sub-surface water flow and drainage. This has significant consequences for the sediment geochemical environment. This disturbance is evident for at least two decades following restoration and is likely to be irreversible. It has important implications for plant establishment in particular, ecosystem services including flood regulation, nutrient cycling and wild

Geochemistry of environmentally sensitive trace elements in Permian coals from the Huainan coalfield, Anhui, China

Science.gov (United States)

Chen, J.; Liu, Gaisheng; Jiang, M.; Chou, C.-L.; Li, H.; Wu, B.; Zheng, Lingyun; Jiang, D.

2011-01-01

To study the geochemical characteristics of 11 environmentally sensitive trace elements in the coals of the Permian Period from the Huainan coalfield, Anhui province, China, borehole samples of 336 coals, two partings, and four roof and floor mudstones were collected from mineable coal seams. Major elements and selected trace elements were determined by inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), and hydride generation atomic absorption spectrometry (HAAS). The depositional environment, abundances, distribution, and modes of occurrence of trace elements were investigated. Results show that clay and carbonate minerals are the principal inorganic constituents in the coals. A lower deltaic plain, where fluvial channel systems developed successively, was the likely depositional environment of the Permian coals in the Huainan coalfield. All major elements have wider variation ranges than those of Chinese coals except for Mg and Fe. The contents of Cr, Co, Ni, and Se are higher than their averages for Chinese coals and world coals. Vertical variations of trace elements in different formations are not significant except for B and Ba. Certain roof and partings are distinctly higher in trace elements than underlying coal bench samples. The modes of occurrence of trace elements vary in different coal seams as a result of different coal-forming environments. Vanadium, Cr, and Th are associated with aluminosilicate minerals, Ba with carbonate minerals, and Cu, Zn, As, Se, and Pb mainly with sulfide minerals. ?? 2011 Elsevier B.V.

Trace elements in agroecosystems and impacts on the environment.

Science.gov (United States)

He, Zhenli L; Yang, Xiaoe E; Stoffella, Peter J

2005-01-01

sensitive, changes in microbial biomass, activity, and community structure as a result of increased metal concentration in soil may be used as indicators of soil contamination or soil environmental quality. Future research needs to focus on the balance of trace elements in an agroecosystem, elaboration of soil chemical and biochemical parameters that can be used to diagnose soil contamination with or deficiency in trace elements, and quantification of trace metal transport from an agroecosystem to the environment.

Geochemical reconnaissance for uranium in the Palmyrides region of central Syria

International Nuclear Information System (INIS)

Jubeli, Y.M.

1990-01-01

An account is given of the application of multielement reconnaissance rock chemistry, coupled with ground scintillation γ-ray measurements, to the investigation of the dispersion patterns of uranium and other major and trace elements in the rocks of the arid Palmyrides region of central Syria. The region is underlain by 10 km of sediments that accumulated in an interplatform depression during the Mesozoic and Caenozoic. Uranium and associated elements were syngenetically incorporated into the Upper Cretaceous and Lower Palaeogene sediments - especially phosphorites, which are well represented in the region. The oxidizing environment of the region has facilitated the subsequent geochemical redistribution of uranium. In the investigation more than 400 lithogeochemical samples collected from an area of approximately 9000 km 2 were analysed for over 30 elements. The resulting data were interpreted with the aid of univariate and multivariate statistical methods and the areal distribution of uranium, its associated elements, multivariate geochemical functions and factor scores were mapped with the use of computer graphics. Anomalies of U are accompanied by concentrations of As, Se, V, Mo, Zn, Cd, Cu, Ni and P in various combinations. The highest U concentrations are found in the Upper Cretaceous, which contains a high proportion of phosphatic rocks; younger sediments contain progressively less U. Uranium anomalies close to faults, which have provided conduits for wider U migration, are superimposed on this pattern. Lithogeochemical methods thus define geochemical dispersion patterns with good contrast and delineate areas for further investigation. (author)

Geologic-geochemical characteristics of Guidong granitic massif and recognition of geo-tectonic environment at the time of its emplacement

Energy Technology Data Exchange (ETDEWEB)

Jianhong, Li; Shanyuan, Wei; Mingyue, Feng [Beijing Research Inst. of Uranium Geology, Beijing (China); Liang, Liang [East China Inst. of Technology, Fuzhou (China)

2004-11-01

Based on the study of geologic characteristics, such as mineralogic assemblage, structural and textural features of granite of Guidong granitic massif, and by using petrochemical, trace-element and isotopic data, and some petrochemical, trace-element and isotopic diagrams widely applied to the identification of geo-tectonic environments, authors recognize that Guidong granitic massif was emplaced in post-orogenic collision environment. (authors)

Geochemical landscapes of the conterminous United States; new map presentations for 22 elements

Science.gov (United States)

Gustavsson, N.; Bolviken, B.; Smith, D.B.; Severson, R.C.

2001-01-01

Geochemical maps of the conterminous United States have been prepared for seven major elements (Al, Ca, Fe, K, Mg, Na, and Ti) and 15 trace elements (As, Ba, Cr, Cu, Hg, Li, Mn, Ni, Pb, Se, Sr, V, Y, Zn, and Zr). The maps are based on an ultra low-density geochemical survey consisting of 1,323 samples of soils and other surficial materials collected from approximately 1960-1975. The data were published by Boerngen and Shacklette (1981) and black-and-white point-symbol geochemical maps were published by Shacklette and Boerngen (1984). The data have been reprocessed using weighted-median and Bootstrap procedures for interpolation and smoothing.

Geochemical conditions and the occurrence of selected trace elements in groundwater basins used for public drinking-water supply, Desert and Basin and Range hydrogeologic provinces, 2006-11: California GAMA Priority Basin Project

Science.gov (United States)

Wright, Michael T.; Fram, Miranda S.; Belitz, Kenneth

2015-01-01

The geochemical conditions, occurrence of selected trace elements, and processes controlling the occurrence of selected trace elements in groundwater were investigated in groundwater basins of the Desert and Basin and Range (DBR) hydrogeologic provinces in southeastern California as part of the Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA PBP is designed to provide an assessment of the quality of untreated (raw) groundwater in the aquifer systems that are used for public drinking-water supply. The GAMA PBP is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey and the Lawrence Livermore National Laboratory.

World wide intercomparison of trace element measurements in marine sediments SD-M-2/TM

International Nuclear Information System (INIS)

Mee, L.D.; Oregioni, B.

1991-09-01

The accurate and precise determination of trace elements in marine sediments is an important aspect of geochemical studies of the marine environment and for assessing the levels and pathways of marine pollutants. Past intercomparison studies conducted by the Marine Environment Laboratory of IAEA (formerly the International Laboratory of Marine Radioactivity) have focussed upon near-shore marine sediments where trace metal contamination is frequently observed. The present exercise was designed to study a typical oxidised deep-sea sediment characterized by a preponderance of fine particle clays. Analysis of such material is a routine matter for most geochemists but represents a ''baseline sample'' for marine pollution chemists. The present exercise represented a unique opportunity for chemists worldwide to intercompare their analytical methodologies for deep-sea sediments. By statistically examining the data from this study, the material can be certified for future use as a reference material - apparently the only one of its kind available throughout the world. 6 refs, figs and tabs

Significance of geochemical characterization to performance at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Simmons, A.M.

1993-01-01

The U.S. concept for permanent disposal of high-level radioactive waste resembles those of other countries in that it relies upon burial in a deep geologic medium. This concept relies upon multiple barriers to retard transport of radionuclides to the accessible environment; those barriers consist of the waste form, waste container, engineered barrier system (including possible backfill) and retardant properties of the host rock. Because mobilization of radionuclides is fundamentally a geochemical problem, an understanding of past, present, and future geochemical processes is a requisite part of site characterization studies conducted by the U.S. Department of Energy at Yucca Mountain, Nevada. Geochemical information is needed for evaluating three favorable conditions (the rates of geochemical processes, conditions that promote precipitation or sorption of radionuclides or prohibit formation of colloids, and stable mineral assemblages) and four potentially adverse conditions of the site (groundwater conditions that could increase the chemical reactivity of the engineered barried system or reduce sorption, potential for gaseous radionuclide movement, and oxidizing groundwaters) for key issues of radionuclide release, groundwater quality, and stability of the geochemical environment. Preliminary results of long-term heating experiments indicate that although zeolites can be modified by long-term, low temperature reactions, their beneficial sorptive properties will not be adversely affected. Mineral reactions will be controlled by the aqueous activity of silica in groundwater with which the minerals are in contact. Geochemical barriers alone may satisfy release requirements to the accessible environment for many radionuclides; however, additional site specific geochemical and mineralogical data are needed to test existing and future radionuclide transport models

Fraction-specific controls on the trace element distribution in iron formations : Implications for trace metal stable isotope proxies

NARCIS (Netherlands)

Oonk, Paul B.H.; Tsikos, Harilaos; Mason, Paul R.D.; Henkel, Susann; Staubwasser, Michael; Fryer, Lindi; Poulton, Simon W.; Williams, Helen M.

2017-01-01

Iron formations (IFs) are important geochemical repositories that provide constraints on atmospheric and ocean chemistry, prior to and during the onset of the Great Oxidation Event. Trace metal abundances and their Mo-Cr-U isotopic ratios have been widely used for investigating ocean redox processes

Concerning evaluation of eco-geochemical background in remediation strategy

Science.gov (United States)

Korobova, Elena; Romanov, Sergey

2015-04-01

The geochemical concept of biosphere developed by V.I. Vernadsky states the geological role of the living organisms in the course of their active chemical interaction with the inert matter (Vernadsky, 1926, 1960). Basing on this theory it is reasonable to suggest that coevolution of living organisms and their environment led to development of the dynamically stable biogeocenoses precisely adequate to their geochemical environment. Soil cover was treated by V.I. Vernadsky as a balanced bio-inert matter resulting from this interaction. Appearance of human mind and then a civilization led to global expansion of human beings, first able to survive in unfavorable geochemical conditions and then starting chemical transformation of the environment to satisfy the growing demands of mankind in food and energy. The residence in unfavorable environment and local contamination was followed by appearance of endemic diseases of plants, animals and man. Therefore zonal, regional and local chemical composition of the soil cover formed in natural conditions may be used for estimation of the optimum geochemical background, most adequate for the corresponding zonal biogeocenoses and species. Moreover, the natural geochemical background and technogenic fields have unequal spatial structure and this facilitates their identification that may be relatively easy realized in remediation strategy. On the assumption of the foregoing, the adequate methodical approach to remediation of technogenically affected areas should account of the interaction of the existing natural and the newly formed technogenic geochemical fields and include the following steps: 1) the study and mapping of geochemical structure of the natural geochemical background basing on soil maps; 2) the study of contaminants and mapping spatial distribution of technogenic releases; 3) construction of risk maps for the target risk groups with due regard to natural ecological threshold concentration in context of risk degree for

A unified approach to model uptake kinetics of trace elements in complex aqueous – solid solution systems

International Nuclear Information System (INIS)

Thien, Bruno M.J.; Kulik, Dmitrii A.; Curti, Enzo

2014-01-01

Highlights: • There are several models able to describe trace element partitioning in growing minerals. • To describe complex systems, those models must be embedded in a geochemical code. • We merged two models into a unified one suitable for implementation in a geochemical code. • This unified model was tested against coprecipitation experimental data. • We explored how our model reacts to solution depletion effects. - Abstract: Thermodynamics alone is usually not sufficient to predict growth-rate dependencies of trace element partitioning into host mineral solid solutions. In this contribution, two uptake kinetic models were analyzed that are promising in terms of mechanistic understanding and potential for implementation in geochemical modelling codes. The growth Surface Entrapment Model (Watson, 2004) and the Surface Reaction Kinetic Model (DePaolo, 2011) were shown to be complementary, and under certain assumptions merged into a single analytical expression. This Unified Uptake Kinetics Model was implemented in GEMS3K and GEM-Selektor codes ( (http://gems.web.psi.ch)), a Gibbs energy minimization package for geochemical modelling. This implementation extends the applicability of the unified uptake kinetics model to accounting for non-trivial factors influencing the trace element partitioning into solid solutions, such as the changes in aqueous solution composition and speciation, or the depletion effects in closed geochemical systems

Proceedings of the workshop on geochemical modeling

International Nuclear Information System (INIS)

1986-01-01

The following collection of papers was presented at a workshop on geochemical modeling that was sponsored by the Office of Civilian Radioactive Waste Management Program at the Lawrence Livermore National Laboratory (LLNL). The LLNL Waste Management Program sponsored this conference based on their belief that geochemical modeling is particularly important to the radioactive waste disposal project because of the need to predict the consequences of long-term water-rock interactions at the proposed repository site. The papers included in this volume represent a subset of the papers presented at the Fallen Leaf Lake Conference and cover a broad spectrum of detail and breadth in a subject that reflects the diverse research interests of the conference participants. These papers provide an insightful look into the current status of geochemical modeling and illustrate how various geochemical modeling codes have been applied to problems of geochemical interest. The emphasis of these papers includes traditional geochemical modeling studies of individual geochemical systems, the mathematical and theoretical development and refinement of new modeling capabilities, and enhancements of data bases on which the computations are based. The papers in this proceedings volume have been organized into the following four areas: Geochemical Model Development, Hydrothermal and Geothermal Systems, Sedimentary and Low Temperature Environments, and Data Base Development. The participants of this symposium and a complete list of the talks presented are listed in the appendices

Proceedings of the workshop on geochemical modeling

Energy Technology Data Exchange (ETDEWEB)

1986-01-01

The following collection of papers was presented at a workshop on geochemical modeling that was sponsored by the Office of Civilian Radioactive Waste Management Program at the Lawrence Livermore National Laboratory (LLNL). The LLNL Waste Management Program sponsored this conference based on their belief that geochemical modeling is particularly important to the radioactive waste disposal project because of the need to predict the consequences of long-term water-rock interactions at the proposed repository site. The papers included in this volume represent a subset of the papers presented at the Fallen Leaf Lake Conference and cover a broad spectrum of detail and breadth in a subject that reflects the diverse research interests of the conference participants. These papers provide an insightful look into the current status of geochemical modeling and illustrate how various geochemical modeling codes have been applied to problems of geochemical interest. The emphasis of these papers includes traditional geochemical modeling studies of individual geochemical systems, the mathematical and theoretical development and refinement of new modeling capabilities, and enhancements of data bases on which the computations are based. The papers in this proceedings volume have been organized into the following four areas: Geochemical Model Development, Hydrothermal and Geothermal Systems, Sedimentary and Low Temperature Environments, and Data Base Development. The participants of this symposium and a complete list of the talks presented are listed in the appendices.

Geochemical atlas of Kichevo and the environs

International Nuclear Information System (INIS)

Stafilov, Trajche; Bacheva, Katerina; Sulejmani, Florije; Shajn, Robert

2011-01-01

The aim of this study is to present the results of a first systematic investigations of spatial distribution of different chemical elements in surface soil over of the Kichevo region known for its coal mine and thermo electrical power plant 'Oslomej'. The studies on the atmospheric deposition of trace metals over the entire territory of the Republic of Macedonia identified the most polluted areas and characterize different pollution sources. It was found that the most important sources trace metal deposition are ferrous and non-ferrous smelters including the emission from the thermo electrical power plants using coal. For this reason, the goal of this work was to determine the content of 19 major and trace elements in the soil from the town of Kichevo and its surroundings and to assess the size of the area eventually affected by the thermo electrical power plant situated near the town.

Geochemical and hydrodynamic controls on arsenic and trace metal cycling in a seasonally stratified US sub-tropical reservoir

International Nuclear Information System (INIS)

Brandenberger, Jill M.; Louchouarn, Patrick; Herbert, Bruce; Tissot, Philippe

2004-01-01

The phase distribution of trace metals and oxyanions was investigated within a South Texas watershed hosting a high density of surface uranium mine pits and tailings. The objectives of the study were to evaluate the potential impact of these old uranium mining sites on the watershed with particular emphasis on spatial and temporal changes in water quality of a reservoir that serves as the major source of freshwater to a population of ∼ 350,000 people in the region. A livestock pond, bordered by uranium mine tailings, was used as a model case-study site to evaluate the cycling of uranium mine-derived oxyanions under changing redox conditions. Although the pond showed seasonal thermal and chemical stratification, geochemical cycling of metals was limited to Co and Pb, which seemed to be mostly associated with redox cycling of Mn mineral phases, and U, which suggested reductive precipitation in the ponds hypolimnion. Uranium levels, however, were too low to support strong inputs from th e tailings into the water column of the pond. The strong relations observed between particulate Cr, Cs, V and Fe suggest that these metals are associated with a stable particulate phase (probably allochthonous aluminosilicates) enriched in unreactive iron. This observation is supported by a parallel relationship in sediments collected across a broad range of sediment depositional processed (and histories) in the basin. Arsenic, though selectively enriched in the ponds water column, remained stable and mostly in solution throughout the depth of the profile and showed no sign of geochemical cycling or interaction with Fe-rich particles. We found no evidence of anthropogenic impacts of U mines beyond the purely local scale. Arsenic does decrease in concentration downstream of uranium mining sites but its presence within the Nueces drainage basin is related to interactions between surface and ground waters with uranium-rich geological formations rather than long-scale transport of

Geochemical and hydrodynamic controls on arsenic and trace metal cycling in a seasonally stratified US sub-tropical reservoir

International Nuclear Information System (INIS)

Brandenberger, J.; Louchouarn, P.; Herbert, B.; Tissot, P.

2004-01-01

The phase distribution of trace metals and oxyanions, including U and As, in 2 surface water bodies was investigated within a South Texas watershed hosting a high density of surface U mine pits and tailings. The objectives of the study were to evaluate the environmental legacy of U mining, with particular emphasis on the spatial and temporal variability of water quality in Lake Corpus Christi, a downstream reservoir that serves as the major water resource to a population of ∼350,000 people in the region. Lyssy Pond, a livestock pond bordered by U mine tailings, was used as a model case-study site to evaluate the cycling of U mine-derived oxyanions under changing redox conditions. Although the pond showed seasonal thermal and chemical stratification, geochemical cycling of metals was limited to Co and Pb, which was correlated with redox cycling of Mn mineral phases, and U, which suggested reductive precipitation in the pond's hypolimnion. Uranium levels, however, were too low to support strong inputs from the tailings into the water column of the pond. The strong relationships observed between particulate Cr, Cs, V, and Fe suggest that these metals are associated with a stable particulate phase (probably allochthonous alumino-silicates) enriched in unreactive Fe. This observation is supported by a parallel relationship in sediments collected across a broad range of sediment depositional processes (and histories) in the basin. Arsenic, though selectively enriched in the pond's water column, was dominated by dissolved species throughout the depth of the profile and showed no sign of geochemical cycling or interaction with Fe-rich particles. Arsenic (and other oxyanions) in the water columns of Lake Corpus Christi and Lyssy pond were not affected by the abundant presence of Fe-rich particles but instead behaved conservatively. No evidence was found of anthropogenic impacts of U mines beyond the purely local scale. Arsenic's presence within the Nueces drainage basin

Trace element distribution and 235U/238U ratios in Euphrates waters and in soils and tree barks of Dhi Qar province (southern Iraq)

International Nuclear Information System (INIS)

Riccobono, Francesco; Perra, Guido; Pisani, Anastasia; Protano, Giuseppe

2011-01-01

To assess the quality of the environment in southern Iraq after the Gulf War II, a geochemical survey was carried out. The survey provided data on the chemistry of Euphrates waters, as well as the trace element contents, U and Pb isotopic composition, and PAH levels in soil and tree bark samples. The trace element concentrations and the 235 U/ 238 U ratio values in the Euphrates waters were within the usual natural range, except for the high contents of Sr due to a widespread presence of gypsum in soils of this area. The trace element contents in soils agreed with the common geochemistry of soils from floodplain sediments. Some exceptions were the high contents of Co, Cr and Ni, which had a natural origin related to ophiolitic outcrops in the upper sector of the Euphrates basin. The high concentrations of S and Sr were linked to the abundance of gypsum in soils. A marked geochemical homogeneity of soil samples was suggested by the similar distribution pattern of rare earth elements, while the 235 U/ 238 U ratio was also fairly homogeneous and within the natural range. The chemistry of the tree bark samples closely reflected that of the soils, with some notable exceptions. Unlike the soils, some tree bark samples had anomalous values of the 235 U/ 238 U ratio due to mixing of depleted uranium (DU) with the natural uranium pool. Moreover, the distribution of some trace elements (such as REEs, Th and Zr) and the isotopic composition of Pb in barks clearly differed from those of the nearby soils. The overall results suggested that significant external inputs occurred implying that once formed the DU-enriched particles could travel over long distances. The polycyclic aromatic hydrocarbon concentrations in tree bark samples showed that phenanthrene, fluoranthene and pyrene were the most abundant components, indicating an important role of automotive traffic. - Highlights: → This is a contribution to the knowledge of the Iraqi environment after Gulf War II. → In

Geochemical Constraints for Mercury's PCA-Derived Geochemical Terranes

Science.gov (United States)

Stockstill-Cahill, K. R.; Peplowski, P. N.

2018-05-01

PCA-derived geochemical terranes provide a robust, analytical means of defining these terranes using strictly geochemical inputs. Using the end members derived in this way, we are able to assess the geochemical implications for Mercury.

[Study on the method for the determination of trace boron, molybdenum, silver, tin and lead in geochemical samples by direct current arc full spectrum direct reading atomic emission spectroscopy (DC-Arc-AES)].

Science.gov (United States)

Hao, Zhi-hong; Yao, Jian-zhen; Tang, Rui-ling; Zhang, Xue-mei; Li, Wen-ge; Zhang, Qin

2015-02-01

The method for the determmation of trace boron, molybdenum, silver, tin and lead in geochemical samples by direct current are full spectrum direct reading atomic emission spectroscopy (DC-Arc-AES) was established. Direct current are full spectrum direct reading atomic emission spectrometer with a large area of solid-state detectors has functions of full spectrum direct reading and real-time background correction. The new electrodes and new buffer recipe were proposed in this paper, and have applied for national patent. Suitable analytical line pairs, back ground correcting points of elements and the internal standard method were selected, and Ge was used as internal standard. Multistage currents were selected in the research on current program, and each current set different holding time to ensure that each element has a good signal to noise ratio. Continuous rising current mode selected can effectively eliminate the splash of the sample. Argon as shielding gas can eliminate CN band generating and reduce spectral background, also plays a role in stabilizing the are, and argon flow 3.5 L x min(-1) was selected. Evaporation curve of each element was made, and it was concluded that the evaporation behavior of each element is consistent, and combined with the effects of different spectrographic times on the intensity and background, the spectrographic time of 35s was selected. In this paper, national standards substances were selected as a standard series, and the standard series includes different nature and different content of standard substances which meet the determination of trace boron, molybdenum, silver, tin and lead in geochemical samples. In the optimum experimental conditions, the detection limits for B, Mo, Ag, Sn and Pb are 1.1, 0.09, 0.01, 0.41, and 0.56 microg x g(-1) respectively, and the precisions (RSD, n=12) for B, Mo, Ag, Sn and Pb are 4.57%-7.63%, 5.14%-7.75%, 5.48%-12.30%, 3.97%-10.46%, and 4.26%-9.21% respectively. The analytical accuracy was

Open-water and under-ice seasonal variations in trace element content and physicochemical associations in fluvial bed sediment.

Science.gov (United States)

Doig, Lorne E; Carr, Meghan K; Meissner, Anna G N; Jardine, Tim D; Jones, Paul D; Bharadwaj, Lalita; Lindenschmidt, Karl-Erich

2017-11-01

Across the circumpolar world, intensive anthropogenic activities in the southern reaches of many large, northward-flowing rivers can cause sediment contamination in the downstream depositional environment. The influence of ice cover on concentrations of inorganic contaminants in bed sediment (i.e., sediment quality) is unknown in these rivers, where winter is the dominant season. A geomorphic response unit approach was used to select hydraulically diverse sampling sites across a northern test-case system, the Slave River and delta (Northwest Territories, Canada). Surface sediment samples (top 1 cm) were collected from 6 predefined geomorphic response units (12 sites) to assess the relationships between bed sediment physicochemistry (particle size distribution and total organic carbon content) and trace element content (mercury and 18 other trace elements) during open-water conditions. A subset of sites was resampled under-ice to assess the influence of season on these relationships and on total trace element content. Concentrations of the majority of trace elements were strongly correlated with percent fines and proxies for grain size (aluminum and iron), with similar trace element grain size/grain size proxy relationships between seasons. However, finer materials were deposited under ice with associated increases in sediment total organic carbon content and the concentrations of most trace elements investigated. The geomorphic response unit approach was effective at identifying diverse hydrological environments for sampling prior to field operations. Our data demonstrate the need for under-ice sampling to confirm year-round consistency in trace element-geochemical relationships in fluvial systems and to define the upper extremes of these relationships. Whether contaminated or not, under-ice bed sediment can represent a "worst-case" scenario in terms of trace element concentrations and exposure for sediment-associated organisms in northern fluvial systems

Distribution of uranium and some trace elements in groundwater of eastern delta, egypt

International Nuclear Information System (INIS)

Hamza, M.S.; Aly, A.I.M.; Swailem, F.M.; Elreedy, W.; Nada, A.

1986-01-01

The distribution pattern of uranium and some trace elements in groundwater of eastern Nile delta indicate general trend of increasing trace element concentration from west and south to North and east direction. This trend is most probably due to extensive leaching from the soil due to recharge from irrigation water. The geochemical correlation among trace elements was also investigated. Possible industrial pollution in bahtim area was detected.1 fig.,4 tab

Compilation of radiometric age and trace-element geochemical data, Yucca Mountain and surrounding areas of southwestern Nevada

International Nuclear Information System (INIS)

Weiss, S.I.; Noble, D.C.; Larson, L.T.

1994-01-01

This document is a compilation of available radiometric age and trace-element geochemical data for volcanic rocks and episodes of hydrothermal activity in Yucca Mountain and the surrounding region of southwestern Nevada. Only the age determinations considered to be geologically reasonable (consistent with stratigraphic relations) are listed below. A number of the potassium-argon (K-Ar) ages of volcanic rocks given by Kistler, Marvin et al., Noble et al., Weiss et al., and Noble et al. are not included as these ages have been shown to be incorrect or disturbed by hydrothermal alteration based on subsequent stratigraphic and/or petrographic data and the recognition of errors in K-Ar age determinations related to incomplete extraction of argon. In cases where absolute ages are tightly constrained by high precision 40 Ar/ 39 Ar ages and unequivocal stratigraphic relations, we have omitted the less precise K-Ar age data. Similarly, the more precise single-crystal laser-fusion 40 Ar/ 39 Ar age determinations of certain units are reported and less precise ages by multi-grain bulk-fusion 40 Ar/ 39 Ar methods are not included. This compilation does not include age data for basaltic rocks of Pliocene and Quaternary age in the Yucca Mountain region

Geochemistry of recent aragonite-rich sediments in Mediterranean karstic marine lakes: Trace elements as pollution and palaeoredox proxies and indicators of authigenic mineral formation.

Science.gov (United States)

Sondi, Ivan; Mikac, Nevenka; Vdović, Neda; Ivanić, Maja; Furdek, Martina; Škapin, Srečo D

2017-02-01

This study investigates the geochemical characteristics of recent shallow-water aragonite-rich sediments from the karstic marine lakes located in the pristine environment on the island of Mljet (Adriatic Sea). Different trace elements were used as authigenic mineral formation, palaeoredox and pollution indicators. The distribution and the historical record of trace elements deposition mostly depended on the sedimentological processes associated with the formation of aragonite, early diagenetic processes governed by the prevailing physico-chemical conditions and on the recent anthropogenic activity. This study demonstrated that Sr could be used as a proxy indicating authigenic formation of aragonite in a marine carbonate sedimentological environment. Distribution of the redox sensitive elements Mo, Tl, U and Cd was used to identify changes in redox conditions in the investigated lake system and to determine the geochemical cycle of these elements through environmental changes over the last 100 years. The significant enrichment of these elements and the presence of early formed nanostructured authigenic framboidal pyrite in laminated deeper parts of sediment in Malo Jezero, indicate sporadic events of oxygen-depleted euxinic conditions in the recent past. Concentrations of trace elements were in the range characteristic for non-contaminated marine carbonates. However, the increase in the concentrations of Zn, Cu, Pb, Sn, Bi in the upper-most sediment strata of Veliko Jezero indicates a low level of trace element pollution, resulting from anthropogenic inputs over the last 40 years. The presence of butyltin compounds (BuTs) in the surface sediment of Veliko Jezero additionally indicates the anthropogenic influence in the recent past. Copyright © 2016 Elsevier Ltd. All rights reserved.

Proceedings of the 6. International Conference on the Biogeochemistry of Trace Elements. CD ed.

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

This international conference provided a forum for researchers from around the world to exchange research notes of subjects dealing with the biogeochemistry of trace elements. The conference proceedings included 456 papers, of which 34 have been indexed separately for inclusion in the database. Each presentation included an introduction to a study, materials and methods, results and discussion and a conclusion. The conference was divided into special oral symposia (SO), general oral sessions (GO), a special poster session (SP) and a general poster session (GP). A wide range of topics were presented including: biosorption of trace elements and the bioavailability of metals for uptake and effects; chemical remediation; adsorption reactions on soils and sediments; fractionation of metals in soils; diagenetic transformations; arsenic content and distribution; metal speciation; the role of metal-organic interactions; phytoremediation; contents and distribution in soils and waters; soil amendments; mercury and human and animal health; mercury in the environment; aqueous speciation; phyto-, microbial and chemical remediation tools for metal contaminated soils and groundwater; geochemical surface controls on trace element fate; temporal trends of trace metals in biota; biomonitoring; transport in soils and waters; analytical techniques; metal/mineral interactions with microorganisms; the chemistry of trace elements in fly ash; ecotoxicology; groundwater; and, soil amendments. refs., tabs., figs.

Alterations in geochemical associations in artificially disturbed deep-sea sediments

Digital Repository Service at National Institute of Oceanography (India)

Nath, B.N.; Parthiban, G.; Banaulikar, S.; Sarkar, S.

Alterations in Geochemical Associations in Artificially Disturbed Deep-Sea Sediments B. NAGENDER NATH, G. PARTHIBAN, AND S. BANAULIKAR National Institute of Oceanography, Dona Paula, Goa, India SUBHADEEP SARKAR Department of Geology and Geophysics, Indian... the lithogenic component by transporting it from other locations within the Basin during commercial mining operations. Keywords manganese nodule mining, artificial benthic disturbance experiment, environmental impact assessment, metals Trace metals in marine...

study on trace contaminants control assembly for sealed environment chamber

Science.gov (United States)

Pang, L. P.; Wang, J.; Liu, L. K.; Liu, H.

The biological and Physicochemical P C life support technologies are all important parts to establish a human Closed Ecological Life Support System CELSS for long-duration mission The latter has the advantages of lower power consumption lower mass and higher efficiency therefore researchers often incorporate the use of biological systems with P C life support technologies to continuously recycle air water and part of the solid waste stream generated such as the Russian BLSS and the NASA-sponsored Lunar-Mars Life Support Test Project LMLSTP In short these tests were very successful in integrating biological and P C life support technologies for long-duration life support Therefore we should use a combination of integrated biological with P C life support technologies in a human CELSS Human construction materials plants animals and soils release much trace toxic gases in a CELSS and they will inhibit plant growth and badly affect human health when their concentrations rise over their threshold levels The effect of biological trace contaminant control technologies is slower especially for a human sealed chamber because human produce much more methane and other contaminants A regenerative Trace Contaminant Control Subsystem TCCS with P C technology is a more important part in this case to control quickly the airborne contaminants levels and assure human in good condition in a sealed chamber This paper describes a trace contaminant control test facility incorporated a 8 m3 sealed environment chamber a regenerative TCCS with P C

Geochemical signatures of tephras from Quaternary Antarctic Peninsula volcanoes

OpenAIRE

Kraus,Stefan; Kurbatov,Andrei; Yates,Martin

2013-01-01

In the northern Antarctic Peninsula area, at least 12 Late Plelstocene-Holocene volcanic centers could be potential sources of tephra layers in the region. We present unique geochemical fingerprints for ten of these volcanoes using major, trace, rare earth element, and isotope data from 95 samples of tephra and other eruption products. The volcanoes have predominantly basaltic and basaltic andesitic compositions. The Nb/Y ratio proves useful to distinguish between volcanic centers located on ...

Evaluation of trace elements distribution in water, sediment, soil and cassava plant in Muria peninsula environment by NAA method

International Nuclear Information System (INIS)

Muryono, H.; Sumining; Agus Taftazani; Kris Tri Basuki; Sukarman, A.

1999-01-01

The evaluation of trace elements distribution in water, sediment, soil and cassava plant in Muria peninsula by NAA method were done. The nuclear power plant (NPP) and the coal power plant (CPP) will be built in Muria peninsula, so, the Muria peninsula is an important site for samples collection and monitoring of environment. River-water, sediment, dryland-soil and cassava plant were choosen as specimens samples from Muria peninsula environment. The analysis result of trace elements were used as a contributed data for environment monitoring before and after NPP was built. The trace elements in specimens of river-water, sediment, dryland-soil and cassava plant samples were analyzed by INAA method. It was found that the trace elements distribution were not evenly distributed. Percentage of trace elements distribution in river-water, sediment, dryland-soil and cassava leaves were 0.00026-0.037% in water samples, 0.49-62.7% in sediment samples, 36.29-99.35% in soil samples and 0.21-99.35% in cassava leaves. (author)

Evaluation of trace elements distribution in water, sediment, soil and cassava plant in Muria peninsula environment by NAA method

Energy Technology Data Exchange (ETDEWEB)

Muryono, H.; Sumining; Agus Taftazani; Kris Tri Basuki; Sukarman, A. [Yogyakarta Nuclear Research Center, Yogyakarta (Indonesia)

1999-10-01

The evaluation of trace elements distribution in water, sediment, soil and cassava plant in Muria peninsula by NAA method were done. The nuclear power plant (NPP) and the coal power plant (CPP) will be built in Muria peninsula, so, the Muria peninsula is an important site for samples collection and monitoring of environment. River-water, sediment, dryland-soil and cassava plant were choosen as specimens samples from Muria peninsula environment. The analysis result of trace elements were used as a contributed data for environment monitoring before and after NPP was built. The trace elements in specimens of river-water, sediment, dryland-soil and cassava plant samples were analyzed by INAA method. It was found that the trace elements distribution were not evenly distributed. Percentage of trace elements distribution in river-water, sediment, dryland-soil and cassava leaves were 0.00026-0.037% in water samples, 0.49-62.7% in sediment samples, 36.29-99.35% in soil samples and 0.21-99.35% in cassava leaves. (author)

Correlation between sub-micron surface roughness of iron oxide encrustations and trace element concentrations

International Nuclear Information System (INIS)

Fischer, Cornelius; Karius, Volker; Luettge, Andreas

2009-01-01

Iron oxide encrustations are formed on black slate surfaces during oxidative weathering of iron sulfide and phosphate bearing, organic matter-rich slates. Synchronously, trace elements are released during ongoing weathering. Laser ablation ICP-MS analyses of a weathered and encrusted slate showed that major portions of the V, Cu, As, Mo, Pb, Th, and U reside in the encrustation. Recently a potential relationship between several micrometer to 500 nm surface topography roughness of such encrustations and its uranium concentration was shown. Based on laser scanning microscopy measurements, the present study shows that this interrelation must be expanded to small submicron-sized half-pores with diameters between 100 nm and 500 nm. We demonstrate that the relationship is not limited to topography variations of a single encrustation in the hand-specimen scale. Surface topography and geochemical analyses of iron oxide encrustations from several locations but from the same geochemical environment and with similar weathering history showed that the concentrations of U, P, Cu, and Zn correlate inversely with the surface roughness parameter F. This parameter represents the total surface area and is - in this case - a proxy for the root-mean square surface roughness Rq. This study substantiates the environmental importance that micrometer- to submicrometer topography variations of fluid-rock interfaces govern the trapping of trace elements.

Correlation between sub-micron surface roughness of iron oxide encrustations and trace element concentrations

Energy Technology Data Exchange (ETDEWEB)

Fischer, Cornelius, E-mail: cornelius@rice.edu [Department of Earth Science, MS-126, Rice University, 6100 Main Street, Houston, TX 77005 (United States); Geowissenschaftliches Zentrum der Universitaet Goettingen, Abt. Sedimentologie and Umweltgeologie, Goldschmidtstr. 3, D-37077 Goettingen (Germany); Karius, Volker [Geowissenschaftliches Zentrum der Universitaet Goettingen, Abt. Sedimentologie and Umweltgeologie, Goldschmidtstr. 3, D-37077 Goettingen (Germany); Luettge, Andreas [Department of Earth Science, MS-126, Rice University, 6100 Main Street, Houston, TX 77005 (United States); Department of Chemistry, Rice University, 6100 Main Street, Houston, TX 77005 (United States)

2009-08-01

Iron oxide encrustations are formed on black slate surfaces during oxidative weathering of iron sulfide and phosphate bearing, organic matter-rich slates. Synchronously, trace elements are released during ongoing weathering. Laser ablation ICP-MS analyses of a weathered and encrusted slate showed that major portions of the V, Cu, As, Mo, Pb, Th, and U reside in the encrustation. Recently a potential relationship between several micrometer to 500 nm surface topography roughness of such encrustations and its uranium concentration was shown. Based on laser scanning microscopy measurements, the present study shows that this interrelation must be expanded to small submicron-sized half-pores with diameters between 100 nm and 500 nm. We demonstrate that the relationship is not limited to topography variations of a single encrustation in the hand-specimen scale. Surface topography and geochemical analyses of iron oxide encrustations from several locations but from the same geochemical environment and with similar weathering history showed that the concentrations of U, P, Cu, and Zn correlate inversely with the surface roughness parameter F. This parameter represents the total surface area and is - in this case - a proxy for the root-mean square surface roughness Rq. This study substantiates the environmental importance that micrometer- to submicrometer topography variations of fluid-rock interfaces govern the trapping of trace elements.

Geologic and geochemical studies of the New Albany Shale Group (Devonian-Mississippian) in Illinois. Final report

Energy Technology Data Exchange (ETDEWEB)

Bergstrom, R.E.; Shimp, N.F.

1980-06-30

The Illinois State Geological Survey is conducting geological and geochemical investigations to evaluate the potential of New Albany Group shales as a source of hydrocarbons, particularly natural gas. Geological studies include stratigraphy and structure, mineralogic and petrographic characterization; analyses of physical properties; and development of a computer-based resources evaluation system. Geochemical studies include organic carbon content and trace elements; hydrocarbon content and composition; and adsorption/desorption studies of gas through shales. Separate abstracts have been prepared for each task reported.

Use of trace elements as indicators for underground fluid circulations in karstic environment; Utilisation des elements en trace comme traceurs des circulations souterraines en milieu karstique (site du Lamalou, Herault)

Energy Technology Data Exchange (ETDEWEB)

Pane-Escribe, M B

1995-06-29

The geochemical study of the trace element behaviour in karstic groundwaters has been carried out over the experimental site of Lamalou (Herault, France). Routine measurements of the physico-chemical parameters and of the dissolved elements concentrations have been achieved during two hydrological cycles. Radon has been monitored by passive detectors and by automatic electronic probes. Trace elements (Sc, Ti, V, Cr, Ni, Cu, Zn, As Rb, Sr, Mo, Cd, Sb, Cs, Ba, Th, U) were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The first part of this work presents the methodologies employed with in particular the improvement of the analytical performances of ICP-MS for water samples analysis. The detection limit for each considered element has been determined. The short and long term reproducibility for the samples analysis has also been tested. The second part of this study presents the treatment and interpretation of the results. This analysis has pointed our the influence of the aquifer structure on the chemical elements distribution. The trace and major elements concentrations are effectively related to the fracturing state of the reservoir and allow to individualize the high transmissivity zones from zones with a lower transmissivity in this mono-lithological context, trace elements appear to be particularly efficient tracers for determining the water origin and circulation their spatial and temporal behaviour leads to identify three different origins for the water mineralization over the studied area: limestones, clays and external sources (rainfalls and occasional pollutions). (author). 154 refs.

Geochemical investigation of UMTRAP designated site at Grand Junction, Colorado

International Nuclear Information System (INIS)

Markos, G.; Bush, K.J.

1983-09-01

This report is the result of a geochemical investigation of the former uranium mill and tailings site at Grand Junction, Colorado. The objectives of the investigation are to characterize the geochemistry, to determine the contaminant distribution resulting from the former milling activities and tailings, and to infer chemical pathways and transport mechanisms from the contaminant distribution. The results should be used to model contaminant migration and to develop criteria for long-term containment media, such as a cover system which is impermeable to contaminant migration. This report assumes a familiarity with the hydrologic conditions of the site and the geochemical concepts underlying the investigation. The results reported are based on a sampling of waters in two seasons and solid material from the background, the area adjacent to the site, and the site. The solid samples were water extracted to remove easily soluble salts and acid extracted to remove carbonates and hydroxides. The water extracts and solid samples were analyzed for the major and trace elements. A limited number of samples were analyzed for radiological components. The report includes the methods of sampling, sample processing, analysis, and data interpretation. Four major conclusions are: (1) trace element concentrations in shallow subsurface waters adjacent to the tailings temporally vary up to an order of magnitude; (2) the riverbank soils and borehole waters are contaminated with uranium, radium, and trace elements from discharge of tailings solids and solutions during the active time of the mill; however, the movement of contaminants toward the Colorado River does not appear to be significant; (3) the Colorado River adjacent to the tailings is not contaminated; and (4) trace metals have accumulated at both the tailings/cover and tailings/soil interface because of precipitation reactions caused by chemical differences between the two materials

Gamma Spectrometric Determination of U, Th, K and Some Geochemical Applications

International Nuclear Information System (INIS)

Dodona, A.; Tashko, A.

2001-01-01

The application of 'in situ' gamma-spectrometric method (''infinite'' environment), made possible the simultanious determination of U, Th and K. 4 channel gamma-spectrometric analyser with NaI(TI) scintilation counter crystal detector (103 cm 3 φ=50x50mm) was used to determin U, Th(more than 1-2 ppm) and K (more than 1%) in laboratory conditions. The detector was inserted into a lead camera and calibrated for measurement geometry with vessel of ''Marineli'' type of a 17o cm 3 volume. The study of main factors, which influence in the gamma spectrometric measurements, (the technical, physical, geometrical and time parameters) has been carried out. International standards of U, Th, K and internal monitoring standard samples are used for the calibration. External analytical control has been realized by other radiometric and chemical methods. The detection limits ( 1 ppm Th, 2ppm U and 1% K) and the relative errors (17-20% for 1-10 ppm U, Th and 10-15% for more than 10 ppm U, Th and more than 1% K) guarantee a quantitative analysis that may be used successfully in the geochemical studies. Some geochemical applications, based on the content of Th, U and Th/U ratio in rocks samples that we have we have analyzed with this method, are shown in this paper. U, Th and their ratio are used as trace elements to indicate the differences between the acidic magmatic rocks of Albania (Th/U ratio=2-6 and>10). The bimodal character of Th/U scattering in ignimbrides and monzonites (Korabi zone) shows that in addition to the ''normal'' rocks, there are also some ones enriched with Th, So, the differential analysis of Th, U, and K may be used as geochemical exploration criteria for the radioactive and non-radioactive mineralization, such as REE (Rare Earth Elements), phospghorites, bauxites, placers etc. (authors)

A geochemical atlas of North Carolina, USA

Science.gov (United States)

Reid, J.C.

1993-01-01

A geochemical atlas of North Carolina, U.S.A., was prepared using National Uranium Resource Evaluation (NURE) stream-sediment data. Before termination of the NURE program, sampling of nearly the entire state (48,666 square miles of land area) was completed and geochemical analyses were obtained. The NURE data are applicable to mineral exploration, agriculture, waste disposal siting issues, health, and environmental studies. Applications in state government include resource surveys to assist mineral exploration by identifying geochemical anomalies and areas of mineralization. Agriculture seeks to identify areas with favorable (or unfavorable) conditions for plant growth, disease, and crop productivity. Trace elements such as cobalt, copper, chromium, iron, manganese, zinc, and molybdenum must be present within narrow ranges in soils for optimum growth and productivity. Trace elements as a contributing factor to disease are of concern to health professionals. Industry can use pH and conductivity data for water samples to site facilities which require specific water quality. The North Carolina NURE database consists of stream-sediment samples, groundwater samples, and stream-water analyses. The statewide database consists of 6,744 stream-sediment sites, 5,778 groundwater sample sites, and 295 stream-water sites. Neutron activation analyses were provided for U, Br, Cl, F, Mn, Na, Al, V, Dy in groundwater and stream water, and for U, Th, Hf, Ce, Fe, Mn, Na, Sc, Ti, V, Al, Dy, Eu, La, Sm, Yb, and Lu in stream sediments. Supplemental analyses by other techniques were reported on U (extractable), Ag, As, Ba, Be, Ca, Co, Cr, Cu, K, Li, Mg, Mo, Nb, Ni, P, Pb, Se, Sn, Sr, W, Y, and Zn for 4,619 stream-sediment samples. A small subset of 334 stream samples was analyzed for gold. The goal of the atlas was to make available the statewide NURE data with minimal interpretation to enable prospective users to modify and manipulate the data for their end use. The atlas provides only

Regional geochemical maps of uranium in Northern Scotland: Environmental and economic considerations

International Nuclear Information System (INIS)

Plant, J.

1978-01-01

The Institute of Geological Sciences began to prepare a series of regional geochemical maps at a scale of 1:250000, showing the surface distribution of those trace elements which are of economic and environmental significance. Particular interest was shown in uranium, important both for a nuclear fuel, and also for fundamental studies of geological processes. The first series of maps was prepared for the northern Highlands of Scotland. Natural levels of uranium in rocks, soils and water are reviewed. The reasons for selecting Northern Scotland and the effect of the environment on the methods of sampling are discussed. A brief summary is given of some of the main applications of these maps, the most important being to economic geology, agriculture, and medical geography. The maps should make it possible to ensure that development of mineral resources and environmental planning are soundly based. (U.K.)

The IUGS/IAGC Task Group on Global Geochemical Baselines

Science.gov (United States)

Smith, David B.; Wang, Xueqiu; Reeder, Shaun; Demetriades, Alecos

2012-01-01

The Task Group on Global Geochemical Baselines, operating under the auspices of both the International Union of Geological Sciences (IUGS) and the International Association of Geochemistry (IAGC), has the long-term goal of establishing a global geochemical database to document the concentration and distribution of chemical elements in the Earth’s surface or near-surface environment. The database and accompanying element distribution maps represent a geochemical baseline against which future human-induced or natural changes to the chemistry of the land surface may be recognized and quantified. In order to accomplish this long-term goal, the activities of the Task Group include: (1) developing partnerships with countries conducting broad-scale geochemical mapping studies; (2) providing consultation and training in the form of workshops and short courses; (3) organizing periodic international symposia to foster communication among the geochemical mapping community; (4) developing criteria for certifying those projects whose data are acceptable in a global geochemical database; (5) acting as a repository for data collected by those projects meeting the criteria for standardization; (6) preparing complete metadata for the certified projects; and (7) preparing, ultimately, a global geochemical database. This paper summarizes the history and accomplishments of the Task Group since its first predecessor project was established in 1988.

Specialization of Bacillus in the Geochemically Challenged Environment of Death Valley

Science.gov (United States)

Kopac, S.

2014-04-01

Death Valley is the hottest, driest place in North America, a desert with soils containing toxic elements such as boron and lead. While most organisms are unable to survive under these conditions, a diverse community of bacteria survives here. What has enabled bacteria to adapt and thrive in a plethora of extreme and stressful environments where other organisms are unable to grow? The unique environmental adaptations that distinguish ecologically distinct bacterial groups (ecotypes) remain a mystery, in contrast to many animal species (perhaps most notably Darwin's ecologically distinct finch species). We resolve the ecological factors associated with recently diverged ecotypes of the soil bacteria Bacillus subtilis and Bacillus licheniformis, isolated from the dry, geochemically challenging soils of Death Valley, CA. To investigate speciation associated with challenging environmental parameters, we sampled soil transects along a 400m stretch that parallels a decrease in salinity adjacent to a salt flat; transects also encompass gradients in soil B, Cu, Fe, NO3, and P, all of which were quantified in our soil samples. We demarcated strains using Ecotype Simulation, a sequence-based algorithm. Each ecotype's habitat associations were determined with respect to salinity, B, Cu, Fe, NO3, and P. In addition, our sample strains were tested for tolerance of copper, boron and salinity (all known to inhibit growth at high concentrations) by comparing their growth over a 20 hour period. Ecotypes differed in their habitat associations with salinity, boron, copper, iron, and other ecological factors; these environmental dimensions are likely causing speciation of B. subtilis-licheniformis ecotypes at our sample site. Strains also differed in tolerance of boron and copper, providing evidence that our sequence-based demarcations reflect real differences in metabolism. By better understanding the relationship between bacterial speciation and the environment, we can begin to

Assessment of soil pollution through trace element contamination in a coal mine environment of Jharia

International Nuclear Information System (INIS)

Singh, Gurdeep; Shrivastava, B.K.

1997-01-01

Coal mining environment is associated with liberation of several trace elements. Soils in such regions particularly have been polluted with these trace elements from a wide range of sources. Trace elements such as lead, copper, iron, zinc, chromium, manganese, cobalt, nickel, cadmium, etc. have caused major human health problems in several parts of the world. Concern over such incidents has prompted numerous investigations into the metabolism and toxic effects of these elements. The trace element contamination of soils (e.g. roadside, overburden dump, residential area etc.) in a part of the Jharia coal field running through a large industrial zone was studied. Representative soil samples from several highly polluted spots of the mining areas were collected and analysed. Results of the investigation revealed that the soils are polluted with trace elements to an appreciable level. Pollution index for soil was developed on the basis of observed concentration levels of trace elements of the study area which may help in better understanding of pollution analysis in coal mining areas. (author)

Linking geochemical processes in mud volcanoes with arsenic mobilization driven by organic matter.

Science.gov (United States)

Liu, Chia-Chuan; Kar, Sandeep; Jean, Jiin-Shuh; Wang, Chung-Ho; Lee, Yao-Chang; Sracek, Ondra; Li, Zhaohui; Bundschuh, Jochen; Yang, Huai-Jen; Chen, Chien-Yen

2013-11-15

The present study deals with geochemical characterization of mud fluids and sediments collected from Kunshuiping (KSP), Liyushan (LYS), Wushanting (WST), Sinyangnyuhu (SYNH), Hsiaokunshui (HKS) and Yenshuikeng (YSK) mud volcanoes in southwestern Taiwan. Chemical constituents (cations, anions, trace elements, organic carbon, humic acid, and stable isotopes) in both fluids and mud were analyzed to investigate the geochemical processes and spatial variability among the mud volcanoes under consideration. Analytical results suggested that the anoxic mud volcanic fluids are highly saline, implying connate water as the probable source. The isotopic signature indicated that δ(18)O-rich fluids may be associated with silicate and carbonate mineral released through water-rock interaction, along with dehydration of clay minerals. Considerable amounts of arsenic in mud irrespective of fluid composition suggested possible release through biogeochemical processes in the subsurface environment. Sequential extraction of As from the mud indicated that As was mostly present in organic and sulphidic phases, and adsorbed on amorphous Mn oxyhydroxides. Volcanic mud and fluids are rich in organic matter (in terms of organic carbon), and the presence of humic acid in mud has implications for the binding of arsenic. Functional groups of humic acid also showed variable sources of organic matter among the mud volcanoes being examined. Because arsenate concentration in the mud fluids was found to be independent from geochemical factors, it was considered that organic matter may induce arsenic mobilization through an adsorption/desorption mechanism with humic substances under reducing conditions. Organic matter therefore plays a significant role in the mobility of arsenic in mud volcanoes. Copyright © 2012 Elsevier B.V. All rights reserved.

Geochemical character of Southern African Kimberlites: a new approach based on isotopic constraints

International Nuclear Information System (INIS)

Smith, C.B.; Gurney, J.J.; Ebrahim, N.

1985-01-01

Major and trace element compositions of southern African kimberlite samples previously analysed for isotopic compositions confirm that isotopically defined Group I (basaltic) and Group II (micaceous) variants have distinctive geochemical signatures. These signatures are generally consistent with geochemical variation in petrographically defined types. Stepwise discriminant function analysis is used to define the most important geochemical distinctions at the group level and to derive a procedure which successfully classifies a large number of unknowns based on chemical composition only. In comparison to Group I, Group II kimberlites have consistently higher abundances of SiO 2 , K 2 O, Pb, Rb, Ba and LREE, and lower abundances of TiO 2 and Nb. In conjunction with isotopic results, the distinctions in incompatible element contents in particular are believed to reflect broad differences in source rock character. Results are consistent with derivation of Group I kimberlites from asthenospheric-like sources similar to those from which oceanic island basalts are produced. In contrast, Group II kimberlites are inferred to originate from sources within ancient stabilized subcontinental lithosphere characterized by time-averaged incompatible element enrichment. Group I kimberlites can be further subdivided into two isotopically similar types to some degree correlative with tectonic environment. Compared to subgroup IA (on-craton), IB kimberlites have lower SiO 2 and higher CaO, FeO + Fe 2 O 3 and volatile contents in addition to somewhat greater TiO 2 , P 2 O 5 , Nb, Zr and Y abundances, and tend to occur outside the inferred boundaries of the Kaapvaal Craton though exceptions are present and new unpublished data suggest that this group may be relatively common on the craton

Petrographic and geochemical data for Cenozoic volcanic rocks of the Bodie Hills, California and Nevada

Science.gov (United States)

du Bray, Edward A.; John, David A.; Box, Stephen E.; Vikre, Peter G.; Fleck, Robert J.; Cousens, Brian L.

2013-04-23

Petrographic and geochemical data for Cenozoic volcanic rocks of the Bodie Hills, California and Nevada // // This report presents petrographic and geochemical data for samples collected during investigations of Tertiary volcanism in the Bodie Hills of California and Nevada. Igneous rocks in the area are principally 15–6 Ma subduction-related volcanic rocks of the Bodie Hills volcanic field but also include 3.9–0.1 Ma rocks of the bimodal, post-subduction Aurora volcanic field. Limited petrographic results for local basement rocks, including Mesozoic granitoid rocks and their metamorphic host rocks, are also included in the compilation. The petrographic data include visual estimates of phenocryst abundances as well as other diagnostic petrographic criteria. The geochemical data include whole-rock major oxide and trace element data, as well as limited whole-rock isotopic data.

Assessing the risks of trace elements in environmental materials under selected greenhouse vegetable production systems of China

International Nuclear Information System (INIS)

Chen, Yong; Huang, Biao; Hu, Wenyou; Weindorf, David C.; Liu, Xiaoxiao; Niedermann, Silvana

2014-01-01

The risk assessment of trace elements of different environmental media in conventional and organic greenhouse vegetable production systems (CGVPS and OGVPS) can reveal the influence of different farming philosophy on the trace element accumulations and their effects on human health. These provide important basic data for the environmental protection and human health. This paper presents trace element accumulation characteristics of different land uses; reveals the difference of soil trace element accumulation both with and without consideration of background levels; compares the trace element uptake by main vegetables; and assesses the trace element risks of soils, vegetables, waters and agricultural inputs, using two selected greenhouse vegetable systems in Nanjing, China as examples. Results showed that greenhouse vegetable fields contained significant accumulations of Zn in CGVPS relative to rice–wheat rotation fields, open vegetable fields, and geochemical background levels, and this was the case for organic matter in OGVPS. The comparative analysis of the soil medium in two systems with consideration of geochemical background levels and evaluation of the geo-accumulation pollution index achieved a more reasonable comparison and accurate assessment relative to the direct comparison analysis and the evaluation of the Nemerow pollution index, respectively. According to the Chinese food safety standards and the value of the target hazard quotient or hazard index, trace element contents of vegetables were safe for local residents in both systems. However, the spatial distribution of the estimated hazard index for producers still presented certain specific hotspots which may cause potential risk for human health in CGVPS. The water was mainly influenced by nitrogen, especially for CGVPS, while the potential risk of Cd and Cu pollution came from sediments in OGVPS. The main inputs for trace elements were fertilizers which were relatively safe based on relevant

Assessing the risks of trace elements in environmental materials under selected greenhouse vegetable production systems of China

Energy Technology Data Exchange (ETDEWEB)

Chen, Yong [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Huang, Biao, E-mail: bhuang@issas.ac.cn [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Hu, Wenyou [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Weindorf, David C.; Liu, Xiaoxiao [Department of Plant and Soil Science, Texas Tech University, Lubbock, TX (United States); Niedermann, Silvana [Department of Environmental Systems Science, Institute of Agricultural Science, ETH Zurich, 8092 Zurich (Switzerland)

2014-02-01

The risk assessment of trace elements of different environmental media in conventional and organic greenhouse vegetable production systems (CGVPS and OGVPS) can reveal the influence of different farming philosophy on the trace element accumulations and their effects on human health. These provide important basic data for the environmental protection and human health. This paper presents trace element accumulation characteristics of different land uses; reveals the difference of soil trace element accumulation both with and without consideration of background levels; compares the trace element uptake by main vegetables; and assesses the trace element risks of soils, vegetables, waters and agricultural inputs, using two selected greenhouse vegetable systems in Nanjing, China as examples. Results showed that greenhouse vegetable fields contained significant accumulations of Zn in CGVPS relative to rice–wheat rotation fields, open vegetable fields, and geochemical background levels, and this was the case for organic matter in OGVPS. The comparative analysis of the soil medium in two systems with consideration of geochemical background levels and evaluation of the geo-accumulation pollution index achieved a more reasonable comparison and accurate assessment relative to the direct comparison analysis and the evaluation of the Nemerow pollution index, respectively. According to the Chinese food safety standards and the value of the target hazard quotient or hazard index, trace element contents of vegetables were safe for local residents in both systems. However, the spatial distribution of the estimated hazard index for producers still presented certain specific hotspots which may cause potential risk for human health in CGVPS. The water was mainly influenced by nitrogen, especially for CGVPS, while the potential risk of Cd and Cu pollution came from sediments in OGVPS. The main inputs for trace elements were fertilizers which were relatively safe based on relevant

Late Guadalupian evolution of the Delaware Basin: insights from stable isotope and trace element geochemistry

Science.gov (United States)

Smith, B.; Kerans, C.

2017-12-01

Accurate characterization of mixed carbonate and evaporite deposits requires an understanding of basin-scale physical, chemical, and biological processes. In these settings, carbonate geochemistry often responds to changes in the prevailing conditions in the water column. It follows that the geochemical record presents a potential aid for interpretation of depositional systems provided that it is relatively free of diagenetic overprint. This is seldom the case in shallow-water settings as processes such as meteoric diagenesis and early dolomitization obscure or erase the original geochemical signal. Fine grained deep-water sediments are more likely to retain their original geochemical characteristics. If reliable shelf-to-basin correlations can be established, then basinal deposits provide critical data not only for the interpretation of deep water environments, but overall basin evolution as well. This study examines variations in trace element and stable isotope geochemistry from the Delaware Basin of West Texas and New Mexico. Interpretation of geochemical data within a pre-existing shelf-to-basin stratigraphic framework suggests a link between basin water chemistry and sea level changes during the entirety of the Guadalupian. This link is supported analogies to modern silled basins where changes in sea level and thus recharge across the sill can control nutrient input, circulation, and bottom water oxygenation. In light of these relationships, the filling of the Delaware Basin with basin-centered evaporites at the end of the Guadalupian likely represents the culmination of a more gradual, cyclic evolution towards basin restriction. Ongoing work will continue to focus on tying regional-scale changes in basin water chemistry to the combined geochemical and physical sedimentological records.

Geochemical monitoring using noble gases and carbon isotopes: study of a natural reservoir

International Nuclear Information System (INIS)

Jeandel, E.

2008-12-01

To limit emissions of greenhouse gases in the atmosphere, CO 2 geological sequestration appears as a solution in the fight against climate change. The development of reliable monitoring tools to ensure the sustainability and the safety of geological storage is a prerequisite for the implementation of such sites. In this framework, a geochemical method using noble gas and carbon isotopes geochemistry has been tested on natural and industrial analogues. The study of natural analogues from different geological settings showed systematic behaviours of the geochemical parameters, depending on the containment sites, and proving the effectiveness of these tools in terms of leak detection and as tracers of the behaviour of CO 2 . Moreover, an experience of geochemical tracing on a natural gas storage has demonstrated that it is possible to identify the physical-chemical processes taking place in the reservoir to a human time scale, increasing interest in the proposed tool and providing general information on its use. (author)

Trace-element geochemistry of coal resource development related to environmental quality and health

Energy Technology Data Exchange (ETDEWEB)

1980-01-01

This report assesses for decision makers and those involved in coal resource development the environmental and health impacts of trace-element effects arising from significant increases in the use of coal, unless unusual precautions are invoked. Increasing demands for energy and the pressing need for decreased dependence of the United States on imported oil require greater use of coal to meet the nation's energy needs during the next decade. If coal production and consumption are increased at a greatly accelerated rate, concern arises over the release, mobilization, transportation, distribution, and assimilation of certain trace elements, with possible adverse effects on the environment and human health. It is, therefore, important to understand their geochemical pathways from coal and rocks via air, water, and soil to plants, animals, and ultimately humans, and their relation to health and disease. To address this problem, the Panel on Trace Element Geochemistry of Coal Resource Development Related to Health (PECH) was established. Certain assumptions were made by the Panel to highlight the central issues of trace elements and health and to avoid unwarranted duplication of other studies. Based on the charge to the Panel and these assumptions, this report describes the amounts and distribution of trace elements related to the coal source; the various methods of coal extraction, preparation, transportation, and use; and the disposal or recycling of the remaining residues or wastes. The known or projected health effects are discussed at the end of each section.

Trace element geochemistry of the South Atlantic Bight. Progress report

International Nuclear Information System (INIS)

Windom, H.L.; Wallace, G.T.

1980-03-01

This report summarizes research conducted during the past year under DOE Contract EY-76-S-09-0890. During this time, studies have been continued in the mid to outer continental shelf region. We have also initiated nearshore studies designed to elucidate processes influencing the fate of trace elements in estuaries and the coastal frontal zone. A smaller effort has been concerned with preliminary geochemical studies of uranium-thorium natural decay series radionuclides and with improvement, calibration, and expansion of our trace element laboratory procedures

The distribution pattern of trace elements in Pedra do Fogo formation, permian of Maranhao Basin and it application as an environment indicator of sedimentation

International Nuclear Information System (INIS)

Oliveira, C.M. de.

1982-01-01

The present investigation consisted of a geochemical study of the medium and upper layers of the Pedra do Fogo Formation aiming at correlating its elemental distribution pattern with the sedimentary environment where that formation was deposited. Pelitic material with carbonate content below 30% was sampled in the three different outcrops of the Pedra do Fogo Formation for mineralogical and chemical analyses. Illite and dolomite, with subordinate amounts of smectite, calcite, quartz and K-feldspar were determined by X-ray diffraction techniques as the constituents of the mineral assemblages. Trace element (B, Ba, Co, Cr, Cu, Ga, Li, Mn, Ni, P, V, Pb, Sr, Rb and Zn), CO sub(2) and K concentrations were determined by emission spectrography, atomic absorption spectrometry and colorimetry. The interpretation of the chemical data based on B-V, Ga-B, B-K sub(2) O and B-Ga-Rb diagrams and on B content indicates a wite range of variation for the medium salinity during the deposition of the Pedra do Fogo rocks. Accordingly, the observed sequence is composed of intercalations of marine and fresh water sediments, the latter being dominant. The marine intercalations are more frequent in the bottom of the sampled stratigraphic section and become progressively rarer towards the top layers which were deposited in a typically fresh water environment. (author)

Adjustment of geochemical background by robust multivariate statistics

Science.gov (United States)

Zhou, D.

1985-01-01

Conventional analyses of exploration geochemical data assume that the background is a constant or slowly changing value, equivalent to a plane or a smoothly curved surface. However, it is better to regard the geochemical background as a rugged surface, varying with changes in geology and environment. This rugged surface can be estimated from observed geological, geochemical and environmental properties by using multivariate statistics. A method of background adjustment was developed and applied to groundwater and stream sediment reconnaissance data collected from the Hot Springs Quadrangle, South Dakota, as part of the National Uranium Resource Evaluation (NURE) program. Source-rock lithology appears to be a dominant factor controlling the chemical composition of groundwater or stream sediments. The most efficacious adjustment procedure is to regress uranium concentration on selected geochemical and environmental variables for each lithologic unit, and then to delineate anomalies by a common threshold set as a multiple of the standard deviation of the combined residuals. Robust versions of regression and RQ-mode principal components analysis techniques were used rather than ordinary techniques to guard against distortion caused by outliers Anomalies delineated by this background adjustment procedure correspond with uranium prospects much better than do anomalies delineated by conventional procedures. The procedure should be applicable to geochemical exploration at different scales for other metals. ?? 1985.

Geochemical homogeneity of tuffs at the potential repository level, Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Peterman, Zell E.; Cloke, Paul

2001-01-01

In a potential high-level radioactive waste repository at Yucca Mountain, Nevada, radioactive waste and canisters, drip shields protecting the waste from seepage and from rock falls, the backfill and invert material of crushed rock, the host rock, and water and gases contained within pores and fractures in the host rock together would form a complex system commonly referred to as the near-field geochemical environment. Materials introduced into the rock mass with the waste that are designed to prolong containment collectively are referred to as the Engineered Barrier System, and the host rock and its contained water and gases compose the natural system. The interaction of these component parts under highly perturbed conditions including temperatures well above natural ambient temperatures will need to be understood to assess the performance of the potential repository for long-term containment of nuclear waste. The geochemistry and mineralogy of the rock mass hosting the emplacement drifts must be known in order to assess the role of the natural system in the near-field environment. Emplacement drifts in a potential repository at Yucca Mountain would be constructed in the phenocryst-poor member of the Topopah Spring Tuff which is composed of both lithophysal and nonlithophysal zones. The chemical composition of the phenocryst-poor member has been characterized by numerous chemical analyses of outcrop samples and of core samples obtained by surface-based drilling. Those analyses have shown that the phenocryst-poor member of the Topopah Spring Tuff is remarkably uniform in composition both vertically and laterally. To verify this geochemical uniformity and to provide rock analyses of samples obtained directly from the potential repository block, major and trace elements were analyzed in core samples obtained from drill holes in the cross drift, which was driven to provide direct access to the rock mass where emplacement drifts would be constructed

Geochemical, hydrological, and biological cycling of energy residual. Research plan

International Nuclear Information System (INIS)

Wobber, F.J.

1983-03-01

Proposed research goals and specific research areas designed to provide a base of fundamental scientific information so that the geochemical, hydrological, and biophysical mechanisms that contribute to the transport and long term fate of energy residuals in natural systems can be understood are described. Energy development and production have resulted in a need for advanced scientific information on the geochemical transformations, transport rates, and potential for bioaccumulation of contaminants in subsurface environments

High-level radioactive waste disposal: Key geochemical issues and information needs for site characterization

International Nuclear Information System (INIS)

Brooks, D.J.; Bembia, P.J.; Bradbury, J.W.; Jackson, K.C.; Kelly, W.R.; Kovach, L.A.; Mo, T.; Tesoriero, J.A.

1986-01-01

Geochemistry plays a key role in determining the potential of a high-level radioactive waste disposal site for long-term radionuclide containment and isolation. The Nuclear Regulatory Commission (NRC) has developed a set of issues and information needs important for characterizing geochemistry at the potential sites being investigated by the Department of Energy Basalt Waste Isolation Project, Nevada Nuclear Waste Storage Investigations project, and Salt Repository Project. The NRC site issues and information needs consider (1) the geochemical environment of the repository, (2) changes to the initial geochemical environment caused by construction and waste emplacement, and (3) interactions that affect the transport of waste radionuclides to the accessible environment. The development of these issues and information needs supports the ongoing effort of the NRC to identify and address areas of geochemical data uncertainty during prelicensing interactions

Orientation geochemical survey for uranium exploration using 230Th

International Nuclear Information System (INIS)

Xia Dingliang.

1985-01-01

The distribution of 230 Th in soils, rocks and ores and its relationship with respect to uranium ore formation are discussed for its possible use in geochemical exploration for U. 230 Th, U and Ra, being members of the same decay series, are different in their geochemical behavior upon which the study is orientated. Twenty uranium deposits and occurrences located in western and southern Hunan province are tested. Geochemical data obtained are comprehensively correlated. It is suggested that 230 Th is useful not only in U-Ra disequilibrium study but also in understanding the geochemical evolution of U ores. The data aid to interpret the genesis of uranium deposits and to assess the radioactive anomalies and uranium-bearing zones. Therefore, it can be adopted as a tool for searching in deep-buried uranium ores. The field procedure is rather simple and flexible to meet any geological environment. It is easy to read out and is less influnced by any kind of interference. In case of disequilibrium caused by oxidation and reduction during the period of ore formation it still gives good indication compared with that of radiometry, radonmetry and geochemical sampling for U

Izu-Bonin rear-arc magmatism: Geochemical investigation of volcanoclastic material

OpenAIRE

Sæbø, Andreas

2017-01-01

Studied samples from the Izu Bonin rear arc show a distinct geochemical pattern that resemble the modern continental crust. In contrast to the volcanic front, samples from the Izu Bonin rear arc show enrichment of LREE (La, Ce, Pr, Nd) and higher K2O at a given SiO2. This suggest that processes leading up to the geochemistry observed in the rear arc is fundamental in creating the modern continental crust. Additional isotopic and trace element analysis from volcanic material rec...

NEW GEOCHEMICAL DATA OF BASALTS IN THE TSOROIDOG AREA, CENTRAL MONGOLIA

Directory of Open Access Journals (Sweden)

T. Oyunchimeg

2017-01-01

Full Text Available At present, geochemical data are widely used for reconstructing geodynamic settings, especially, volcanic rocks of mafic composition, i.e., basalts, because they are widespread in many orogenic belts and are indicative of different geodynamic environments. In general, we propose the reconstruction of the tectonic settings of basalts according to their relationships with associated ocean plate stratigraphy (OPS sediments, their petrogenesis and their geochemical features.

Geochemical study of coral skeletons from the Puerto Morelos Reef, southeastern Mexico

Science.gov (United States)

Kasper-Zubillaga, Juan J.; Armstrong-Altrin, John S.; Rosales-Hoz, Leticia

2014-12-01

Geochemical analyses in coral skeletons have been used as a proxy of marine environmental conditions and to understand the mechanisms of adsorption of chemical elements into the coral skeletons and growth forms. However, little attention has been given to show the possible differences in the growth rates of corals based upon major, trace, rare earth element and microprobe analyses to examine the physical-chemical conditions influencing those differences. Our goal is to show how branch and fan corals incorporate elements into their skeletons comparing them with their coral growth rates. We determine the development of the skeletons of two branching (Acropora palmata, Acropora cervicornis) and one fan shaped (Gorgonia ventalina) colonies in the Puerto Morelos Reef, southeastern Mexico based upon geochemical data and the influence of terrigenous input into the species. Mg and Sr concentrations were the most statistically significant elements among the species studied suggesting that Mg concentration in Gorgonia ventalina is probably not linked to its growth rate. Mn content in the sea water is adsorbed by the three corals during past growth rates during high rainfall events. Sr concentration may be associated with the growth rate of Acropora palmata. Little differences in the growth rate in Acropora palmata may be associated with low rates of calcitization, negligible changes in the Sr concentration and little influence of temperature and water depth in its growth. Trace elements like Cr, Co, Ni and V adsorbed by the corals are influenced by natural concentration of these elements in the sea-water. Rare earth elements in the corals studied suggests abundant inorganic ions CO32- with variable pH in modern shallow well-oxygenated sea water. Lack of terrigenous input seawards is supported by geochemical, geomorphological and biological evidences. This study is an example of how geochemical data are useful to observe the differences in environmental conditions related to

Sulfide geochemical survey in Dawahan, Larap, Camarines Norte (Southern Luzon), Philippines

International Nuclear Information System (INIS)

Santos, G. Jr.

1979-07-01

Sulfide geochemical activation analysis survey was conducted in Southern Luzon, Philippines. Trace elements in the rocks of Dawahan, Larap, Camarines Norte, particularly in the sulfide fraction of the rocks were determined and correlated in the search for mineral deposits in the project area. The study has shown that the Cu, V, Co, Pb, Mn, Zn, Ni, Au, Ag and As distributions in Dawahan are log normal with Cu, As and V having an excess of low values. There is a direct relationship between the mineralizations of Ag and Pb with Cu mineralization. Fair geochemical correlations were observed between Cu-Zn, Cu-As and Cu-Co. Low negative or inverse correlation exists between Cu-Mn, Cu-V and Cu-Au. Silver is a good pathfinder for copper deposits in Dawahan and adjacent areas and most probably including the Paracale mining district

DEPOSITIONAL ENVIRONMENT AND ORGANIC GEOCHEMICAL CHARACTERISTICS OF LOWER EOCENE BITUMINOUS ROCKS, IN THE KÜRNÜÇ/GÖYNÜK-BOLU AREA

Directory of Open Access Journals (Sweden)

Ali SARI

2016-12-01

Full Text Available In this study, dark gray and dark brown colored, organic-carbon rich bituminous rocks (bituminous marl and bituminous shale exposing around the Kürnüç area (Göynük, Bolu are investigated by means of or- ganic geochemical characteristics. In this respect, rock lithologies, depositional environments, rock source potential, kerogen and organic maturity types and hydrocarbon generation potentials of bituminous rocks were determined. For this reason, pyrolysis (Rock Eval–VI analysis, gas chromatography (GC and gas chromatography-mass spectrometer (GC-MS analyses were carried out. In addition, spore color index (SCI was determined with organic petrographic method and stable carbon analysis (δ13C of the samples were also conducted. Lithology of the studied samples is of clastic source and the depositional environ- ment is a lagoon with a partial connection to the sea. In bituminous rocks with excellent source rock potential TOC values are in the range of 2.52-8.38 wt % (average 6.08 wt %. With the exception of two samples (Type II kerogen type of all samples is Type I. According to pyrolysis, GC and GC-MS organic maturity results, all the samples are in immature stage. Organic geochemical data indicate that bituminous rocks have an excellent oil generation potential and there is no organic contamination.

In situ geochemical properties of clays subject to thermal loading

International Nuclear Information System (INIS)

Chapman, N.A.

1980-01-01

Compositional variation and geochemical environment in an argillaceous unit are a function of age, depth of burial and mode of origin. This paper considers the variation limits likely to be encountered in potential repository host rocks and examines the significance of factors such as porosity, pore-fluid pressure, total fluid content, and major and accessory mineral component behaviors in controlling the geochemical environment in the neighbourhood of a thermally active waste canister. Particular attention is paid to the use of Eh-pH diagrams in assessing corrosion environments and nuclide speciation. The paper outlines the variables which must be considered when endeavouring to interpret such plots (e.g. temperature, concentration, concurrent reactions and probabilities) and uses the behavior of various iron minerals found in clay deposits under specific conditions to illustrate the complexities. The overall thermal stability of various clay and accessory minerals is discussed and extended to attempt to predict behavior under deep repository conditions, using available data on the diagenetic characteristics of clay-rich sediments. The physical behavior of fluids in plastic clays is considered and methods evaluated for deriving induced geochemical conditions in a thermally active repository. The latter section is particularly related to canister corrosion studies, in situ experiments, and waste dissolution parameters

Geochemical investigation of UMTRAP designated site at Salt Lake City, Utah

International Nuclear Information System (INIS)

Markos, G.; Bush, K.J.

1983-09-01

This report is the result of a geochemical investigation of the former uranium mill and tailings site at Salt Lake City, Utah. This is one in a series of site specific geochemical investigations performed on the inactive uranium mill tailings included in the Uranium Mill Tailings Remedial Action Project. The objectives of the investigation are to characterize the geochemistry, to determine the contaminant distribution resulting from the former milling activities and tailings, and to infer chemical pathways and transport mechanisms from the contaminant distribution. The results will be used to model contaminant migration and to develop criteria for long-term containment media such as a cover system which is impermeable to contaminant migration. This report assumes a familiarity with the hydrologic conditions of the site and the geochemical concepts underlying the investigation. The results reported are based on a one-time sampling of waters and solid material from the background, the area adjacent to the site, and the site. The solid samples were water extracted to remove easily soluble salts and acid extracted to remove carbonates and hydroxides. The water extracts and solid samples were anlyzed for the major and trace elements. The report includes the methods of sampling, sample processing, analysis, and data interpretation. Four major conclusions are: (1) sediments in the ditches and creeks adjacent to the site contain tailings, however, the waters were generally not contaminated; (2) tailings are mixed with the soils within a meter below the tailings in some locations, however, water-soluble contaminants decrease to below background levels within 30 cm below the tailings; (3) there has not been significant acid seepage into the soils below the tailings; and (4) salt crusts on the tailings contain trace elements, with the elements that form chloride complexes having the greatest accumulation

Multielement geochemical reconnaissance for uranium in the Palmyrides region of central Syria

International Nuclear Information System (INIS)

Jubeli, Y.M.; Hale, M.

1988-01-01

Multielement reconnaissance geochemistry coupled with ground scintillation gamma ray measurements has been used to investigate the dispersion patterns of uranium and other major and trace elements in the arid Palmyrides region of central Syria. Over 500 geochemical samples of outcropping rock, wadi and playa sediments, overburden and groundwaters were taken over an area of approximately 9000 sq km. Most samples were analyzed for 25 major and trace elements by nebulization ICPAES; for As, Sb, Bi and Se by hydride generation and ICPAES; and for U, Th and La and other REE by neutron activation analysis. The resulting data were interpreted with the aid of univariate and multivariate statistical methods. The areal distributions of U, its associated elements, multivariate geochemical functions and factor scores were mapped using computer graphics. Results of the factor analysis indicate that the primary lithogeochemical dispersion patterns of uranium and associated elements are controlled by a combination of structural, lithological and environmental factors. Uranium and associated elements have subsequently been leached out of the phosphorite and other U enriched clayey limestones and carbonate rocks into the hydro- geologic regime. Redistribution of these elements is taking place along fracture zones and major faults. A degree of urnaium accumulation in a Neogene aquifer of the Ad-Daww basin is evident

Evaluation of disposal site geochemical performance using a containment factor

International Nuclear Information System (INIS)

Lerman, A.; Domenico, P.A.; Bartlett, J.W.

1988-01-01

The containment factor is a measure of retention by geologic setting of wastes released from a repository. The factor is alternatively defined either in terms of several measurable hydrological and geochemical parameters, or in terms of amounts of waste components that may be released to the geologic setting and, subsequently, to the environment. Containment factors for individual waste components in a given geologic setting are functions of groundwater to rock volume ratios, sorption or exchange characteristics of the rocks, and containment time to groundwater travel time ratios. For high-level radioactive wastes, containment factors based on the NRC and EPA limit values for cumulative releases from waste and to the environment provide a measure of the geochemical performance of the geologic setting in tuff, basalt, and salt. The containment factor values for individual nuclides from high-level wastes indicate that for some of the nuclides containment may be achieved by groundwater travel time along. For other nuclides, additional performance functions need to be allocated to geochemical retention by such processes as sorption, ion-exchange or precipitation

Geochemical characterization of the siliciclastic rocks of Chitravati ...

Indian Academy of Sciences (India)

V Somasekhar

2018-05-23

May 23, 2018 ... Chitravati Group of Cuddapah Supergroup to decipher the provenance and depositional environment. Both the units ... Based on major element geochemical classification diagram, Pulivendla Quartzite .... The youngest age limit of the Nallamalai ...... eastern Oregon and western Idaho, USA: Implications for.

Application of petroleum markers to geochemical and environmental investigations

International Nuclear Information System (INIS)

Abu-Elgheit, M.A.; El-Gayar, M.S.; Hegazi, A.H.

1998-01-01

Application of trace-metal and biological markers to geochemical studies has shown that crude oils could be correlated or differentiated according to their geologic age. The V/Ni, V/Σ Ni, Mg, Fe, and pristine to phytane (Pr/Ph) markers were almost uniform in Gulf of Suez crude oils, revealing their same origin, yet showing marked differences in Western Desert crude oils, reflecting varying degrees of their maturity and migrational history. The significance of petroleum markers was extended to monitoring of oil spill sources. Weathering of spills usually renders their source identification questionable by infrared or gas chromatography profiles. Since evaporative loss light petroleum fractions does not appreciably affect the high-Molecular Weight components with which trace metals, isoprenoids, hopanes, and steranes are associated, V/Ni, Pr/Ph, m/z 191, and m/z 217 mass chromatogram fragments were found reliable in fingerprinting oil spill sources in Mediterranean waters

Geochemical baseline studies of soil in Finland

Science.gov (United States)

Pihlaja, Jouni

2017-04-01

The soil element concentrations regionally vary a lot in Finland. Mostly this is caused by the different bedrock types, which are reflected in the soil qualities. Geological Survey of Finland (GTK) is carrying out geochemical baseline studies in Finland. In the previous phase, the research is focusing on urban areas and mine environments. The information can, for example, be used to determine the need for soil remediation, to assess environmental impacts or to measure the natural state of soil in industrial areas or mine districts. The field work is done by taking soil samples, typically at depth between 0-10 cm. Sampling sites are chosen to represent the most vulnerable areas when thinking of human impacts by possible toxic soil element contents: playgrounds, day-care centers, schools, parks and residential areas. In the mine districts the samples are taken from the areas locating outside the airborne dust effected areas. Element contents of the soil samples are then analyzed with ICP-AES and ICP-MS, Hg with CV-AAS. The results of the geochemical baseline studies are published in the Finnish national geochemical baseline database (TAPIR). The geochemical baseline map service is free for all users via internet browser. Through this map service it is possible to calculate regional soil baseline values using geochemical data stored in the map service database. Baseline data for 17 elements in total is provided in the map service and it can be viewed on the GTK's web pages (http://gtkdata.gtk.fi/Tapir/indexEN.html).

The effects of trace element content on pyrite oxidation rates

Science.gov (United States)

Gregory, D. D.; Lyons, T.; Cliff, J. B.; Perea, D. E.; Johnson, A.; Romaniello, S. J.; Large, R. R.

2017-12-01

Pyrite acts as both an important source and sink for many different metals and metalloids in the environment, including many that are toxic. Oxidation of pyrite can release these elements while at the same time producing significant amounts of sulfuric acid. Such issues are common in the vicinity of abandoned mines and smelters, but, as pyrite is a common accessory mineral in many different lithologies, significant pyrite oxidation can occur whenever pyritic rocks are exposed to oxygenated water or the atmosphere. Accelerated exposure to oxygen can occur during deforestation, fracking for petroleum, and construction projects. Geochemical models for pyrite oxidation can help us develop strategies to mitigate these deleterious effects. An important component of these models is an accurate pyrite oxidation rate; however, current pyrite oxidation rates have been determined using relatively pure pyrite. Natural pyrite is rarely pure and has a wide range of trace element concentrations that may affect the oxidation rate. Furthermore, the position of trace elements within the mineral lattice can also affect the oxidation rate. For example, elements such as Ni and Co, which substitute into the pyrite lattice, are thought to stabilize the lattice and thus prevent pyrite oxidation. Alternatively, trace elements that are held within inclusions of other minerals could form a galvanic cell with the surrounding pyrite, thus enhancing pyrite oxidation rates. In this study, we present preliminary analyses from three different pyrite oxidation experiments each using natural pyrite with different trace element compositions. These results show that the pyrite with the highest trace element concentration has approximately an order of magnitude higher oxidation rate compared to the lowest trace element sample. To further elucidate the mechanisms, we employed microanalytical techniques to investigate how the trace elements are held within the pyrite. LA-ICPMS was used to determine the

Effects of cleaning methods upon preservation of stable isotopes and trace elements in shells of Cyprideis torosa (Crustacea, Ostracoda): Implications for palaeoenvironmental reconstruction

Science.gov (United States)

Roberts, L. R.; Holmes, J. A.; Leng, M. J.; Sloane, H. J.; Horne, D. J.

2018-06-01

The trace element (Sr/Ca and Mg/Ca) and stable isotope (δ18O and δ13C) geochemistry of fossil ostracod valves provide valuable information, particularly in lacustrine settings, on palaeo-water composition and palaeotemperature. The removal of sedimentary and organic contamination prior to geochemical analysis is essential to avoid bias of the results. Previous stable isotope and trace element work on ostracod shells has, however, employed different treatments for the removal of contamination beyond simple 'manual' cleaning using a paint brush and methanol under a low-power binocular microscope. For isotopic work pre-treatments include chemical oxidation, vacuum roasting and plasma ashing, and for trace element work sonication, chemical oxidation and reductive cleaning. The impact of different treatments on the geochemical composition of the valve calcite has not been evaluated in full, and a universal protocol has not been established. Here, a systematic investigation of the cleaning methods is undertaken using specimens of the ubiquitous euryhaline species, Cyprideis torosa. Cleaning methods are evaluated by undertaking paired analyses on a single carapace (comprising two valves); in modern ostracods, whose valves are assumed to be unaltered, the two valves should have identical geochemical and isotopic composition. Hence, when one valve is subjected to the chosen treatment and the other to simple manual cleaning any difference in composition can confidently be assigned to the treatment method. We show that certain cleaning methods have the potential to cause alteration to the geochemical signal, particularly Mg/Ca and δ18O, and hence have implications for palaeoenvironmental reconstructions. For trace-element determinations we recommend cleaning by sonication and for stable isotope analysis, oxidation by hydrogen peroxide. These methods remove contamination, yet do not significantly alter the geochemical signal.

Geochemical Constraints on the Size of the Moon-Forming Giant Impact

Science.gov (United States)

Piet, Hélène; Badro, James; Gillet, Philippe

2017-12-01

Recent models involving the Moon-forming giant impact hypothesis have managed to reproduce the striking isotopic similarity between the two bodies, albeit using two extreme models: one involves a high-energy small impactor that makes the Moon out of Earth's proto-mantle; the other supposes a gigantic collision between two half-Earths creating the Earth-Moon system from both bodies. Here we modeled the geochemical influence of the giant impact on Earth's mantle and found that impactors larger than 15% of Earth mass result in mantles always violating the present-day concentrations of four refractory moderately siderophile trace elements (Ni, Co, Cr, and V). In the aftermath of the impact, our models cannot further discriminate between a fully and a partially molten bulk silicate Earth. Then, the preservation of primordial geochemical reservoirs predating the Moon remains the sole argument against a fully molten mantle after the Moon-forming impact.

Assessment of acid leachable trace metals in sediment cores from River Uppanar, Cuddalore, Southeast coast of India

International Nuclear Information System (INIS)

Ayyamperumal, T.; Jonathan, M.P.; Srinivasalu, S.; Armstrong-Altrin, J.S.; Ram-Mohan, V.

2006-01-01

An acid leachable technique is employed in core samples (C1, C2 and C3) to develop a baseline data on the sediment quality for trace metals of River Uppanar, Cuddalore, southeast coast of India. Acid leachable metals (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn and Cd) indicate peak values at the sulphidic phase and enrichment of metals in the surface layers are due to the anthropogenic activities. Association of trace metals with Fe, Mn indicates their adsorption onto Fe-Mn oxyhydroxides and their correlation with S indicate that they are precipitated as metal sulphides. Factor analysis identified three possible types of geochemical associations and the supremacy of trace metals along with Fe, Mn, S and mud supports their geochemical associations. Factor analysis also signifies that anthropogenic activities have affected both the estuarine and fresh water regions of River Uppanar. - Both natural and anthropogenic factors are affecting metals in sediments

Modeled near-field environment porosity modifications due to coupled thermohydrologic and geochemical processes

International Nuclear Information System (INIS)

Glassley, W. E.; Nitao, J. J.

1998-01-01

Heat deposited by waste packages in nuclear waste repositories can modify rock properties by instigating mineral dissolution and precipitation along hydrothermal flow pathways. Modeling this reactive transport requires coupling fluid flow to permeability changes resulting from dissolution and precipitation. Modification of the NUFT thermohydrologic (TH) code package to account for this coupling in a simplified geochemical system has been used to model the time- dependent change in porosity, permeability, matrix and fracture saturation, and temperature in the vicinity of waste-emplacement drifts, using conditions anticipated for the potential Yucca Mountain repository. The results show, within a few hundred years, dramatic porosity reduction approximately 10 m above emplacement drifts. Most of this reduction is attributed to deposition of solute load at the boiling front, although some of it also results from decreasing temperature along the flow path. The actual distribution of the nearly sealed region is sensitive to the time- dependent characteristics of the thermal load imposed on the environment and suggests that the geometry of the sealed region can be engineered by managing the waste-emplacement strategy

Linking geochemical processes in mud volcanoes with arsenic mobilization driven by organic matter

Energy Technology Data Exchange (ETDEWEB)

Liu, Chia-Chuan; Kar, Sandeep [Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan (China); Jean, Jiin-Shuh, E-mail: jiinshuh@mail.ncku.edu.tw [Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan (China); Wang, Chung-Ho [Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan (China); Lee, Yao-Chang [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Sracek, Ondra [OPV s.r.o. (Groundwater Protection Ltd.), Bělohorská 31, 169 00 Praha 6 (Czech Republic); Department of Geology, Faculty of Science, Palacký University, 17. listopadu 12, 771 46 Olomouc (Czech Republic); Li, Zhaohui [Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan (China); Department of Geosciences, University of Wisconsin – Parkside, Kenosha, WI 53144 (United States); Bundschuh, Jochen [Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan (China); Faculty of Engineering and Surveying and National Centre for Engineering in Agriculture, The University of Southern Queensland, Toowoomba (Australia); Yang, Huai-Jen [Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan (China); Chen, Chien-Yen [Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi 621, Taiwan (China)

2013-11-15

Highlights: ► Study represents geochemical characteristics and their spatial variability among six mud volcanoes of southern Taiwan. ► Anoxic mud volcanic fluids containing high NaCl imply connate water as the possible source. ► δ{sup 18}O-rich fluids is associated with silicate and carbonate mineral released through water–rock interaction. ► High As content in mud and its sequential extraction showed mostly adsorbed As on organic and sulphidic phases. ► Organic matter specially humic acid showed redox dependence and it may play an important role in binding and mobility of arsenic. -- Abstract: The present study deals with geochemical characterization of mud fluids and sediments collected from Kunshuiping (KSP), Liyushan (LYS), Wushanting (WST), Sinyangnyuhu (SYNH), Hsiaokunshui (HKS) and Yenshuikeng (YSK) mud volcanoes in southwestern Taiwan. Chemical constituents (cations, anions, trace elements, organic carbon, humic acid, and stable isotopes) in both fluids and mud were analyzed to investigate the geochemical processes and spatial variability among the mud volcanoes under consideration. Analytical results suggested that the anoxic mud volcanic fluids are highly saline, implying connate water as the probable source. The isotopic signature indicated that δ{sup 18}O-rich fluids may be associated with silicate and carbonate mineral released through water–rock interaction, along with dehydration of clay minerals. Considerable amounts of arsenic in mud irrespective of fluid composition suggested possible release through biogeochemical processes in the subsurface environment. Sequential extraction of As from the mud indicated that As was mostly present in organic and sulphidic phases, and adsorbed on amorphous Mn oxyhydroxides. Volcanic mud and fluids are rich in organic matter (in terms of organic carbon), and the presence of humic acid in mud has implications for the binding of arsenic. Functional groups of humic acid also showed variable sources of

Variation of Geochemical Signatures and Correlation of Biomarkers in Icelandic Mars Analogue Environments

Science.gov (United States)

Gentry, D.; Amador, E. S.; Cable, M. L.; Cantrell, T.; Chaudry, N.; Cullen, T.; Duca, Z. A.; Jacobsen, M. B.; McCaig, H. C.; Murukesan, G.; Rennie, V.; Schwieterman, E. W.; Stevens, A. H.; Tan, G.; Yin, C.; Stockton, A.; Cullen, D.; Geppert, W.

2015-12-01

Exploration missions to Mars rely on rovers to perform deep analyses over small sampling areas; however, landing site selection is done using large-scale but low-resolution remote sensing data. Using Earth analogue environments to estimate the small-scale spatial and temporal distributions of key geochemical signatures and (for habitability studies) biomarkers helps ensure that the chosen sampling strategies meet mission science goals. We conducted two rounds of analogue expeditions to recent Icelandic lava fields. In July 2013, we tested correlation between three common biomarker assays: cell quantification via fluorescence microscopy, ATP quantification via bioluminescence, and quantitative PCR with universal primer sets. Sample sites were nested at four spatial scales (1 m, 10 m, 100 m, and > 1 km) and homogeneous at 'remote imaging' resolution (overall temperature, apparent moisture content, and regolith grain size). All spatial scales were highly diverse in ATP, bacterial 16S, and archaeal 16S DNA content; nearly half of sites were statistically different in ATP content at α = 0.05. Cell counts showed significant variation at the 10 m and 100 m scale; at the > 1 km scale, the mean counts were not distinguishable, but the median counts were, indicating differences in underlying distribution. Fungal 18S DNA content similarly varied at 1 m, 10 m, and 100 m scales only. Cell counts were not correlated with ATP or DNA content at any scale. ATP concentration and DNA content for all three primer sets were positively correlated. Bacterial DNA content was positively correlated with archaeal and fungal DNA content, though archaeal correlation was weak. Fungal and archaeal correlation was borderline. In July 2015, we repeated the sampling strategy, with the addition of a smaller-scale sampling grid of 10 cm and a third > 1 km location. This expedition also measured reflectance of the tephra cover and preserved mineral samples for future Raman spectroscopy in order to

Coupling R and PHREEQC: an interactive and extensible environment for efficient programming of geochemical models

Science.gov (United States)

De Lucia, Marco; Kühn, Michael

2013-04-01

PHREEQC [1] is a widely used non-interactive open source software for speciation, batch-reactions, one-dimensional transport, and inverse geochemical caclulations. It represents the tool of choice for many researchers and practicioners for a broad set of geochemical problems, underground CO2 storage among others. Its open source nature, the flexibility to program arbitrary kinetic laws for the chemical reactions, as well as a thorough implementation of the Pitzer formalism explain its success and longevity. However, its non-interactive architecture make it cumbersome to couple PHREEQC to transport programs to achieve reactive transport simulations [2], but also to overcome the limitations of PHREEQC itself regarding the setup of large numbers of simulations - for example exploring wide ranges of conditions - and the graphical evaluation of the results. This has been the main motivation leading to the development of an interface with the high level language and environment for statistical computing and graphics GNU R [3]. The interface consists of minor modifications in PHREEQC's C source code, only affecting data I/O, plus on the R side a bunch of helper functions used to setup the simulations - basically automated manipulation of PHREEQC's input files, which are text files - and to collect and visualize the results. The most relevant subset of PHREEQC's capabilities and features are fully usable through the interface. Illustratory examples for the utility of this programmable interface were given in the framework of the research project this developement originated from: CLEAN [4], a project investigating the feasibility of enhanced gas recovery combined with CO2 storage. This interface allowed us to successfully and easily manipulate, compare and refit chemical databases, perform sensitivity analysis by combinatory variations of parameters, and all that in an environment which is both scriptable and interactive, with all results directly available for further

Isotopic tracing of perchlorate in the environment

Science.gov (United States)

Sturchio, Neil C.; Böhlke, John Karl; Gu, Baohua; Hatzinger, Paul B.; Jackson, W. Andrew; Baskaran, Mark

2012-01-01

Isotopic measurements can be used for tracing the sources and behavior of environmental contaminants. Perchlorate (ClO 4 − ) has been detected widely in groundwater, soils, fertilizers, plants, milk, and human urine since 1997, when improved analytical methods for analyzing ClO 4 −concentration became available for routine use. Perchlorate ingestion poses a risk to human health because of its interference with thyroidal hormone production. Consequently, methods for isotopic analysis of ClO 4 − have been developed and applied to assist evaluation of the origin and migration of this common contaminant. Isotopic data are now available for stable isotopes of oxygen and chlorine, as well as 36Cl isotopic abundances, in ClO 4 − samples from a variety of natural and synthetic sources. These isotopic data provide a basis for distinguishing sources of ClO 4 − found in the environment, and for understanding the origin of natural ClO 4 − . In addition, the isotope effects of microbial ClO 4 − reduction have been measured in laboratory and field experiments, providing a tool for assessing ClO 4 − attenuation in the environment. Isotopic data have been used successfully in some areas for identifying major sources of ClO 4 − contamination in drinking water supplies. Questions about the origin and global biogeochemical cycle of natural ClO 4 − remain to be addressed; such work would benefit from the development of methods for preparation and isotopic analysis of ClO 4 − in samples with low concentrations and complex matrices.

Trace and rare earth elements fractionation in volcanic- and sediment-hosted Mn ores: a study case of Sardinia (western Italy).

Science.gov (United States)

Sinisi, Rosa

2015-04-01

It is widely accepted that, regardless of the geological environment (continental, marine or hydrothermal), the occurrences of clay minerals and/or mineral phases with clay-type crystal structure (as zeolites and Mn-oxides), play a key role in the trace elements and REEs uptake processes. The REE resources are produced mostly from ion-adsorption type REE deposits of southern China that are formed by weathering of granitic rocks and subsequent chemical adsorption of REE on clay minerals. A significant group of minerals with a high metal uptake capacity is represented by Mn oxides. Their "tunnel" structure, in fact, allows both the absorption (inside the minerals) and adsorption (outside the minerals) of cations and anions producing metal accumulations with economic and environmental significance. However, the ores, mainly that forming within sedimentary environment, often have impurities due to presence of minerals unrelated to mineralization. These minerals can significantly alter the compositional features of the ores and suggest misleading conclusions. In Sardinia (Italy, western Mediterranean), Mn-oxide mineralizations occur and recently their origin has been discussed and identified (Sinisi et al. 2012). In this study the mineralogical and chemical compositions of the Sardinian sediment-hosted and volcanic-hosted Mn-ore are exhibit exploring the possibility that they can represent exploitable trace and REE mineralizations. High contents of metals characterize these Mn deposits. Besides some trace elements (Ni, Cr, Zn, Cu, As, Pb, and U) that commonly typify the Mn oxi-hydroxide ores, all rare earth elements showed high concentrations in the Sardinian deposits, comparable to those of the main actually exploited REE sinks. For this reason, a simple statistical data treatment (R-mode Factor Analysis) was performed on fifteen and nineteen samples of sediment-hosted and volcanic-hosted Mn ore respectively, in order to identify both the mineral phases trapping trace

Geochemical Fractionations and Mobility of Arsenic, Lead and Cadmium in Sediments of the Kanto Plain, Japan.

Science.gov (United States)

Hossain, Sushmita; Oguchi, Chiaki T.; Hachinohe, Shoichi; Ishiyama, Takashi; Hamamoto, Hideki

2014-05-01

Lowland alluvial and floodplain sediment play a major role in transferring heavy metals and other elements to groundwater through sediment water interaction in changing environmental conditions. However identification of geochemical forms of toxic elements such as arsenic (As), lead (Pb) and cadmium (Cd) requires risk assessment of sediment and subsequent groundwater pollution. A four steps sequential extraction procedure was applied to characterize the geochemical fractionations of As, Pb and Cd for 44 sediment samples including one peat sample from middle basin area of the Nakagawa river in the central Kanto plain. The studied sediment profile extended from the bottom of the river to 44 m depth; sediment samples were collected at 1m intervals from a bored core. The existing sedimentary facies in vertical profile are continental, transitional and marine. There are two aquifers in vertical profile; the upper aquifer (15-20m) contains fine to medium sand whereas medium to coarse sand and gravelly sand contain in lower aquifer (37-44m). The total As and Pb contents were measured by the X-Ray Fluorescence analysis which ranged from 4 to 23 mg/kg of As and 10 to 27 mg/kg of Pb in sediment profile. The three trace elements and major heavy metals were determined by ICP/MS and ICP/AES, and major ions were measured by an ion chromatograph. The marine sediment is mainly Ca-SO4 type. The Geochemical analysis showed the order of mobility trends to be As > Pb > Cd for all the steps. The geochemical fractionations order was determined to be Fe-Mn oxide bound > carbonate bound > ion exchangeable > water soluble for As and Pb whereas the order for Cd is carbonate bound > Fe-Mn oxide bound > ion exchangeable > water soluble. The mobility tendency of Pb and Cd showed high in fine silty sediment of marine environment than for those from continental and transitional environments. In the case of As, the potential mobility is very high (>60%) in the riverbed sediments and clayey silt

Natural and anthropogenic trace metal contamination and load assessment in the Oum Er-Rbia river basin, Morocco

International Nuclear Information System (INIS)

Schone, Selina; Zahry, Fatiha; Matschullat, Jorg; Bounakhla, Moussa

2008-01-01

Due to natural constraints and its fast socio-economic development Morocco is confronted with serious problems both in terms of water quantity and water quality management. In order to counteract the water quality degradation a comprehensive understanding of the geochemical and hydrological functioning as well as the bahavior of inorganic contaminants in large riverine systems under semiarid conditions shall be developed within the scope of this pilot study. Within the scope of a dissertation project Mrs Zahry has already investigated the physical and geochemical characteristics of the oum Er-Rbia river basin in Morocco. Water, sediment and suspended matter samples were analyzed in order to assess the trace metal contamination of the river. Due to the lack of the local geochemical backgrounds levels the results were normalised to common international standards. But because of the spatial and temporal variability of the geochemical background global standards are not appropriate to answer regional and local problems. Following up the work of Mrs Zahry the project shall for the first time ever in Morocco provide local geochemical backgrounds levels of various media in the large-scale Oum ErRbia river basin to establish regional geochemical standards and to assess the watercourse contamination in terms of anthropogenic contributions of trace metals. The research project will be conducted in cooperation between the CNESTEN, Morocco and the Technical University Bergakademie Freiberg in Germany. The project has started of the aquisation of geo-basis data to develop a sampling strategy. All field investigations (sampling, run-off measurements), analytical work and data analysis will be done in direct collaboration with the Moroccan Scientists [fr

A preliminary study on the geochemical environment for deep geological disposal of high level radioactive waste in Korea

International Nuclear Information System (INIS)

Kim, Chun Soo; Bae, Dae Seok; Kim, Kyung Su; Koh, Yong Kwon; Park, Byoung Yun

2000-03-01

Geochemical study on the groundwater from crystalline rocks (granite and gneiss) for the deep geological disposal of high-level radioactive waste was carried out in order to elucidate the hydrogeochemical and isotope characteristics and geochemical evolution of the groundwater. Study areas are Jungwon, Chojeong, Youngcheon and Yusung for granite region, Cheongyang for gneiss region, and Yeosu for volcanic region. Groundwaters of each study areas weree sampled and analysed systematically. Groundwaters can be grouped by their chemistry and host rock. Origin of the groundwater was proposed by isotope ( 18 O, 2 H, 13 C, 34 S, 87 Sr, 15 N) studies and the age of groundwater was inferred from their tritium contents. Based ont the geochemical and isotope characteristics, the geochemical evolutions of each types of groundwater were simulated using SOLVEQ/CHILLER and PHREEQC programs

Trace element correlations as clues to the origin of tektites and impactites

International Nuclear Information System (INIS)

Koeberl, C.; Kluger, F.; Kiesl, W.

1986-01-01

Elemental ratios constitute an important geochemical tool for the evaluation of genetic correlations between different materials. We have investigated the behaviour of several trace element ratios and their correlations in some terrestrial impact glasses (tektites and impactites from the Australasian and moldavite strewn field, a Darwin glass sample and material from Zhamanshin and Aouelloul impact crater). Some well known geochemical pairs are discussed: K/Sc, K/Rb, K/Zr, K/Cs, K/Ba, K/U, Ti/Zr, Cr/Ni, Rb/Zr, Ba/Rb, Ba/Zr, La/Yb and Th/Sm. Correlation coefficients for some of the pairs have also been calculated. In all these pairs we see a clear distinction between different bodies of the solar system, which is due to the different stages of differentiation of the respective bodies, since the elements discussed here behave differently in various geochemical processes. (author)

Geochemical study of military bases impact on the environment in Belarus

International Nuclear Information System (INIS)

Kudelsky, A.V.; Lukashev, V.K.; Kovalyov, A.A.

2000-01-01

It has been established that the geochemical and ecological situation in the sites formerly occupied by military bases does not satisfy nature management and living standards. The concentrations of heavy metals (Pb, Zn, Cd, Mo and Cu), oil products and semi-volatile organic compounds in soil and ground which exceed the permissible contamination limits make them dangerous for utilisation and require cleaning up measures

Geochemical characterization of Parana Basin volcanic rocks: petrogenetic implications

International Nuclear Information System (INIS)

Marques, L.S.

1988-01-01

A detailed study of the geochemical characteristics of Parana Basin volcanic rocks is presented. The results are based on the analyses of major and trace elements of 158 samples. Ninety three of these volcanic samples belong to 8 flow sequences from Rio Grande do Sul and Santa Catarina States. The remaining sixty five samples are distributed over the entire basin. In order to study the influence of crustal contamination processes in changing chemical characteristics of the volcanic rocks, 47 samples representative of the crystalline basement of the southern and southeastern Parana Basin were also analysed. Several petrogenetic models were tested to explain the compocional variability of the volcanic rocks, in particular those of southern region. The results obtained sugest an assimilation-fractional crystallization process as viable to explain the differences of both the chemical characteristics and Sr isotope initial ratios observed in basic and intermediate rocks. A model involving melting processes of basic material, trapped at the base of the crust, with composition similar to low and high TiO 2 basalts appears to be a possibility to originate the Palmas and Chapeco acid melts, respectively. The study of ''uncontaminated'' or poorly contaminated low TiO 2 basic rocks from the southern, central and northern regions shows the existence of significant differences in the geochemical charactetistics according to their geographical occurrence. A similar geochemical diversity is also observed in high TiO 2 basalts and Chapeco volcanics. Differences in incompatible element ratios between low and high TiO 2 ''uncontaminated'' or poorly contaminated basalts suggest that they could have been produced by different degrees of melting in a garnet peridotite source. Geochemical and isotopic (Sr and Nd) data also support the view that basalts from northern and southern regions of Parana Basin originated from mantle source with different composition. (author) [pt

Uranium exploration data and global geochemical baselines: The need for co-ordinated action

International Nuclear Information System (INIS)

Darnley, A.G.

1997-01-01

Public concern about environmental problems continues. In order to assess the magnitude of potential problems it is necessary to have comprehensive information. The absence of quantitative geochemical data to map the surface composition of the earth is one of the major information gaps in present day environmental science. An IAEA Technical Committee meeting held in November 1993 reviewed the uses of uranium exploration data for environmental purposes. Most attention was focussed on data involving radiation measurements. Uranium exploration programmes conducted since 1970 in many countries collected a considerable amount of geochemical survey data, providing information about the distribution of non-radioactive elements in the natural environment. Canada is one of several countries where such data provided the foundation for national geochemical mapping; other countries could benefit from similar actions. Increasing importance is being attached by governments to the need to enact effective environmental legislation concerning ''safe levels'' of many chemical substances. Such legislation requires geochemical variations in the natural environment. It is becoming necessary to make quantitative comparisons of element abundances across national boundaries, and from continent to continent. In 1995 the IAEA, with other organizations, supported UNESCO to publish a report concerned with the establishment of a Global Geochemical Reference Network. This is designed to provide a framework to connect all types of geochemical survey, to move towards international compatibility of data. The report contains recommendations relating to the standardization of field and laboratory methods; the use of the most sensitive analytical techniques; and standardization of data management. Ground and airborne gamma ray spectrometry, and nuclear laboratory techniques are all discussed. Following the publication of the report, the International Union of Geological Sciences has now established a

Geochemical Exploration Techniques Applicable in the Search for Copper Deposits

Science.gov (United States)

Chaffee, Maurice A.

1975-01-01

media. Samples of ice and snow have been used for limited geochemical surveys. Both geobotanical and biogeochemical surveys have been successful in locating copper deposits in many parts of the world. Micro-organisms, including bacteria and algae, are other unproved media that should be studied. Animals can be used in geochemical-prospecting programs. Dogs have been used quite successfully to sniff out hidden and exposed sulfide minerals. Tennite mounds are commonly composed of subsurface material, but have not as yet proved to be useful in locating buried mineral deposits. Animal tissue and waste products are essentially unproved but potentially valuable sampling media. Knowledge of the location of areas where trace-element-associated diseases in animals and man are endemic as well as a better understanding of these diseases, may aid in identifying regions that are enriched in or depleted of various elements, including copper. Results of analyses of gases in the atmosphere are proving valuable in mineral-exploration surveys. Studies involving metallic compounds exhaled by plants into the atmosphere, and of particulate matter suspended in the atmosphere are reviewed these methods may become important in the future. Remote-sensing techniques are useful for making indirect measurements of geochemical responses. Two techniques applicable to geochemical exploration are neutron-activation analysis and gamma-ray spectrometry. Aerial photography is especially useful in vegetation surveys. Radar imagery is an unproved but potentially valuable method for use in studies of vegetation in perpetually clouded regions. With the advent of modern computers, many new techniques, such as correlation analysis, regression analysis, discriminant analysis, factor analysis, cluster analysis, trend-surface analysis, and moving-average analysis can be applied to geochemical data sets. Selective use of these techniques can provide new insights into the interpretatio

On the bioavailability of trace metals in surface sediments: a combined geochemical and biological approach.

Science.gov (United States)

Roosa, Stéphanie; Prygiel, Emilie; Lesven, Ludovic; Wattiez, Ruddy; Gillan, David; Ferrari, Benoît J D; Criquet, Justine; Billon, Gabriel

2016-06-01

The bioavailability of metals was estimated in three river sediments (Sensée, Scarpe, and Deûle Rivers) impacted by different levels of Cu, Cd, Pb, and Zn (Northern France). For that, a combination of geochemistry and biological responses (bacteria and chironomids) was used. The results obtained illustrate the complexity of the notion of "bioavailability." Indeed, geochemical indexes suggested a low toxicity, even in surface sediments with high concentrations of total metals and a predicted severe effect levels for the organisms. This was also suggested by the abundance of total bacteria as determined by DAPI counts, with high bacterial cell numbers even in contaminated areas. However, a fraction of metals may be bioavailable as it was shown for chironomid larvae which were able to accumulate an important quantity of metals in surface sediments within just a few days.We concluded that (1) the best approach to estimate bioavailability in the selected sediments is a combination of geochemical and biological approaches and that (2) the sediments in the Deûle and Scarpe Rivers are highly contaminated and may impact bacterial populations but also benthic invertebrates.

A preliminary study on the geochemical environment for deep geological disposal of high level radioactive waste in Korea

Energy Technology Data Exchange (ETDEWEB)

Kim, Chun Soo; Bae, Dae Seok; Kim, Kyung Su; Koh, Yong Kwon; Park, Byoung Yun

2000-03-01

Geochemical study on the groundwater from crystalline rocks (granite and gneiss) for the deep geological disposal of high-level radioactive waste was carried out in order to elucidate the hydrogeochemical and isotope characteristics and geochemical evolution of the groundwater. Study areas are Jungwon, Chojeong, Youngcheon and Yusung for granite region, Cheongyang for gneiss region, and Yeosu for volcanic region. Groundwaters of each study areas weree sampled and analysed systematically. Groundwaters can be grouped by their chemistry and host rock. Origin of the groundwater was proposed by isotope ({sup 18}O, {sup 2}H, {sup 13}C, {sup 34}S, {sup 87}Sr, {sup 15}N) studies and the age of groundwater was inferred from their tritium contents. Based ont the geochemical and isotope characteristics, the geochemical evolutions of each types of groundwater were simulated using SOLVEQ/CHILLER and PHREEQC programs.

Enzyme leaching of surficial geochemical samples for detecting hydromorphic trace-element anomalies associated with precious-metal mineralized bedrock buried beneath glacial overburden in northern Minnesota

Science.gov (United States)

Clark, Robert J.; Meier, A.L.; Riddle, G.; ,

1990-01-01

One objective of the International Falls and Roseau, Minnesota, CUSMAP projects was to develop a means of conducting regional-scale geochemical surveys in areas where bedrock is buried beneath complex glacially derived overburden. Partial analysis of B-horizon soils offered hope for detecting subtle hydromorphic trace-element dispersion patterns. An enzyme-based partial leach selectively removes metals from oxide coatings on the surfaces of soil materials without attacking their matrix. Most trace-element concentrations in the resulting solutions are in the part-per-trillion to low part-per-billion range, necessitating determinations by inductively coupled plasma/mass spectrometry. The resulting data show greater contrasts for many trace elements than with other techniques tested. Spatially, many trace metal anomalies are locally discontinuous, but anomalous trends within larger areas are apparent. In many instances, the source for an anomaly seems to be either basal till or bedrock. Ground water flow is probably the most important mechanism for transporting metals toward the surface, although ionic diffusion, electrochemical gradients, and capillary action may play a role in anomaly dispersal. Sample sites near the Rainy Lake-Seine River fault zone, a regional shear zone, often have anomalous concentrations of a variety of metals, commonly including Zn and/or one or more metals which substitute for Zn in sphalerite (Cd, Ge, Ga, and Sn). Shifts in background concentrations of Bi, Sb, and As show a trend across the area indicating a possible regional zoning of lode-Au mineralization. Soil anomalies of Ag, Co, and Tl parallel basement structures, suggesting areas that may have potential for Cobalt/Thunder Baytype silver viens. An area around Baudette, Minnesota, which is underlain by quartz-chlorite-carbonate-altered shear zones, is anomalous in Ag, As, Bi, Co, Mo, Te, Tl, and W. Anomalies of Ag, As, Bi, Te, and W tend to follow the fault zones, suggesting potential

Geochemical exploration for uranium

International Nuclear Information System (INIS)

1988-01-01

This Technical Report is designed mainly to introduce the methods and techniques of uranium geochemical exploration to exploration geologists who may not have had experience with geochemical exploration methods in their uranium programmes. The methods presented have been widely used in the uranium exploration industry for more than two decades. The intention has not been to produce an exhaustive, detailed manual, although detailed instructions are given for a field and laboratory data recording scheme and a satisfactory analytical method for the geochemical determination of uranium. Rather, the intention has been to introduce the concepts and methods of uranium exploration geochemistry in sufficient detail to guide the user in their effective use. Readers are advised to consult general references on geochemical exploration to increase their understanding of geochemical techniques for uranium

Trace elements as quantitative probes of differentiation processes in planetary interiors

International Nuclear Information System (INIS)

Drake, M.J.

1980-01-01

Abundances of trace elements in extrusive igneous rocks may be used as petrological and geochemical probes of the source regions of the rocks if differentiation processes, partition coefficients, phase equilibria, and initial concentrations in the source region are known. The characteristic trace element signature that each mineral in the source region imparts on the magma forms the conceptual basis for trace element modeling. The task of the trace element geochemist is to solve mathematically the inverse problem. Given trace element abundances in a magma, what is the ode of its source region. The most successful modeling has been performed for small planetary bodies which underwent relatively simple igneous differentiation events. An example is the eucrite parent body, a planet which produced basals at approx. =4.6 Gy. and has been quiescent ever since. This simple differentiation history permits the calculation of its bulk composition (a feldspathic peridotite) and has led to the tentative identification of asteroid 4 Westa as the eucrite parent body. The differentiation of iron meteorite groups in parent body cores is amenable to similar treatment. The 'anomalous' behavior of Cr, suggests that IIIA, B irons and main group pallasites equilibrated with troilite, spinel, ferromagnesian silicates, or some combination thereof. The moon has undergone more complex differentiation, and quantitative geochemical modeling is correspondingly more difficult. Nevertheless, modeling the two-stage evolution of mare basals raises the possibility that the primordial moon did not have chondritic relative abundances of such refractory elements as Ca, Al, U, and the rare-earth elements. The nonchondritic element ratios are characteristic of planetary, not nebular, fractionation processes and are consistent with the derivation of the moon from a precursor planet, possibly the earth

Along and Across Arc Variation of the Central Andes by Single Crystal Trace Element Analaysis

Science.gov (United States)

Michelfelder, G.; Sundell, T.; Wilder, A.; Salings, E. E.

2017-12-01

Along arc and across arc geochemical variations at continental volcanic arcs are influenced by a number of factors including the composition and thickness of the continental crust, mantle heterogeneity, and fluids from the subducted slab. Whole rock geochemical trends along and across the arc front of the Central Volcanic Zone (CVZ) have been suggested to be primarily influenced by the composition and thickness of the crust. In the CVZ, Pb isotopic domains relate volcanic rock compositions to the crustal basement and systematically varies with crustal age. It has been shown repeatedly that incompatible trace element trends and trace element ratios can be used to infer systematic geochemical changes. However, there is no rule linking magmatic process or chemical heterogeneity/ homogeneity as a result of large crustal magma storage reservoirs such as MASH zones to the observed variation. Here we present a combination of whole rock major- and trace element data, isotopic data and in situ single crystal data from plagioclase, pyroxene and olivine for six stratovolcanoes along the arc front and in the back arc of the CVZ. We compare geochemical trends at the whole and single crystal scale. These volcanoes include lava flows and domes from Cerro Uturuncu in the back-arc, Aucanquilcha, Ollagüe, San Pedro-San Pablo, Lascar, and Lazufre from the arc front. On an arc-wide scale, whole rock samples of silicic lavas from these six composite volcanoes display systematically higher K2O, LILE, REE and HFSE contents and 87Sr/86Sr ratios with increasing distance from the arc-front. In contrast, the lavas have systematically lower Na2O, Sr, and Ba contents; LILE/HFSE ratios; 143Nd/144Nd ratios; and more negative Eu anomalies. Silicic magmas along the arc-front reflecting melting of young, mafic composition source rocks with the continental crust becoming increasingly older and more felsic toward the east. These trends are paralleled in the trace element compositions of plagioclase

The research on the geochemical characteristics of Longyuanba composite pluton in Nanling region

International Nuclear Information System (INIS)

Zhang Min; Chen Peirong; Ling Hongfei

2006-01-01

The Longyuanba composite pluton, located in the eastern part of the Nanling Range, is an important part of the Nanling granites belt, which was regarded as a portion of Yanshanian epoch Pitou pluton to the east of it, and was lowly studied. The newest research shows that, the main body of Longyuanba pluton formed in Indosinian, different from Pitou pluton, which is Yanshanian. From main elements geochemical characteristics, there is obvious gap between Indosinian granites, Yanshanian granites and Yanshanian syenites in major oxides composition, which implies that there is possibly no fractional crystallization relationship between them. Form trace element geochemical characteristics, Indosinian Σ granites are enriched in LREE and high in REE. Yanshanian granites are depleted in MREE and low in Σ REE and ratios of Th/U, Nb/Ta, Zr/Hf, and obvious in fraction. The above characteristics show that, liquid action was rather strong in Yanshanian magmatism. Yanshanian syenites are enriched in high field elements and REE, are similar with A-type granite. Sr, Nd isotopic geochemical characteristics show that, Longyuanba composite pluton belongs to crust-original S-type granite and its original resource is early-Proterozoic crust from crust-mantle fraction. (authors)

The potential of mid- and near-infrared diffuse reflectance spectroscopy for determining major- and trace-element concentrations in soils from a geochemical survey of North America

Science.gov (United States)

Reeves, J. B.; Smith, D.B.

2009-01-01

In 2004, soils were collected at 220 sites along two transects across the USA and Canada as a pilot study for a planned soil geochemical survey of North America (North American Soil Geochemical Landscapes Project). The objective of the current study was to examine the potential of diffuse reflectance (DR) Fourier Transform (FT) mid-infrared (mid-IR) and near-infrared (NIRS) spectroscopy to reduce the need for conventional analysis for the determination of major and trace elements in such continental-scale surveys. Soil samples (n = 720) were collected from two transects (east-west across the USA, and north-south from Manitoba, Canada to El Paso, Texas (USA), n = 453 and 267, respectively). The samples came from 19 USA states and the province of Manitoba in Canada. They represented 31 types of land use (e.g., national forest, rangeland, etc.), and 123 different land covers (e.g., soybeans, oak forest, etc.). The samples represented a combination of depth-based sampling (0-5 cm) and horizon-based sampling (O, A and C horizons) with 123 different depths identified. The set was very diverse with few samples similar in land use, land cover, etc. All samples were analyzed by conventional means for the near-total concentration of 49 analytes (Ctotal, Ccarbonate and Corganic, and 46 major and trace elements). Spectra were obtained using dried, ground samples using a Digilab FTS-7000 FT spectrometer in the mid- (4000-400 cm-1) and near-infrared (10,000-4000 cm-1) at 4 cm-1 resolution (64 co-added scans per spectrum) using a Pike AutoDIFF DR autosampler. Partial least squares calibrations were develop using: (1) all samples as a calibration set; (2) samples evenly divided into calibration and validation sets based on spectral diversity; and (3) samples divided to have matching analyte concentrations in calibration and validation sets. In general, results supported the conclusion that neither mid-IR nor NIRS would be particularly useful in reducing the need for conventional

Data for the geochemical investigation of UMTRAP designated site at Monument Valley, Arizona

International Nuclear Information System (INIS)

Markos, G.; Bush, K.J.

1983-09-01

This report contains the geochemical data and the methods of data collection from the former tailings site at Monument Valley, Arizona. Data are from a one-time sampling of waters and solid material from the background, the area adjacent to the site, and the site. Selected solid samples are water extracted to remove easily soluble salts. The waters and extracts of solid samples were analyzed for selected major and trace elements. 3 refs., 2 figs., 1 tab

Proceedings of the scientific meeting on `parameters for assessing the mobility of trace substances in the environment`

Energy Technology Data Exchange (ETDEWEB)

Fukui, Masami; Fujinawa, Katsuyuki [eds.

1996-04-01

This issue is the collection of the paper presented at the title meeting on `parameters for assessing the mobility of trace substances in the environment`. The 18 of the presented papers are indexed individually. (J.P.N.)

Proceedings of the scientific meeting on 'parameters for assessing the mobility of trace substances in the environment'

International Nuclear Information System (INIS)

Fukui, Masami; Fujinawa, Katsuyuki

1996-04-01

This issue is the collection of the paper presented at the title meeting on 'parameters for assessing the mobility of trace substances in the environment'. The 18 of the presented papers are indexed individually. (J.P.N.)

Geochemical sensitivity analysis: Identification of important geochemical parameters for performance assessment studies

International Nuclear Information System (INIS)

Siegel, M.; Guzowski, R.; Rechard, R.; Erickson, K.

1986-01-01

The EPA Standard for geologic disposal of high level waste requires demonstration that the cumulative discharge of individual radioisotopes over a 10,000 year period at points 5 kilometers from the engineered barrier system will not exceed the limits prescribed in 40 CFR Part 191. The roles of the waste package, engineered facility, hydrogeology and geochemical processes in limiting radionuclide releases all must be considered in calculations designed to assess compliance of candidate repositories with the EPA Standard. In this talk, they will discuss the geochemical requirements of calculations used in these compliance assessments. In addition, they will describe the complementary roles of (1) simple models designed to bound the radionuclide discharge over the widest reasonable range of geochemical conditions and scenarios and (2) detailed geochemical models which can provide insights into the actual behavior of the radionuclides in the ground water. Finally, they will discuss development of sensitivity/uncertainty techniques designed to identify important site-specific geochemical parameters and processes using data from a basalt formation

New data on the geological environment of the natural reactors

International Nuclear Information System (INIS)

Gauthier-Lafaye, F.; Besnus, Y.; Weber, F.

1978-01-01

Since the Libreville symposium in 1975 knowledge of the geological environment of the reactors has advanced as a result of a more extensive study of the Francevillian uranium deposits. In the Oklo deposit a detailed stratigraphy of the Cl bed (uraniferous mineralized bed) has been established, making it possible to re-establish stratigraphically the position of the natural reactors. A tectonic analysis of the Oklo deposit has revealed the special features of the Oklo structure and the reaction zones situated in the shear troughs. Petrographic studies have revealed the presence of two types of ore with distinct modes of formation. In the first case, the role played by organic materials seems predominant, while in the second case migrations of oxidizing solutions are the main source of the reconcentrations. Finally, a geochemical study made of samples from Oklo and Okelobondo points to the existence of an ''isolated'' geochemical phase containing uranium and a certain number of trace elements. This phase is associated with the organic material. This study also deals with the migration of lead at Oklo and Mounana. (author)

Anthropogenic radionuclides in the environment

Energy Technology Data Exchange (ETDEWEB)

Hu, Q; Weng, J; Wang, J

2007-11-15

Studies of radionuclides in the environment have entered a new era with the renaissance of nuclear energy and associated fuel reprocessing, geological disposal of high-level nuclear wastes, and concerns about national security with respect to nuclear non-proliferation. This work presents an overview of anthropogenic radionuclide contamination in the environment, as well as the salient geochemical behavior of important radionuclides. We first discuss the following major anthropogenic sources and current development that contribute to the radionuclide contamination of the environment: (1) nuclear weapons program; (2) nuclear weapons testing; (3) nuclear power plants; (4) commercial fuel reprocessing; (5) geological repository of high-level nuclear wastes, and (6) nuclear accidents. Then, we summarize the geochemical behavior for radionuclides {sup 99}Tc, {sup 129}I, and {sup 237}Np, because of their complex geochemical behavior, long half-lives, and presumably high mobility in the environment. Biogeochemical cycling and environment risk assessment must take into account speciation of these redox-sensitive radionuclides.

Developing protocols for geochemical baseline studies: An example from the Coles Hill uranium deposit, Virginia, USA

International Nuclear Information System (INIS)

Levitan, Denise M.; Schreiber, Madeline E.; Seal, Robert R.; Bodnar, Robert J.; Aylor, Joseph G.

2014-01-01

Highlights: • We outline protocols for baseline geochemical surveys of stream sediments and water. • Regression on order statistics was used to handle non-detect data. • U concentrations in stream water near this unmined ore were below regulatory standards. • Concentrations of major and trace elements were correlated with stream discharge. • Methods can be applied to other extraction activities, including hydraulic fracturing. - Abstract: In this study, we determined baseline geochemical conditions in stream sediments and surface waters surrounding an undeveloped uranium deposit. Emphasis was placed on study design, including site selection to encompass geological variability and temporal sampling to encompass hydrological and climatic variability, in addition to statistical methods for baseline data analysis. The concentrations of most elements in stream sediments were above analytical detection limits, making them amenable to standard statistical analysis. In contrast, some trace elements in surface water had concentrations that were below the respective detection limits, making statistical analysis more challenging. We describe and compare statistical methods appropriate for concentrations that are below detection limits (non-detect data) and conclude that regression on order statistics provided the most rigorous analysis of our results, particularly for trace elements. Elevated concentrations of U and deposit-associated elements (e.g. Ba, Pb, and V) were observed in stream sediments and surface waters downstream of the deposit, but concentrations were below regulatory guidelines for the protection of aquatic ecosystems and for drinking water. Analysis of temporal trends indicated that concentrations of major and trace elements were most strongly related to stream discharge. These findings highlight the need for sampling protocols that will identify and evaluate the temporal and spatial variations in a thorough baseline study

Distribution of trace elements in the natural waters of Bacino del Cordevole (Dolomite Alps, Agordo, Belluno, Italy)

International Nuclear Information System (INIS)

Brondi, M.; De Cassan, M.; Gragnani, R.; Orlandi, C.; Paganin, G.

1989-12-01

This work deals with (the study of the) distribution and circulation of trace elements in Italian aquifers corresponding to a wide range of environmental conditions, such as water chemism, lithology, hydrogeology, geochemical conditions as well as level of contamination. During 1985 the hydrogeochemical study was carried out on springs and surface waters from an area located in the East-Alpine- Range (Agordo, BL). The waters salinity is generally low (100+200 mg/1 of t.d.s.). Some springs, leaching levels of gypsum in the Bellerophon formation, present salinity values higher than 1 g/1. In the studied area the chemisa of the water is widely influenced by lithology. In fact different percentage ratios of principal cations and anions were observed for groups of samples: waters leaching carbonatic-rocks show the highest in Ca/Mg and HCO 3 ratios; waters coming from volcanic or metamorphic formations have the lowest Ca+Mg ratio; waters leaching gypsum horizons show the highest sulphates ratio. The content of trace elements are generally very low and show non significant contamination of the examined area. The high Zn contents of the springs 36 and 37 are due to the presence of heavy metal mineralization near the sampling sites. Vanadium reaches relative high contents in the samples 22 (11μg/l) and 35 (9 μg/1), that flow in volcanic rocks. In general, the higher vanadium contents correspond to waters in volcanites. Uranium and molybdenum exhibit significant correlation coefficient with the electric conductance, respectively r=0,87 and r=0,51. These two elements are characterized by high geochemical mobility and generally their concentrations increase with increasing salinity if precipitation processes do not occur. The geochemical characteristics of elements and peculiar geochemical processes effect trace concentrations element more than lithology. In fact only vanadium contents show a significant correlation with volcanic rocks. (author)

Isotopic and trace element characteristics of rhyolites from the Valles Caldera, New Mexico. Final technical report

Energy Technology Data Exchange (ETDEWEB)

Self, S.; Sykes, M.L. [Hawaii Univ., Honolulu, HI (United States). Dept. of Geology and Geophysics; Wolff, J.A. [Texas Univ., Arlington, TX (United States). Dept. of Geology; Skuba, C.E. [McMaster Univ., Hamilton, ON (Canada). Dept. of Geology

1991-09-01

This report is a summary of work supported by DOE grant No. DE-FGO5-87ER13795 that was completed or is still in progress. The stated purpose of this grant was to collect geochemical information (trace element, radiogenic isotope and stable oxygen and hydrogen isotope) on samples from core holes VC-I and VC-2a in the Valles caldera in order to establish a consistent detailed intracaldera stratigraphy and relate this to extracaldera volcanic rock units of the Jemez Mountains. Careful stratigraphic control of the intracaldera units is necessary to evaluate models of caldera formation, ignimbrite deposition, and resurgence. Combined stable and radiogenic isotope and trace element data will also provide major insights to petrogenesis of the Bandelier magma system. The composition of non-hydrothermally altered samples from outflow units of the Bandelier Tuff and related volcanics must be known to assess isotopic variations of intracaldera ignimbrite samples. On detailed examination of the VC-2a core samples, it became apparent that hydrothermal alteration is so extensive that no geochemical information useful for stratigraphic fingerprinting or petrogenesis could be obtained, and that correlation with other intracaldera units and extracaldera units must be made on the basis of stratigraphic position and gross lithologic characteristics. Accordingly, we emphasize geochemical data from the extracaldera Bandelier Tuffs and related units which will be useful for comparison with proposed drill hole VC-4 and for any future studies of the region. The stable isotope, radiogenic isotope and trace element data obtained from this project, combined with existing major and trace element data for volcanic rocks from this area, provide an extensive data base essential to future Continental Scientific Drilling Program projects in the Jemez Mountains of New Mexico.

Trace element concentrations in freshwater mussels and macrophytes as related to those in their environment

Directory of Open Access Journals (Sweden)

Gian Maria BEONE

2003-02-01

Full Text Available This study was primarily designed to contribute to the debate "Do accumulator species reflect the element contamination level of their environment?" This research was carried out: 1 to know the distribution of 15 trace elements and calcium in shell and soft tissues of three species of freshwater mussels and macrophytes; 2 to compare the accumulation capacity of each trace element by mussels and by eight species of macrophytes and 3 to test the relationships between the metal concentrations in the mussels and macrophytes and those in water and sediments. The variability of element residues in the mussels is the major limit to accumulator monitoring. The most important causes are: seasonal cycle, physical environment and biological factors such as the size, age and growth rate. This research was designed to eliminate the consequence of variability deriving from the season and the environment. To this end the mussels and macrophytes were collected at the same time from the same habitat: Ranco Bay, Lago Maggiore, Northern Italy. In addition, the element concentrations in more size-classes of the most abundant mussel species (Unio pictorum and Dreissena polymorpha were measured. Trace elements were analyzed by Inductive Coupled Plasma-Mass Spectrometry (ICP-MS. By arranging the data in sequences of decreasing element concentrations in the organisms as well as in water and sediments, we were able to compare the accumulating ability of the tested species and evaluate their capacity to reflect environmental availability. Neither the sequences in the shell nor those in the tissues were similar to the sequence in the water. The differences between the sequences of the mussel tissues and those of the sediments were less striking than those between shells and sediments. Similar results were obtained by macrophytes. In conclusion, the results of this study (which mimics the monitoring practice prove that bioaccumulators cannot be used to evaluate the

Distribution and seasonal variation of trace metals in surface sediments of the Mandovi estuary, west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Alagarsamy, R.

The concentration and distribution of selected trace metals in surface sediments of the Mandovi estuary were studied to determine the extent of anthropogenic inputs from mining activities and to estimate the effects of monsoon on geochemical...

Of the necessity of knowledge of the natural pedo-geochemical background content in the evaluation of the contamination of soils by trace elements.

Science.gov (United States)

Baize, D; Sterckeman, T

2001-01-08

In order to evaluate the contamination of the Dornach (Switzerland) site within the framework of the CEEM-Soil project, each participating team was allowed to take a maximum of 15 samples. The French team's sampling was organized in such a way as to answer the following questions: (i) what is the natural concentration of the soils at this site (local pedo-geochemical background content)?; (ii) what are the levels of Cd, Cu, Pb and Zn contamination of the soil?; (iii) what is the depth reached by the surface contamination that is derived from atmospheric fallout?; (iv) how is the contamination spread along the longest axis of the area under study? The relationships between total Fe and the trace metals have allowed local variations in the natural pedo-geochemical background content to be detected and thus permitted the anthropogenic contamination to be estimated. There would appear to be a low level of Pb contamination over all the site investigated (an increase of the order of 5-10 mg kg(-1) on the background level), limited to the surface humus-bearing layers. There is also a significant contamination by Cu over all of the site (an increase of the order of 30-40 mg kg(-1)). This contamination has remained in the surface horizons (0-20 cm). Very high Zn and Cd concentrations have been found in the four surface (0-4 cm) and deep horizons (15-70 cm) taken under the forest and very much lower values in the samples taken from cultivated soils. The most likely explanation is an unequal inheritance between the upper part of the site (wooded with thinner very clayey soils) and the lower cultivated part of the site (with thicker less clayey soils developed in a loamy material). For various reasons, it seems unlikely that a contamination of the wooded part should be so much higher than the cultivated part due to the interception of atmospheric dust by the trees. The local pedo-geochemical background Cd and Zn content of the upper wooded part proved to be clearly higher than

Diffusive exchange of trace elements between basaltic-andesite and dacitic melt: Insights into potential metal fractionation during magma mixing

Science.gov (United States)

Fiege, A.; Ruprecht, P.; Simon, A. C.; Holtz, F.

2017-12-01

Mafic magma recharge is a common process that triggers physical and chemical mixing in magmatic systems and drives their evolution, resulting in, e.g., hybridization and volcanic eruptions. Once magma-magma contact is initiated, rapid heat-flux commonly leads to the formation of a cooling-induced crystal mush on the mafic side of the interface. Here, on a local scale (µm to cm), at the magma-magma interface, melt-melt diffusive exchange is required to approach equilibrium. Significant chemical potential gradients drive a complex, multi-element mass flux between the two systems (Liang, 2010). This diffusive-equilibration often controls crystal dissolution rates within the boundary layers and, thus, the formation of interconnected melt or fluid networks. Such networks provide important pathways for the transport of volatiles and trace metals from the mafic recharge magma to the felsic host magma, where the latter may feed volcanic activities and ore deposits. While major element diffusion in silicate melts is mostly well understood, even in complex systems, the available data for many trace element metals are limited (Liang, 2010; Zhang et al., 2010). Differences in diffusivity in a dynamic, mixing environment can cause trace element fractionation, in particular during crystallization and volatile exsolution and separation. This may affect trace element signatures in phenocrysts and magmatic volatile phases that can form near a magma-magma boundary. As a result, the chemistry of volcanic gases and magmatic-hydrothermal ore deposits may be partially controlled by such mixing phenomena. We performed melt-melt diffusion-couple experiments at 150 MPa, 1100°C, FMQ, FMQ+1 and FMQ+3 (FMQ: fayalite-magnetite-quartz oxygen fugacity buffer). Hydrated, sulfur-bearing cylinders of dacite and basaltic andesite were equilibrated for up to 20 h. Major and trace element gradients were measured by using laser-ablation ICP-MS and electron microprobe analyses. The results we will

Evaluating the earliest traces of Archean sub-seafloor life by NanoSIMS

Science.gov (United States)

Mcloughlin, N.; Grosch, E. G.; Kilburn, M.; Wacey, D.

2012-12-01

The Paleoarchean sub-seafloor has been proposed as an environment for the emergence of life with titanite microtextures in pillow lavas argued to be the earliest traces of microbial micro-tunneling (Furnes et al. 2004). Here we use a nano-scale ion microprobe (NanoSIMS) to evaluate possible geochemical traces of life in 3.45 Ga pillow lavas of the Barberton Greenstone Belt, South Africa. We investigated both surface and drill core samples from the original "Biomarker" outcrop in the Hooggenoeg Fm. Pillow lava metavolcanic glass contain clusters of segmented microcrystalline titanite filaments, ~4μm across and sedimentary sulfides (δ34S = +8 to -23‰). We propose that the Hooggenoeg sulfides probably formed during early fluid-rock-microbe interaction involving sulfate-reducing microbes (c.f. Rouxel et al. 2008). The pillow lavas were then metamorphosed, the glass transformed to a greenschist facies assemblage and titanite growth encapsulated the microbial sulfides. In summary, the extreme sulfur isotope fractionations reported here independently point towards the potential involvement of microbes in the alteration of Archean volcanic glass. In situ sulfur isotope analysis of basalt-hosted sulfides may provide an alternative approach to investigating the existence of an Archean sub-seafloor biosphere that does not require the mineralization of early microbial microborings with organic linings.

Trace element characterisation of Cretaceous Orange Basin hydrocarbon source rocks

International Nuclear Information System (INIS)

Akinlua, A.; Adekola, S.A.; Swakamisa, O.; Fadipe, O.A.; Akinyemi, S.A.

2010-01-01

Research highlights: → Vanadium and nickel contents indicate that the rock samples from the Orange Basin have marine organic matter input. → The organic matter of the Orange Basin source rocks were deposited in reducing conditions. → Despite the similarities in the organic matter source input and depositional environment of the samples from the two well, cross plots of Co/Ni versus V/Ni and Mo/Ni versus Co/Ni were able to reveal their subtle differences. → Cluster analysis classified the samples into three groups based on subtle differences in their .thermal maturity. - Abstract: Trace elements in the kerogen fraction of hydrocarbon source rock samples from two wells obtained from the Cretaceous units of the Orange Basin, South Africa were determined using X-ray fluorescence spectrometry, in order to determine their distribution and geochemical significances. The concentrations of the elements (As, Ce, Co, Cu, Fe, Mo, Ni, Pb and V) determined ranged from 0.64 to 47,300 ppm for the samples analysed. The total organic carbon (TOC) values indicate that the samples are organic rich but did not show any trend with the distribution of the trace metals except Ce, Mo and Pb. Dendrogram cluster analysis discriminated the samples into three groups on the basis of their level of thermal maturity. Thermal maturity has a significant effect on the distribution of the trace metals. Cobalt/Ni and V/Ni ratios and cross plots of the absolute values of V and Ni indicate that the samples had significant marine organic matter input. The V and Ni contents and V/(V + Ni) ratio indicate that the organic matter of the source rocks had been deposited in reducing conditions. Despite the similarities in the organic matter source input and depositional environment of the organic matter of the samples from the two well, cross plots of Co/Ni versus V/Ni and Mo/Ni versus Co/Ni were able to reveal subtle differences. Cluster analysis of the samples was also able to reveal the subtle

Ray-tracing techniques to assess the electromagnetic field radiated by radio base stations: Application and experimental validation in an urban environment

International Nuclear Information System (INIS)

Adda, S.; Anglesio, L.; D'Amore, G.; Mantovan, M.; Menegolli, M.

2004-01-01

This paper aims to validate a ray-tracing model for electromagnetic field calculation, which is used in urban environments to predict irradiation from radio base stations for population exposure evaluation. Validation was carried out through a measurement campaign by choosing measurement points in order to test different propagation environments and analysing broadcast control channels through narrow band measurements. Comparison of the calculated and measured fields indicates that the ray-tracing model used calculates electric field with good accuracy, in spite of the fact that the propagation environment is not described in detail, because of difficulties in modelling the geometrical and electrical characteristics of urban areas. Differences between the calculated and measured results remain below 1.5 dB, with a mean value of 1 dB. (authors)

Trace elements assessment in agricultural and desert soils of Aswan area, south Egypt: Geochemical characteristics and environmental impacts

Science.gov (United States)

Darwish, Mohamed Abdallah Gad; Pöllmann, Hebert

2015-12-01

Determination of chemical elements, Al, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, P, Pb, Sc, Sr, Ti, Y, and Zn have been performed in agricultural and desert soils and alfalfa (Medicago sativa) at Aswan area. Consequently, the pollution indices, univariate and multivariate statistical methods have been applied, in order to assess the geochemical characteristics of these elements and their impact on soil environmental quality and plant, and to reach for their potential input sources. The investigation revealed that the mean and range values of all element concentrations in agricultural soil are higher than those in desert soil. Furthermore, the agricultural soil displayed various degrees of enrichment and pollution of Cd, Zn, Mo, Co, P, Ti, Pb. The geochemical pattern of integrated pollution indices gave a clear image of extreme and strong pollution in the agricultural soil stations, their poor quality with high risk to human health and considered as a tocsin for an alert. In contrast, the desert soil is the good environmental quality and safe for plant, animal and human health. Alfalfa is tolerant plant and considered as a biomarker for P and Mo in polluted agricultural soil. Four geochemical associations of analyzing elements in agricultural soil and three ones in desert soil have been generated, and their enhancements were essentially caused by various anthropogenic activities and geogenic sources. The investigation also revealed that the broad extended desert soil is fruitful and promising as cultivable lands for agricultural processes in the futures.

Proceedings of the scientific meeting on 'behavior and distributions of trace substances in the environment'

International Nuclear Information System (INIS)

Fukui, M.; Matsuzuru, H.

1998-02-01

The scientific meeting was held at the Research Reactor Institute, Kyoto University on December 11-12, 1997. This single report covers all aspects concerning association of trace substances such as pesticides/herbicides, organic chemicals and radionuclides in the environment. The reason for having this meeting is to describe the distribution and behavior of trace substances in which the emphasis is directed towards the dynamic interaction between the soil-sediment-water system and the contaminants. The Chernobyl accident raised the attention on the fate of radionuclides released in the environment and stimulated many scientists, who carry out large scale 'field experiments' without using a tracer in a laboratory. Of course, fundamental laboratory studies are necessary to give direction to and to understand observations from field studies. These activities have brought a lot of knowledge and understanding towards revealing a part of the complexity of the transport processes. It is hoped that the assembled experts, will not only dwell on distinct scientific issues, but also be able to draw firm conclusions with respect to the effective environmental management of the ecological aspects of hazardous materials. The 25 of the presented papers are indexed individually. (J.P.N.)

Trace metals in Antarctica related to climate change and increasing human impact.

Science.gov (United States)

Bargagli, R

2000-01-01

in most samples of atmospheric particulates, snow, ice, soils, and marine sediments from Antarctica can be taken as global background levels. Comparison between the results of trace element surveys in marine waters of the Southern Ocean and in other seas is practically impossible. The upwelling or subduction of water masses, the seasonality in ice cover and in phytoplankton biomass, the low fallout of atmospheric dust, and many other peculiar characteristics of the Southern Ocean make concentrations of trace metals in surface waters quite variable in space and time. The depletion of nutrients in surface waters, which is a regular feature of many marine environments, rarely occurs in the Southern Ocean. Waters in some regions are characterized by very low concentrations of Fe and Mn, whereas in others the content of Cd is relatively high at the beginning of summer and may decrease about one order of magnitude during the phytoplankton bloom. Although in most Antarctic coastal ecosystems the input of metals from geochemical and anthropogenic sources and from long-range transport is negligible, concentrations of Cd in the waters and biota may be higher than in waters and related species of organisms from polluted coastal areas. Like the Southern Ocean, Antarctic lakes have many peculiar characteristics. They are often perennially ice covered and without outlet, and their water, which is gained only from short-term melting of snow and glaciers in summer, is lost mainly by sublimation of surface ice. Several lakes are distinctly stratified: the water under the ice may be cool, rich in oxygen, and among the cleanest and clearest of natural waters, whereas water near the bottom becomes anoxic, tepid, and richer in major and trace elements. Considering the specificity of Antarctic environments, to evaluate the extent and consequences of global changes and increasing human activities in Antarctica itself, research on the biogeochemistry of trace metals and monitoring programs

The Variscan calc-alkalic plutonism of western Corsica: mineralogy and major and trace element geochemistry

Science.gov (United States)

Cocherie, A.; Rossi, Ph.; Le Bel, L.

1984-10-01

Petrographic and structural observations on the calc-alkalic plutonism of western Corsica revealed the existence of several successively emplaced units associated with large basic bodies. The present mineralogical and geochemical study deals with the genesis, evolution and relationships of these different units. Basic plutonism is represented by three genetically linked types of rock: norites and troctolites with cumulate textures characterized by low REE contents and either no Eu anomaly or a positive Eu anomaly; gabbros with enriched LREE relatively to HREE patterns, probably close to an initial basaltic liquid; and diorites ranging up to charnockites which represent liquids evolved to varying degrees, mainly by fractional crystallization. Trace element data and studies on the evolution of pyroxene pairs demonstrate the consanguinity of these calc-alkaline basic rocks which are derived from a high alumina basaltic melt. The various granitoids (granodiorites, monzogranites and leucocratic monzogranites, i.e., adamellites) have distinct evolution trends as shown by the composition of their mafic minerals and by trace element distributions. They cannot be considered as being derivatives of the basic suite and they cannot be related by a common fractionation sequence. Rather, they represent distinctive batches of crustal anatexis. In addition, hybridization phenomena with the basic melt are noticed in granodiorites. The particular problem of the low La/Yb, Eu/Eu∗ and the high U, Th, Cs leucocratic monzogranites is discussed in detail. In addition to more conventional trace element diagrams, the simultaneous statistical treatment of all the geochemical data by correspondence factor analysis is shown to be a very use tool in distinguishing between the different units and to classify the elements according to their geochemical properties.

DS-ARP: a new detection scheme for ARP spoofing attacks based on routing trace for ubiquitous environments.

Science.gov (United States)

Song, Min Su; Lee, Jae Dong; Jeong, Young-Sik; Jeong, Hwa-Young; Park, Jong Hyuk

2014-01-01

Despite the convenience, ubiquitous computing suffers from many threats and security risks. Security considerations in the ubiquitous network are required to create enriched and more secure ubiquitous environments. The address resolution protocol (ARP) is a protocol used to identify the IP address and the physical address of the associated network card. ARP is designed to work without problems in general environments. However, since it does not include security measures against malicious attacks, in its design, an attacker can impersonate another host using ARP spoofing or access important information. In this paper, we propose a new detection scheme for ARP spoofing attacks using a routing trace, which can be used to protect the internal network. Tracing routing can find the change of network movement path. The proposed scheme provides high constancy and compatibility because it does not alter the ARP protocol. In addition, it is simple and stable, as it does not use a complex algorithm or impose extra load on the computer system.

Alaska Geochemical Database (AGDB)-Geochemical data for rock, sediment, soil, mineral, and concentrate sample media

Science.gov (United States)

Granitto, Matthew; Bailey, Elizabeth A.; Schmidt, Jeanine M.; Shew, Nora B.; Gamble, Bruce M.; Labay, Keith A.

2011-01-01

The Alaska Geochemical Database (AGDB) was created and designed to compile and integrate geochemical data from Alaska in order to facilitate geologic mapping, petrologic studies, mineral resource assessments, definition of geochemical baseline values and statistics, environmental impact assessments, and studies in medical geology. This Microsoft Access database serves as a data archive in support of present and future Alaskan geologic and geochemical projects, and contains data tables describing historical and new quantitative and qualitative geochemical analyses. The analytical results were determined by 85 laboratory and field analytical methods on 264,095 rock, sediment, soil, mineral and heavy-mineral concentrate samples. Most samples were collected by U.S. Geological Survey (USGS) personnel and analyzed in USGS laboratories or, under contracts, in commercial analytical laboratories. These data represent analyses of samples collected as part of various USGS programs and projects from 1962 to 2009. In addition, mineralogical data from 18,138 nonmagnetic heavy mineral concentrate samples are included in this database. The AGDB includes historical geochemical data originally archived in the USGS Rock Analysis Storage System (RASS) database, used from the mid-1960s through the late 1980s and the USGS PLUTO database used from the mid-1970s through the mid-1990s. All of these data are currently maintained in the Oracle-based National Geochemical Database (NGDB). Retrievals from the NGDB were used to generate most of the AGDB data set. These data were checked for accuracy regarding sample location, sample media type, and analytical methods used. This arduous process of reviewing, verifying and, where necessary, editing all USGS geochemical data resulted in a significantly improved Alaska geochemical dataset. USGS data that were not previously in the NGDB because the data predate the earliest USGS geochemical databases, or were once excluded for programmatic reasons

Brent coal typing by combined optical and geochemical studies

Energy Technology Data Exchange (ETDEWEB)

Ducazeaux, J.; Le Tran, K.; Nicolas, G. (Societe Nationale des Petroles d' Aquitaine (SNPA), 64 - Pau (France))

1991-12-01

Palynological,petrographical and organic geochemical studies show that various kinds of coal occur throughout the Middle Jurassic Brent Group in the Viking Graben. Two types of coal with strong contrast in terms of source rock potential are thoroughly investigated in this study. It is found that they are relevant to two distinct organic facies. Though having the same organic carbon content, they are very different with respect to the petroleum generating potential, one being a conventional gas-prone coal of type III kerogen and the other one of type II-(III) kerogen which should be considered as an oil-generating coal. Explanations are sought for the difference observed, both geochemically and optically. Palynological study shows the occurrence of two distinct communities of land plants in relation with the depositional environment and climatic changes, whilst coal petrographical study shows that the macerals are unevenly and differently distributed in these two coal types. The original organic material and the depositional environment appear to be the main controlling factors. 13 Refs.; 8 Figs.

a Baseline Study of Physico-Chemical Parameters and Trace Metals in Waters of Manakudy, South-West Coast of India

Science.gov (United States)

Subramanian, M.; Muthumanikkam, J.

2013-05-01

The transport of trace metals from the land to ocean has a number of different routes and efficiencies. The sources of toxic elements into the rivers to be debouched into the sea through estuaries are either weathered naturally from the soils and rocks or introduced anthropogenically from point or non-point sources, in labile form or in particulate form. However, recent studies indicate that the transport of trace elements to the aquatic environment is much more complex than what has been thought. The chemistry and ecology of an estuarine system are entirely different from the fluvial as well as the marine system. Estuarine environment is characterized by a constantly changing mixture of salt and freshwater. In the present study area Manakudy estuary is situated about 8 kilometres north west of Kanyakumari (Latitude N 08 05 21.8 and Longitude E 077 29 03.7). To gain a better understanding of the geochemical behavior of physico-chemical parameters and trace elements in the estuary and to examine variations in associated chemical changes, 20 water samples were collected throughout the Manakudy estuary, a minor river in south-western India. These samples, collected in typical dry season during 2012, were analyzed for physico-chemical parameters, dissolved major and trace elements. Our results show that dissolved Na, Mg, Ca and Cl behave conservatively along the salinity gradient. The concentration of nutrients is normal and they are due to the higher organic activity in soils as well as faster rates of chemical weathering reaction in the source region. The concentration of major ions is due to tidal influence and it increases with salinity and the nutrients do behave non-conservatively due to biogenic removal. The conservative behaviour of the trace metals with salinity has been strongly affected by the introduction of these metals by external sources. Even though the trace metals in the contaminated water have been removed and incorporated in sediments due to

Trace element patterns in Dutch coastal dunes after 50 years of artificial recharge with Rhine River water

NARCIS (Netherlands)

Stuijfzand, P.J.

2014-01-01

Trace elements (TEs) are important in water quality monitoring of managed aquifer recharge (MAR) systems, because they need to be tested against maximum permissible concentrations (MPCs), and some can be used as a tracer of either infiltration water, pollution or geochemical processes. The behavior

Geochemical prerequisites of petroleum-gas formation in the Mesozoic-Cenozoic sedimentary layer of the world's oceans

Energy Technology Data Exchange (ETDEWEB)

Trotsyuk, V Ya

1979-05-01

A summarization is given of the latest material on the geochemistry of trace organic matter of Mesozoic-Cenozoic deposits of the world's oceans, obtained as a result of deep-sea drilling. Trace organic matter was found to be present in the sedimentary layers of the ocean outskirts in amounts near that found in the continental stratosphere, but that content was five times less in the interior region of the oceans. The trace organic matter of deposits in the marginal region of the oceans was found to have a significant petroleum-gas matrix potential with respect to the level of content and composition characteristics. The distribution of organic carbon was found to be uneven in variously aged horizons of the Mesozoic-Cenozoic. The maximum content of organic carbon was noted in the Neogene-Quaternary and lower Cretaceous deposits. An elevated content of trace organic matter was found to be characteristic of the oceanic stratisphere in lithological mixed sediments: terrigenous-carbonate and terrigenous-silicons was 1.5 times greater than the trace organic matter in clays. Fundamental geochemical propagation laws were formulated, possibly for petroleum-gas-bearing sediment basins under the ocean bottom and beyond the shelf. 18 references, 3 figures.

Geochemical and isotopic determination of deep groundwater contributions and salinity to the shallow groundwater and surface water systems, Mesilla Basin, New Mexico, Texas, and Mexico

Science.gov (United States)

Robertson, A.; Carroll, K. C.; Kubicki, C.; Purtshert, R.

2017-12-01

The Mesilla Basin/Conejos-Médanos aquifer system, extending from southern New Mexico to Chihuahua, Mexico, is a priority transboundary aquifer under the 2006 United States­-Mexico Transboundary Aquifer Assessment Act. Declining water levels, deteriorating water quality, and increasing groundwater use by municipal, industrial, and agricultural users on both sides of the international border raise concerns about long-term aquifer sustainability. Relative contributions of present-day and "paleo" recharge to sustainable fresh groundwater yields has not been determined and evidence suggests that a large source of salinity at the distal end of the Mesilla Basin is saline discharge from deep groundwater flow. The magnitude and distribution of those deep saline flow paths are not determined. The contribution of deep groundwater to discharge and salinity in the shallow groundwater and surface water of the Mesilla Basin will be determined by collecting discrete groundwater samples and analyzing for aqueous geochemical and isotopic tracers, as well as the radioisotopes of argon and krypton. Analytes include major ions, trace elements, the stable isotopes of water, strontium and boron isotopes, uranium isotopes, the carbon isotopes of dissolved inorganic carbon, noble gas concentrations and helium isotope ratios. Dissolved gases are extracted and captured from groundwater wells using membrane contactors in a process known as ultra-trace sampling. Gas samples are analyzed for radioisotope ratios of krypton by the ATTA method and argon by low-level counting. Effectiveness of the ultra-trace sampling device and method was evaluated by comparing results of tritium concentrations to the krypton-85 content. Good agreement between the analyses, especially in samples with undetectable tritium, indicates that the ultra-trace procedure is effective and confirms that introduction of atmospheric air has not occurred. The geochemistry data indicate a complex system of geochemical

Geochemical investigation of UMTRAP designated site at Durango, Colorado

International Nuclear Information System (INIS)

Markos, G.; Bush, K.J.

1983-09-01

This report is the result of a geochemical investigation of the former uranium mill and tailings site at Durango, Colorado. This is one in a series of site specific geochemical investigations performed on the inactive uranium mill tailings included in the UMTRA Project. The objectives of the investigation are to characterize the geochemistry, to determine the contaminant distribution resulting from the former milling activities and tailings, and to infer chemical pathways and transport mechanisms from the contaminant distribution. The results will be used to model contaminant migration and to develop criteria for long-term containment media such as a cover system which is impermeable to contaminant migration. This report assumes a familiarity with the hydrologic conditions of the site and the geochemical concepts underlying the investigation. The results reported are based on a one-time sampling of waters and solid material from the background, the area adjacent to the site, and the site. The solid samples are water extracted remove easily soluble salts and acids extracted to remove cabonates and hydroxides. The water extracts and solid samples were analyzed for the major and trace elements. A limited number of samples were analyzed for radiological components. The report includes the methods of sampling, sample processing, analysis, and data interpretation. Three major conclusions are: (1) carbonate salts and low TDS characterize the tailings; (2) the adjacent area and raffinate ponds contain contaminants deposited by a single event of fluid permeation of the soils; and (3) the Animas River adjacent to the site has elevated gross alpha activity attributed to 226 Ra in the sediments derived from the tailings or milling activities

TAPIR--Finnish national geochemical baseline database.

Science.gov (United States)

Jarva, Jaana; Tarvainen, Timo; Reinikainen, Jussi; Eklund, Mikael

2010-09-15

In Finland, a Government Decree on the Assessment of Soil Contamination and Remediation Needs has generated a need for reliable and readily accessible data on geochemical baseline concentrations in Finnish soils. According to the Decree, baseline concentrations, referring both to the natural geological background concentrations and the diffuse anthropogenic input of substances, shall be taken into account in the soil contamination assessment process. This baseline information is provided in a national geochemical baseline database, TAPIR, that is publicly available via the Internet. Geochemical provinces with elevated baseline concentrations were delineated to provide regional geochemical baseline values. The nationwide geochemical datasets were used to divide Finland into geochemical provinces. Several metals (Co, Cr, Cu, Ni, V, and Zn) showed anomalous concentrations in seven regions that were defined as metal provinces. Arsenic did not follow a similar distribution to any other elements, and four arsenic provinces were separately determined. Nationwide geochemical datasets were not available for some other important elements such as Cd and Pb. Although these elements are included in the TAPIR system, their distribution does not necessarily follow the ones pre-defined for metal and arsenic provinces. Regional geochemical baseline values, presented as upper limit of geochemical variation within the region, can be used as trigger values to assess potential soil contamination. Baseline values have also been used to determine upper and lower guideline values that must be taken into account as a tool in basic risk assessment. If regional geochemical baseline values are available, the national guideline values prescribed in the Decree based on ecological risks can be modified accordingly. The national geochemical baseline database provides scientifically sound, easily accessible and generally accepted information on the baseline values, and it can be used in various

Geochemical characteristics of the Permian sedimentary rocks from Qiangtang Basin: Constraints for paleoenvironment and paleoclimate

Directory of Open Access Journals (Sweden)

Junjie Hu

2017-01-01

Full Text Available Qiangtang Basin is expected to become important strategic petroleum exploitation area in China. However, little research has been done on the Permian strata in this area. This paper presents Lower Permian Zhanjin Formation geochemical data from the Jiaomuri area, reconstructing the paleo-depositional environment and providing information for further petroleum exploration. The geochemical characteristics of 19 samples were investigated. These geochemical samples show a developed mud flat characteristic with light rich clay content. The geological data were used to constrain the paleoredox environment, which proved that these sediments were deposited mainly beneath a slightly oxic water column with relatively low paleoproductivity as evidenced by the P/Ti (mean of 0.07 and Ba/Al (mean of 20.5. Palaeoclimate indexes such as the C-value (0.24-1.75 and Sr/Cu (1.28-11.58 reveal a humid climatic condition during Zhanjin Formation sediment deposition. The ω(LaN/ω(YbN ratio values indicate a fast sedimentary rate during the deposition period.

Role of geochemical background at evaluation of investment attractiveness of recreational territories

Directory of Open Access Journals (Sweden)

Vdovina Ol'ga Konstantinovna

2014-09-01

Full Text Available The article shows the role of natural geochemical background when estimating investment attractiveness of recreational areas. It is noted, that geochemical background influence on people's sickness rate isn't considered now. Though it's understood, that even insignificant increase of geochemical background in relation to percentage abundance of Earth crest may lead to endemic diseases of people, animals and plants. An indicator of geochemical endemicity areas was proposed for assessing the impact of storage elements and of a lack of geological environment on human health. Thanks to this measure, and taking into account landscape features of the area, the authors allocated lands, dangerous and potentially dangerous in terms of endemicity. The importance of ratings was achieved by the use of those factors that could have a great influence on the cost of land development. This includes, first of all, the factors that affect population health, and economic and geographic factors that minimize the cost of the territory development and the factors that give rise to financial risks and risks of human losses. The main risk factors include: potential ecological and geochemical risk; high absolute heights, development and activity of dangerous geological processes and phenomena. Systemacity of researches was reached by using factors, that characterize the object from different aspects; readiness of area infrastructure to its exploration and possible risks. Objectivity was achieved by the use of figures obtained from the results of geochemical and engineering surveys with their metrological support.

Lead Isotopes in Olivine-Phyric Shergottite Tissint: Implications for the Geochemical Evolution of the Shergottite Source Mantle

Science.gov (United States)

Moriwaki, R.; Usui, T.; Simon, J. I.; Jones, J. H.; Yokoyama, T.

2015-01-01

Geochemically-depleted shergottites are basaltic rocks derived from a martian mantle source reservoir. Geochemical evolution of the martian mantle has been investigated mainly based on the Rb-Sr, Sm-Nd, and Lu-Hf isotope systematics of the shergottites [1]. Although potentially informative, U-Th- Pb isotope systematics have been limited because of difficulties in interpreting the analyses of depleted meteorite samples that are more susceptible to the effects of near-surface processes and terrestrial contamination. This study conducts a 5-step sequential acid leaching experiment of the first witnessed fall of the geochemically-depleted olivinephyric shergottite Tissint to minimize the effect of low temperature distrubence. Trace element analyses of the Tissint acid residue (mostly pyroxene) indicate that Pb isotope compositions of the residue do not contain either a martian surface or terrestrial component, but represent the Tissint magma source [2]. The residue has relatively unradiogenic initial Pb isotopic compositions (e.g., 206Pb/204Pb = 10.8136) that fall within the Pb isotope space of other geochemically-depleted shergottites. An initial µ-value (238U/204Pb = 1.5) of Tissint at the time of crystallization (472 Ma [3]) is similar to a time-integrated mu- value (1.72 at 472 Ma) of the Tissint source mantle calculated based on the two-stage mantle evolution model [1]. On the other hand, the other geochemically-depleted shergottites (e.g., QUE 94201 [4]) have initial µ-values of their parental magmas distinctly lower than those of their modeled source mantle. These results suggest that only Tissint potentially reflects the geochemical signature of the shergottite mantle source that originated from cumulates of the martian magma ocean

Geochemical haloes as an indication of over oil and gas fields in the Arctic shelf

Science.gov (United States)

Kholmiansky, Mikhail; Anokhin, Vladimir

2013-04-01

Hydrocarbon deposits at the Arctic shelf of Russia are a source of jet dispersion of heavy metals that forms haloes in sediments and in the bottom layer of sea water. The intensity of the haloes and their spatial position are jointly determined by geological structure of their source and the environment, i.e., hydrocarbon deposits in host rocks, seafloor lithodynamics and oceanographic factors. Based on theoretical works of Kholmyansky and Putikov (2000; 2006; 2008), an application of electrochemical modification of electric prospecting for offshore hydrocarbon exploration and detailed survey of the morphology of deposits was developed. Specialized equipment was developed for studies of electrochemical features of bottom water layer. With this equipment one can detect ion anomalies in water and determine the type of deposit as gas, gas hydrate, gas condensate or oil. At operation, the unit with equipment is towed underwater off the stern of research vessel. Type and configuration of deposits are determined based on occurrence of trace heavy metals detected by ion-selective electrodes. The proposed method was applied to study a few hydrocarbon fields in Barents and Kara seas in 2001 -2012 including Shtokman, Medyn, Polyarnoe, Prirazlomnoye and others. The results allowed us to trace the margins of the deposits in more detail, and geochemical data, in addition, showed the type of deposits. In general, the method has proven efficient and applicable to a wide range of hydrocarbon deposits.

Fate and transport of trace metals and rare earth elements in the Snake River, an AMD/ARD-impacted watershed. Montezuma, Colorado USA.

Science.gov (United States)

McKnight, D. M.; Rue, G.

2017-12-01

Recent research in Snake River Watershed, located near the historic boomtown of Montezuma and adjacent the Continental Divide in the Colorado Rocky Mountains, has revealed the distinctive occurrence of rare earth elements (REE) at high concentrations. Here the weathering of the mineralized lithology naturally generates acid rock drainage (ARD) in addition to drainage recieved from abandoned mine adits throughout the area, results in aqueous REE concentrations three orders of magnitude higher than in most major rivers. The dominant mechanism responsible for this enrichment; their dissolution from secondary and accessory mineral stocks, abundant in REEs, promoted by the low pH waters generated from geochemical weathering of disseminated sulfide minerals. While REEs behave conservatively in acidic conditions, as well as in the presence of stabilizing ligands such as sulfate, downstream circumneutral inputs from pristine streams and a rising pH are resulting in observed fractional losses of heavy rare earth elements as well as partitioning towards colloidal and solid phases. These finding in combination with the established role of dissolved organic matter (DOM) in binding with both trace metals and REEs, suggest that competitive interactions, complexation, and scavenging are likely contributing to these proportional losses. However, outstanding questions yet remain regarding the effects of an increasing flux of trace metals as well as REEs from the Snake River Watershed into Dillon Reservoir, a major drinking water supply for the City of Denver, in part due to hydroclimatological drivers that are enhancing geochemical weathering and reducing groundwater recharge in alpine areas across the Colorado Rockies. Based on these findings also we seek to broaden this body of work to further investigate the behavior of rare earth elements (REE) in other aquatic environment as well the influence of trace metals, DOM, and pH in altering their reactivity and subsequent watershed

Tracing climatic conditions during the deposition of late Cretaceous-early Eocene phosphate beds in Morocco by geochemical compositions of biogenic apatite fossils

Science.gov (United States)

Kocsis, L.; Gheerbrant, E.; Mouflih, M.; Cappetta, H.; Yans, J.; Ulianov, A.; Amaghzaz, M.

2012-04-01

Morocco's Western Atlantic coast was covered by shallow seas during the late Cretaceous-early Eocene when large amount of phosphate rich sediments were deposited. This time interval envelops a major part of the last greenhouse period and gives the opportunity to study the event's characteristics in shallow water settings. These phosphate deposits are extremely rich in vertebrate fossils, while other types of fossils are rare or often poorly preserved. Hence the local stratigraphy is based on the most abundant marine vertebrate fossils, on the selachian fauna (sharks and rays). Our geochemical investigations were also carried out on these remains, though in some cases frequently found coprolites were involved as well. The main goal of our study was to test whether stable isotope compositions (δ18OPO4, δ13C) of these fossils reflect any of the hyperthermal events and/or the related perturbations in the carbon cycle during the early Paleogene (Lourens et al. 2005) and whether these geochemical signals can be used to refine the local stratigraphy. Additionally, the samples were analyzed for trace element composition in order to better assess local taphonomy and burial conditions. The samples came from two major phosphate regions, the Ouled Abdoun and the Ganntour Basins and they were collected either directly on the field during excavations (Sidi Chennane) or were obtained from museum collections with known stratigraphical position (Sidi Daoui, Ben Guerrir). The phosphate oxygen isotopic compositions of shark teeth display large range across the entire series (18.5-22.4 ) which can partly be related to the habitat of sharks. For instance the genus Striatolamnia often yielded the highest δ18O values indicating possible deep water habitat. Despite the large variation in δ18O values, a general isotope trend is apparent. In the Maastrichtian after a small negative shift, the δ18O values increase till the Danian from where the trend decrease till the Ypresian. The

Geochemical differentiation processes for arc magma of the Sengan volcanic cluster, Northeastern Japan, constrained from principal component analysis

Science.gov (United States)

Ueki, Kenta; Iwamori, Hikaru

2017-10-01

In this study, with a view of understanding the structure of high-dimensional geochemical data and discussing the chemical processes at work in the evolution of arc magmas, we employed principal component analysis (PCA) to evaluate the compositional variations of volcanic rocks from the Sengan volcanic cluster of the Northeastern Japan Arc. We analyzed the trace element compositions of various arc volcanic rocks, sampled from 17 different volcanoes in a volcanic cluster. The PCA results demonstrated that the first three principal components accounted for 86% of the geochemical variation in the magma of the Sengan region. Based on the relationships between the principal components and the major elements, the mass-balance relationships with respect to the contributions of minerals, the composition of plagioclase phenocrysts, geothermal gradient, and seismic velocity structure in the crust, the first, the second, and the third principal components appear to represent magma mixing, crystallizations of olivine/pyroxene, and crystallizations of plagioclase, respectively. These represented 59%, 20%, and 6%, respectively, of the variance in the entire compositional range, indicating that magma mixing accounted for the largest variance in the geochemical variation of the arc magma. Our result indicated that crustal processes dominate the geochemical variation of magma in the Sengan volcanic cluster.

Studying uranium migration in natural environment: experimental approach and geochemical modeling

International Nuclear Information System (INIS)

Phrommavanh, V.

2008-10-01

The present study deals with characterizing uranium migration in a limited zone of Le Bouchet site, a former uranium ore treatment facility, which is dismantled and the rehabilitation of which is under process. Some wastes are packed in a rehabilitated disposal nearby, called the Itteville site. In the framework of the monitoring of the deposit environment (air, water, sediment) set by prefectorial decrees, a piezometer (PZPK) located downstream to the latter, has shown total dissolved uranium peaks each winter since the 1990's. PZPK collects both the interstitial water of a calcareous peat formation, between the surface and 3 m, and an alluvial aquifer near 6 m of depth. Firstly, a hydrogeochemical characterization of the site has evidenced the uranium source term, which is present in the peat soil near 0.8 m, hence excluding any leaching from the waste disposal. Actually, a few microparticles of uranium oxide and mixed uranium-thorium oxide have been detected, but they do not represent the major part of the source term. Secondly, water chemistry of the peat soil water and PZPK has been monitored every two months from 2004 to 2007 in order to understand the reasons of the seasonal fluctuations of [U]tot.diss.. Completed with geochemical modeling and a bacterial identification by 16S rDNA sequence analysis, water chemistry data showed an important sulfate-reducing bacterial activity in summertime, leading to reducing conditions and therefore, a total dissolved uranium content limited by the low solubility of uraninite U IV O 2 (s). In wintertime, the latter bacterial activity being minimal and the effective pluviometry more important, conditions are more oxidant, which favors U(VI), more soluble, notably as the Ca 2 UO 2 (CO 3 ) 3 (aq) complex, evidenced by TRLFS. Finally, bacterial activity has been reproduced in laboratory in order to better characterize its impact on uranium solubility in the peat soil. Various parameters were tested (C sources, temperature

Experimental insights into geochemical changes in hydraulically fractured Marcellus Shale

International Nuclear Information System (INIS)

Marcon, Virginia; Joseph, Craig; Carter, Kimberly E.; Hedges, Sheila W.; Lopano, Christina L.; Guthrie, George D.; Hakala, J. Alexandra

2017-01-01

Hydraulic fracturing applied to organic-rich shales has significantly increased the recoverable volume of methane available for U.S. energy consumption. Fluid-shale reactions in the reservoir may affect long-term reservoir productivity and waste management needs through changes to fracture mineral composition and produced fluid chemical composition. We performed laboratory experiments with Marcellus Shale and lab-generated hydraulic fracturing fluid at elevated pressures and temperatures to evaluate mineral reactions and the release of trace elements into solution. Results from the experiment containing fracturing chemicals show evidence for clay and carbonate dissolution, secondary clay and anhydrite precipitation, and early-stage (24–48 h) fluid enrichment of certain elements followed by depletion in later stages (i.e. Al, Cd, Co, Cr, Cu, Ni, Sc, Zn). Other elements such as As, Fe, Mn, Sr, and Y increased in concentration and remained elevated throughout the duration of the experiment with fracturing fluid. Geochemical modeling of experimental fluid data indicates primary clay dissolution, and secondary formation of smectites and barite, after reaction with fracturing fluid. Changes in aqueous organic composition were observed, indicating organic additives may be chemically transformed or sequestered by the formation after hydraulic fracturing. The NaCl concentrations in our fluids are similar to measured concentrations in Marcellus Shale produced waters, showing that these experiments are representative of reservoir fluid chemistries and can provide insight on geochemical reactions that occur in the field. These results can be applied towards evaluating the evolution of hydraulically-fractured reservoirs, and towards understanding geochemical processes that control the composition of produced water from unconventional shales. - Highlights: • Metal concentrations could be at their peak in produced waters recovered 24–48 after fracturing. • Carbonate

Chemical elements in the environment: multi-element geochemical datasets from continental to national scale surveys on four continents

Science.gov (United States)

Caritat, Patrice de; Reimann, Clemens; Smith, David; Wang, Xueqiu

2017-01-01

During the last 10-20 years, Geological Surveys around the world have undertaken a major effort towards delivering fully harmonized and tightly quality-controlled low-density multi-element soil geochemical maps and datasets of vast regions including up to whole continents. Concentrations of between 45 and 60 elements commonly have been determined in a variety of different regolith types (e.g., sediment, soil). The multi-element datasets are published as complete geochemical atlases and made available to the general public. Several other geochemical datasets covering smaller areas but generally at a higher spatial density are also available. These datasets may, however, not be found by superficial internet-based searches because the elements are not mentioned individually either in the title or in the keyword lists of the original references. This publication attempts to increase the visibility and discoverability of these fundamental background datasets covering large areas up to whole continents.

Modeling Background Radiation in our Environment Using Geochemical Data

Energy Technology Data Exchange (ETDEWEB)

Malchow, Russell L.; Marsac, Kara [University of Nevada, Las Vegas; Burnley, Pamela [University of Nevada, Las Vegas; Hausrath, Elisabeth [Uniiversity of Nevada, Las Vegas; Haber, Daniel [University of Nevada, Las Vegas; Adcock, Christopher [University of Nevada, Las Vegas

2015-02-01

Radiation occurs naturally in bedrock and soil. Gamma rays are released from the decay of the radioactive isotopes K, U, and Th. Gamma rays observed at the surface come from the first 30 cm of rock and soil. The energy of gamma rays is specific to each isotope, allowing identification. For this research, data was collected from national databases, private companies, scientific literature, and field work. Data points were then evaluated for self-consistency. A model was created by converting concentrations of U, K, and Th for each rock and soil unit into a ground exposure rate using the following equation: D=1.32 K+ 0.548 U+ 0.272 Th. The first objective of this research was to compare the original Aerial Measurement System gamma ray survey to results produced by the model. The second objective was to improve the method and learn the constraints of the model. Future work will include sample data analysis from field work with a goal of improving the geochemical model.

Coupled geochemical and solute transport code development

International Nuclear Information System (INIS)

Morrey, J.R.; Hostetler, C.J.

1985-01-01

A number of coupled geochemical hydrologic codes have been reported in the literature. Some of these codes have directly coupled the source-sink term to the solute transport equation. The current consensus seems to be that directly coupling hydrologic transport and chemical models through a series of interdependent differential equations is not feasible for multicomponent problems with complex geochemical processes (e.g., precipitation/dissolution reactions). A two-step process appears to be the required method of coupling codes for problems where a large suite of chemical reactions must be monitored. Two-step structure requires that the source-sink term in the transport equation is supplied by a geochemical code rather than by an analytical expression. We have developed a one-dimensional two-step coupled model designed to calculate relatively complex geochemical equilibria (CTM1D). Our geochemical module implements a Newton-Raphson algorithm to solve heterogeneous geochemical equilibria, involving up to 40 chemical components and 400 aqueous species. The geochemical module was designed to be efficient and compact. A revised version of the MINTEQ Code is used as a parent geochemical code

Application of cluster analysis to geochemical compositional data for identifying ore-related geochemical anomalies

Science.gov (United States)

Zhou, Shuguang; Zhou, Kefa; Wang, Jinlin; Yang, Genfang; Wang, Shanshan

2017-12-01

Cluster analysis is a well-known technique that is used to analyze various types of data. In this study, cluster analysis is applied to geochemical data that describe 1444 stream sediment samples collected in northwestern Xinjiang with a sample spacing of approximately 2 km. Three algorithms (the hierarchical, k-means, and fuzzy c-means algorithms) and six data transformation methods (the z-score standardization, ZST; the logarithmic transformation, LT; the additive log-ratio transformation, ALT; the centered log-ratio transformation, CLT; the isometric log-ratio transformation, ILT; and no transformation, NT) are compared in terms of their effects on the cluster analysis of the geochemical compositional data. The study shows that, on the one hand, the ZST does not affect the results of column- or variable-based (R-type) cluster analysis, whereas the other methods, including the LT, the ALT, and the CLT, have substantial effects on the results. On the other hand, the results of the row- or observation-based (Q-type) cluster analysis obtained from the geochemical data after applying NT and the ZST are relatively poor. However, we derive some improved results from the geochemical data after applying the CLT, the ILT, the LT, and the ALT. Moreover, the k-means and fuzzy c-means clustering algorithms are more reliable than the hierarchical algorithm when they are used to cluster the geochemical data. We apply cluster analysis to the geochemical data to explore for Au deposits within the study area, and we obtain a good correlation between the results retrieved by combining the CLT or the ILT with the k-means or fuzzy c-means algorithms and the potential zones of Au mineralization. Therefore, we suggest that the combination of the CLT or the ILT with the k-means or fuzzy c-means algorithms is an effective tool to identify potential zones of mineralization from geochemical data.

A Geochemical Reaction Model for Titration of Contaminated Soil and Groundwater at the Oak Ridge Reservation

Science.gov (United States)

Zhang, F.; Parker, J. C.; Gu, B.; Luo, W.; Brooks, S. C.; Spalding, B. P.; Jardine, P. M.; Watson, D. B.

2007-12-01

This study investigates geochemical reactions during titration of contaminated soil and groundwater at the Oak Ridge Reservation in eastern Tennessee. The soils and groundwater exhibits low pH and high concentrations of aluminum, calcium, magnesium, manganese, various trace metals such as nickel and cobalt, and radionuclides such as uranium and technetium. The mobility of many of the contaminant species diminishes with increasing pH. However, base additions to increase pH are strongly buffered by various precipitation/dissolution and adsorption/desorption reactions. The ability to predict acid-base behavior and associated geochemical effects is thus critical to evaluate remediation performance of pH manipulation strategies. This study was undertaken to develop a practical but generally applicable geochemical model to predict aqueous and solid-phase speciation during soil and groundwater titration. To model titration in the presence of aquifer solids, an approach proposed by Spalding and Spalding (2001) was utilized, which treats aquifer solids as a polyprotic acid. Previous studies have shown that Fe and Al-oxyhydroxides strongly sorb dissolved Ni, U and Tc species. In this study, since the total Fe concentration is much smaller than that of Al, only ion exchange reactions associated with Al hydroxides are considered. An equilibrium reaction model that includes aqueous complexation, precipitation, ion exchange, and soil buffering reactions was developed and implemented in the code HydroGeoChem 5.0 (HGC5). Comparison of model results with experimental titration curves for contaminated groundwater alone and for soil- water systems indicated close agreement. This study is expected to facilitate field-scale modeling of geochemical processes under conditions with highly variable pH to develop practical methods to control contaminant mobility at geochemically complex sites.

A 100-year record of climate change and human activities inferred from the geochemical composition of sediments in Chaiwopu Lake, arid northwest China

Directory of Open Access Journals (Sweden)

Wen Liu

2016-01-01

Full Text Available An 81-cm sediment core from Chaiwopu Lake in arid northwest China was analyzed for 137Cs activity and concentrations of major and trace elements. We used these data to discriminate between the influence of climate change and human activities on the geochemical change of the lake sediments over the past century. Elements Al, K, Ba, Ti, V, Fe, Ni, Mn, Li, and Be were mainly from detrital. Ca, Sr, and Mg concentrations were controlled by chemical weathering processes. Na came mainly from salt precipitation caused by a decline in water level. Enrichment factors for Pb and P in recent deposits are large, indicating they were influenced by human activies. Geochemical conditions during the past century can be divided into three stages: i From ca. 1900 to the1950s element concentrations varied widely and frequently. In general, concentrations of typical mobile elements Ca, Sr, and Mg stay relatively high whereas values for other elements remained relatively low. This was interpreted to reflect variable climate under conditions of weak surface erosion intensity. ii From the 1950s to the early 2000s, element concentrations display less variability. The Al, K, Ba, Ti, P, Cr, V, Fe, Ni, Mn, Co, Cu, Li, Zn, Be, Pb, and Na contents were generally higher, whereas contents of Ca, Sr, and Mg were on average lower. This indicates that the regional environment was conducive to surface erosion. Enrichment of trace metals and major elements in the sediment reflects enhanced human activities. iii In the last decade, Pb and P exhibited a great increase, possibly associated with the input from fossil fuel combustion, sewage discharge and non-point-source pollution in the watershed. The lake volume decreased substantially because of groundwater extraction for municipal water, which resulted in a marked increase in salinity and enhanced Na precipitation.

Geochemical Investigations of Groundwater Stability

International Nuclear Information System (INIS)

Bath, Adrian

2006-05-01

groundwaters, and also by stable isotopes and uranium isotopes in secondary minerals. Information on timing of water and solute movements is important because it indicates any correlation with the timing of external events that might have perturbed and destabilised the groundwater system in the past, and allows a timescale to be estimated for the persistence of stable conditions. Data from a number of published site investigation projects and research programmes are reviewed to illustrate the patterns of geochemical data and the relationships between them, and how these are interpreted in terms of hydrodynamic stability. Data from Aespoe and Stripa and from exploratory boreholes at Finnsjoen and other sites in Sweden are compiled and discussed. Preliminary data from SKB's ongoing site investigations at Simpevarp/Laxemar and Forsmark are not considered in detail but their general similarities with Aespoe and Finnsjoen/SFR respectively are introduced into the discussion of geochemical evidence for groundwater stability in inland and coastal areas. Relevant data from Finnish sites including Olkiluoto, from the Whiteshell URL area in Canada, from Sellafield in the UK, and from the Tono area and URL in Japan are also summarised in appendices and discussed because they add further insights into the interpretation of geochemical indicators for a range of geological environments. The compiled data provide only limited scope for comparison of groundwater evolution and stability between inland and coastal areas in Sweden, because of the patchiness of representative data especially from early site studies. The external changes that might have perturbed stable groundwater conditions in the past are glaciation (i.e. melt water, mechanical loading/unloading and permafrost) and varying sea water infiltration at coastal sites due to changes in palaeo-Baltic and isostatic conditions. The present distributions of palaeo-Baltic sea water in groundwaters at coastal sites vary, reflecting local

Obtaining reasonable assurance on geochemical aspects of performance assessment of deep geologic repositories

International Nuclear Information System (INIS)

Van Luik, A.E.; Serne, R.J.

1986-01-01

Providing reasonable assurance that a deep geologic disposal system will perform as required by regulation involves, in part, the building of confidence by providing a sound scientific basis for the site characterization, engineered system design, and system performance modeling efforts. Geochemistry plays a role in each of these activities. Site characterization must result in a description of the in situ geochemical environment that will support the design of the engineered system and the modeling of the transport of specific radionuclides to the accessible environment. Judging the adequacy of this site characterization effort is a major aspect of providing reasonable assurance. Within site characterization, there are a number of geochemical issues that need to be addressed such as the usefulness of natural analog studies, and assessing the very long-term stability of the site geochemistry, given expected temperature and radiation conditions

Geochemical Data Package for Performance Assessment Calculations Related to the Savannah River Site

Energy Technology Data Exchange (ETDEWEB)

Kaplan, Daniel I. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-07-22

The Savannah River Site (SRS) disposes of low-level radioactive waste (LLW) and stabilizes high-level radioactive waste (HLW) tanks in the subsurface environment. Calculations used to establish the radiological limits of these facilities are referred to as Performance Assessments (PA), Special Analyses (SA), and Composite Analyses (CA). The objective of this document is to revise existing geochemical input values used for these calculations. This work builds on earlier compilations of geochemical data (2007, 2010), referred to a geochemical data packages. This work is being conducted as part of the on-going maintenance program of the SRS PA programs that periodically updates calculations and data packages when new information becomes available. Because application of values without full understanding of their original purpose may lead to misuse, this document also provides the geochemical conceptual model, the approach used for selecting the values, the justification for selecting data, and the assumptions made to assure that the conceptual and numerical geochemical models are reasonably conservative (i.e., bias the recommended input values to reflect conditions that will tend to predict the maximum risk to the hypothetical recipient). This document provides 1088 input parameters for geochemical parameters describing transport processes for 64 elements (>740 radioisotopes) potentially occurring within eight subsurface disposal or tank closure areas: Slit Trenches (ST), Engineered Trenches (ET), Low Activity Waste Vault (LAWV), Intermediate Level (ILV) Vaults, Naval Reactor Component Disposal Areas (NRCDA), Components-in-Grout (CIG) Trenches, Saltstone Facility, and Closed Liquid Waste Tanks. The geochemical parameters described here are the distribution coefficient, Kd value, apparent solubility concentration, k_s value, and the cementitious leachate impact factor.

Trace elements in tourmalines from massive sulfide deposits and tourmalinites: Geochemical controls and exploration applications

Science.gov (United States)

Griffin, W.L.; Slack, J.F.; Ramsden, A.R.; Win, T.T.; Ryan, C.G.

1996-01-01

Trace element contents of tourmalines from massive sulfide deposits and tourmalinites have been determined in situ by proton microprobe; >390 analyses were acquired from 32 polished thin sections. Concentrations of trace elements in the tourmalines vary widely, from Sr, Ba, and Ca). Base metal proportions in the tourmalines show systematic patterns on ternary Cu-Pb-Zn diagrams that correlate well with the major commodity metals in the associated massive sulfide deposits. For example, data for tourmalines from Cu-Zn deposits (e.g., Ming mine, Newfoundland) fall mainly on the Cu-Zn join, whereas those from Pb-Zn deposits (e.g., Broken Hill, Australia) plot on the Pb-Zn join; no data fall on the Cu-Pb join, consistent with the lack of this metal association in massive sulfide deposits. The systematic relationship between base metal proportions in the tourmalines and the metallogeny of the host massive sulfide deposits indicates that the analyzed tourmalines retain a strong chemical signature of their original hydrothermal formation, in spite of variable metamorphic recrystallization. Such trace element patterns in massive sulfide tourmalines may be useful in mineral exploration, specifically for the evaluation of tourmaline concentrations in rocks, soils, and stream sediments.

A study of element migration in the Maqarin site (Jordan) by the means of column experiments: II. trace elements (Cr, Se, Mo, Re)

International Nuclear Information System (INIS)

Trotignon, L.; Bienvenu, P.; Provitina, O.; Rose, J.; Khoury, H.; Trocellier, P.; Mercier, F.; Raimbault, L.

2005-01-01

Full text of publication follows: The site of Maqarin (Jordan), in which natural cements occur as a result of the combustion metamorphism of a bio-micrite, is studied since 1989 as a natural analogue for the long term evolution of a cementitious repository environment [1]. Several trace elements of interest (Cr, Se, Mo, Re) are mobilized on this site by percolating groundwaters and migrate along high pH plumes. Laboratory scale column experiments were conducted in which crushed materials (cement, bio-micrite) collected on site were submitted to leaching by deionized water or Ca(OH) 2 equilibrated solutions. The evolution of Cr, Mo, Se and Re was monitored in leachates during the experiments. Characterizations of the solid phase using several techniques were also conducted in order to locate these elements in the mineral phases. Comparison of experimental data with records of trace element concentration in Maqarin groundwaters gives some insight on Re, Cr, Se and Mo sources and sinks in this environment. Both the imprint of the past combustion event and present day redox transformations explain several features of the datasets. However, due to the high complexity of the cements, in which trace elements are often distributed among several mineral phases, it is presently not possible to link in a straightforward way individual mineral dissolution processes and trace element signals in waters. [1] Khoury H. N., Salameh E., Clark I. D., Fritz P., Bajjali W., Milodowski A. E., Cave M. R. and Alexander W. R. 1992. A natural analogue of high pH cement pore waters from the Maqarin area of northern Jordan. I: Introduction to the site. J. Geochem. Explor. 46: 117-132. (authors)

Maceral and geochemical characteristics of oil shale 2 from the Huangxian Basin, China

Energy Technology Data Exchange (ETDEWEB)

Sun, Yuzhuang; Lin, Mingyue; Li, Haimei; Zhang, Hongjian; Li, Shifeng; Jin, Kankun [Hebei Architectural Science and Technology Inst., Handan, Hebei (China)

2001-07-01

Five samples of Oil Shale 2 from the Huangxian Basin have been analysed by coal petrographic and geochemical methods in order to study its formation environment. Higher alginite ratios and hopanes in Oil Shale 2 indicate a lower plants and anoxic environment. Two ternary diagrams of 'facies diagnostic' macerals and biomarkers were used to interpret the depositional environments of organic matter in Oil Shale 2. In both diagrams, Oil Shale 2 plots in a lower plant zone, and was deposited in a deeper water environment. (Author)

Metal and trace element assessment of estuary sediments from Santos, Brazil, by neutron activation and atomic absorption techniques

International Nuclear Information System (INIS)

Amorim, Eduardo P.; Favaro, Deborah I.T.; Berbel, Glaucia B.B.; Braga, Elisabete S.

2007-01-01

In order to better understanding geochemical and environmental processes and their possible changes due to anthropogenic activities trace metal analyses and their distribution in marine sediments are commonly undertaken. The present study reports result concerning the distribution of some major, trace and rare earth elements in the Santos estuarine marine sediments. Thirteen bottom sediment samples (SV0501 to SV0513) were collected in this estuary, including regions of Sao Vicente, Santos, Cubatao, Vicente de Carvalho and Santos' Bay, in the summer of 2005. Multielemental analysis was carried out by instrumental neutron activation analysis (INAA). For total mercury determination cold vapor atomic absorption technique (CV AAS) was employed. In both cases methodology validation was performed by certified reference material analyses. The results obtained for multielemental concentrations in the sediment samples were compared with NASC (North American Shale Composite) values. The concentration values obtained for As and metals Cr, Hg and Zn in the sediment samples were compared to Canadian Council of Minister of the Environment (CCME) oriented values (TEL and PEL values). In general, the samples located near the Cubatao region showed higher concentrations for all elements analyzed probably due to the high impact of industrial activities. (author)

Metal and trace element assessment of estuary sediments from Santos, Brazil, by neutron activation and atomic absorption techniques

Energy Technology Data Exchange (ETDEWEB)

Amorim, Eduardo P.; Favaro, Deborah I.T. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mails: ducamorim@yahoo.com.br; defavaro@ipen.br; Berbel, Glaucia B.B.; Braga, Elisabete S. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. Oceanografico. Lab. de Nutrientes, Micronutrientes e Tracos nos Oceanos - LABNUT]. E-mail: edsbraga@usp.br

2007-07-01

In order to better understanding geochemical and environmental processes and their possible changes due to anthropogenic activities trace metal analyses and their distribution in marine sediments are commonly undertaken. The present study reports result concerning the distribution of some major, trace and rare earth elements in the Santos estuarine marine sediments. Thirteen bottom sediment samples (SV0501 to SV0513) were collected in this estuary, including regions of Sao Vicente, Santos, Cubatao, Vicente de Carvalho and Santos' Bay, in the summer of 2005. Multielemental analysis was carried out by instrumental neutron activation analysis (INAA). For total mercury determination cold vapor atomic absorption technique (CV AAS) was employed. In both cases methodology validation was performed by certified reference material analyses. The results obtained for multielemental concentrations in the sediment samples were compared with NASC (North American Shale Composite) values. The concentration values obtained for As and metals Cr, Hg and Zn in the sediment samples were compared to Canadian Council of Minister of the Environment (CCME) oriented values (TEL and PEL values). In general, the samples located near the Cubatao region showed higher concentrations for all elements analyzed probably due to the high impact of industrial activities. (author)

Investigation of trace elements in Guangxi ancient pottery by INAA

International Nuclear Information System (INIS)

Peng Zicheng; Sun Weidong; Huang Yunlan

1997-01-01

Guangxi Zhuang Nationality Autonomous Region is an original place for manufacture of ancient pottery in China since Zenpiyan site, dated 9240-10370 years ago, was excavated. Contents of trace elements La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, U, Th, Sc, Ta, Ba, Cs, Rb, Sr and Zr in 44 pottery shards from Guangxi sites, dated from 1450 B.C. to 200 A.D., were determined by INAA and XRF. The provenances of the 44 samples are postulated by the analyses of geochemical parameters

Landscape and bio- geochemical strategy for monitoring transformation and reclamation of the soil mining sites

Science.gov (United States)

Korobova, Elena

2010-05-01

Sites of active or abandoned mining represent areas of considerable technogenic impact and need scientifically ground organization of their monitoring and reclamation. The strategy of monitoring and reclamation depends on the scale and character of the physical, chemical and biological consequences of the disturbances. The geochemical studies for monitoring and rehabilitation of the career-dump complexes should methodically account of formation of the particular new landforms and the changes in circulation of the remobilized elements of the soil cover. However, the general strategy should account of both the initial and transformed landscape geochemical structure of the area with due regard to the natural and new content of chemical elements in the environmental components. For example the tailings and waste rocks present new geochemical fields with specifically different concentration of chemical elements that cause formation of new geochemical barriers and landscapes. The way of colonization of the newly formed landscapes depends upon the new geochemical features of the technogenic environment and the adaptive ability of local and intrusive flora. The newly formed biogeochemical anomalies need organization of permanent monitoring not only within the anomaly itself but also of its impact zones. Spatial landscape geochemical monitoring combined with bio-geochemical criteria of threshold concentrations seems to be a helpful tool for decision making on reclamation and operation of the soil mining sites to provide a long-term ecologically sustainable development of the impact zone as a whole.

Tectonic origin of serpentinites on Syros, Greece: Geochemical signatures of abyssal origin preserved in a HP/LT subduction complex

Science.gov (United States)

Cooperdock, Emily H. G.; Raia, Natalie H.; Barnes, Jaime D.; Stockli, Daniel F.; Schwarzenbach, Esther M.

2018-01-01

This study combines whole rock trace and major element geochemistry, and stable isotope (δD and δ18O) analyses with petrographic observations to deduce the origin and tectonic setting of serpentinization of ultramafic blocks from the exhumed HP/LT Aegean subduction complex on Syros, Greece. Samples are completely serpentinized and are characterized by mineral assemblages that consist of variable amounts of serpentine, talc, chlorite, and magnetite. δD and δ18O values of bulk rock serpentinite powders and chips (δD = - 64 to - 33‰ and δ18O = + 5.2 to + 9.0‰) reflect hydration by seawater at temperatures serpentinization by seawater, followed by secondary fluid-rock interactions with a sedimentary source pre- or syn-subduction. Whole rock major element, trace element, and REE analyses record limited melt extraction, exhibit flat REE patterns, and do not show pronounced Eu anomalies. The geochemical signatures preserved in these serpentinites argue against a mantle wedge source, as has been previously speculated for ultramafic rocks on Syros. Rather, the data are consistent with derivation from abyssal peridotites in a hyper-extended margin setting or mid-ocean ridge and fracture zone environment. In either case, the data suggest an extensional and/or oceanic origin associated with the Cretaceous opening of the Pindos Ocean and not a subduction-related derivation from the mantle wedge.

Geochemical of trace elements in volcanics rocks Peninsula Fildes, Fildes Bay Rey Jorge island, south Shetland

International Nuclear Information System (INIS)

Masquelin, H.; Vaz Chavez, N.

1987-01-01

The authors present some geochemical data derived from the multielement analysis of three different types of volcanic rocks collected around Fildes Bay on King George Island, South Shetland. Volcanic rocks from Fildes Peninsula Group may be distinguished from those Marian Cove by their hydrothermal alteration. Apparently the correlation between NI ands Cr allows for the observation of the stratigraphic separation of samples of the same kind. Consequently, the correlation between Cu and As show a distinction between Marian Cove propylitised tuffites and both Brecciated Andesites and pyroclastic rock from Fildes Peninsula Group.

Hydrological and geochemical investigation on the volcanic rock and gneissic rock area

Energy Technology Data Exchange (ETDEWEB)

Koh, Yong Kwon; Jeong, Chan Ho; Ryu, Kun Seok; Kim, Byoung Yeop; Park, Hyung Kun; Yu, Sang Woo; Jang, Hyu Kun; Lee, Suk Chi; Choi, Ki Young; Jeon, Hyu Woong; Kim, Do Hyoung [Daejong University, Daejeon (Korea, Republic of)

2010-01-15

The purpose of this study is to supply the basic data and optimum study site among volcanic rock area and gneissic rock area for high-level radioactive waste disposal. For this purpose, geological, hydrogeological and geochemical data from previously published literatures were collected and analyzed. In this study, we selected 36 volcanic rock sites and 26 gneissic sites as the candidate sites for high level radwaste disposal. Finally, for four sites(M-1, M-13, V-1 and V-13 sites) were selected as the study sites. The geochemical characteristics of groundwaters of each study site were statistically analyzed. The nitrate contamination and the sea water mixing will be important factors on the assessment of behaviour of radionuclides under groundwater environment. From the deep geothermal study, alkaline and sodium-bicarbonate chemical environment, and sea water mixing should be considered as the key factors for the deep disposal of high-level radioactive waste

Fate of nine recycled water trace organic contaminants and metal(loid)s during managed aquifer recharge into a anaerobic aquifer: Column studies.

Science.gov (United States)

Patterson, B M; Shackleton, M; Furness, A J; Pearce, J; Descourvieres, C; Linge, K L; Busetti, F; Spadek, T

2010-03-01

Water quality changes associated with the passage of aerobic reverse osmosis (RO) treated recycled water through a deep anaerobic pyritic aquifer system was evaluated in sediment-filled laboratory columns as part of a managed aquifer recharge (MAR) strategy. The fate of nine recycled water trace organic compounds along with potential negative water quality changes such as the release of metal(loid)s were investigated in large-scale columns over a period of 12 months. The anaerobic geochemical conditions provided a suitable environment for denitrification, and rapid (half-life 100 days). High retardation coefficients (R) determined for many of the trace organics (R 13 to 67) would increase aquifer residence time and be beneficial for many of the slow degrading compounds. However, for the trace organics with low R values (1.1-2.6) and slow degradation rates (half-life > 100 days), such as N-nitrosodimethylamine, N-nitrosomorpholine and iohexol, substantial biodegradation during aquifer passage may not occur and additional investigations are required. Only minor transient increases in some metal(loid) concentrations were observed, as a result of either pyrite oxidation, mineral dissolution or pH induced metal desorption, followed by metal re-sorption downgradient in the oxygen depleted zone. Crown Copyright 2009. Published by Elsevier Ltd. All rights reserved.

Geochemical factors in borehole-shaft plug longevity

International Nuclear Information System (INIS)

Roy, D.M.

1981-01-01

Geochemical investigations that address factors controlling the longevity of repository sealing materials in a geochemical environment are discussed. Studies are being made of cement-based materials as major candidates for seals for borehole plugging, and shaft and tunnel sealing in certain potential repository environments. Factors controlling the extent of attainment of equilibrium of the plug components with time and the rate of approach to a state of stable equilibrium of the plug component chemical subsystem within the total system are discussed. The effect of these factors on changes in physical, mechanical and thermal properties of a seal system, and the consequent effectiveness of the seal in preventing transport of radioactive waste species are the dominant features to be determined. Laboratory experiments on the effects of anticipated temperature, pressure, and environmental factors (including chemical composition and specific rock type) are described. Thermodynamic studies are used to determine the potentially stable reaction products under conditions similar to those anticipated for the repository boreholes, shafts, and tunnels during and after the operating stage. Multitemperature reaction series are studied, and reaction kinetics are investigated for the purpose of predicting the course of likely reactions. Detailed studies of permeability, diffusion, and interfacial properties and chemical and microphase characterization of the products of experiments are carried out. Characterization studies of old and ancient cements, mortars, and concretes and prototype man-made seal materials are performed to further assess the factors associated with longevity

Trace elements distribution in environmental compartments

Energy Technology Data Exchange (ETDEWEB)

Queiroz, Juliana C. de; Peres, Sueli da Silva; Godoy, Maria Luiza D.P., E-mail: suelip@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-11-01

Trace elements term defines the presence of low concentrations metals at environment. Some of them are considered biologically essential, as Co, Cu and Mn. Others can cause detriment to environment and human health, as Pb, Cd, Hg, As, Ti and U. A large number of them have radioactive isotopes, implying the evaluation of risks for human health should be done considering the precepts of environmental radiological protection. The ecosystem pollution with trace elements generates changes at the geochemistry cycle of these elements and in environmental quality. Soils have single characteristics when compared with another components of biosphere (air, water and biota), cause they introduce themselves not only as a drain towards contaminants, but also as natural buffer that control the transport of chemical elements and other substances for atmosphere, hydrosphere and biota. The main purpose of environmental monitoring program is to evaluate the levels of contaminants in the various compartments of the environment: natural or anthropogenic, and to assess the contribution of a potential contaminant source on the environment. Elemental Composition for the collected samples was determined by inductively coupled plasma mass spectroscopy. The main objective of this work was to evaluate the map baseline of concentration of interest trace elements in environmental samples of water, sediment and soil from Environmental Monitoring Program of Instituto de Radioprotecao e Dosimetria (IRD). The samples were analyzed using an inductively coupled plasma mass spectrometer (ICP-MS) at IRD. >From the knowledge of trace elements concentrations, could be evaluated the environmental quality parameters at the studied ecosystems. The data allowed evaluating some relevant aspects of the study of trace elements in soil and aquatic systems, with emphasis at the distribution, concentration and identification of main anthropic sources of contamination at environment. (author)

Trace elements distribution in environmental compartments

International Nuclear Information System (INIS)

Queiroz, Juliana C. de; Peres, Sueli da Silva; Godoy, Maria Luiza D.P.

2017-01-01

Trace elements term defines the presence of low concentrations metals at environment. Some of them are considered biologically essential, as Co, Cu and Mn. Others can cause detriment to environment and human health, as Pb, Cd, Hg, As, Ti and U. A large number of them have radioactive isotopes, implying the evaluation of risks for human health should be done considering the precepts of environmental radiological protection. The ecosystem pollution with trace elements generates changes at the geochemistry cycle of these elements and in environmental quality. Soils have single characteristics when compared with another components of biosphere (air, water and biota), cause they introduce themselves not only as a drain towards contaminants, but also as natural buffer that control the transport of chemical elements and other substances for atmosphere, hydrosphere and biota. The main purpose of environmental monitoring program is to evaluate the levels of contaminants in the various compartments of the environment: natural or anthropogenic, and to assess the contribution of a potential contaminant source on the environment. Elemental Composition for the collected samples was determined by inductively coupled plasma mass spectroscopy. The main objective of this work was to evaluate the map baseline of concentration of interest trace elements in environmental samples of water, sediment and soil from Environmental Monitoring Program of Instituto de Radioprotecao e Dosimetria (IRD). The samples were analyzed using an inductively coupled plasma mass spectrometer (ICP-MS) at IRD. >From the knowledge of trace elements concentrations, could be evaluated the environmental quality parameters at the studied ecosystems. The data allowed evaluating some relevant aspects of the study of trace elements in soil and aquatic systems, with emphasis at the distribution, concentration and identification of main anthropic sources of contamination at environment. (author)

Trace elemental analysis of bituminous coals using the Heidelberg proton microprobe

Energy Technology Data Exchange (ETDEWEB)

Chen, J R; Kneis, H; Martin, B; Nobiling, R; Traxel, K [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany, F.R.); Heidelberg Univ. (Germany, F.R.). Physikalisches Inst.); Chao, E C.T.; Minkin, J A [Geological Survey, Reston, VA (USA)

1981-03-01

Trace elements in coal can occur as components of either the organic constituents (macerals) or the inorganic constituents (minerals). Studies of the concentrations and distribution of the trace elements are vital to understanding the geochemical milieu in which the coal was formed and in evaluating the attempts to recover rare but technologically valuable metals. In addition, information on the trace element concentrations is important in predicting the environmental impact of burning particular coals, as many countries move toward greater utilization of coal reserves for energy production. Traditionally, the optical and the electron microscopes and more recently the electron microprobe have been used in studying the components of coal. The proton-induced X-ray emission (PIXE) microprobe offers a new complementary approach with an order of magnitude or more better minimum detection limit. We present the first measurements with a PIXE microprobe of the trace element concentrations of bituminous coal samples. Elemental analyses of the coal macerals-vitrinite, exinite, and inertinite - are discussed for three coal samples from the Eastern U.S.A., three samples from the Western U.S.A., and one sample from the Peoples Republic of China.

Trace element partitioning between ilmenite, armalcolite and anhydrous silicate melt: Implications for the formation of lunar high-Ti mare basalts

NARCIS (Netherlands)

Kan Parker, M. van; Mason, P.R.D.; Westrenen, W. van

2011-01-01

We performed a series of experiments at high pressures and temperatures to determine the partitioning of a wide range of trace elements between ilmenite (Ilm), armalcolite (Arm) and anhydrous lunar silicate melt, to constrain geochemical models of the formation of titanium-rich melts in the Moon.

Indications of a major Neolithic trade route? An archaeometric geochemical and Sr, Pb isotope study on amphibolitic raw material from present day Europe

International Nuclear Information System (INIS)

Christensen, A.-M.; Holm, P.M.; Schuessler, U.; Petrasch, J.

2006-01-01

In order to interpret pre-historic cultural interactions, the provenance of amphibolitic raw material used for flat-axes and adzes in lower to middle Neolithic cultures throughout present day Germany were investigated by elemental and Sr, Pb isotopic methods. Within all settlements studied, a homogeneous actinolite-hornblende schist rock type (AHS) was found to be massively dominating, with a distinct petrography of needle-shaped actinolite interwoven with single larger grains of hornblende along with calcic plagioclase and large amounts of ilmenite. Geochemically, the AHS group is very homogeneous and has a signature of an enriched basaltic precursor with high concentrations of particularly the LIL-elements. The geochemical signature is relatively rare and can not be matched in nearby geological outcrops, wherefore the conclusion of 'imported material' is quickly reached. Strontium and Pb isotopic analyses of the AHS were compared to the isotopic composition of amphibolitic rocks with similar petrography and trace elemental signatures within possible archaeological trade regions. The isotopic data of the archaeological material point roughly to a Proterozoic age of the stone used; an age which can be reasonable matched to a single outcrop situated at Jistebsko within the Czech Republic. This area further shows archaeological traces of prehistoric mining. Based on petrographic, geochemical and isotopic evidence, this area is here presented as the provenance area of the stone raw material, which later spread throughout prehistoric Europe - establishing contact and trade routes between Neolithic cultures

Reconnaissance geochemical survey for uranium and related industrial minerals in Cebu Island

International Nuclear Information System (INIS)

Reyes, R.Y.; Ramos, A.F.; Magsambol, W.N.; Hernandez, E.

1989-03-01

Consistent with the program of evaluating the nuclear mineral resource potential and related industrial minerals of the Philippines, a reconnaissance geochemical survey was conducted in Cebu with considerable success. The total area covered by the survey was about 5,088 sq. kms. The survey consisted of systematic collection of 857 geochemical stream and water and heavy mineral samples, and measurement of radioactivity in over 352 stations. The average sampling density was about one set of samples per 15 to 30 sq. kms. All solid samples were analyzed for U, Cu, Pb, Zn, Mn, Ag, Co and Ni. Uranium, radon and conductivity were measured on most water samples collected. A total of 4,518 elemental determinations were involved. All field and analytical data were treated by statistics, and the computed parameters data were correlated with the geology of the area to establish anomalous zones. Four areas were delineated for possible uranium mineralization. Of the areas, the Mandaue river area is the most interesting for uranium. The contact zone between the diorite and the sedimentary rocks in this area appears to be a favorable geological environment for uranium mineralization. The other anomalous uranium values were found to be related with the guano and phosphate deposits. Uranium was also shown to be independent of the other seven elements in the geologic environment of Cebu. No definite elemental association could be established at present. This study also marks the thorough utilization of Q'GAS, Cadplot and Autocad, all microcomputer-based programs/systems, in the evaluation and interpretation of exploration-oriented geochemical and geological data, and with more significance in the sense that computer generated quality geochemical maps were produced, a first in the country. (Author). Appendices (23); 23 figs; 13 refs.; 4 tabs

Present and Future Challenges in Trace and Ultra-Trace Analysis

International Nuclear Information System (INIS)

Toulhoat, P.

2005-01-01

The analysis of trace and ultra-trace elements is continuously stimulating the progress in analytical chemistry. Environmental chemistry, radiochemistry, biology, health, agri-food are prescribers of trace analyses, with continuously increasing exigencies: lowering detection limits, lowering costs and analysis time, improving the quality of analytical information. Precise data about the chemical identity and chemical environment of analytes are now requested. Such pieces of information, beyond simple numerical data and confidence intervals, are necessary to understand studied systems, and to predict their evolution. From environmental contamination cases, one can envisage the various aspects of a problem, with for each of them its own exigencies and specificities in terms of analytical methods and approaches. The detection of traces and ultra-traces of actinides and fission products has been recently revisited and stimulates new technological developments (non proliferation issues, waste management). Data on their speciation in geological and biological media are essential for evaluating the safety of nuclear waste repositories. Various techniques are now used to determine speciation in liquid samples or on surfaces, with tremendous spatial resolutions or sensitivities. A new revolution in analytical chemistry is expected with the development of micro- or nano-analytical technologies. (author)

Hydro-geochemical modeling of subalpine urbanized area: geochemical characterization of the shallow and deep aquifers of the urban district of Como (first results).

Science.gov (United States)

Terrana, Silvia; Brunamonte, Fabio; Frascoli, Francesca; Ferrario, Maria Francesca; Michetti, Alessandro Maria; Pozzi, Andrea; Gambillara, Roberto; Binda, Gilberto

2016-04-01

One of the greatest environmental and social-economics threats is climate change. This topic, in the next few years, will have a significant impact on the availability of water resources of many regions. This is compounded by the strong anthropization of water systems that shows an intensification of conflicts for water resource exploitation. Therefore, it is necessary a sustainable manage of natural resources thorough knowledge of the hosting territories. The development of investigation and data processing methods are essential to reduce costs for the suitable use and protection of resources. Identify a sample area for testing the best approach is crucial. This research aims to find a valid methodology for the characterization, modeling and management of subalpine urban aquifers, and the urban district of Como appears perfect. The city of Como is located at the southern end of the western sector of Lake Como (N Italy). It is a coastal town, placed on a small alluvial plain, therefore in close communication with the lake. The plain is drained by two streams, which are presently artificially buried, and have an underground flow path in the urban section till the mouth. This city area, so, is suitable for this project as it is intensely urbanized, its dimensions is not too extensive and it is characterized by two aquifers very important and little known. These are a shallow aquifer and a deep aquifer, which are important not only for any water supply, but also for the stability of the ground subsidence in the city. This research is also the opportunity to work in a particular well-known area with high scientific significance; however, there is complete absence of information regarding the deep aquifer. Great importance has also the chosen and used of the more powerful open source software for this type of area, such as PHREEQC, EnvironInsite, PHREEQE etc., used for geological and geochemical data processing. The main goal of this preliminary work is the

The Fate of Trace Contaminants in a Crewed Spacecraft Cabin Environment

Science.gov (United States)

Perry, Jay L.; Kayatin, Matthew J.

2016-01-01

Trace chemical contaminants produced via equipment offgassing, human metabolic sources, and vehicle operations are removed from the cabin atmosphere by active contamination control equipment and incidental removal by other air quality control equipment. The fate of representative trace contaminants commonly observed in spacecraft cabin atmospheres is explored. Removal mechanisms are described and predictive mass balance techniques are reviewed. Results from the predictive techniques are compared to cabin air quality analysis results. Considerations are discussed for an integrated trace contaminant control architecture suitable for long duration crewed space exploration missions.

Geochemical modeling of reactions and partitioning of trace metals and radionuclides during titration of contaminated acidic sediments.

Science.gov (United States)

Zhang, Fan; Luo, Wensui; Parker, Jack C; Spalding, Brian P; Brooks, Scott C; Watson, David B; Jardine, Philip M; Gu, Baohua

2008-11-01

Many geochemical reactions that control aqueous metal concentrations are directly affected by solution pH. However, changes in solution pH are strongly buffered by various aqueous phase and solid phase precipitation/dissolution and adsorption/desorption reactions. The ability to predict acid-base behavior of the soil-solution system is thus critical to predict metal transport under variable pH conditions. This studywas undertaken to develop a practical generic geochemical modeling approach to predict aqueous and solid phase concentrations of metals and anions during conditions of acid or base additions. The method of Spalding and Spalding was utilized to model soil buffer capacity and pH-dependent cation exchange capacity by treating aquifer solids as a polyprotic acid. To simulate the dynamic and pH-dependent anion exchange capacity, the aquifer solids were simultaneously treated as a polyprotic base controlled by mineral precipitation/ dissolution reactions. An equilibrium reaction model that describes aqueous complexation, precipitation, sorption and soil buffering with pH-dependent ion exchange was developed using HydroGeoChem v5.0 (HGC5). Comparison of model results with experimental titration data of pH, Al, Ca, Mg, Sr, Mn, Ni, Co, and SO4(2-) for contaminated sediments indicated close agreement suggesting that the model could potentially be used to predictthe acid-base behavior of the sediment-solution system under variable pH conditions.

Using geochemical indicators to distinguish high biogeochemical activity in floodplain soils and sediments

Energy Technology Data Exchange (ETDEWEB)

Kenwell, Amy [Hydrologic Sciences and Engineering Program, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401 (United States); Navarre-Sitchler, Alexis, E-mail: asitchle@mines.edu [Hydrologic Sciences and Engineering Program, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401 (United States); Prugue, Rodrigo [Hydrologic Sciences and Engineering Program, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401 (United States); Spear, John R. [Department of Civil and Environmental Engineering, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401 (United States); Hering, Amanda S. [Department of Applied Mathematics and Statistics, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401 (United States); Maxwell, Reed M. [Hydrologic Sciences and Engineering Program, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401 (United States); Carroll, Rosemary W.H. [Desert Research Institute, Division of Hydrologic Sciences, 2215 Raggio Parkway, Reno, NV 89512 (United States); Williams, Kenneth H. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

2016-09-01

A better understanding of how microbial communities interact with their surroundings in physically and chemically heterogeneous subsurface environments will lead to improved quantification of biogeochemical reactions and associated nutrient cycling. This study develops a methodology to predict potential elevated rates of biogeochemical activity (microbial “hotspots”) in subsurface environments by correlating microbial DNA and aspects of the community structure with the spatial distribution of geochemical indicators in subsurface sediments. Multiple linear regression models of simulated precipitation leachate, HCl and hydroxylamine extractable iron and manganese, total organic carbon (TOC), and microbial community structure were used to identify sample characteristics indicative of biogeochemical hotspots within fluvially-derived aquifer sediments and overlying soils. The method has been applied to (a) alluvial materials collected at a former uranium mill site near Rifle, Colorado and (b) relatively undisturbed floodplain deposits (soils and sediments) collected along the East River near Crested Butte, Colorado. At Rifle, 16 alluvial samples were taken from 8 sediment cores, and at the East River, 46 soil/sediment samples were collected across and perpendicular to 3 active meanders and an oxbow meander. Regression models using TOC and TOC combined with extractable iron and manganese results were determined to be the best fitting statistical models of microbial DNA (via 16S rRNA gene analysis). Fitting these models to observations in both contaminated and natural floodplain deposits, and their associated alluvial aquifers, demonstrates the broad applicability of the geochemical indicator based approach. - Highlights: • Biogeochemical characterization of alluvial floodplain soils and sediments was performed to investigate parameters that may indicate microbial hot spot formation. • A correlation between geochemical parameters (total organic carbon and

Using geochemical indicators to distinguish high biogeochemical activity in floodplain soils and sediments

International Nuclear Information System (INIS)

Kenwell, Amy; Navarre-Sitchler, Alexis; Prugue, Rodrigo; Spear, John R.; Hering, Amanda S.; Maxwell, Reed M.; Carroll, Rosemary W.H.; Williams, Kenneth H.

2016-01-01

A better understanding of how microbial communities interact with their surroundings in physically and chemically heterogeneous subsurface environments will lead to improved quantification of biogeochemical reactions and associated nutrient cycling. This study develops a methodology to predict potential elevated rates of biogeochemical activity (microbial “hotspots”) in subsurface environments by correlating microbial DNA and aspects of the community structure with the spatial distribution of geochemical indicators in subsurface sediments. Multiple linear regression models of simulated precipitation leachate, HCl and hydroxylamine extractable iron and manganese, total organic carbon (TOC), and microbial community structure were used to identify sample characteristics indicative of biogeochemical hotspots within fluvially-derived aquifer sediments and overlying soils. The method has been applied to (a) alluvial materials collected at a former uranium mill site near Rifle, Colorado and (b) relatively undisturbed floodplain deposits (soils and sediments) collected along the East River near Crested Butte, Colorado. At Rifle, 16 alluvial samples were taken from 8 sediment cores, and at the East River, 46 soil/sediment samples were collected across and perpendicular to 3 active meanders and an oxbow meander. Regression models using TOC and TOC combined with extractable iron and manganese results were determined to be the best fitting statistical models of microbial DNA (via 16S rRNA gene analysis). Fitting these models to observations in both contaminated and natural floodplain deposits, and their associated alluvial aquifers, demonstrates the broad applicability of the geochemical indicator based approach. - Highlights: • Biogeochemical characterization of alluvial floodplain soils and sediments was performed to investigate parameters that may indicate microbial hot spot formation. • A correlation between geochemical parameters (total organic carbon and

Geochemical Investigations of Groundwater Stability

Energy Technology Data Exchange (ETDEWEB)

Bath, Adrian [Intellisci Ltd., Loughborough (United Kingdom)

2006-05-15

groundwaters, and also by stable isotopes and uranium isotopes in secondary minerals. Information on timing of water and solute movements is important because it indicates any correlation with the timing of external events that might have perturbed and destabilised the groundwater system in the past, and allows a timescale to be estimated for the persistence of stable conditions. Data from a number of published site investigation projects and research programmes are reviewed to illustrate the patterns of geochemical data and the relationships between them, and how these are interpreted in terms of hydrodynamic stability. Data from Aespoe and Stripa and from exploratory boreholes at Finnsjoen and other sites in Sweden are compiled and discussed. Preliminary data from SKB's ongoing site investigations at Simpevarp/Laxemar and Forsmark are not considered in detail but their general similarities with Aespoe and Finnsjoen/SFR respectively are introduced into the discussion of geochemical evidence for groundwater stability in inland and coastal areas. Relevant data from Finnish sites including Olkiluoto, from the Whiteshell URL area in Canada, from Sellafield in the UK, and from the Tono area and URL in Japan are also summarised in appendices and discussed because they add further insights into the interpretation of geochemical indicators for a range of geological environments. The compiled data provide only limited scope for comparison of groundwater evolution and stability between inland and coastal areas in Sweden, because of the patchiness of representative data especially from early site studies. The external changes that might have perturbed stable groundwater conditions in the past are glaciation (i.e. melt water, mechanical loading/unloading and permafrost) and varying sea water infiltration at coastal sites due to changes in palaeo-Baltic and isostatic conditions. The present distributions of palaeo-Baltic sea water in groundwaters at coastal sites vary, reflecting

Some geochemical considerations for a potential repository site in tuff at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Erdal, B.R.; Bish, D.L.; Crowe, B.M.; Daniels, W.R.; Ogard, A.E.; Rundberg, R.S.; Vaniman, D.T.; Wolfsberg, K.

1982-01-01

The Nevada Nuclear Waste Storage Investigations, which is evaluating potential locations for a high-level waste repository at the Nevada Test Site and environs, is currently focusing its investigations on tuff, principally in Yucca Mountain, as a host rock. This paper discusses some of the geochemical investigations. Particular emphasis is placed on definition of some basic elements and necessary technical approaches for the geochemistry data acquisition and modeling program. Some site-specific tuff geochemical information that is important for site selection and repository performance will be identified and the current status of knowledge will then be discussed

Geochemical analysis of Minho Estuary sedimentary record and its contribution to palaeoenvironmental evolution

International Nuclear Information System (INIS)

Ivarez-Iglesias, P. A.

2009-01-01

Two sediment cores (∼30 m long) were retrieved at the mouth of the Minho Estuary to assess its palaeoenvironmental evolution for the last millennia. Samples were characterized by Energy-Dispersive X-Ray Fluorescence Spectrometry and Instrumental Neutron Activation Analysis, complemented by sedimentological analyses. Provenance of major and trace element contents (lithogenic or biogenic, continental or marine) is assessed. The influence of grain size effect on total element concentration is discussed. Most of the samples present a negative Eu anomaly. Sedimentological and geochemical parameters allow differentiating four geological units - fluvial, marine, estuarine and sand barrier - which reflects the temporal evolution of the Minho Estuary. (author)

Behaviour of trace element concentration in human organs in dependence of age and environment

International Nuclear Information System (INIS)

Persigehl, M.; Schicha, H.; Kasperek, K.; Feinendegen, L.E.; Kernforschungsanlage Juelich G.m.b.H.

1977-01-01

To study the behaviour of trace elements in dependence of age and environment, samples of skin, lung, heart, aorta, kidney, liver and brain were assayed for concentrations of Fe, Zn, Rb, Co, Cr, Se, Sc, Sb, Cs, Al and partly Eu. All samples were dried at 100 deg C for two days. Instrumental neutron-activation analysis was used to determine the element concentrations. The neutron flux was 5 x 10 13 n cm -2 sec -1 . After decay of the short lived radioisotopes, the Al-concentration was measured following a second irradiation of 1 minute and directly comparing with a standard sample. Nearly all element concentrations changed with processing age, but they showed no clear correlation to either parameter assessed. The non-essential elements Se, Sb and Sc were increasingly concentrated in all organs except the skin. Comparing lung samples of patients from highly industrialized regions with those of lesser industrialization, the elements Sc, Al, Sb, Eu and Co were accumulated by a factor of 10 to 100. Thus the concentrations of trace elements in human organism also depend on the degree of industrialization. (T.G.)

MINTEQ, Geochemical Equilibria in Ground Water

International Nuclear Information System (INIS)

Krupka, K.M.

1990-01-01

1 - Description of program or function: MINTEQ is a geochemical program to model aqueous solutions and the interactions of aqueous solutions with hypothesized assemblages of solid phases. It was developed for the Environmental Protection Agency to perform the calculations necessary to simulate the contact of waste solutions with heterogeneous sediments or the interaction of ground water with solidified wastes. MINTEQ can calculate ion speciation/solubility, adsorption, oxidation-reduction, gas phase equilibria, and precipitation/dissolution of solid phases. MINTEQ can accept a finite mass for any solid considered for dissolution and will dissolve the specified solid phase only until its initial mass is exhausted. This ability enables MINTEQ to model flow-through systems. In these systems the masses of solid phases that precipitate at earlier pore volumes can be dissolved at later pore volumes according to thermodynamic constraints imposed by the solution composition and solid phases present. The ability to model these systems permits evaluation of the geochemistry of dissolved traced metals, such as low-level waste in shallow land burial sites. MINTEQ was designed to solve geochemical equilibria for systems composed of one kilogram of water, various amounts of material dissolved in solution, and any solid materials that are present. Systems modeled using MINTEQ can exchange energy and material (open systems) or just energy (closed systems) with the surrounding environment. Each system is composed of a number of phases. Every phase is a region with distinct composition and physically definable boundaries. All of the material in the aqueous solution forms one phase. The gas phase is composed of any gaseous material present, and structurally distinct solid forms a separate phase. 2 - Method of solution: MINTEQ applies the fundamental principles of thermodynamics to solve geochemical equilibria from a set of mass balance equations, one for each component. Because the

Geochemical and chronological characteristics of Xiangcaoping granite pluton in Miaoershan area

International Nuclear Information System (INIS)

Li Wuwei; Wang Gan; Chen Weifeng; Zhao Kuidong

2010-01-01

Xiangcaoping granite pluton is mainly composed of medium-macro grain porphyritic biotite. The age of signle zircon dated by SHRIMP U-Pb is 211 ± 2 Ma, which suggest s that this pluton was formed during Indosinan. The geochemical characteristics is A > CNK, trace elements spider chart is slightly oblique to the right, enriched in LREE and bears obvious negative Eu anomaly which is similar to that of the S-type granite in South China. High ("8"7Sr/"8"6Sr)_i and low ε_N_d (t) suggest that this pluton was derived from partial melting of middle maturity Precambrian basement rock, which was rich in uranium and had supplied enough U element to the formation of Xiangcaoping granite pluton. (authors)

The Nasca and Palpa geoglyphs: geophysical and geochemical data

Science.gov (United States)

Hartsch, Kerstin; Weller, Andreas; Rosas, Silvia; Reppchen, Gunter

2009-10-01

The Nasca geoglyphs in the stone desert in southern Peru are part of our world cultural heritage. These remarkable drawings have roused the interest of scientists from different disciplines. Here we report the results of integrated geophysical, petrophysical, mineralogical, and geochemical investigations of the geoglyphs at six test sites in the stone desert around Nasca and Palpa. The geomagnetic measurements revealed clear indications of subsurface structures that differ from the visible surface geoglyphs. The high-resolution geoelectrical images show unexpected resistivity anomalies underneath the geoglyphs down to a depth of about 2 m. Remarkable structures were revealed in both vertical and lateral directions. No evidence was found of geochemical or mineralogical alterations of the natural geogenic materials (desert pavement environment versus geoglyphs). Neither salts nor other mineral materials were used by the Nasca people to alter or prepare the surfaces of geoglyphs. This supports the hypothesis that the Nasca people simply removed stone material down to the natural hard pan horizon to create the geoglyphs.

The effects of sorting by aeolian processes on the geochemical characteristics of surface materials: a wind tunnel experiment

Science.gov (United States)

Wang, Xunming; Lang, Lili; Hua, Ting; Zhang, Caixia; Li, Hui

2018-03-01

The geochemical characteristics of aeolian and surface materials in potential source areas of dust are frequently employed in environmental reconstructions as proxies of past climate and as source tracers of aeolian sediments deposited in downwind areas. However, variations in the geochemical characteristics of these aeolian deposits that result from near-surface winds are currently poorly understood. In this study, we collected surface samples from the Ala Shan Plateau (a major potential dust source area in Central Asia) to determine the influence of aeolian processes on the geochemical characteristics of aeolian transported materials. Correlation analyses show that compared with surface materials, the elements in transported materials (e.g., Cu, As, Pb, Mn, Zn, Al, Ca, Fe, Ga, K, Mg, P, Rb, Co, Cr, Na, Nb, Si, and Zr) were subjected to significant sorting by aeolian processes, and the sorting also varied among different particle size fractions and elements. Variations in wind velocity were significantly correlated with the contents of Cr, Ga, Sr, Ca, Y, Nd, Zr, Nb, Ba, and Al, and with the Zr/Al, Zr/Rb, K/Ca, Sr/Ca, Rb/Sr, and Ca/Al ratios. Given the great variation in the geochemical characteristics of materials transported under different aeolian processes relative to those of the source materials, these results indicate that considerable uncertainty may be introduced to analyses by using surface materials to trace the potential source areas of aeolian deposits that accumulate in downwind areas.

The use of geochemical barriers for reducing contaminants emanating from uranium mill tailings

International Nuclear Information System (INIS)

Groffman, A.R.; Longmire, P.; Mukhopadhyay, B.; Downs, W.

1991-01-01

A problem facing the Department of Energy's Uranium Mill Tailings Remediation Action (UMTRA) Project is the contamination of local ground water by leachate emanating form the tailings piles. These fluids have a low pH and contain heavy metals and trace elements such as arsenic, molybdenum, nitrate, selenium, and uranium. In order to meet ground water standards low hydraulic conductivity covers are installed over the tailings embankment. in some cases it may be necessary to install a geochemical barrier down gradient from the tailings embankment in order to remove the hazardous constituents. By using geochemical barriers to reduce undesirable species form a contaminant plume, fluids emanating form beneath a repository can in effect be scrubbed before entering the water table. Materials containing adsorbing clays, iron oxyhydroxides and zeolites, and reducing materials such as coal and peat, are being used effectively to attenuate contaminants form uranium mill tailings. Experiments to directly determine attenuation capacities of selected buffer/adsorption materials were conducted in the laboratory. Batch leach tests were conducted in lieu of column tests when the hydraulic conductivity of materials was too low to use in columns and shales

Field-based tests of geochemical modeling codes: New Zealand hydrothermal systems

International Nuclear Information System (INIS)

Bruton, C.J.; Glassley, W.E.; Bourcier, W.L.

1993-12-01

Hydrothermal systems in the Taupo Volcanic Zone, North Island, New Zealand are being used as field-based modeling exercises for the EQ3/6 geochemical modeling code package. Comparisons of the observed state and evolution of the hydrothermal systems with predictions of fluid-solid equilibria made using geochemical modeling codes will determine how the codes can be used to predict the chemical and mineralogical response of the environment to nuclear waste emplacement. Field-based exercises allow us to test the models on time scales unattainable in the laboratory. Preliminary predictions of mineral assemblages in equilibrium with fluids sampled from wells in the Wairakei and Kawerau geothermal field suggest that affinity-temperature diagrams must be used in conjunction with EQ6 to minimize the effect of uncertainties in thermodynamic and kinetic data on code predictions

Efficient Time-Domain Ray-Tracing Technique for the Analysis of Ultra-Wideband Indoor Environments including Lossy Materials and Multiple Effects

Directory of Open Access Journals (Sweden)

F. Saez de Adana

2009-01-01

Full Text Available This paper presents an efficient application of the Time-Domain Uniform Theory of Diffraction (TD-UTD for the analysis of Ultra-Wideband (UWB mobile communications for indoor environments. The classical TD-UTD formulation is modified to include the contribution of lossy materials and multiple-ray interactions with the environment. The electromagnetic analysis is combined with a ray-tracing acceleration technique to treat realistic and complex environments. The validity of this method is tested with measurements performed inside the Polytechnic building of the University of Alcala and shows good performance of the model for the analysis of UWB propagation.

Geochemical prospecting for uranium and thorium deposits

International Nuclear Information System (INIS)

Boyle, R.W.

1980-01-01

A brief review of analytical geochemical prospecting methods for uranium and thorium is given excluding radiometric techniques, except those utilized in the determination of radon. The indicator (pathfinder) elements useful in geochemical surveys are listed for each of the types of known uranium and thorium deposits; this is followed by sections on analytical geochemical surveys based on rocks (lithochemical surveys), unconsolidated materials (pedochemical surveys), natural waters and sediments (hydrochemical surveys), biological materials (biogeochemical surveys) and gases (atmochemical surveys). All of the analytical geochemical methods are applicable in prospecting for thorium and uranium, particularly where radiometric methods fail due to attenuation by overburden, water, deep leaching and so on. Efficiency in the discovery of uranium and/or thorium orebodies is promoted by an integrated methods approach employing geological pattern recognition in the localization of deposits, analytical geochemical surveys, and radiometric surveys. (author)

Geochemistry of trace elements and REE in phosphate deposits of el Sibaiya west AREA, nile valley

International Nuclear Information System (INIS)

Aly, M.M.; Hussein, H.A.; Elkammar, A.A.; Mahdy, A.I.

1994-01-01

The present work deals essentially with the study of the geochemistry of trace elements and rare earth elements (REE s) patterns in the upper cretaceous phosphate deposit in El Sibaiya west area located on the western side of the River Nile. About 20 Km south from Esna town, upper Egypt. It was evident throughout this study that the average shale normalized pattern of six analyzed rare earth elements indicates that the phosphate deposits under study were deposited under marine environment. In addition some geochemical ratios such as Cl/Br and Na/Br have been proposed as indicators of the paleosalinity of the upper cretaceous tethys compared with the nowadays sea. Uranium equilibrium status of the studied phosphate deposits suggests a remarkably secondary enrichment at the lower horizon at the expense of the upper one due to downward leaching. Such secondary enrichment of uranium is thought to take place under oxidizing vadose conditions by the action of descending meteoric water. 6 fig., 4 tab

Geochemical Implications of CO2 Leakage Associated with Geologic Storage: A Review

Energy Technology Data Exchange (ETDEWEB)

Harvey, Omar R.; Qafoku, Nikolla; Cantrell, Kirk J.; Brown, Christopher F.

2012-07-09

Leakage from deep storage reservoirs is a major risk factor associated with geologic sequestration of carbon dioxide (CO2). Different scientific theories exist concerning the potential implications of such leakage for near-surface environments. The authors of this report reviewed the current literature on how CO2 leakage (from storage reservoirs) would likely impact the geochemistry of near surface environments such as potable water aquifers and the vadose zone. Experimental and modeling studies highlighted the potential for both beneficial (e.g., CO2 re sequestration or contaminant immobilization) and deleterious (e.g., contaminant mobilization) consequences of CO2 intrusion in these systems. Current knowledge gaps, including the role of CO2-induced changes in redox conditions, the influence of CO2 influx rate, gas composition, organic matter content and microorganisms are discussed in terms of their potential influence on pertinent geochemical processes and the potential for beneficial or deleterious outcomes. Geochemical modeling was used to systematically highlight why closing these knowledge gaps are pivotal. A framework for studying and assessing consequences associated with each factor is also presented in Section 5.6.

Source rock identification of sediments using trace element ratios and 13C isotope data - a case study from Pondicherry region

International Nuclear Information System (INIS)

Tirumalesh, K.; Kulkarni, U.P.; Singh, Gursharan; Ramakumar, K.L.; Chidambaram, S.

2012-01-01

Compositional characteristics of source rocks are generally well recorded in sedimentary deposits and provide valuable information about nature of source rocks even though weathering, physical sorting and deposition environment influence the sediment geochemistry. In this paper we report major, trace element and 13 C isotope data of cutting samples collected from Quaternary, Tertiary and Cretaceous formations in Pondicherry area. The distribution patterns and inter elemental correlations are used to identify source rock composition and carbon isotope compositions to understand the sediment deposition conditions. Mineralogy of the bulk sediment indicates presence of Quartz, K-feldspar, Calcite, Mg-calcite, Aragonite and Clay minerals. Compared to upper continental crust values most of these sediments show lower concentration of all elements except Ca and Zn at some depths. The depletion is probably associated with weathering of feldspar and removal of elements through solution. This also increases the proportion of quartz relative to source rock. The ratios of redox sensitive elements (Th/U) infer oxic weathering in shallow sediments. Elemental ratios (La/Sc, Th/Sc, Th/Cr, Th/Co) and ternary plots (La-Th-Sc and Th-Hf-Co) indicate contribution of felsic source rocks with varying degree of weathering. These plots also infer the inherent heterogeneity in the source rocks. Hafnium correlations with other trace elements suggest contribution of Tonalitic rocks in addition to granite to these sediments. The geochemical characteristics of the sediments are found to be similar to that of sediments belonging to similar geology in nearby regions. Presence of shallow marine condition during the sedimentation is inferred from the detrital index (DI) values, which is further supported by the presence of fibrous clay minerals in ESEM scans. This study also brings out the utility of δ 13 C information to reinforce the geochemical and mineralogical inferences. (author)

Statistical tables and charts showing geochemical variation in the Mesoproterozoic Big Creek, Apple Creek, and Gunsight formations, Lemhi group, Salmon River Mountains and Lemhi Range, central Idaho

Science.gov (United States)

Lindsey, David A.; Tysdal, Russell G.; Taggart, Joseph E.

2002-01-01

The principal purpose of this report is to provide a reference archive for results of a statistical analysis of geochemical data for metasedimentary rocks of Mesoproterozoic age of the Salmon River Mountains and Lemhi Range, central Idaho. Descriptions of geochemical data sets, statistical methods, rationale for interpretations, and references to the literature are provided. Three methods of analysis are used: R-mode factor analysis of major oxide and trace element data for identifying petrochemical processes, analysis of variance for effects of rock type and stratigraphic position on chemical composition, and major-oxide ratio plots for comparison with the chemical composition of common clastic sedimentary rocks.

Potential transformation of trace species including aircraft exhaust in a cloud environment. The `Chedrom model`

Energy Technology Data Exchange (ETDEWEB)

Ozolin, Y.E.; Karol, I.L. [Main Geophysical Observatory, St. Petersburg (Russian Federation); Ramaroson, R. [Office National d`Etudes et de Recherches Aerospatiales (ONERA), 92 - Chatillon (France)

1997-12-31

Box model for coupled gaseous and aqueous phases is used for sensitivity study of potential transformation of trace gases in a cloud environment. The rate of this transformation decreases with decreasing of pH in droplets, with decreasing of photodissociation rates inside the cloud and with increasing of the droplet size. Model calculations show the potential formation of H{sub 2}O{sub 2} in aqueous phase and transformation of gaseous HNO{sub 3} into NO{sub x} in a cloud. This model is applied for exploration of aircraft exhausts evolution in plume inside a cloud. (author) 10 refs.

Potential transformation of trace species including aircraft exhaust in a cloud environment. The `Chedrom model`

Energy Technology Data Exchange (ETDEWEB)

Ozolin, Y E; Karol, I L [Main Geophysical Observatory, St. Petersburg (Russian Federation); Ramaroson, R [Office National d` Etudes et de Recherches Aerospatiales (ONERA), 92 - Chatillon (France)

1998-12-31

Box model for coupled gaseous and aqueous phases is used for sensitivity study of potential transformation of trace gases in a cloud environment. The rate of this transformation decreases with decreasing of pH in droplets, with decreasing of photodissociation rates inside the cloud and with increasing of the droplet size. Model calculations show the potential formation of H{sub 2}O{sub 2} in aqueous phase and transformation of gaseous HNO{sub 3} into NO{sub x} in a cloud. This model is applied for exploration of aircraft exhausts evolution in plume inside a cloud. (author) 10 refs.

Petrological mineralogical and geochemical characterization of the granitoids and fracture fillings developed in Ratones Mines (Spain)

International Nuclear Information System (INIS)

Buil Gutierrez, B.

2002-01-01

The petrological, mineralogical and geochemical characterisation of the granitoids and fracture fillings developed in the Ratones Mine (Caceres, Spain) has been done in order to understand rock-water interaction processes which control water geochemical parameters. Special interest has been devoted to the analysis and interpretation of REE patterns in the solid phase (granitoids and fracture fillings) because they constitute geochemical tracers in water-rock interaction process. Moreover, REE are considered as actinide analogues. In order to characterise the solid phase (granitoids and fracture fillings) several investigation scales (system, outcrop, whole rock, mineral and geochemical components) have been considered and different types of samples have been analysed. These factors control the methodological approach used in this investigation. The analytical methods we have used in this investigation are microscope, qualitative and semi-quantitative methods (XRD, SEM,EDAX) and quantitative methods (ICP-MS, XRF, EM, LAM-IC-MS). The bulk of the granitoids located around the Ratones Mine Belongs to the alkaline feldspar granite-sienogranite lihotype and they show a peraluminous and subalkaline pattern. From the mineralogical point of view, they are composed by quartz, K-feldspar (Or>90%), showing sericitation, moscovitization and turmolinization altherations, alkaline plagioclase (An-=-3%), usually altered to sericite, saussirite and less frequently affected by moscovitization processes, Fe-Al biotite, frequently affected by chloritization processes and sometimes replaced by muscovite, and finally muscovite (>2% celadonite and <4% paragonite) both of primary and secondary origin. The differences observed between the different lithotypes are related with the modal proportion of the principal minerals,with the presence or absence of certain accessory minerals ( turmaline, cordierite), with specific textural patterns, grain size and also with the richness in specific

Geochemical Evolution of the Louisville Seamount Chain

Science.gov (United States)

Vanderkluysen, L.; Mahoney, J. J.; Koppers, A. A.; Lonsdale, P. F.

2007-12-01

The Louisville seamount chain is a 4300 km long chain of submarine volcanoes in the southwestern Pacific that is commonly thought to represent a hotspot track. It spans an ~80 Myr age range, comparable to that of the Hawaiian-Emperor chain (Koppers et al., G-cubed, 5 (6), 2004). The few previously dredged igneous samples are dominantly basaltic and alkalic, and have been inferred to represent post-shield volcanism (Hawkins et al., AGU Monograph, 43, 235, 1987). Their isotope and trace element signatures suggest an unusually homogenous mantle source (Cheng et al., AGU Monograph, 43, 283, 1987). Dredging in 2006, during the AMAT02RR cruise of the R.V. Revelle, was carried out in the hope of recovering both shield and post-shield samples and of exploring the geochemical evolution of the chain. Igneous rocks were recovered from 33 stations on 23 seamounts covering some 47 Myr of the chain's history. Our study, focusing on the major and trace element and Sr, Nd and Pb isotopic characteristics of these samples, shows that all are alkalic basalts, basanites and tephrites containing normative nepheline. Variations in major and trace elements appear to be controlled predominantly by variable extents of melting and fractional crystallization, with little influence from mantle source heterogeneity. Indeed, age-corrected isotopic values define only a narrow range, in agreement with long-term source homogeneity relative to the scale of melting; e.g., ɛNd varies from +4.1 to +5.7, 206Pb/204Pb from 19.048 to 19.281, and 87Sr/86Sr from 0.70362 to 0.70398. These values broadly fall within the fields of the proposed "C" or "FOZO" mantle end-members. However, small variations are present, with less radiogenic Nd and Pb isotope ratios at the older, western end of the chain, defining a trend toward a broadly EM2-like composition. Although some workers have postulated that the Louisville hotspot was the source of the ~120 Myr Ontong Java Plateau, our samples are isotopically distinct

Trace-element speciation and partitioning in environmental geochemistry and health

Energy Technology Data Exchange (ETDEWEB)

Farmer, J.G.; Gibson, M.J.; Lovell, M.A.

1983-09-01

Establishment of the chemical form and associations of trace elements is important in the scientifc and medical fields related to environmental geochemistry and health. Fundamental understanding of trace-element behavior, the realistic formulation of historical perspectives of trace-element contamination, an assessment of environmental transformation processes and a thorough appraisal of environment-related ill health and disease all depend on knowledge of the chemical speciation and partitioning of trace elements. These topics and the development of analytical speciation techniques and procedures are discussed with reference to trace-element studies in the Department of Forensic Medicine and Science, University of Glasgow, on lacustrine sediments and water, the atmosphere, soil and street dirt of an urban environment, and human biological fluids. 206 references, 4 figures.

An efficient ray tracing method for propagation prediction along a mobile route in urban environments

Science.gov (United States)

Hussain, S.; Brennan, C.

2017-07-01

This paper presents an efficient ray tracing algorithm for propagation prediction in urban environments. The work presented in this paper builds upon previous work in which the maximum coverage area where rays can propagate after interaction with a wall or vertical edge is described by a lit polygon. The shadow regions formed by buildings within the lit polygon are described by shadow polygons. In this paper, the lit polygons of images are mapped to a coarse grid superimposed over the coverage area. This mapping reduces the active image tree significantly for a given receiver point to accelerate the ray finding process. The algorithm also presents an efficient method of quickly determining the valid ray segments for a mobile receiver moving along a linear trajectory. The validation results show considerable computation time reduction with good agreement between the simulated and measured data for propagation prediction in large urban environments.

Trace elements and Pb isotopes in soils and sediments impacted by uranium mining

Energy Technology Data Exchange (ETDEWEB)

Cuvier, A., E-mail: alicia.cuvier@hotmail.fr [ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse (France); IRSN/PRP-ENV/SESURE/Laboratoire d' études radioécologiques en milieu continental et marin, BP 1, 13108 Saint Paul Lez Durance Cedex (France); Pourcelot, L. [IRSN/PRP-ENV/SESURE/Laboratoire d' études radioécologiques en milieu continental et marin, BP 1, 13108 Saint Paul Lez Durance Cedex (France); Probst, A. [ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse (France); Prunier, J. [Observatoire Midi-Pyrénées, laboratoire Géosciences Environnement Toulouse, CNRS/IRD/Université Paul Sabatier, 14 avenue Edouard Belin, 31400 Toulouse (France); Le Roux, G., E-mail: gael.leroux@ensat.fr [ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse (France)

2016-10-01

The purpose of this study is to evaluate the contamination in As, Ba, Co, Cu, Mn, Ni, Sr, V, Zn and REE, in a high uranium activity (up to 21,000 Bq ∙ kg{sup −1}) area, downstream of a former uranium mine. Different geochemical proxies like enrichment factor and fractions from a sequential extraction procedure are used to evaluate the level of contamination, the mobility and the availability of the potential contaminants. Pb isotope ratios are determined in the total samples and in the sequential leachates to identify the sources of the contaminants and to determine the mobility of radiogenic Pb in the context of uranium mining. In spite of the large uranium contamination measured in the soils and the sediments (EF ≫ 40), trace element contamination is low to moderate (2 < EF < 5), except for Ba (5 < EF < 15), due to the precipitation of barium sulfate resulting from mining activities. Most of the trace elements are associated with the most mobile fractions of the sediments/soils, implying an enhanced potential availability. Even if no Pb enrichment is highlighted, the Pb isotopic signature of the contaminated soils is strongly radiogenic. Measurements performed on the sequential leachates reveal inputs of radiogenic Pb in the most mobile fractions of the contaminated soil. Inputs of low-mobile radiogenic Pb from mining activities may also contribute to the Pb signature recorded in the residual phase of the contaminated samples. We demonstrate that Pb isotopes are efficient tools to trace the origin and the mobility of the contaminants in environments affected by uranium mining. - Highlights: • Contamination of soils is evidenced by a multiproxy approach. • Enrichment factors highlight a low contamination except for U, S and Ba. • Pb isotope ratios point out inputs of radiogenic Pb from the mine. • Radiogenic Pb is mainly in the acid-soluble and the reducible fractions.

Geochemical, hydrological and biological cycling of energy residuals. Research plan: subsurface transport program

International Nuclear Information System (INIS)

Wobber, F.J.

1985-09-01

Because natural processes associated with the release and the transport of organic compounds, trace metals, and radionuclides are incompletely understood, research in this area is critical if the long term scientific uncertainties about contaminant transport are to be resolved. The processes that control mobilization and attenuation of energy residuals in soils and geological strata, their hydrological transport to and within ground water regimes, and their accumulation in biological systems require research attention. A summary of DOE's core research program is described. It is designed to provide a base of fundamental scientific information so that the geochemical hydrological, and biophysical mechanics that contribute to the transport and long term fate of energy related contaminants in natural systems can be understood

RAY TRACING IMPLEMENTATION IN JAVA PROGRAMMING LANGUAGE

OpenAIRE

Aybars UĞUR; Mustafa TÜRKSEVER

2002-01-01

In this paper realism in computer graphics and components providing realism are discussed at first. It is mentioned about illumination models, surface rendering methods and light sources for this aim. After that, ray tracing which is a technique for creating two dimensional image of a three-dimensional virtual environment is explained briefly. A simple ray tracing algorithm was given. "SahneIzle" which is a ray tracing program implemented in Java programming language which ...

Geochemical characteristics of oil sands fluid petroleum coke

International Nuclear Information System (INIS)

Nesbitt, Jake A.; Lindsay, Matthew B.J.; Chen, Ning

2017-01-01

The geochemical characteristics of fluid petroleum coke from the Athabasca Oil Sands Region (AOSR) of northern Alberta, Canada were investigated. Continuous core samples were collected to 8 m below surface at several locations (n = 12) from three coke deposits at an active oil sands mine. Bulk elemental analyses revealed the coke composition was dominated by C (84.2 ± 2.3 wt%) and S (6.99 ± 0.26 wt%). Silicon (9210 ± 3000 mg kg"−"1), Al (5980 ± 1200 mg kg"−"1), Fe (4760 ± 1200 mg kg"−"1), and Ti (1380 ± 430 mg kg"−"1) were present in lesser amounts. Vanadium (1280 ± 120 mg kg"−"1) and Ni (230 ± 80 mg kg"−"1) exhibited the highest concentrations among potentially-hazardous minor and trace elements. Sequential extractions revealed potential for release of these metals under field-relevant conditions. Synchrotron powder X-ray diffraction revealed the presence of Si and Ti oxides, organically-complexed V and hydrated Ni sulfate, and provided information about the asphaltenic carbon matrix. X-ray absorption near edge structure (XANES) spectroscopy at the V and Ni K-edges revealed that these metals were largely hosted in porphyrins and similar organic complexes throughout coke grains. Minor differences among measured V and Ni K-edge spectra were largely attributed to slight variations in local coordination of V(IV) and Ni(II) within these organic compounds. However, linear combination fits were improved by including reference spectra for inorganic phases with octahedrally-coordinated V(III) and Ni(II). Sulfur and Fe K-edge XANES confirmed that thiophenic coordination and pyritic-ilmenitic coordination are predominant, respectively. These results provide new information on the geochemical and mineralogical composition of oil sands fluid petroleum coke and improve understanding of potential controls on associated water chemistry. - Highlights: • Oil sands fluid petroleum coke contains wide range of major, minor and

Tracers and tracing methods

International Nuclear Information System (INIS)

Leclerc, J.P.

2001-01-01

The first international congress on 'Tracers and tracing methods' took place in Nancy in May 2001. The objective of this second congress was to present the current status and trends on tracing methods and their applications. It has given the opportunity to people from different fields to exchange scientific information and knowledge about tracer methodologies and applications. The target participants were the researchers, engineers and technologists of various industrial and research sectors: chemical engineering, environment, food engineering, bio-engineering, geology, hydrology, civil engineering, iron and steel production... Two sessions have been planned to cover both fundamental and industrial aspects: 1)fundamental development (tomography, tracer camera visualization and particles tracking; validation of computational fluid dynamics simulations by tracer experiments and numerical residence time distribution; new tracers and detectors or improvement and development of existing tracing methods; data treatments and modeling; reactive tracer experiments and interpretation) 2)industrial applications (geology, hydrogeology and oil field applications; civil engineering, mineral engineering and metallurgy applications; chemical engineering; environment; food engineering and bio-engineering). The program included 5 plenary lectures, 23 oral communications and around 50 posters. Only 9 presentations are interested for the INIS database

Geochemical signatures of uranium deposits within stream sediment of humid intertropical environment example from Gabon Francevillien deposits

International Nuclear Information System (INIS)

Nganzi, C.

1983-01-01

In the frame of geochemical prospection of uranium ores, the method based on adsorption is used for interpreting anomalies in classical methods. This study shows the importance of adsorption from specific surface area determined by the B.E.T. method [fr

Integration of remote sensing, geochemical and field data in the Qena-Safaga shear zone: Implications for structural evolution of the Eastern Desert, Egypt

Science.gov (United States)

El-Din, Gamal Kamal; Abdelkareem, Mohamed

2018-05-01

The Qena-Safaga shear zone (QSSZ) represents a significant structural characteristic in the Eastern Desert of Egypt. Remote Sensing, field and geochemical data were utilized in the present study. The results revealed that the QSSZ dominated by metamorphic complex (MC) that intruded by syn-tectonic granitoids. The low angle thrust fault brings calc-alkaline metavolcanics to overlie MC and its association. Subsequently, the area is dissected by strike-slip faults and the small elongated basins of Hammamat sediments of Precambrian were accumulated. The MC intruded by late-to post-tectonic granites (LPG) and Dokhan Volcanics which comprise felsic varieties forming distinctive columnar joints. Remote sensing analysis and field data revealed that major sub-vertical conspicuous strike-slip faults (SSF) including sinistral NW-SE and dextral ca. E-W shaped the study area. Various shear zones that accompanying the SSF are running NW-SE, NE-SW, E-W, N-S and ENE-WSW. The obtained shear sense presented a multiphase of deformation on each trend. i.e., the predominant NW-SE strike-slip fault trend started with sinistral displacement and is reactivated during later events to be right (dextral) strike slip cutting with dextral displacement the E-W trending faults; while NE-SW movements are cut by both the N-S and NNW - SSE trends. Remote sensing data revealed that the NW-SE direction that dominated the area is associated with hydrothermal alteration processes. This allowed modifying the major and trace elements of the highly deformed rocks that showed depletion in SiO2 and enrichments in Fe2O3, MnO, Al2O3, TiO2, Na2O, K2O, Cu, Zn and Pb contents. The geochemical signatures of major and trace elements revealed two types of granites including I-type calc-alkaline granites (late-to post-tectonic) that formed during an extensional regime. However, syn-tectonic granitoids are related to subduction-related environment.

Field-based tests of geochemical modeling codes usign New Zealand hydrothermal systems

International Nuclear Information System (INIS)

Bruton, C.J.; Glassley, W.E.; Bourcier, W.L.

1994-06-01

Hydrothermal systems in the Taupo Volcanic Zone, North Island, New Zealand are being used as field-based modeling exercises for the EQ3/6 geochemical modeling code package. Comparisons of the observed state and evolution of the hydrothermal systems with predictions of fluid-solid equilibria made using geochemical modeling codes will determine how the codes can be used to predict the chemical and mineralogical response of the environment to nuclear waste emplacement. Field-based exercises allow us to test the models on time scales unattainable in the laboratory. Preliminary predictions of mineral assemblages in equilibrium with fluids sampled from wells in the Wairakei and Kawerau geothermal field suggest that affinity-temperature diagrams must be used in conjunction with EQ6 to minimize the effect of uncertainties in thermodynamic and kinetic data on code predictions

LASER SPECTROSCOPY AND TRACE ELEMENT ANALYSIS Chapter from the Energy and Environment Division Annual Report 1980

Energy Technology Data Exchange (ETDEWEB)

Various, Authors

1981-05-01

In order to control pollutants resulting from energy production and utilization, adequate methods are required for monitoring the level of various substances often present at low concentrations. The Energy and Environment Division Applied Research in Laser Spectroscopy & Analytical Techniques Program is directed toward meeting these needs, Emphasis is on the development of physical methods, as opposed to conventional chemical analysis techniques. The advantages, now widely recognized, include ultra-high sensitivity coupled with minimal sample preparation. In some instances physical methods provide multi-parameter measurements which often provide the only means of achiev·ing the sensitivity necessary for the detection of trace contaminants. Work is reported in these areas: APPLIED PHYSICS AND LASER SPECTROSCOPY RESEARCH; MICROPROCESSOR CONTROLLER ANODIC STRIPPING VOLTAMETER FOR TRACE METALS ANALYSIS IN WATER; THE SURVEY OF INSTRUMENTATION FOR ENVIRONMENTAL MONITORING; THE POSSIBLE CHRONDRITIC NATURE OF THE DANISH CRETACEOUS~TERTIARY BOUNDARY; IMPROVEMENT OF THE SENSITIVITY AND PRECISION OF NEUTRON ACTIVATION ANALYSIS OF SOME ELEMENTS IN PLANKTON AND PLANKTONIC FISH; and SOURCES OF SOME SECONDARILY WORKED OBSIDIAN ARTIFACTS FROM TIKAL, GUATEMALA.

Sources of anthropogenic radionuclides in the environment: a review

International Nuclear Information System (INIS)

Hu Qinhong; Weng Jianqing; Wang Jinsheng

2010-01-01

Studies of radionuclides in the environment have entered a new era with the renaissance of nuclear energy and associated fuel reprocessing, geological disposal of high-level nuclear wastes, and concerns about national security with respect to nuclear non-proliferation. This work presents an overview on sources of anthropogenic radionuclides in the environment, as well as a brief discussion of salient geochemical behavior of important radionuclides. We first discuss the following major anthropogenic sources and current developments that have lead, or could potentially contribute, to the radionuclide contamination of the environment: (1) nuclear weapons program; (2) nuclear weapons testing; (3) nuclear power plants; (4) uranium mining and milling; (5) commercial fuel reprocessing; (6) geological repository of high-level nuclear wastes that include radionuclides might be released in the future, and (7) nuclear accidents. Then, we briefly summarize the inventory of radionuclides 99 Tc and 129 I, as well as geochemical behavior for radionuclides 99 Tc, 129 I, and 237 Np, because of their complex geochemical behavior, long half-lives, and presumably high mobility in the environment; biogeochemical cycling and environment risk assessment must take into account speciation of these redox-sensitive radionuclides.

Integration of NURE and other data sets, southwest Montana and northeast Idaho: an orientation study to characterize mineralized environments. National Uranium Resource Evaluation

International Nuclear Information System (INIS)

Madson, M.E.; Karp, K.E.; D'Andrea, R.F. Jr.; Morrison, B.C.

1983-04-01

Mineralized environments in the Dillon, Butte, Hamilton, and Elk City 1 0 x 2 0 NTMS Quadrangles were identified and characterized from the National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance and Aerial Radiometric and Magnetic Survey data, folio data, and other data sets used in this study. Methods applied to reconnaissance for uranium during the NURE program were used successfully in this project to recognize and delineate locales that have mineral-resource potential. These methods included preparation and interpretation of maps of geochemical, aerial radiometric, and aeromagentic data, as well as interpretation of univariate and multivariate statistical analyses of NURE data sets. Data interpretations were conducted by a contingency approach that puts a variety of statistical and cartographic tools at the disposal of the geologist. These tools were applied selectively to the data until the geochemical and geophysical signature of an anomalous locale was described and characterized to the geologist's satisfaction. Ten areas known to be mineralized were described as type localities and used to calibrate the geochemical and geophysical models employed in the study. Other areas exhibiting anomalous geochemical and (or) geophysical characteristics were analogized to the type localities. Thirty anomalous areas were delineated during this study; 17 of the 30 are believed to warrant further investigation. Three locales contain Tertiary intrusive bodies that were delineated on the basis of their characteristic signatures and trace-element contents. 5 figures, 10 tables

RAY TRACING IMPLEMENTATION IN JAVA PROGRAMMING LANGUAGE

Directory of Open Access Journals (Sweden)

Aybars UĞUR

2002-01-01

Full Text Available In this paper realism in computer graphics and components providing realism are discussed at first. It is mentioned about illumination models, surface rendering methods and light sources for this aim. After that, ray tracing which is a technique for creating two dimensional image of a three-dimensional virtual environment is explained briefly. A simple ray tracing algorithm was given. "SahneIzle" which is a ray tracing program implemented in Java programming language which can be used on the internet is introduced. As a result, importance of network-centric ray tracing software is discussed.

The Narssaq-project - a geochemical, ecological environmental research project

International Nuclear Information System (INIS)

Soerensen, H.; Rose-Hansen, J.

1978-01-01

Two types of mineral occurrences near the town of Narssaq in South Greenland are recorded to be worth mining in the near future: the uranium occurrences at Kvanefjeld in the northern part of the Ilimaussaq intrusion and the zirconium occurrences in the southern part on the south coast of the Kangerdluarssuk fjord. Consideration of the environment plays a large part in discussions regarding the exploitation of these minerals. A report is given of the geochemical, ecological environmental investigations carried out at Narssaq since 1974. (BP)

Trace Fossils as Indicators of Depositional Sequence Boundaries in Lower Carboniferous Deep-Sea Fan Environment Moravice Formation, Czech Republic

Czech Academy of Sciences Publication Activity Database

Lehotský, T.; Bábek, O.; Mikuláš, Radek; Zapletal, J.

2002-01-01

Roč. 14, - (2002), s. 59-60 ISSN 1210-9606. [Áelazno 2002. Meeting of the Czech Tectonic Studies Group /7./. Áelazno, 09.05.2002-12.05.2002] R&D Projects: GA ČR GA205/00/0118 Keywords : trace fossils * Carboniferous * Deep- Sea Environment Subject RIV: DB - Geology ; Mineralogy http://geolines.gli.cas.cz/fileadmin/volumes/volume14/G14-059.pdf

Petrological, geochemical and isotopic characteristics of lignite and calcified lignite from mining area Pesje, Velenje Basin, Slovenia

Science.gov (United States)

Vrabec, Mirijam; Markič, Miloš; Vrabec, Marko; Jaćimović, Radojko; Kanduč, Tjaša

2014-05-01

Lignite (organic rich) and calcified lignite (inorganic rich) samples from excavation field -50c mining area Pesje, Velenje Basin, Slovenia were investigated. During geological and structural mapping lignite and calcified lignite samples were systematically taken for determination of their petrological, geochemical and isotopic characteristics. Lignite is composed of fine detritical gelified matrix. At least five different types of calcified lignite were recognized forming laminations, calcifications after wood, petrified wood and complete replacements of lignite with carbonate. All measured parameters so far indicate geochemical processes during sedimentation of the Velenej Basin. After macroscopic description samples were split to organic and inorganic component (Ward, 1984) and powdered in an agate mortar for geochemical and isotopic analyses. Major and trace elements (As, B, Ba, Cd, Co, Cr, Cu, Hg, Mn, Mo, Sb, Se, Th, U, Zn) in these samples were determined by instrumental neutron activation analysis (INAA) using k-0 standardization method (Jaćimović et al, 2002). The isotopic composition of carbon and nitrogen was determined using a Europa 20-20 continuous flow IRMS ANCA-SL preparation module. A 1 mg amount of a sample was weighed in a tin capsule for carbon and 10 mg for nitrogen analysis. Samples for carbon analyses were pretreated with 1 M HCl to remove carbonates. Carbonate samples from carbonate-rich strata and calcified xylite were first roasted at 450 deg C (Krantz et al., 1987). Three miligrams of carbonate sample was transformed into CO2 by reaction with anhydrous H3PO4 at 55 deg C under vacuum (McCrea, 1950) and measured with GV 2003 isotope ratio mass spectrometer. Measured isotopic composition of oxygen as VPDB values was recalculated to the VSMOW reference standard to enable the comparison with data from other coal basins. SEM/EDXS of carbonate rich sediments was performed with JEOL JSM 5800 electron microanalyzer scanning electron microscope

Geochemical modeling: a review

International Nuclear Information System (INIS)

Jenne, E.A.

1981-06-01

Two general families of geochemical models presently exist. The ion speciation-solubility group of geochemical models contain submodels to first calculate a distribution of aqueous species and to secondly test the hypothesis that the water is near equilibrium with particular solid phases. These models may or may not calculate the adsorption of dissolved constituents and simulate the dissolution and precipitation (mass transfer) of solid phases. Another family of geochemical models, the reaction path models, simulates the stepwise precipitation of solid phases as a result of reacting specified amounts of water and rock. Reaction path models first perform an aqueous speciation of the dissolved constituents of the water, test solubility hypotheses, then perform the reaction path modeling. Certain improvements in the present versions of these models would enhance their value and usefulness to applications in nuclear-waste isolation, etc. Mass-transfer calculations of limited extent are certainly within the capabilities of state-of-the-art models. However, the reaction path models require an expansion of their thermodynamic data bases and systematic validation before they are generally accepted

Geochemical modeling: a review

Energy Technology Data Exchange (ETDEWEB)

Jenne, E.A.

1981-06-01

Two general families of geochemical models presently exist. The ion speciation-solubility group of geochemical models contain submodels to first calculate a distribution of aqueous species and to secondly test the hypothesis that the water is near equilibrium with particular solid phases. These models may or may not calculate the adsorption of dissolved constituents and simulate the dissolution and precipitation (mass transfer) of solid phases. Another family of geochemical models, the reaction path models, simulates the stepwise precipitation of solid phases as a result of reacting specified amounts of water and rock. Reaction path models first perform an aqueous speciation of the dissolved constituents of the water, test solubility hypotheses, then perform the reaction path modeling. Certain improvements in the present versions of these models would enhance their value and usefulness to applications in nuclear-waste isolation, etc. Mass-transfer calculations of limited extent are certainly within the capabilities of state-of-the-art models. However, the reaction path models require an expansion of their thermodynamic data bases and systematic validation before they are generally accepted.

A Geographic Information System (GIS) analysis for trace metal assessment of sediments in the Gulf of Paria, Trinidad

International Nuclear Information System (INIS)

Ragbirsingh, Y.; Norville, W.

2005-01-01

The Gulf of Paria is a semi-enclosed shallow basin with increasing coastal development activities along Trinidad's west coast. Sediments present a host for trace metal pollutants from overlying waters, therefore determination of their content is critical in evaluating and detecting sources of marine pollution. This paper presents a Geographic Information System (GIS) analysis of geochemical assessment for trace metals in coastal sediments of the Gulf of Paria. This GIS approach facilitates interpretation of the spatial relationships among key environmental processes. The GIS development involves the integration of spatial and attribute data pertaining to bathymetry, current systems, topography, rivers, land use/land cover and coastal sediments. It employs spatial interpolation and retrieval operations to analyze the total trace metal concentrations of aluminum, copper and lead in the sediments and the clay-enriched sediments, to determine whether they are related to sediment type or are affected by the discharge from anthropogenic sources. Spatial distribution modeling of element concentrations are produced to indicate contamination plumes from possible anthropogenic sources such as rivers entering the Gulf of Paria, and to reveal potential hot spots and dispersion patterns. A direct spatial correlation between clay-enriched sediments and high concentrations of aluminum and lead is detected, however regions of high concentrations of copper and lead indicate a relationship to anthropogenic sources. The effectiveness of GIS for visualization, spatial query and overlay of geochemical analysis is demonstrated [es

Assessing man-induced environmental changes in the Sepetiba Bay (Southeastern Brazil) with geochemical and satellite data

Science.gov (United States)

Araújo, Daniel Ferreira; Peres, Lucas G. M.; Yepez, Santiago; Mulholland, Daniel S.; Machado, Wilson; Tonhá, Myller; Garnier, Jérémie

2017-10-01

The Sepetiba Bay, Southeastern Brazil, has undergone intense environmental changes due to anthropogenic influence. This work aims to: (i) evaluate the changes in the drainage landscape use over the last decades, (ii) identify new and past punctual and diffuse anthropogenic sources and assess risks of man-induced disturbances of the coastal zones of Sepetiba. A multivariate statistics approach on the sediment's elemental geochemical dataset discriminated three groups: the electroplating waste-affected elements (As, Cd, Pb, Cu and Zn), terrigenous elements (Si, K, Ti, Al and Fe), and biogenic and carbonate-derived elements (Ca, Mg, Mn, P, Ni, and Cr). Sediment core profiles of trace elements evidence records of former environmental impacts from old metallurgical wastes. Analysis of two Landsat images from 30 years ago and 2015 reveals a decrease in the mangrove area of nearly 26%. The ongoing suppression of mangroves could enhance the release of trace elements into the Sepetiba Bay, increasing the risks to human and biota health.

NOAA and MMS Marine Minerals Geochemical Database

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Marine Minerals Geochemical Database was created by NGDC as a part of a project to construct a comprehensive computerized bibliography and geochemical database...

Use of partial dissolution techniques in geochemical exploration

Science.gov (United States)

Chao, T.T.

1984-01-01

Application of partial dissolution techniques to geochemical exploration has advanced from an early empirical approach to an approach based on sound geochemical principles. This advance assures a prominent future position for the use of these techniques in geochemical exploration for concealed mineral deposits. Partial dissolution techniques are classified as single dissolution or sequential multiple dissolution depending on the number of steps taken in the procedure, or as "nonselective" extraction and as "selective" extraction in terms of the relative specificity of the extraction. The choice of dissolution techniques for use in geochemical exploration is dictated by the geology of the area, the type and degree of weathering, and the expected chemical forms of the ore and of the pathfinding elements. Case histories have illustrated many instances where partial dissolution techniques exhibit advantages over conventional methods of chemical analysis used in geochemical exploration. ?? 1984.

Rock magnetic and geochemical analyses of surface sediment characteristics in deep ocean environments: A case study across the Ryukyu Trench

Science.gov (United States)

Kawamura, N.; Kawamura, K.; Ishikawa, N.

2008-03-01

Magnetic minerals in marine sediments are often dissolved or formed with burial depth, thereby masking the primary natural remanent magnetization and paleoclimate signals. In order to clarify the present sedimentary environment and the progressive changes with burial depth in the magnetic properties, we studied seven cores collected from the Ryukyu Trench, southwest Japan. Magnetic properties, organic geochemistry, and interstitial water chemistry of seven cores are described. Bottom water conditions at the landward slope, trench floor, and seaward slope are relatively suboxic, anoxic, and oxic, respectively. The grain size of the sediments become gradually finer with the distance from Okinawa Island and finer with increasing water depth. The magnetic carriers in the sediments are predominantly magnetite and maghemized magnetite, with minor amounts of hematite. In the topmost sediments from the landward slope, magnetic minerals are diluted by terrigenous materials and microfossils. The downcore variations in magnetic properties and geochemical data provided evidence for the dissolution of fine-grained magnetite with burial depth under an anoxic condition.

Molecular fossils in modern genomes provide physiological and geochemical insights to the ancient earth (Invited)

Science.gov (United States)

Dupont, C.; Caetano-Anolles, G.

2010-12-01

The genomes of extant organisms are ultimately derived from ancient life, thus theoretically contain insight to ancient physiology, ecology, and environments. In particular, metalloenzymes may be particularly insightful. The fundamental chemistry of trace elements dictates the molecular speciation and reactivity both within cells and the environment at large. Using protein structure and comparative genomics, we elucidate several major influences this chemistry has had upon biology. All of life exhibits the same proteome size-dependent scaling for the number of metal-binding proteins within a proteome. This fundamental evolutionary constant shows that the selection of one element occurs at the exclusion of another, with the eschewal of Fe for Zn and Ca being a defining feature of eukaryotic pro- teomes. Early life lacked both the structures required to control intracellular metal concentrations and the metal-binding proteins that catalyze electron transport and redox transformations. The development of protein structures for metal homeostasis coincided with the emergence of metal-specific structures, which predomi- nantly bound metals abundant in the Archean ocean. Potentially, this promoted the diversification of emerging lineages of Archaea and Bacteria through the establishment of biogeochemical cycles. In contrast, structures binding Cu and Zn evolved much later, pro- viding further evidence that environmental availability influenced the selection of the elements. The late evolving Zn-binding proteins are fundamental to eukaryotic cellular biology, and Zn bioavailabil- ity may have been a limiting factor in eukaryotic evolution. The results presented here provide an evolutionary timeline based on genomic characteristics, and key hypotheses can be tested by alternative geochemical methods.

Study of Propagation Mechanisms in Dynamical Railway Environment to Reduce Computation Time of 3D Ray Tracing Simulator

Directory of Open Access Journals (Sweden)

Siham Hairoud

2013-01-01

Full Text Available In order to better assess the behaviours of the propagation channel in a confined environment such as a railway tunnel for subway application, we present an optimization method for a deterministic channel simulator based on 3D ray tracing associated to the geometrical optics laws and the uniform theory of diffraction. This tool requires a detailed description of the environment. Thus, the complexity of this model is directly bound to the complexity of the environment and specifically to the number of facets that compose it. In this paper, we propose an algorithm to identify facets that have no significant impact on the wave propagation. This allows us to simplify the description of the geometry of the modelled environment by removing them and by this way, to reduce the complexity of our model and therefore its computation time. A comparative study between full and simplified environment is led and shows the impact of this proposed method on the characteristic parameters of the propagation channel. Thus computation time obtained from the simplified environment is 6 times lower than the one of the full model without significant degradation of simulation accuracy.

Geochemical and mineralogical characteristics of Lithomargic clay

African Journals Online (AJOL)

Administrator

Geochemical and mineralogical characteristics of Lithomargic clay. GEOCHEMICAL AND .... tries, as filling material in the pulp and paper, toothpaste and paint industries as well ..... tions very vital to human health and other ac- tivities of man.

Olfactory memory traces in Drosophila.

Science.gov (United States)

Berry, Jacob; Krause, William C; Davis, Ronald L

2008-01-01

In Drosophila, the fruit fly, coincident exposure to an odor and an aversive electric shock can produce robust behavioral memory. This behavioral memory is thought to be regulated by cellular memory traces within the central nervous system of the fly. These molecular, physiological, or structural changes in neurons, induced by pairing odor and shock, regulate behavior by altering the neurons' response to the learned environment. Recently, novel in vivo functional imaging techniques have allowed researchers to observe cellular memory traces in intact animals. These investigations have revealed interesting temporal and spatial dynamics of cellular memory traces. First, a short-term cellular memory trace was discovered that exists in the antennal lobe, an early site of olfactory processing. This trace represents the recruitment of new synaptic activity into the odor representation and forms for only a short period of time just after training. Second, an intermediate-term cellular memory trace was found in the dorsal paired medial neuron, a neuron thought to play a role in stabilizing olfactory memories. Finally, a long-term protein synthesis-dependent cellular memory trace was discovered in the mushroom bodies, a structure long implicated in olfactory learning and memory. Therefore, it appears that aversive olfactory associations are encoded by multiple cellular memory traces that occur in different regions of the brain with different temporal domains.

Alteration and geochemical zoning in Bodie Bluff, Bodie mining district, eastern California

Science.gov (United States)

Herrera, P.A.; Closs, L.G.; Silberman, M.L.

1993-01-01

Banded, epithermal quartz-adularia veins have produced about 1.5 million ounces of gold and 7 million ounces of silver from the Bodie mining district, eastern California. The veins cut dacitic lava flows, pyroclastic rocks and intrusions. Sinter boulders occur in a graben structure at the top of Bodie Bluff and fragments of sinter and mineralized quartz veins occur in hydrothermal breccias nearby. Explosive venting evidently was part of the evolution of the ore-forming geothermal systems which, at one time, must had reached the paleosurface. Previous reconnaissance studies at Bodie Bluff suggested that the geometry of alteration mineral assemblages and distribution of some of the major and trace elements throughout the system correspond to those predicted by models of hot-spring, volcanic rock hosted precious metal deposits (Silberman, 1982; Silberman and Berger, 1985). The current study was undertaken to evaluate these sugestions further. About 500 samples of quartz veins and altered rocks, including sinter, collected over a vertical extent of 200 meters within Bodie Bluff were petrographically examined and chemically analyzed for trace elements by emission spectrographic and atomic absorption methods. Sixty-five samples were analyzed for major elements by X-ray fluorescence methods. The results of these analyses showed that, in general, alteration mineral assemblage and vertical geochemical zoning patterns follow those predicted for hot-spring deposits, but that geochemical zoning patterns for sinter and quartz veins (siliceous deposits), and altered wall rocks are not always similar. The predicted depth-concentration patterns for some elements, notably Au, Ag, Hg, and Tl in quartz veins, and Hg, As and Ag in wall rocks were not as expected, or were perturbed by the main ore producing zone. For both quartz veins and altered wall rocks, the main ore zone had elevated metal contents. Increased concentration of many of these elements could indicate proximity to this

Geochemical investigation of groundwater in the Tono area, Japan. Chemical characteristics and groundwater evolution

International Nuclear Information System (INIS)

Iwatsuki, Teruki; Hama, Katsuhiro; Yoshida, Hidekazu

1997-01-01

Geochemical investigations form an important part of the R and D program at the Tono study site, central Japan. Detailed geological structure and groundwater chemistry have been studied to understand the geochemical environment in the sedimentary and crystalline rocks distributed in this area. The chemical evolution of the groundwater in the sedimentary rocks is characterized with the variation in Na + , Ca 2+ and HCO 3 - concentrations, and ion exchange and dissolution of calcite are dominant reactions in the evolution of groundwater. Geological investigation shows that a fracture system of crystalline rock can be classified into:intact zone, moderately fractured zone and intensely fractured zone, according to the frequency and the width of fractures and fractured zones. The groundwater in the intact and fractured zones of crystalline rock are characterized by Na + -Ca 2+ -HCO 3 - or Na + -HCO 3 - dominated water, and Na + -Ca 2+ -Fe 2+ -HCO 3 - dominated water. The chemical evolution of groundwater is, generally, controlled by water-rock interaction between plagioclase, iron minerals and groundwater. The groundwater at depth of G.L.-186m in the crystalline rock at the Tono area is characterized by the mixture between the oxidized surface water and the reduced groundwater. The investigation based on correlation between geological structures and groundwater chemistry can be applied to understand the geochemical environment in deep crystalline rock, and will support the development of a realistic hydrogeochemical model. (author)

Trace element analysis: a diagnostic tool

International Nuclear Information System (INIS)

Qureshi, I.H.; Cheema, M.N.

1976-09-01

The human mody continuously assimilates a variety of elements from the environment, and the concentration of these elements in the blood is regulated by means of various homeostatic mechanisms. Some of the elements, though present in very small amounts, have highly specialized functions in initiating many biochemical reactions. These elements, known as essential trace elements, are closely related to human diseases since their deficiency or excess induces physiological changes. Many diseases such as hypertension, atherosclerosis, diabetes, etc., are related to an imbalance in trace element. The measurement of trace elements in body fluids and tissues can, therefore, be effectively employed for diagnostic tests

Geochemical evaluation of marginal basins in the south of Bahia state, Brazil

International Nuclear Information System (INIS)

Gaglianone, P.C.; Trindade, L.A.F.; Nascimento, M.M. do

1987-01-01

Geochemical analyses were performed on more than 700 rock samples and 4 oil samples, from Mucuri, Cumuruxatiba and Jequitinhonha basins, offshore Bahia state, Brazil. The methods employed in this study includes the evaluation of organic carbon contents, Rock-Eval pyrolysis, vitrinite reflectance, carbon isotopes, assessment of oils and extrats by liquid and gas chromatography and gas chromatography - spectrometry. Three main source rock systems have been identified in offshore Bahia: the Mucuri shales from Rio da Serra and Aratu Stages lower Neocomian related to a lacustrine fresh water environment; the Jiquia shales (Upper Neocomian) deposited in a lacustrine saline water environment, and the Alagoas Shales related to an evaporitic environment of Aptian age. (author) [pt

Geochemistry of Late Mesozoic mafic dykes in western Fujian Province of China:Sr-Nd isotope and trace element constraints

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

The Bancun diabase dyke and the Bali hornblende gabbro dyke in western Fuiian Province were emplaced in the Early and Late Cretaceous periods,respectively;the former is designated to calc-alkaline series and the latter to K-high-calc-alkaline rock series.Both the dykes are characterized by such geochemical characteristics as high Al and Na2O＞K2O.As for the Bancun dyke,A12O3=16.32%-17.54%and K2O/Na2O=0.65-0.77;as for the Bali dyke,A12O3=16.89%-17.81%and K2O,Na2O=O.93-O.99.Both the Bancun and Bali mafic dykes are relatively endched in LILE and LREE,but depleted in HSFE, displaying the geochemical characteristics of continental marginal arc,with high initial Sr isotopic ratios and low εNd values,The (87Sr/86Sr)i ratios of the Bancun diabase dyke are within the range of 0.708556-0.70903 and their εNd(t)values vary between-6.8 and-6.3;those of the Bali hornblende dyke are within the range of 0.708556-0.710746 and their εNd(t) values are -4.7--4.7,showing the characteristics of enriched mantle EM Ⅱ.The isotope and trace element data showed that the mafic dykes have not experienced obvious crustal contamination,and metasomatism caused by subduction fluids is the main factor leading to LILE and UREE enrichments.The enriched mantle is the source region for the mafic dykes,and mixing of subduction fluid metasomatized enriched mantle and EM Ⅱ-type mantle constituted the mantle source region of both the Bancun and Bali mafic dykes.Upwelling of the asthenosphere mantle provided sufficient heat energy for the generation of magmas.In accordance with the discrimination diagram of their tectonic settings as well as their trace element geochemical characteristics,it is considered that the dykes both at Bancun and Bali possess the characteristics of continental marginal arc,revealing the tectonic environment of formation of the mafic dykes,the continental dynamic background as an intraplate tensional belt in which the mafic dykes were emplaced.Meanwhile,it is also indicated

Modeling ion exchange in clinoptilolite using the EQ3/6 geochemical modeling code

International Nuclear Information System (INIS)

Viani, B.E.; Bruton, C.J.

1992-06-01

Assessing the suitability of Yucca Mtn., NV as a potential repository for high-level nuclear waste requires the means to simulate ion-exchange behavior of zeolites. Vanselow and Gapon convention cation-exchange models have been added to geochemical modeling codes EQ3NR/EQ6, allowing exchange to be modeled for up to three exchangers or a single exchanger with three independent sites. Solid-solution models that are numerically equivalent to the ion-exchange models were derived and also implemented in the code. The Gapon model is inconsistent with experimental adsorption isotherms of trace components in clinoptilolite. A one-site Vanselow model can describe adsorption of Cs or Sr on clinoptilolite, but a two-site Vanselow exchange model is necessary to describe K contents of natural clinoptilolites

Experimental studies on the geochemical behaviour of 54-Mn considering coastal and deep sea sediments

International Nuclear Information System (INIS)

Guegueniat, P.; Boust, D.; Dupont, J.P.; Aprosi, G.

1985-01-01

In order to study the geochemical behaviour of 54-Mn in the marine environment (Mn/sup 2+/) 200 sediments gathered in deep sea and in coastal waters were contaminated experimentally. To correlate the various results, the oxidation processes occurring with or without sediments should be specified. During this experimental work, the geochemical behaviour of manganese is dealt with using a radioactive tracer (54-Mn) in the divalent state and sediments collected on french littoral (160) in deep sea (30). The latest data published offer an excellent assessment of research findings on manganese in marine and estuary environments and testify to the interest constantly generated by this subject. It is difficult to establish a priori any predictions on the behaviour of manganese based on the properties of a given environment, notably as concerns redox conditions. The oxidation of manganese was found to be governed by a very slow autocatalysis mechanism capable of being concealed by surface catalyses on mineral phases in suspension or oxidation due to bacteria. The residence time in sea water vary considerably depending on the case from a few days to some tens of years

Similarity in Evolutionary Histories of Eocene Sediments from Subathu and Cambay Basins: Geochemical and Palaeontological Studies

Science.gov (United States)

Chaudhuri, S.; Halder, K.; Sarkar, S.

2017-12-01

A systematic comparative study of microfaunal assemblage and representative geochemical elements from two Cenozoic basins of India, Mangrol-Valia Lignite Mine section (21°30'52''N:73°12'20.5''E) of Cambay Shale Formation, western India and Jigni section (33°14'45"N:74°22'0"E) from Subathu Formation in northern India was undertaken to infer the paleoenvironment, palaeobathymetry and paleoclimate of these successions. Despite a gamut of work already carried out in these two basins, the sedimentary successions still await a correlative-detailed process-based facies, geochemical characterization and paleoenvironmental analysis. With a view to fulfill this gap, the present work was carried out by studying bulk rock XRD, XRF, clay mineralogy and analyzing calcareous microfossil foraminifera from samples at equivalent depth of these two basins which are situated thousands of kilometers apart and in different tectonic settings. The faunal assemblage of Eocene sediments of Mangrol-Valia section is indicative of shallow marine and inner shelf deposition with medium oxygen supply, while that of the Jigni section suggests primarily a shallow marine condition, which gradually changes to open marine condition with time. It is pertinent to note that the two basins of Cenozoic India started their lithosuccession with coal bearing strata. Well preserved pectin aragonite shells also indicate that primarily these two basins experienced low energy lagoonal environment. The fossil assemblage in both basins also suggests a tropical moist to terrestrial lowland environment. Geochemical analysis shows that the Mangrol-Valia section mineralogically comprises of kaolinite, siderite, quartz, smectite and kaolinite with higher abundance throughout the succession indicating chemical weathering of Deccan basement and high erosional environment. Calcite is the main constituent of Jigni section that indicates intracratonic rift settings. Medium to high quartz content and other detrital

Geochemical Characterization of Copper Tailings after Legume Revegetation

Directory of Open Access Journals (Sweden)

Justine Perry T. Domingo

2014-12-01

Full Text Available Knowledge on the geochemistry of mine tailings is important in understanding the challenges in establishing vegetation cover on tailings dumps and mined out areas. In this study, the mineralogy and trace element composition of copper tailings were examined. Two legume species, Calopogonium mucunoides and Centrosema molle, were utilized to investigate the possible effects of these plants in the geochemical development of mine tailings into soil-like material. The initial mineralogical and chemical analysis of the tailings samples indicated poor conditions for plant growth—minimal levels of major nutrients and organic matter as well as elevated copper concentrations. Despite these conditions, the two legume species exhibited good growth rates. Both legumes have likewise signif icantly reduced heavy metal concentrations in the tailings, indicating the possibility of metal hyperaccumulation in the plant tissue. The mineral composition has been retained even after revegetation; nevertheless, breakdown of primary minerals and subsequent formation of clay minerals were detected. These results provide insights on the transformation of toxic materials into habitable substrates for sustained plant growth.

Proceedings of 13. International Geochemical Exploration Symposium. 2. Brazilian Geochemical Congress

International Nuclear Information System (INIS)

1989-01-01

Some works about geochemistry are presented, including themes about geochemical exploration, lithogeochemistry and isotope geochemistry, environmental geochemistry, analyical geochemistry, geochemistry of carbonatites and rare earth elements and organic geochemistry. (C.G.C.) [pt

Report on the intercomparison run Soil-5 for the determination of trace elements in soil

Energy Technology Data Exchange (ETDEWEB)

Dybczynski, R; Tugsavul, A; Suschny, O

1978-01-01

he knowledge of the elemental composition of soil, and especially its trace element content is of interest to many investigators active in various fields of research. Among these concerned are not only agricultural chemists and soil scientists, but also biochemists, environmentalists, nutritionists and others. The increased recognition of the essentially on one hand and toxicity on the other, of certain trace elements towards animals and man, has led to intensified studies of the pathways of trace elements in nature, particularly in the environmental research. Not only atmosphere, hydrosphere and biological tissues, but also soil is examined. Essential and toxic trace elements may pass from soil to plants (by which they are sometimes effectively concentrated) and further through food chains to Man. The interest in the analysis of soil for the content of many trace and also some major elements is therefore rapidly increasing. Hence, there seems to be an obvious need for a reference material with established 'recommended values' of as many elements as possible which could be used for checking the quality of analytical work of the laboratories engaged in soil analyses. At the same time well-characterized soil, containing high levels of minerals can be also of interest for geochemists as a complement to already existing geochemical reference samples.

40 CFR 227.6 - Constituents prohibited as other than trace contaminants.

Science.gov (United States)

2010-07-01

... trace contaminants. 227.6 Section 227.6 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Environmental Impact § 227.6 Constituents prohibited as other than trace contaminants. (a) Subject to the..., of materials containing the following constituents as other than trace contaminants will not be...

The geochemical atlas of Alaska, 2016

Science.gov (United States)

Lee, Gregory K.; Yager, Douglas B.; Mauk, Jeffrey L.; Granitto, Matthew; Denning, Paul; Wang, Bronwen; Werdon, Melanie B.

2016-06-21

A rich legacy of geochemical data produced since the early 1960s covers the great expanse of Alaska; careful treatment of such data may provide significant and revealing geochemical maps that may be used for landscape geochemistry, mineral resource exploration, and geoenvironmental investigations over large areas. To maximize the spatial density and extent of data coverage for statewide mapping of element distributions, we compiled and integrated analyses of more than 175,000 sediment and soil samples from three major, separate sources: the U.S. Geological Survey, the National Uranium Resource Evaluation program, and the Alaska Division of Geological & Geophysical Surveys geochemical databases. Various types of heterogeneity and deficiencies in these data presented major challenges to our development of coherently integrated datasets for modeling and mapping of element distributions. Researchers from many different organizations and disparate scientific studies collected samples that were analyzed using highly variable methods throughout a time period of more than 50 years, during which many changes in analytical techniques were developed and applied. Despite these challenges, the U.S. Geological Survey has produced a new systematically integrated compilation of sediment and soil geochemical data with an average sample site density of approximately 1 locality per 10 square kilometers (km2) for the entire State of Alaska, although density varies considerably among different areas. From that compilation, we have modeled and mapped the distributions of 68 elements, thus creating an updated geochemical atlas for the State.

Spatial distribution of trace elements in the surface sediments of a major European estuary (Loire Estuary, France): Source identification and evaluation of anthropogenic contribution

Science.gov (United States)

Coynel, Alexandra; Gorse, Laureline; Curti, Cécile; Schafer, Jörg; Grosbois, Cécile; Morelli, Guia; Ducassou, Emmanuelle; Blanc, Gérard; Maillet, Grégoire M.; Mojtahid, Meryem

2016-12-01

Assessing the extent of metal contamination in estuarine surface sediments is hampered by the high heterogeneity of sediment characteristics, the spatial variability of trace element sources, sedimentary dynamics and geochemical processes in addition to the need of accurate reference values for deciphering natural to anthropogenic contribution. Based on 285 surface sediment samples from the Loire Estuary, the first high-resolution spatial distributions are presented for grain-size, particulate organic carbon (POC) and the eight metals/metalloids identified as priority contaminants (Cd, Zn, Pb, Cu, As, Cr, Ni, Hg) plus Ag (an urban tracer). Grain-size and/or POC are major factors controlling the spatial distribution of trace element concentrations. The V-normalized trace metal concentrations divided by the V-normalized concentrations in the basin geochemical background showed the highest Enrichment Factors for Ag and Hg (EF; up to 34 and 140, respectively). These results suggest a severe contamination in the Loire Estuary for both elements. Intra-estuarine Ag and Hg anomalies were identified by comparison between respective normalized concentrations in the Loire Estuary surface sediments and those measured in the surface sediments at the outlet of the Loire River System (watershed-derived). Anthropogenic intra-estuarine Ag and Hg stocks in the uppermost centimetre of the sediment compared with rough annual fluvial flux estimates suggest that the overall strong Enrichment Factors for Ag (EFAg) and and Hg (EFHg) in the Loire Estuary sediments are mainly due to watershed-derived inputs, highlighting the need of high temporal hydro-geochemical monitoring to establish reliable incoming fluxes. Significant correlations obtained between EFCd and EFAg, EFCu and POC and EFHg and POC revealed common behavior and/or sources. Comparison of trace element concentrations with ecotoxicological indices (Sediment Quality Guidelines) provides first standardized information on the

The deposition of trace elements in the environs of a power station

International Nuclear Information System (INIS)

Godbeer, W.C.; Swaine, D.J.

1995-01-01

The fate of trace elements during combustion is discussed, followed by the deposition of trace elements from the atmosphere and from coal firing. Methods of measuring deposition are described. Data from a four year long investigation of deposition around the Wallerawang power station is given. Sphagnum moss was used as a collector. 74 refs., 8 figs., 5 tabs

Some isotopic and geochemical anomalies observed in Mexico prior to large scale earthquakes and volcanic eruptions

International Nuclear Information System (INIS)

Cruz R, S. de la; Armienta, M.A.; Segovia A, N.

1992-05-01

A brief account of some experiences obtained in Mexico, related with the identification of geochemical precursors of volcanic eruptions and isotopic precursors of earthquakes and volcanic activity is given. The cases of three recent events of volcanic activity and one large earthquake are discussed in the context of an active geological environment. The positive results in the identification of some geochemical precursors that helped to evaluate the eruptive potential during two volcanic crises (Tacana 1986 and Colima 1991), and the significant radon-in-soil anomalies observed during a volcanic catastrophic eruption (El Chichon, 1982) and prior to a major earthquake (Michoacan, 1985) are critically analysed. (Author)

Some isotopic and geochemical anomalies observed in Mexico prior to large scale earthquakes and volcanic eruptions

Energy Technology Data Exchange (ETDEWEB)

Cruz R, S. de la; Armienta, M A; Segovia A, N

1992-05-15

A brief account of some experiences obtained in Mexico, related with the identification of geochemical precursors of volcanic eruptions and isotopic precursors of earthquakes and volcanic activity is given. The cases of three recent events of volcanic activity and one large earthquake are discussed in the context of an active geological environment. The positive results in the identification of some geochemical precursors that helped to evaluate the eruptive potential during two volcanic crises (Tacana 1986 and Colima 1991), and the significant radon-in-soil anomalies observed during a volcanic catastrophic eruption (El Chichon, 1982) and prior to a major earthquake (Michoacan, 1985) are critically analysed. (Author)

Trace elements in oil shale. Progress report, 1976--1979

Energy Technology Data Exchange (ETDEWEB)

Chappell, W.R.

1979-01-01

The overall objective of the program is to evaluate the environmental and health consequences of the release of toxic trace elements (As, B, F, Mo, Se) by shale oil production and use. Some of the particularly significant results are: The baseline geochemical survey shows that stable trace elements maps can be constructed for numerous elements and that the trends observed are related to geologic and climatic factors. Shale retorted by above-ground processes tends to be very homogeneous (both in space and in time) in trace element content. This implies that the number of analytical determinations required of processed shales is not large. Leachate studies show that significant amounts of B, F, And Mo are released from retorted shales and while B and Mo are rapidly flushed out, F is not. On the other hand, As, Se, and most other trace elements ae not present in significant quantities. Significant amounts of F and B are also found in leachates of raw shales. Very large concentrations of reduced sulfur species are found in leachates of processed shale. Upon oxidation a drastic lowering in pH is observed. Preliminary data indicates that this oxidation is catalyzed by bacteria. Very high levels of B and Mo are taken up in some plants growing on processed shale with and without soil cover. These amounts depend upon the process and various site specific characteristics. In general, the amounts taken up decrease with increasing soil cover. On the other hand, we have not observed significant uptake of As, Se, and F into plants. There is a tendency for some trace elements to associate with specific organic fractions, indicating that organic chelation or complexation may play an important role. In particular, most of the Cd, Se, and Cr in shale oil is associated with the organic fraction containing most of the nitrogen-containing compounds.

Contrasting Cu-Au and Sn-W Granite Metallogeny through the Zircon Geochemical and Isotopic Record

Science.gov (United States)

Gardiner, Nicholas; Hawkesworth, Chris; Robb, Laurence; Whitehouse, Martin; Roberts, Nick; Kirkland, Chris

2017-04-01

Magmatic genesis and evolution - mediated by geodynamic setting - exert a primary control on the propensity of granites to be metal fertile. A revolution in our understanding of these petrogenetic processes has been made through a range of mineral-based tools, most notably the common accessory mineral zircon. There is consequently considerable interest in whether the geochemical and isotopic compositions of zircon can be applied to metallogenic problems. The paired magmatic belts of Myanmar have broadly contrasting metallogenic affinities (Sn-W versus Cu-Au), and are interpreted to have formed on the accretionary margin of the subducting Neo-Tethys Ocean. They therefore present the opportunity to geochemically compare and contrast the zircon compositions in two end-member types of granite-hosted mineral deposits generated in collisional settings. We present an integrated zircon isotope (U-Pb, Lu-Hf, O) and trace element dataset that fingerprint: (a) source; (b) redox conditions; and (c) degree of fractionation. These variables all impact on magma fertility, and our key question to address is whether they can be reliably traced and calibrated within the Myanmar zircon record. Granitoid-hosted zircons from the I-type copper arc have juvenile ɛHf (+7 to +12) and mantle-like δ18O (5.3 ‰), whereas zircons from the S-type tin belt have low ɛHf (-7 to -13) and heavier δ18O (6.2-7.7 ‰). Plotting Hf versus U/Yb reaffirms that the tin belt magmas contain greater crustal contributions than the copper arc rocks. Links between whole rock Rb/Sr and zircon Eu/Eu* highlights that the latter can be used to monitor magma fractionation in systems that crystallize plagioclase (low Sr/Y). Ce/Ce* and Eu/Eu* in zircon are thus sensitive to redox and fractionation respectively, and can be used to evaluate the sensitivity of zircons to the metallogenic affinity of their host rocks. Tin contents that exceed the solubility limit are required in order to make a magmatic

Isotope and ion selectivity in reverse osmosis desalination: geochemical tracers for man-made freshwater.

Science.gov (United States)

Kloppmann, Wolfram; Vengosh, Avner; Guerrot, Catherine; Millot, Romain; Pankratov, Irena

2008-07-01

A systematic measurement of ions and 2H/1H, 7Li/6Li, 11B/10B, 18O/ 16O, and 87Sr/86Sr isotopes in feed-waters, permeates, and brines from commercial reverse osmosis (RO) desalination plants in Israel (Ashkelon, Eilat, and Nitzana) and Cyprus (Larnaca) reveals distinctive geochemical and isotopic fingerprints of fresh water generated from desalination of seawater (SWRO) and brackish water (BWRO). The degree of isotope fractionation during the passage of water and solutes through the RO membranes depends on the medium (solvent-water vs. solutes), chemical speciation of the solutes, their charge, and their mass difference. O, H, and Sr isotopes are not fractionated during the RO process. 7Li is preferentially rejected in low pH RO, and B isotope fractionation depends on the pH conditions. Under low pH conditions, B isotopes are not significantly fractionated, whereas at high pH, RO permeates are enriched by 20 per thousand in 11B due to selective rejection of borate ion and preferential permeation of 11B-enriched boric acid through the membrane. The specific geochemical and isotopic fingerprints of SWRO provide a unique tool for tracing "man-made" fresh water as an emerging recharge component of natural water resources.

Geochemical Characteristics of the Gyeongju LILW Repository II. Rock and Minera

International Nuclear Information System (INIS)

Kim, Geon Young; Koh, Yong Kwon; Choi, Byoung Young; Shin, Seon Ho; Kim, Doo Haeng

2008-01-01

Geochemical study on the rocks and minerals of the Gyeongju low and intermediate level waste repository was carried out in order to provide geochemical data for the safety assessment and geochemical modeling. Polarized microscopy, X-ray diffraction method, chemical analysis for the major and trace elements, scanning electron microscopy (SEM), and stable isotope analysis were applied. Fracture zones are locally developed with various degrees of alteration in the study area. The study area is mainly composed of granodiorite and diorite and their relation is gradational in the field. However, they could be easily distinguished by their chemical property. The granodiorite showed higher Sig 2 content and lower MgO and Fe 2 O 3 contents than the diorite. Variation trends of the major elements of the granodiorite and diorite were plotted on the same line according to the increase of Sig 2 content suggesting that they were differentiated from the same magma. Spatial distribution of the various elements showed that the diorite region had lower Sig 2 , Al 2 O 3 , Na 2 O and K 2 O contents, and higher CaO, Fe 2 O 3 contents than the granodiorite region. Especially, because the differences in the CaO and Na 2 O distribution were most distinct and their trends were reciprocal, the chemical variation of the plagioclase of the granitic rocks was the main parameter of the chemical variation of the host rocks in the study area. Identified fracture-filling minerals from the drill core were montmorillonite, zeolite minerals, chlorite, illite, calcite and pyrite. Especially pyrite and laumontite, which are known as indicating minerals of hydrothermal alteration, were widely distributed in the study area indicating that the study area was affected by mineralization and/or hydrothermal alteration. Sulfur isotope analysis for the pyrite and oxygen-hydrogen stable isotope analysis for the clay minerals indicated that they were originated from the magma. Therefore, it is considered that

Report on the intercomparison for the determination of trace elements in Lake Sediment (SL-1)

Energy Technology Data Exchange (ETDEWEB)

NONE

1979-02-01

The determination of trace element concentrations including those of the rare-earths in geological samples has gained much importance during the past decade. Knowledge of the concentrations of specific elements and of their ratios have proved essential for the understanding of the development of geological strata. With increasing use of instruments in analysis, reference samples have become essential for their calibration and various international organizations have issued reference materials to monitor precision and accuracy in chemical determinations. The IAEA has in the past organized several intercomparisons and prepared reference samples of geochemical materials. The present report deals with a recent intercomparison on the determination of trace elements in Lake Sediment (Sl-1) carried out in 1977-1978 and involving the participation of 43 institutes who returned a total of 2535 individual results on 43 elements.

Geochemical mapping of the Hyeonri, Bongpyeong, Yeongog and Doam sheets (1:50,000)

Energy Technology Data Exchange (ETDEWEB)

Lee, Jin Soo; Seo, Hyo Joon [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

1997-12-01

A geochemical mapping was made on the four quadrangles of the Hyeonri, Bongpyeong, Yeongog and Doam Sheets (1:50,000) located in the northeastern part of South Korea. The area of about 2,500 Km{sup 2} is covered mostly the Precambrian metamorphic rocks and Jurassic granites, and partly by Permo-Triassic sedimentary and Cretaceous granites. Geochemical samples of stream sediment and natural surface water, totally 713 for each media, were systematically collected from in the primary and secondary order streams. The samples were chemically analysed for the trace elements by ICP, and anion elements of water samples were determined by IC. The pH. EC (electrical conductivity) Eh, DO (dissolved oxygen) and bicarbonate were measured in situ by digital portable equipment. Several deposits of gold, fluorite, molybdenite and iron deposits were weakly formed at or around the contact zone between metamorphic rocks and granites. The coal mines were actively operated until 1970`s in the southeastern part of the area. At present, none of them is operating owing to shortage of ore reserves and higher mining cost excepting a few non-metallic or construction stone mines. Geochemical anomalies were revealed out several areas deriving from mineralized factors or effected by some polluted evidences of human life. The anomalies of Pb, Zn, Co, Cr, Cd, etc for sulfide minerals were poorly confined around old prospects or calcareous formation of Chosun Supergroup. The conductivity of stream in the Odae national park is extremely high value to be expecting mineral deposit such as uranium or rare earth metals etc.. The anomalies with Cl, Na, Mg, NO{sub 3}, HCO{sub 3} near or along the expressway and main roads where the population, are densely, were identified to be polluted by human activities and stock-farming. (author). 36 refs., 11 tabs., 57 figs.

Stabilities of nuclear waste forms and their geochemical interactions in repositories

International Nuclear Information System (INIS)

White, W.B.

1980-01-01

The stabilities of high-level nuclear waste forms in a repository environment are briefly discussed. The advantages and disadvantages of such waste forms as borosilicate glass, supercalcine ceramics, and synthetic minerals are presented in context with the different rock types which have been proposed as possible host rocks for repositories. It is concluded that the growing geochemical evidence favors the use of a silicate rock repository because of the effectiveness of aluminosilicate rocks as chemical barriers for most radionuclides

A Spatially Constrained Multi-autoencoder Approach for Multivariate Geochemical Anomaly Recognition

Science.gov (United States)

Lirong, C.; Qingfeng, G.; Renguang, Z.; Yihui, X.

2017-12-01

Separating and recognizing geochemical anomalies from the geochemical background is one of the key tasks in geochemical exploration. Many methods have been developed, such as calculating the mean ±2 standard deviation, and fractal/multifractal models. In recent years, deep autoencoder, a deep learning approach, have been used for multivariate geochemical anomaly recognition. While being able to deal with the non-normal distributions of geochemical concentrations and the non-linear relationships among them, this self-supervised learning method does not take into account the spatial heterogeneity of geochemical background and the uncertainty induced by the randomly initialized weights of neurons, leading to ineffective recognition of weak anomalies. In this paper, we introduce a spatially constrained multi-autoencoder (SCMA) approach for multivariate geochemical anomaly recognition, which includes two steps: spatial partitioning and anomaly score computation. The first step divides the study area into multiple sub-regions to segregate the geochemical background, by grouping the geochemical samples through K-means clustering, spatial filtering, and spatial constraining rules. In the second step, for each sub-region, a group of autoencoder neural networks are constructed with an identical structure but different initial weights on neurons. Each autoencoder is trained using the geochemical samples within the corresponding sub-region to learn the sub-regional geochemical background. The best autoencoder of a group is chosen as the final model for the corresponding sub-region. The anomaly score at each location can then be calculated as the euclidean distance between the observed concentrations and reconstructed concentrations of geochemical elements.The experiments using the geochemical data and Fe deposits in the southwestern Fujian province of China showed that our SCMA approach greatly improved the recognition of weak anomalies, achieving the AUC of 0.89, compared

Reconnaissance Geochemical Study

African Journals Online (AJOL)

distribution patterns. The geochemical distribution maps of the elements reveal that Cu, Pb, Zn, Co, Sc, Ni, Cr, .... After filtration, the leached solutions were diluted with ultra ...... some other rare earth elements in the study area. The occurrence ...

Atmospheric pollution in an urban environment by tree bark biomonitoring--part I: trace element analysis.

Science.gov (United States)

Guéguen, Florence; Stille, Peter; Lahd Geagea, Majdi; Boutin, René

2012-03-01

Tree bark has been shown to be a useful biomonitor of past air quality because it accumulates atmospheric particulate matter (PM) in its outermost structure. Trace element concentrations of tree bark of more than 73 trees allow to elucidate the impact of past atmospheric pollution on the urban environment of the cities of Strasbourg and Kehl in the Rhine Valley. Compared to the upper continental crust (UCC) tree barks are strongly enriched in Mn, Ni, Cu, Zn, Cd and Pb. To assess the degree of pollution of the different sites in the cities, a geoaccumulation index I(geo) was applied. Global pollution by V, Ni, Cr, Sb, Sn and Pb was observed in barks sampled close to traffic axes. Cr, Mo, Cd pollution principally occurred in the industrial area. A total geoaccumulation index I(GEO-tot) was defined; it is based on the total of the investigated elements and allows to evaluate the global pollution of the studied environment by assembling the I(geo) indices on a pollution map. Copyright © 2011 Elsevier Ltd. All rights reserved.

Geochemical modelling: what phenomena are missing

International Nuclear Information System (INIS)

Jacquier, P.

1989-12-01

In the framework of safety assessment of radioactive waste disposal, retention phenomena are usually taken into account by the Kd concept. It is well recognized that this concept is not enough for safety assessment models, because of the several and strong assumptions which are involved in this kind of representation. One way to have a better representation of the retention phenomena, is to substitute for this Kd concept an explicit description of geochemical phenomena and then couple transport codes with geochemical codes in a fully or a two-step procedure. We use currently such codes, but the scope of this paper is to display the limits today of the geochemical modelling in connection with sites analysis for deep disposal. In this paper, we intend to give an overview of phenomena which are missing in the geochemical models, or which are not completely introduced in the models. We can distinguish, on one hand phenomena for which modelling concepts exist such as adsorption/desorption and, on the other hand, phenomena for which modelling concepts do not exist for the moment such as colloids, and complexation by polyelectrolyte solutions (organics). Moreover we have to take care of very low concentrations of radionuclides, which can be expected from the leaching processes in the repository. Under those conditions, some reactions may not occur. After a critical review of the involved phenomena, we intend to stress the main directions of the wishful evolution of the geochemical modelling. This evolution should improve substantially the quality of the above-mentioned site assessments

Coupling of transport and geochemical models

International Nuclear Information System (INIS)

Noy, D.J.

1986-01-01

This report considers mass transport in the far-field of a radioactive waste repository, and detailed geochemical modelling of the ground-water in the near-field. A parallel approach to this problem of coupling transport and geochemical codes is the subject of another CEC report (ref. EUR 10226). Both studies were carried out in the framework of the CEC project MIRAGE. (Migration of radionuclides in the geosphere)

Evolution of geochemical conditions in SFL 3-5

International Nuclear Information System (INIS)

Karlsson, Fred; Lindgren, M.; Skagius, K.; Wiborgh, M.; Engkvist, I.

1999-12-01

The evolution of geochemical conditions in the repository for long-lived low- and intermediate-level waste, SFL 3-5, and in the vicinity of the repository are important when predicting the retention of radionuclides and the long-term stability of engineered barriers. In this study the initial conditions at different repository sites at 300 - 400 m depth, the influence of repository construction and operation, the expected conditions after repository closure and saturation, and the evolution in a long-term perspective are discussed. Groundwaters that are found at these depths have near-neutral pH and are reducing in character, but the composition can vary from saline to non-saline water. The water chemistry in the near-field will mainly be influenced by the composition of the groundwater and by the large amounts of cementitious material that can be found in the repository. Disturbances caused during construction and operation are not expected to be permanent. Studies of old concrete indicate that leaching of concrete is a slow process. The geochemical conditions in the repository are therefore expected to be stable and prevail for hundreds of thousand years. However, the evolution of the surrounding environment may influence the conditions in long-term perspective

Evolution of geochemical conditions in SFL 3-5

Energy Technology Data Exchange (ETDEWEB)

Karlsson, Fred [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Lindgren, M.; Skagius, K.; Wiborgh, M. [Kemakta Konsult AB, Stockholm (Sweden); Engkvist, I. [Barsebaeck Kraft AB (Sweden)

1999-12-01

The evolution of geochemical conditions in the repository for long-lived low- and intermediate-level waste, SFL 3-5, and in the vicinity of the repository are important when predicting the retention of radionuclides and the long-term stability of engineered barriers. In this study the initial conditions at different repository sites at 300 - 400 m depth, the influence of repository construction and operation, the expected conditions after repository closure and saturation, and the evolution in a long-term perspective are discussed. Groundwaters that are found at these depths have near-neutral pH and are reducing in character, but the composition can vary from saline to non-saline water. The water chemistry in the near-field will mainly be influenced by the composition of the groundwater and by the large amounts of cementitious material that can be found in the repository. Disturbances caused during construction and operation are not expected to be permanent. Studies of old concrete indicate that leaching of concrete is a slow process. The geochemical conditions in the repository are therefore expected to be stable and prevail for hundreds of thousand years. However, the evolution of the surrounding environment may influence the conditions in long-term perspective.

Geochemical study of water-rock interaction processes on geothermal systems of alkaline water in granitic massif

International Nuclear Information System (INIS)

Buil gutierrez, B.; Garcia Sanz, S.; Lago San Jose, M.; Arranz Yague, E.; Auque Sanz, L.

2002-01-01

The study of geothermal systems developed within granitic massifs (with alkaline waters and reducing ORP values) is a topic of increasing scientific interest. These systems are a perfect natural laboratory for studying the water-rock interaction processes as they are defined by three main features: 1) long residence time of water within the system, 2) temperature in the reservoir high enough to favour reaction kinetics and finally, 3) the comparison of the chemistry of the incoming and outgoing waters of the system allows for the evaluation of the processes that have modified the water chemistry and its signature, The four geothermal systems considered in this paper are developed within granitic massifs of the Spanish Central Pyrenes; these systems were studied from a geochemical point of view, defining the major, trace and REE chemistry of both waters and host rocks and then characterizing the composition and geochemical evolution of the different waters. Bicarbonate-chloride-sodic and bicarbonate-sodic compositions are the most representative of the water chemistry in the deep geothermal system, as they are not affected by secondary processes (mixing, conductive cooling, etc). (Author)

Geochemical modelling baseline compositions of groundwater

DEFF Research Database (Denmark)

Postma, Diederik Jan; Kjøller, Claus; Andersen, Martin Søgaard

2008-01-01

and variations in water chemistry that are caused by large scale geochemical processes taking place at the timescale of thousands of years. The most important geochemical processes are ion exchange (Valreas and Aveiro) where freshwater solutes are displacing marine ions from the sediment surface, and carbonate......Reactive transport models, were developed to explore the evolution in groundwater chemistry along the flow path in three aquifers; the Triassic East Midland aquifer (UK), the Miocene aquifer at Valreas (F) and the Cretaceous aquifer near Aveiro (P). All three aquifers contain very old groundwaters...... dissolution (East Midlands, Valreas and Aveiro). Reactive transport models, employing the code PHREEQC, which included these geochemical processes and one-dimensional solute transport were able to duplicate the observed patterns in water quality. These models may provide a quantitative understanding...

Modelling of leaching and geochemical processes in an aged MSWIBA subbase layer

Energy Technology Data Exchange (ETDEWEB)

Bendz, David; Suer, Pascal; Sloot, Hans van der; Kosson, David; Flyhammar, Peter

2009-07-15

In a previous project, the accumulated effects of leaching and aging in a subbase layer of bottom ash in a test road were investigated. The test road were constructed in 1987 in Linkoeping, Sweden, and was in use until the start of the Vaendoera Q4-241 study in September 2003. The overall objective of the present study is to bring the evaluation of the previous project (Q4-241) further by taking advantage of the existing data, perform complementary laboratory experiments on four composite samples reflecting different degree of exposure to atmosphere and leaching. The specific objectives were to investigate: (i) what processes and mineral phases that govern leaching of macro- and trace elements and DOC in the bottom ash after 16 years (1987- 2003) of aging under field conditions. (ii) how the hydrologic conditions, infiltration of water and leachate production has evolved with time. The following tests were performed on the composite samples: pH-stat test, column test, Fe/Al oxide extraction and TOC fractioning. Geochemical and hydrological modelling where performed with LeachXS/Orchestra and Hydrus 2-D. Daily precipitation data from the Swedish Meteorological and Hydrological Institute (SMHI) from the Malmslaett (Linkoeping) measurement station was used in the hydrological modelling of January 1988 to the 1st of september 2003. The hydraulic modeling results show that the bottom ash subbase layer endure seasonal wet and dry cycles. The results confirm that, depending on the boundary conditions along the shoulders the capillary potential may drive moisture either in or out of the road body. The water retention parameters for bottom ash were crucial in the hydraulic modeling and the capillary forces in bottom ash were found to be significant with a water retention curve close to silt. This explains the observed depletion of easily soluble salts in the test road. The results showed that the accumulated LS ratio for the bottom ash subbase layer reached about LS:10 in

Environmental responsibilities of livestock feeding using trace mineral supplements

Directory of Open Access Journals (Sweden)

Daniel Brugger

2015-09-01

Full Text Available Trace elements are essential dietary components for livestock species. However, they also exhibit a strong toxic potential. Therefore, their fluxes through the animal organism are tightly regulated by a complex molecular machinery that controls the rate of absorption from the gut lumen as well as the amount of excretion via faeces, urine and products (e.g., milk in order to maintain an internal equilibrium. When supplemented in doses above the gross requirement trace elements accumulate in urine and faeces and, hence, manure. Thereby, trace element emissions represent a potential threat to the environment. This fact is of particular importance in regard to the widely distributed feeding practice of pharmacological zinc and copper doses for the purpose of performance enhancement. Adverse environmental effects have been described, like impairment of plant production, accumulation in edible animal products and the water supply chain as well as the correlation between increased trace element loads and antimicrobial resistance. In the light of discussions about reducing the allowed upper limits for trace element loads in feed and manure from livestock production in the European Union excessive dosing needs to be critically reconsidered. Moreover, the precision in trace element feeding has to be increased in order to avoid unnecessary supplementation and, thereby, heavy metal emissions from livestock production. Keywords: Trace element, Livestock, Homeostasis, Pharmacological supplementation, Accumulation, Environment

Objective computerized approaches for centralized geophysical and geochemical landscape project planning.

Directory of Open Access Journals (Sweden)

Danilyan Eugene Andreevich

2013-10-01

Full Text Available At present landscape design does not represent a scientific subject in strict sense, being a superposition of decorative and applied landscape art and the methods of graphic architectural planning. Serving interests of customers, it does not harmonize with the individual needs of the ground based on landscape geochemistry and ecology. Hence, it results in great number of grounds not consistent with each other according to geochemical criteria. In many cases total soil changing, isolation of natural hydrodynamic drainage, introduction of exotic plants interacting with their environment (including abiotic relations take place, it results in disequilibrium in the ground. Ecological system efficiency needs to be constantly artificially maintained, and that does not support its stability. In other words, without maintaining sufficient conditions, it will be influenced by succession with the course of time, as a particular case of potential gradient equalization. Hence, at present there is an acute problem to develop such a concept of landscape design, that, covering ecological requirements of customers, would be mass one, not producing gradient isolation effect and ecologically self-sustaining in given environment at the same time. It is evident, that to meet these requirements, this concept should not be the product of subjective vision of the author, but direct consequence of geophysical and geochemical landscape condition with theoretical development allowing calculation testing at any scale of geographical zoning.

Lithology and mineralogy recognition from geochemical logging tool data using multivariate statistical analysis.

Science.gov (United States)

Konaté, Ahmed Amara; Ma, Huolin; Pan, Heping; Qin, Zhen; Ahmed, Hafizullah Abba; Dembele, N'dji Dit Jacques

2017-10-01

The availability of a deep well that penetrates deep into the Ultra High Pressure (UHP) metamorphic rocks is unusual and consequently offers a unique chance to study the metamorphic rocks. One such borehole is located in the southern part of Donghai County in the Sulu UHP metamorphic belt of Eastern China, from the Chinese Continental Scientific Drilling Main hole. This study reports the results obtained from the analysis of oxide log data. A geochemical logging tool provides in situ, gamma ray spectroscopy measurements of major and trace elements in the borehole. Dry weight percent oxide concentration logs obtained for this study were SiO 2 , K 2 O, TiO 2 , H 2 O, CO 2 , Na 2 O, Fe 2 O 3 , FeO, CaO, MnO, MgO, P 2 O 5 and Al 2 O 3 . Cross plot and Principal Component Analysis methods were applied for lithology characterization and mineralogy description respectively. Cross plot analysis allows lithological variations to be characterized. Principal Component Analysis shows that the oxide logs can be summarized by two components related to the feldspar and hydrous minerals. This study has shown that geochemical logging tool data is accurate and adequate to be tremendously useful in UHP metamorphic rocks analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Long-term Geochemical Evolution of Lithogenic Versus Anthropogenic Distribution of Macro and Trace Elements in Household Attic Dust.

Science.gov (United States)

Balabanova, Biljana; Stafilov, Trajče; Šajn, Robert; Tănăselia, Claudiu

2017-01-01

Attic dusts were examined as historical archives of anthropogenic emissions, with the goal of elucidating the enrichment pathways associated with hydrothermal exploitation of Cu, Pb, and Zn minerals in the Bregalnica River basin in the eastern part of the Republic of Macedonia. Dust samples were collected from 84 settlements. Atomic emission spectrometry and mass spectrometry with inductively coupled plasma were applied as analytical techniques for the determination of 69 element contents. Multivariate analysis was applied for the extraction of dominant geochemical markers. The lithogenic distribution was simplified to six dominant geochemical markers: F1: Ga-Nb-Ta-Y-(La-Gd)-(Eu-Lu); F2: Be-Cr-Li-Mg-Ni; F3: Ag-Bi-Cd-Cu-In-Mn-Pb-Sb-Te-W-Zn; F4: Ba-Cs-Hf-Pd-Rb-Sr-Tl-Zr; F5: As-Co-Ge-V; and F6: К-Na-Sc-Ti. The anthropogenic effects on the air pollution were marked by a dominance of F3 and secondary dominance of F5. The fifth factor also was determined as a lithogenic marker for the occurrence of the very old Rifeous shales. The first factor also presents a very unique association that despite the heterogeneity relays on natural phenomena of tracking the deposition in areas of Proterosoic gneisses; related to the distribution of fine particles was associated with carbonate-silicate volcanic rocks. Intensive poly-metallic dust depositions were recorded only in the surroundings of localities where the hydrothermal extractions are implemented. Long-term deposition can be considered as pollution indexes for these hot spots. This mainly affects the Cd, Pb, and Zn deposition that is as high as 25, 3900, and 3200 mg/kg, respectively.

Geochemistry of marine and lacustrine bands in the Upper Carboniferous of the Netherlands

NARCIS (Netherlands)

Kombrink, H.; Os, B.J.H. van; Zwan, C.J. van der; Wong, Th.E.

2008-01-01

Geochemical studies on Upper Carboniferous marine bands showed that marked enrichment in redox-sensitive trace elements (uranium (U), vanadium (V), molybdenum (Mo)) mostly occur if they contain Goniatites. Goniatites indicate deposition in relatively distal and deep marine environments. In contrast,

Geochemical characteristics of granitoids and related mafic granulites from the Pan-African Dahomeyide belt, southeastern Ghana

International Nuclear Information System (INIS)

Aidoo, F.

2012-07-01

-23%) and sometimes sericite and microline. The mafic granulites contain SiO 2 content of 43.10-49.40 wt. % with low to moderate Mg# of 37-60. They exhibit fractionated REE patterns with (La/Sm) N = 1.80-5.85 and (La/Yb) N = 3.76-76.30, and negative and positive Eu anomalies (Eu/Eu*'' = 0.68-2.10). The mafic granulites show total REEs content of 17.86-1245.13 ppm with Eu/Eu*'' between 1.01 and 1.36. Two types of mafic granulites are identified with one type displaying un-fractionated (flat), MORB-like REE patterns whereas the other shows slightly fractionated to highly fractionated, IAT-like REE patterns. The primitive mantle-normalised trace element patterns of the granulites show subduction-related geochemical characteristics. The LREE-enriched type show pronounced negative Th, U, Ta, Nb, Zr and Hf anomalies and positive l3a and Sr I) pical arc roots, whereas the un-fractionated type show pronounced Th-U trough, but slightly negative Ta, Nb, Hf, Ti anomalies and positive Ba and Sr anomalies, suggesting subduction inputs in the protolith of the MORB-like granulites. Thus, the mafic granulites show both N-MORB and IAT imprints. The ultramafic rock, AD6, associated with the mafic granulites is composed mainly of pyroxene (60%), plagioclase (13%), olivine (12%), hornblende (6%) and sericite (4%). It contains SiO 2 content of 52.80 wt. %; low TiO 2 (0.25 wt. %) and has very high Mg# of 84. The ultramaf-ic rock also shows total REEs content of 64.85 ppm, very high Cr of 3520 ppm and Ni of 48I ppm. The ultramafic rocks also show typical IAT signatures. In general, the mafic granulites and ultramafic rocks from the suture zone assemblages of the Dahomeyide belt suggest subduction zone magmatism with oceanic crust forming in either a back-arc basin or intra-arc basin environment. The geochemical characteristics of the granitoid gneisses from the external nappes (basement complex) also show subduction-related magmatic activity. Therefore, all the rocks studied

Geochemical mapping study of Panjang island

International Nuclear Information System (INIS)

Sutisna; Sumardjo

2010-01-01

Impact of industrial and regional development are not only related to an improvement of socio-economic, but also to an environmental conservation and sustainable. This impact could be observed on a change of geochemical mapping before and after an operational of the industry. In the relation with a regional development and resources utilization, the geochemical mapping have been done in the aim to know a resources and an elemental distribution at Panjang island. In this research, ko-Instrumental Neutron Activation Analysis (k_0-INAA) have been applied in an elemental quantification on the geochemical mapping. Pencuplikan of geochemical sample have been carried out by using a grid systematic method with a sample density of about 10 sample per square kilometre involved 85 pencuplikan point. The geochemical sample of sediment and soil have been provided as a dry weight of 100 mesh. Internal quality control have done by using a number of Standard Reference Materials obtained from US. Geological Survey. Fifteen elements of Sc, Co, In, Rb, Mo, Ba, Ce, Nd, Eu, La, Yb, Th, U, lr and Hf contained in standard materials have been evaluated. The analysis result show that a relative standard deviation less than 11 %, except for Mo (13 %) and lr (26 %). Fourteen elements of Al, Br, Ca, Co, Eu, Fe, La, U, Na, Ce, Mn, As, Sc and Th have been mapped and presented in this paper. The major elements of Ca, Al and Fe, and minor elements of Mn, U and Sc are distributed at all region. The lanthanide elements of La, Ce and Eu have vary concentration and could be found at the middle to the north of the island. (author)

Contemporaneous deposition of phyllosilicates and sulfates: Using Australian acidic saline lake deposits to describe geochemical variability on Mars

Science.gov (United States)

Baldridge, A.M.; Hook, S.J.; Crowley, J.K.; Marion, G.M.; Kargel, J.S.; Michalski, J.L.; Thomson, B.J.; de Souza, Filho C.R.; Bridges, N.T.; Brown, A.J.

2009-01-01

Studies of the origin of the Martian sulfate and phyllosilicate deposits have led to the hypothesis that there was a marked, global-scale change in the Mars environment from circum-neutral pH aqueous alteration in the Noachian to an acidic evaporitic system in the late Noachian to Hesperian. However, terrestrial studies suggest that two different geochemical systems need not be invoked to explain such geochemical variation.Western Australian acidic playa lakes have large pH differences separated vertically and laterally by only a few tens of meters, demonstrating how highly variable chemistries can coexist over short distances in natural environments. We suggest diverse and variable Martian aqueous environments where the coetaneous formation of phyllosilicates and sulfates at the Australian sites are analogs for regions where phyllosilicates and sulfates coexist on Mars. In these systems, Fe and alkali earth phyllosilicates represent deep facies associated with upwelling neutral to alkaline groundwater, whereas aluminous phyllosilicates and sulfates represent near-surface evaporitic facies formed from more acidic brines. Copyright 2009 by the American Geophysical Union.

Groundwater sources and geochemical processes in a crystalline fault aquifer

Science.gov (United States)

Roques, Clément; Aquilina, Luc; Bour, Olivier; Maréchal, Jean-Christophe; Dewandel, Benoît; Pauwels, Hélène; Labasque, Thierry; Vergnaud-Ayraud, Virginie; Hochreutener, Rebecca

2014-11-01

The origin of water flowing in faults and fractures at great depth is poorly known in crystalline media. This paper describes a field study designed to characterize the geochemical compartmentalization of a deep aquifer system constituted by a graben structure where a permeable fault zone was identified. Analyses of the major chemical elements, trace elements, dissolved gases and stable water isotopes reveal the origin of dissolved components for each permeable domain and provide information on various water sources involved during different seasonal regimes. The geochemical response induced by performing a pumping test in the fault-zone is examined, in order to quantify mixing processes and contribution of different permeable domains to the flow. Reactive processes enhanced by the pumped fluxes are also identified and discussed. The fault zone presents different geochemical responses related to changes in hydraulic regime. They are interpreted as different water sources related to various permeable structures within the aquifer. During the low water regime, results suggest mixing of recent water with a clear contribution of older water of inter-glacial origin (recharge temperature around 7 °C), suggesting the involvement of water trapped in a local low-permeability matrix domain or the contribution of large scale circulation loops. During the high water level period, due to inversion of the hydraulic gradient between the major permeable fault zone and its surrounding domains, modern water predominantly flows down to the deep bedrock and ensures recharge at a local scale within the graben. Pumping in a permeable fault zone induces hydraulic connections with storage-reservoirs. The overlaid regolith domain ensures part of the flow rate for long term pumping (around 20% in the present case). During late-time pumping, orthogonal fluxes coming from the fractured domains surrounding the major fault zone are dominant. Storage in the connected fracture network within the

X-Ray and Radiometrics in Geo-Ecological and Geochemical Mapping

Energy Technology Data Exchange (ETDEWEB)

Fedyanin, S. N. [Navoi Mining and Metallurgical Combinat (Uzbekistan)

2014-05-15

Monitoring of tailing pits of uranium ore conversion products and reserve supplies of low-grade ores stored in dumps is traditionally based on radiation environment on these sites and adjacent territories. The results of gamma-ray spectrometry of solid fractions and radon concentration measurement in liquid and gas phases of technogenic formations are used in radiation hazard evaluation. Radiometric testing practice of low-activity field formations in loose and lump masses shows that due to high emanating ability it is necessary to use dual-channel radiometer for ionizing radiation background record and compensation. Thus gamma-radiometry is not the direct method of uranium content determination and alfa- and beta-radiometry can be correctly used only for sample analysis in laboratory environment. Consequently, distant express testing with the help of X-ray radiometric (XRM) instruments (on calcium, iron, manganese, titanium, copper, arsenic, lead, strontium, selenium, molybdenum, uranium, etc.) is recommended for additional introduction in field observations of radio-ecological environment in mining and processing production tailing and dumps of low-grade ore reserve supplies. Thanks to preliminary areal schemes of geochemical zonality as per XRM data XRM application allows to use the sample limit, given for a wide range of laboratory analyses rationally. Sampling places and their number as well as kinds of laboratory analyses are chosen based on XRM data.It is rather effective to use laboratory variant of atomic absorptive analysis on mercury and stibium in gases (GA), generated in the process of grated samples calcination in muffle furnaces. During the presentation of the report In order to prove the effectiveness of XRM and GA presentation graphics with the results of areal mapping using the above methods and geochemical testing on the territories of Tashkent (Uzbekistan) and Chimkent (Kazakhstan) regions within the framework of the geological and ecological

Factor analytical approaches for evaluating groundwater trace element chemistry data

International Nuclear Information System (INIS)

Farnham, I.M.; Johannesson, K.H.; Singh, A.K.; Hodge, V.F.; Stetzenbach, K.J.

2003-01-01

The multivariate statistical techniques principal component analysis (PCA), Q-mode factor analysis (QFA), and correspondence analysis (CA) were applied to a dataset containing trace element concentrations in groundwater samples collected from a number of wells located downgradient from the potential nuclear waste repository at Yucca Mountain, Nevada. PCA results reflect the similarities in the concentrations of trace elements in the water samples resulting from different geochemical processes. QFA results reflect similarities in the trace element compositions, whereas CA reflects similarities in the trace elements that are dominant in the waters relative to all other groundwater samples included in the dataset. These differences are mainly due to the ways in which data are preprocessed by each of the three methods. The highly concentrated, and thus possibly more mature (i.e. older), groundwaters are separated from the more dilute waters using principal component 1 (PC 1). PC 2, as well as dimension 1 of the CA results, describe differences in the trace element chemistry of the groundwaters resulting from the different aquifer materials through which they have flowed. Groundwaters thought to be representative of those flowing through an aquifer composed dominantly of volcanic rocks are characterized by elevated concentrations of Li, Be, Ge, Rb, Cs, and Ba, whereas those associated with an aquifer dominated by carbonate rocks exhibit greater concentrations of Ti, Ni, Sr, Rh, and Bi. PC 3, and to a lesser extent dimension 2 of the CA results, show a strong monotonic relationship with the percentage of As(III) in the groundwater suggesting that these multivariate statistical results reflect, in a qualitative sense, the oxidizing/reducing conditions within the groundwater. Groundwaters that are relatively more reducing exhibit greater concentrations of Mn, Cs, Co, Ba, Rb, and Be, and those that are more oxidizing are characterized by greater concentrations of V, Cr, Ga

Identification and tracing of Enterococcus spp. by RAPD-PCR in traditional fermented sausages and meat environment.

Science.gov (United States)

Martín, B; Corominas, L; Garriga, M; Aymerich, T

2009-01-01

Four local small-scale factories were studied to determine the sources of enterococci in traditional fermented sausages. Different points during the production of a traditional fermented sausage type (fuet) were evaluated. Randomly amplified polymorphic DNA (RAPD)-PCR was used to type 596 Enterococcus isolates from the final products, the initial meat batter, the casing, the workers' hands and the equipment. Species-specific PCR-multiplex and the partial sequencing of atpA gene and 16S rRNA gene sequencing allowed the identification of the isolates: Enterococcus faecalis (31.4%), Enterococcus faecium (30.7%), Enterococcus sanguinicola (14.9%), Enterococcus devriesei (9.7%), Enterococcus malodoratus (7.2%), Enterococcus gilvus (1.0%), Enterococcus gallinarum (1.3%), Enterococcus casseliflavus (3.4%), Enterococcus hermanniensis (0.2%), and Enterococcus durans (0.2%). A total of 92 different RAPD-PCR profiles were distributed among the different factories and samples evaluated. Most of the genotypes found in fuet samples were traced back to their source. The major sources of enterococci in the traditional fermented sausages studied were mainly the equipment followed by the raw ingredients, although a low proportion was traced back to human origin. This work contributes to determine the source of enterococcal contamination in fermented sausages and also to the knowledge of the meat environment.

Cycling of oxyanion-forming trace elements in groundwaters from a freshwater deltaic marsh

Science.gov (United States)

Telfeyan, Katherine; Breaux, Alexander; Kim, Jihyuk; Kolker, Alexander S.; Cable, Jaye E.; Johannesson, Karen H.

2018-05-01

Pore waters and surface waters were collected from a freshwater system in southeastern Louisiana to investigate the geochemical cycling of oxyanion-forming trace elements (i.e., Mo, W, As, V). A small bayou (Bayou Fortier) receives input from a connecting lake (Lac des Allemands) and groundwater input at the head approximately 5 km directly south of the Mississippi River. Marsh groundwaters exchange with bayou surface water but are otherwise relatively isolated from outside hydrologic forcings, such as tides, storms, and effects from local navigation canals. Rather, redox processes in the marsh groundwaters appear to drive changes in trace element concentrations. Elevated dissolved S(-II) concentrations in marsh groundwaters suggest greater reducing conditions in the late fall and winter as compared to the spring and late summer. The data suggest that reducing conditions in marsh groundwaters initiate the dissolution of Fe(III)/Mn(IV) oxide/hydroxide minerals, which releases adsorbed and/or co-precipitated trace elements into solution. Once in solution, the fate of these elements is determined by complexation with aqueous species and precipitation with iron sulfide minerals. The trace elements remain soluble in the presence of Fe(III)- and SO42-- reducing conditions, suggesting that either kinetic limitations or complexation with aqueous ligands obfuscates the correlation between V and Mo sequestration in sediments with reducing or euxinic conditions.

Terrestrial sedimentary pyrites as a potential source of trace metal release to groundwater – A case study from the Emsland, Germany

International Nuclear Information System (INIS)

Houben, Georg J.; Sitnikova, Maria A.; Post, Vincent E.A.

2017-01-01

Pyrite is a common minor constituent of terrestrial freshwater sediments and a sink for trace elements. Different amounts and morphological types (framboids and euhedral crystals) of sedimentary pyrites were found in the heavy mineral fraction of cores obtained from several drillholes located in the Emsland region, NW Germany. Their trace element contents were investigated to assess their potential for groundwater contamination after oxidation, e.g. induced by dewatering or autotrophic denitrification. Nickel, arsenic and cadmium were found in significant concentrations in pyrite. Geochemical modeling showed that elevated trace metal concentrations in groundwater, potentially exceeding drinking water standards, should preferentially occur in a less than 1 m thick zone situated around the depth of the redoxcline, where nitrate is reduced by pyrite. This was confirmed by depth-specific groundwater sampling in the Emsland and by previously published studies. The absolute concentration of released trace metals depends on their content in the pyrite but also strongly on the nitrate load of groundwater. - Highlights: • Pyrite from heavy mineral fraction of aquifer sediment analyzed for trace metal content. • Pyrites contain significant concentration of trace metals, such as nickel, arsenic, cadmium. • Trace elements are released by autotrophic denitrification. • Reactive transport model predicts small zone of trace element accumulation. • Release of trace elements strongly dependent on nitrate content of groundwater.

Spatial and Temporal Water Quality Dynamics in the Lake Maumelle Reservoir (Arkansas): Geochemical and Planktonic Variance in a Drinking Water Source

Science.gov (United States)

Carey, M. D.; Ruhl, L. S.

2017-12-01

The Lake Maumelle reservoir is Central Arkansas's main water supply. Maintaining a high standard of water quality is important to the over 400,000 residents of this area whom rely on this mesotrophic waterbody for drinking water. Lake Maumelle is also a scenic attraction for recreational boating and fishing. Past research has focused primarily on watershed management with land use/land cover modeling and quarterly water sampling of the 13.91mi2 reservoir. The surrounding land within the watershed is predominately densely forested, with timber farms and the Ouachita National Forest. This project identifies water quality changes spatially and temporally, which have not been as frequently observed, over a 6-month timespan. Water samples were collected vertically throughout the water column and horizontally throughout the lake following reservoir zonation. Parameters collected vertically for water quality profiles are temperature, dissolved oxygen, electrical conductivity, salinity, and pH. Soft sediment samples were collected and pore water was extracted by centrifuge. Cation and anion concentrations in the water samples were determined using ion chromatography, and trace element concentrations were determined using ICPMS. Planktonic abundances were determined using an inverted microscope and a 5ml counting chamber. Trace element, cation, and anion concentrations have been compared with planktonic abundance and location to determine microorganismal response to geochemical variance. During June 2017 sampling, parameters varied throughout the water column (temperature decreased 4 degrees Celsius and dissolved oxygen decreased from 98% to 30% from surface to bottom depths), revealing that the reservoir was becoming stratified. Collected plankton samples revealed the presence of copepod, daphnia, and dinoflagellate algae. Utricularia gibba was present in the littoral zone. Low electrical conductivity readings and high water clarity are consistent with the lake

Geochemical characteristics of Lower Jurassic source rocks in the Zhongkouzi Basin

Science.gov (United States)

Niu, Haiqing; Han, Xiaofeng; Wei, Jianshe; Zhang, Huiyuan; Wang, Baowen

2018-01-01

Zhongkouzi basin is formed in Mesozoic and Cenozoic and developed on the Hercynian folded belt, the degree of exploration for oil and gas is relatively low hitherto. In order to find out the geochemical characteristics of the source rocks and the potentials for hydrocarbon generation. The research result shows that by analysis the geochemical characteristics of outcrop samples and new core samples in Longfengshan Group, Longfengshan Group are most developed intervals of favorable source rocks. They are formed in depression period of the basin when the sedimentary environments is salt water lacustrine and the water is keeping stable; The organic matter abundance is middle-higher, the main kerogen type is II1-II2 and few samples act as III type, The organic matter maturity is low maturity to medium maturity. The organic matter maturity of the source rock from eastern part of the basin is higher than in the western region. The source rock of Longfengshan Group are in the hydrocarbon generation threshold. The great mass of source rocks are matured and in the peak stage of oil generation.

Geochemical geochronology and genesis of granite from Coronel Murta, Northeast of Minas Gerais, Brazil

International Nuclear Information System (INIS)

Soares, A.C.P.; Siga Junior, O.

1987-01-01

Geological, petrographic, geochemical (including rare-earth elements) and geochronological data of the Coronel Murta (Northeast Minas Gerais State) post-tectonic intrusive alkalic granites were summarized in order to discuss their genesis. This paper shows that Coronel Murta granites were generated by anatexis of dominantly metasedimentary rocks, in an ensialic environment, as the late results of an intraplate A-type subduction during the Brazilian Cycle. (author) [pt

Geochemical surface exploration between Bueckeberge Hills and Rehburg Anticline (Lower Saxony Basin, Germany)

Energy Technology Data Exchange (ETDEWEB)

Berner, U. [Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hannover (Germany); Marquardt, D. [Rijksuniversiteit Utrecht (Netherlands)

2013-01-15

The Lower Saxony Basin (LSB) of northwestern Germany is since long a target in hydrocarbon-related research in which the organic-rich Wealden sediments, known to contain good to excellent source rocks, play an important role. We demonstrate that cost effective surface exploration and geochemical research provide significant insight into the petroleum geology of an area of interest. Our research concentrates on a sub-basin in the eastern part of the LSB and aims at assessing the petroleum geology, hydrocarbon potential, depositional environment and tectonics of the Stadthagen syncline using surface samples of Wealden outcrops and evaluating these subsequently with geochemical methods (XRF, total sulfur, total organic carbon, Rock-Eval pyrolysis) and physical property data. The depositional environment in the research area varied significantly throughout the Lower Cretaceous (oxic to anoxic) due to paleoclimate changes and tectonically induced marine ingressions. Microbial sulfate reduction related to the marine ingressions reduced organic matter quality in the basin significantly, supporting the strong vertical variability in hydrocarbon potential of the sediments. Thermal maturity data suggests a complex tectonic history for the Stadthagen syncline. Thermal maturities (oil to wet gas window) combined with a multi-heat flow scenario result in estimated burial and subsequent uplift in the region of more than 2500 m. (orig.)

Geochemical monitoring using noble gases and carbon isotopes: study of a natural reservoir; Monitoring geochimique par couplage entre les gaz rares et les isotopes du carbone: etude d'un reservoir naturel

Energy Technology Data Exchange (ETDEWEB)

Jeandel, E

2008-12-15

To limit emissions of greenhouse gases in the atmosphere, CO{sub 2} geological sequestration appears as a solution in the fight against climate change. The development of reliable monitoring tools to ensure the sustainability and the safety of geological storage is a prerequisite for the implementation of such sites. In this framework, a geochemical method using noble gas and carbon isotopes geochemistry has been tested on natural and industrial analogues. The study of natural analogues from different geological settings showed systematic behaviours of the geochemical parameters, depending on the containment sites, and proving the effectiveness of these tools in terms of leak detection and as tracers of the behaviour of CO{sub 2}. Moreover, an experience of geochemical tracing on a natural gas storage has demonstrated that it is possible to identify the physical-chemical processes taking place in the reservoir to a human time scale, increasing interest in the proposed tool and providing general information on its use. (author)

Geochemical characteristics of Proterozoic granite magmatism from Southern Granulite Terrain, India: Implications for Gondwana

Science.gov (United States)

Yellappa, T.; Rao, J. Mallikharjuna

2018-03-01

Granitoid intrusions occur widely in the Southern Granulite Terrain (SGT) of India, particularly within the Cauvery Suture Zone (CSZ), which is considered as the trace of the Neoproterozoic Mozambique ocean closure. Here we present the petrological and geochemical features of 19 granite plutons across the three major tectonic blocks of the terrain. Our data show a wide variation in the compositions of these intrusions from alkali feldspathic syenite to granite. The whole rock geochemistry of these intrusions displays higher concentrations of SiO2, FeO*, K2O, Ba, Zr, Th, LREE and low MgO, Na2O, Ti, P, Nb, Y and HREE's. The granitoids are metaluminous to slightly peraluminous in nature revealing both I-type and A-type origin. In tectonic discrimination plots, the plutons dominantly show volcanic arc and syn-collisional as well as post-collisional affinity. Based on the available age data together with geochemical constrains, we demonstrate that the granitic magmatism in the centre and south of the terrain is mostly associated with the Neoproterozoic subduction-collision-accretion-orogeny, followed by extensional mechanism of Gondwana tectonics events. Similar widespread granitic activity has also been documented in the Arabian Nubian shield, Madagascar, Sri Lanka and Antarctica, providing similarities for the reconstruction of the crustal fragments of Gondwana supercontinent followed by Pan-African orogeny.

Geochemical and physical drivers of microbial community structure in hot spring ecosystems

Science.gov (United States)

Havig, J. R.; Hamilton, T. L.; Boyd, E. S.; Meyer-Dombard, D. R.; Shock, E.

2012-12-01

Microbial communities in natural systems are typically characterized using samples collected from a single time point, thereby neglecting the temporal dynamics that characterize natural systems. The composition of these communities obtained from single point samples is then related to the geochemistry and physical parameters of the environment. Since most microbial life is adapted to a relatively narrow ecological niche (multiplicity of physical and chemical parameters that characterize a local habitat), these assessments provide only modest insight into the controls on community composition. Temporal variation in temperature or geochemical composition would be expected to add another dimension to the complexity of niche space available to support microbial diversity, with systems that experience greater variation supporting a greater biodiversity until a point where the variability is too extreme. . Hot springs often exhibit significant temporal variation, both in physical as well as chemical characteristics. This is a result of subsurface processes including boiling, phase separation, and differential mixing of liquid and vapor phase constituents. These characteristics of geothermal systems, which vary significantly over short periods of time, provide ideal natural laboratories for investigating how i) the extent of microbial community biodiversity and ii) the composition of those communities are shaped by temporal fluctuations in geochemistry. Geochemical and molecular samples were collected from 17 temporally variable hot springs across Yellowstone National Park, Wyoming. Temperature measurements using data-logging thermocouples, allowing accurate determination of temperature maximums, minimums, and ranges for each collection site, were collected in parallel, along with multiple geochemical characterizations as conditions varied. There were significant variations in temperature maxima (54.5 to 90.5°C), minima (12.5 to 82.5°C), and range (3.5 to 77.5°C) for

Geochemical mapping using stream sediments in west-central Nigeria: Implications for environmental studies and mineral exploration in West Africa

International Nuclear Information System (INIS)

Lapworth, Dan J.; Knights, Katherine V.; Key, Roger M.; Johnson, Christopher C.; Ayoade, Emmanuel; Adekanmi, Michael A.; Arisekola, Tunde M.; Okunlola, Olugbenga A.; Backman, Birgitta; Eklund, Mikael; Everett, Paul A.; Lister, Robert T.; Ridgway, John; Watts, Michael J.; Kemp, Simon J.; Pitfield, Peter E.J.

2012-01-01

This paper provides an overview of regional geochemical mapping using stream sediments from central and south-western Nigeria. A total of 1569 stream sediment samples were collected and 54 major and trace elements determined by ICP-MS and Au, Pd and Pt by fire assay. Multivariate statistical techniques (e.g., correlation analysis and principal factor analysis) were used to explore the data, following appropriate data transformation, to understand the data structure, investigate underlying processes controlling spatial geochemical variability and identify element associations. Major geochemical variations are controlled by source geology and provenance, as well as chemical weathering and winnowing processes, more subtle variations are a result of land use and contamination from anthropogenic activity. This work has identified placer deposits of potential economic importance for Au, REE, Ta, Nb, U and Pt, as well as other primary metal deposits. Areas of higher As and Cr (>2 mg/kg and >70 mg/kg respectively) are associated with Mesozoic and younger coastal sediments in SW Nigeria. High stream sediment Zr concentrations (mean >0.2%), from proximal zircons derived from weathering of basement rocks, have important implications for sample preparation and subsequent analysis due to interferences. Associated heavy minerals enriched in high field strength elements, and notably rare earths, may also have important implications for understanding magmatic processes within the basement terrain of West Africa. This study provides important new background/baseline geochemical values for common geological domains in Nigeria (which extend across other parts of West Africa) for assessment of contamination from urban/industrial land use changes and mining activities. Regional stream sediment mapping is also able to provide important new information with applications across a number of sectors including agriculture, health, land use and planning.

Monitoring active volcanoes: The geochemical approach

Directory of Open Access Journals (Sweden)

Takeshi Ohba

2011-06-01

Full Text Available

The geochemical surveillance of an active volcano aims to recognize possible signals that are related to changes in volcanic activity. Indeed, as a consequence of the magma rising inside the volcanic "plumbing system" and/or the refilling with new batches of magma, the dissolved volatiles in the magma are progressively released as a function of their relative solubilities. When approaching the surface, these fluids that are discharged during magma degassing can interact with shallow aquifers and/or can be released along the main volcano-tectonic structures. Under these conditions, the following main degassing processes represent strategic sites to be monitored.

The main purpose of this special volume is to collect papers that cover a wide range of topics in volcanic fluid geochemistry, which include geochemical characterization and geochemical monitoring of active volcanoes using different techniques and at different sites. Moreover, part of this volume has been dedicated to the new geochemistry tools.

Loess as an environmental archive of atmospheric trace element deposition

Science.gov (United States)

Blazina, T.; Winkel, L. H.

2013-12-01

environmental archive to reconstruct long term natural variations in atmospheric trace element input. By comparing paleomonsoon proxy data with geochemical data we can directly correlate variations in atmospheric trace element input to fluctuations in the EAM. For example we are able to link Se input into the CLP to EAM derived precipitation. In interglacial climatic periods from 2.3-1.56Ma and 1.50-1.29Ma, we find very strong positive correlations between Se concentration and the summer monsoon index, a proxy for effective precipitation. In later interglacial periods from 1.26-0.83Ma and 0.78-0.16Ma, we find dust input plays a greater role. Our findings demonstrate that the CLP is a valuable environmental archive of atmospheric trace element deposition and suggest that other loess deposits worldwide may serve as useful records for investigating long term natural variations in atmospheric trace element cycling.

Geochemical and biological research at the NEA dumpsite for low-level radioactive waste

International Nuclear Information System (INIS)

Rutgers van der Loeff, M.M.; Lavaleye, M.S.S.

1984-01-01

A geochemical and biological study of the sea floor at the NEA dumpsite for low-level radioactive waste is reported. The sea bottom has rather steep hillsides. Slumps are usual phenomena and could be triggered by the dumping operations. The sediment is described in terms of its mineralogical and elemental composition. The variation in CaCO 3 content accounts for most of the variation in the elemental composition and cation exchange capacity. The present depth of the lysocline is shown to be about 4700 m. A description is given of the early diagenetic processes: (1) Mineralization of organic material, (2) Cation exchange, (3) Change in redox conditions and (4) Carbonate dissolution and recrystallization; and discussed in terms of their effects on the redistribution and transport of trace elements and radionuclides within the sediment and between sediment and overlying water. (orig.)

Alligator Rivers Analogue project. Geochemical Data Bases

International Nuclear Information System (INIS)

Bennett, D.G.; Read, D.

1992-01-01

The Koongarra uranium deposit in the Northern Territory of Australia is being studied to evaluate the processes involved in the geochemical alteration of the ore body and the formation of the uranium dispersion fan. A broad range of research is being undertaken into the geochemistry and hydrology of the site with the aim of understanding the transport of radionuclides through the system. During the project a range of geochemical and hydrogeochemical models have been developed to account for measured data from the site and with which to predict site evolution. The majority of these models are based on the premise of thermodynamic chemical equilibrium and employ fundamental thermodynamic data to characterise the chemistry of the system. From the differences which exist between the thermodynamic data bases (Appendices I and II) it is possible to gain a view of the level of uncertainty associated with thermodynamic data in each set of calculations. This report gives a brief introduction to the geochemical processes underlying the models, and details the equations used to quantify the more common of these processes (e.g. aqueous speciation and mineral solubility). A description is given of the computer codes (EQ3/6, PHREEQE, MINTEQ) most commonly used during the project for geochemical modelling. Their key features are highlighted and comparisons made. It is concluded that the degree of uncertainty in geochemical modelling studies arising as a result of using one code rather than another is relatively insignificant when compared to that related to differences in the underlying data bases. 73 refs., 3 figs

Trace metal mobilization in an experimental carbon sequestration scenario

Energy Technology Data Exchange (ETDEWEB)

Marcon, Virginia [University of Wyoming, Geology and Geophysics, Laramie, WY. 82070 (United States); Kaszuba, John [University of Wyoming, Geology and Geophysics, Laramie, WY. 82070 (United States); Univeristy of Wyoming, School of Energy Resources, Larmaie, WY. 82070 (United States)

2013-07-01

Mobilizing trace metals with injection of supercritical CO{sub 2} into deep saline aquifers is a concern for geologic carbon sequestration. Hydrothermal experiments investigate the release of harmful metals from two zones of a sequestration injection reservoir: at the cap-rock-reservoir boundary and deeper within the reservoir, away from the cap-rock. In both systems, Cd, Cr, Cu, Pb, and Zn behave in a similar manner, increasing in concentration with injection, but subsequently decreasing in concentration over time. SEM images and geochemical models indicate initial dissolution of minerals and precipitation of Ca-Mg-Fe carbonates, metal sulfides (i.e. Fe, As, Ag, and Co sulfides), and anhydrite in both systems. The results suggest that Ba, Cu, and Zn will not be contaminants of concern, but Pb, Fe, and As may require careful attention. (authors)

Geochemical distribution of trace metals and organochlorine contaminants of a lake ontario shoreline marsh

Energy Technology Data Exchange (ETDEWEB)

Glooschenko, W A; Capocianco, J; Coburn, J; Glooschenko, V

1981-02-01

Rattray Marsh, an 8 ha marsh on the Lake Ontario shoreline at Mississauga, Ontario, is an important local habitat for waterfowl and shorebirds during spring and fall migration. A study was conducted to determine the distribution of nutrients (carbon, nitrogen, and phosphorus) and potential trace metal and organochlorine pollutants in the marsh as evidenced by the sedimentary concentrations of these compounds. Generally, copper, zinc, lead, and mercury were higher in concentration in local soils than in Lake Ontario sediments. Metals and organic carbon levels did not correlate, and the metals appeared to be associated with silts and clays. Organochlorine contaminants include p,p1-DDE, p,p1-DDD, p,p1-DDT, alpha-chlordane, PCB, mirex, and HCB.

World-wide and regional intercomparison for the determination of trace elements in polluted marine sediment IAEA-356. Report no.56

Energy Technology Data Exchange (ETDEWEB)

Horvat, M; Mee, L D; Oregioni, B [International Atomic Energy Agency, Marine Environment Laboratory, Monaco (Monaco)

1994-09-01

The accurate and precise determination of trace elements in marine sediment samples is an important aspect of geochemical marine pollution studies and for assessing the levels and pathways of marine pollutants. Past intercomparison exercise conducted by the Marine Environment Laboratory of IAEA (formerly the International Laboratory of Marine Radioactivity) has focused upon the near shore sediment (1) and deep sea marine sediment (2) where trace levels of elements was rather low. The present intercomparison exercise on sediment taken from a polluted coastal lagoon was designed in order to fulfill the increased demand for certified reference materials of various origin and the number of parameters that should be studied. Additionally, different instrumental techniques, both nuclear and non-nuclear, were compared, and evaluated. By statistically examining the data from this study, the material can be certified for future use as a reference material. The current exercise was designed not only to test the intercomparability of different instrumental techniques, but also to evaluate the effectiveness of different procedures for sample digestion. Participants were invited to perform 'total' analyses involving, except in the case of neutron activation analysis, a simple partial extraction with 1M hydrochloric acid (2 hours, room temperature). This partial dissolution had a twofold purpose: (i) to differentiate between instrumental (plus contamination during work-up) errors and those resulting from method-specific (matrix) effects; and (ii) to evaluate a simple screening test for the more labile ('easily leached') fraction of trace elements of particular interest to environmental chemists. The present report presents the entire experimental data set and a statistical evaluation of the results for each parameter.

Descriptive statistics and spatial distributions of geochemical variables associated with manganese oxide-rich phases in the northern Pacific

Science.gov (United States)

Botbol, Joseph Moses; Evenden, Gerald Ian

1989-01-01

Tables, graphs, and maps are used to portray the frequency characteristics and spatial distribution of manganese oxide-rich phase geochemical data, to characterize the northern Pacific in terms of publicly available nodule geochemical data, and to develop data portrayal methods that will facilitate data analysis. Source data are a subset of the Scripps Institute of Oceanography's Sediment Data Bank. The study area is bounded by 0° N., 40° N., 120° E., and 100° W. and is arbitrarily subdivided into 14-20°x20° geographic subregions. Frequency distributions of trace metals characterized in the original raw data are graphed as ogives, and salient parameters are tabulated. All variables are transformed to enrichment values relative to median concentration within their host subregions. Scatter plots of all pairs of original variables and their enrichment transforms are provided as an aid to the interpretation of correlations between variables. Gridded spatial distributions of all variables are portrayed as gray-scale maps. The use of tables and graphs to portray frequency statistics and gray-scale maps to portray spatial distributions is an effective way to prepare for and facilitate multivariate data analysis.

Accumulations and sources of uranium, of its daughters and of metallic trace elements in wetlands located around old uranium mining sites

International Nuclear Information System (INIS)

Cuvier, Alicia

2015-01-01

Uranium mining and uranium ore processing increase the environmental activity of U and Th decay products and trace elements, in particular in case of releases to the adjacent rivers. Contaminants accumulate then preferentially in sedimentation areas (such as ponds or lakes) or in wetlands (peat lands, marshes or riverbanks) located downstream to the mine. Wetlands - generally located at the head of watershed - are particularly sensitive to environmental changes and anthropogenic pressure. This poses a risk of release of contaminants from these accumulation areas. The objective of the present study is to propose an easily reproducible methodology - in particular for the orphan mining sites - to identify and characterize accumulation areas. This study also aims to improve our understanding of the mechanisms of accumulation and release, in these areas. This study was performed around the former mining site of Bertholene (France). Standing and mobile in situ gamma spectrometry is used to accurately locate the accumulation areas. Soils, sediments, vegetation, water and peat are also sampled upstream and downstream of the mine, in order to (a) characterize the activities and the disequilibria of the U-Th decay chains and the associated trace elements according to the scale of observation, (b) understand the mechanisms of accumulation and release and (c) identify the potential sources using geochemical proxies and isotopic analyses. The results obtained show that radionuclides are mainly accumulated in a flooding area located downstream the mine. Strong U-238 activities (≥ 20000 Bq.kg"-"1) and strong Ra-226/U-238 and Th-230/Ra-226 activity ratios are recorded, involving preferential inputs of U-238 and Th-230 during flooding events. Trace element contamination is low, except for Mn, Ba and S. Such contaminations are potentially explained by the geochemical composition of the uranium ore and by the past and current processes of ore and water mine. Sequential extractions

Mantle-derived trace element variability in olivines and their melt inclusions

Science.gov (United States)

Neave, David A.; Shorttle, Oliver; Oeser, Martin; Weyer, Stefan; Kobayashi, Katsura

2018-02-01

Trace element variability in oceanic basalts is commonly used to constrain the physics of mantle melting and the chemistry of Earth's deep interior. However, the geochemical properties of mantle melts are often overprinted by mixing and crystallisation processes during ascent and storage. Studying primitive melt inclusions offers one solution to this problem, but the fidelity of the melt-inclusion archive to bulk magma chemistry has been repeatedly questioned. To provide a novel check of the melt inclusion record, we present new major and trace element analyses from olivine macrocrysts in the products of two geographically proximal, yet compositionally distinct, primitive eruptions from the Reykjanes Peninsula of Iceland. By combining these macrocryst analyses with new and published melt inclusion analyses we demonstrate that olivines have similar patterns of incompatible trace element (ITE) variability to the inclusions they host, capturing chemical systematics on intra- and inter-eruption scales. ITE variability (element concentrations, ratios, variances and variance ratios) in olivines from the ITE-enriched Stapafell eruption is best accounted for by olivine-dominated fractional crystallisation. In contrast, ITE variability in olivines and inclusions from the ITE-depleted Háleyjabunga eruption cannot be explained by crystallisation alone, and must have originated in the mantle. Compatible trace element (CTE) variability is best described by crystallisation processes in both eruptions. Modest correlations between host and inclusion ITE contents in samples from Háleyjabunga suggest that melt inclusions can be faithful archives of melting and magmatic processes. It also indicates that degrees of ITE enrichment can be estimated from olivines directly when melt inclusion and matrix glass records of geochemical variability are poor or absent. Inter-eruption differences in olivine ITE systematics between Stapafell and Háleyjabunga mirror differences in melt

Epidemic contact tracing via communication traces.

Directory of Open Access Journals (Sweden)

Katayoun Farrahi

Full Text Available Traditional contact tracing relies on knowledge of the interpersonal network of physical interactions, where contagious outbreaks propagate. However, due to privacy constraints and noisy data assimilation, this network is generally difficult to reconstruct accurately. Communication traces obtained by mobile phones are known to be good proxies for the physical interaction network, and they may provide a valuable tool for contact tracing. Motivated by this assumption, we propose a model for contact tracing, where an infection is spreading in the physical interpersonal network, which can never be fully recovered; and contact tracing is occurring in a communication network which acts as a proxy for the first. We apply this dual model to a dataset covering 72 students over a 9 month period, for which both the physical interactions as well as the mobile communication traces are known. Our results suggest that a wide range of contact tracing strategies may significantly reduce the final size of the epidemic, by mainly affecting its peak of incidence. However, we find that for low overlap between the face-to-face and communication interaction network, contact tracing is only efficient at the beginning of the outbreak, due to rapidly increasing costs as the epidemic evolves. Overall, contact tracing via mobile phone communication traces may be a viable option to arrest contagious outbreaks.

Epidemic contact tracing via communication traces.

Science.gov (United States)

Farrahi, Katayoun; Emonet, Rémi; Cebrian, Manuel

2014-01-01

Traditional contact tracing relies on knowledge of the interpersonal network of physical interactions, where contagious outbreaks propagate. However, due to privacy constraints and noisy data assimilation, this network is generally difficult to reconstruct accurately. Communication traces obtained by mobile phones are known to be good proxies for the physical interaction network, and they may provide a valuable tool for contact tracing. Motivated by this assumption, we propose a model for contact tracing, where an infection is spreading in the physical interpersonal network, which can never be fully recovered; and contact tracing is occurring in a communication network which acts as a proxy for the first. We apply this dual model to a dataset covering 72 students over a 9 month period, for which both the physical interactions as well as the mobile communication traces are known. Our results suggest that a wide range of contact tracing strategies may significantly reduce the final size of the epidemic, by mainly affecting its peak of incidence. However, we find that for low overlap between the face-to-face and communication interaction network, contact tracing is only efficient at the beginning of the outbreak, due to rapidly increasing costs as the epidemic evolves. Overall, contact tracing via mobile phone communication traces may be a viable option to arrest contagious outbreaks.

Preliminary Geochemical and Rock Magnetic Study of a Stalagmite From Quintana Roo, Northeastern Yucatan Peninsula

Science.gov (United States)

Urrutia-Fucugauchi, J.; Perez-Cruz, L.; Zhao, X.; Rebolledo-Vieyra, M.; Rodriguez, A.

2012-04-01

We present the preliminary results of geochemical, stable isotopes and rock magnetic studies of a stalagmite from a cave in eastern Quintana Roo, northern Yucatan peninsula. In the past years, there has been increased interest in understanding the paleoclimatic and paleoenvironmental evolution of the Yucatan peninsula and northern Central America, investigating the relationships between climate variations and the development of the Maya civilization. In particular, the variations in regional precipitation and occurrence of several drought periods, which might have been related to the collapse of the Classic Maya period. Stable isotope data on speleothems from different sites in Yucatan and Central America have provided evidence on changes in precipitation, which have affected the Maya region. The stalagmite is ~47 cm long and about 4-5 cm wide at its base. It was collected from the Hilariós Well cave in Tulum, Quintana Roo. Magnetic susceptibility and geochemical analyses have been completed as part of the initial characterization of the stalagmite, with measurements taken every centimeter. Geochemical analyses have been carried out for x-ray fluorescence, with a Niton XRF analyzer. Magnetic susceptibility was determined with a Bartington MS2 instrument using the high resolution surface probe. Additional rock magnetic analyses include magnetic hysteresis loops and isothermal remanent magnetization (IRM) acquisition, and saturation IRM demagnetization, which have been measured with a MicroMag instrument. Hysteresis loops are diamagnetic, with small varying low-coercivity ferromagnetic components. The elemental compositions of major oxides and trace elements vary with depth. Calcium is the major element and displays a pattern of small amplitude fluctuations with a trend to lower values at the bottom, which are also shown in other elements such as barium. Silica and elements such as titanium and strontium are positively correlated and show an apparent cyclic pattern

A geochemical and isotopic approach to recharge evaluation in semi-arid zones. Past and present

International Nuclear Information System (INIS)

Edmunds, W.M.; Walton, N.R.G.

1980-01-01

The magnitude of any recharge to aquifers in semi-arid and arid zones is the principal uncertainty in estimating a water balance. Recent studies in Cyprus and Libyan Arab Jamahiriya are currently being used to demonstrate the application of geochemical and isotopic techniques, to the determination of both current and palaeo-recharge. In Cyprus, solute profiles of the unsaturated zone have been interpreted to provide estimates of the direct recharge component using a steady-state, mass-balance approach; results from the chloride profiles compare well with recharge estimates using tritium. In addition, it is found that some solute peaks, notably for specific electrical conductance, give a reasonably accurate record of the rainfall history during the period 1950-1975. The solute profile method is relatively unsophisticated and could be more widely applied to recharge estimation in other semi-arid areas of the world. In Libya, a clear distinction can be made using the combined isotopic, hydrological and geochemical results between regional groundwaters recharged to the upper, unconfined aquifer of the Sirte Basin before 13,000 years BP and younger waters recharged locally during the period 5000-7800 years BP. A well-defined fresh-water channel, superimposed upon the regional water quality pattern, can be traced within the aquifer for some 130 km and represents direct evidence of recharge during the Holocene. Some shallow groundwaters of similar composition to the fresh-water channel are also considered to represent recent, if intermittent, recharge which took place during historical times. It is concluded that geochemical and isotopic studies of both the unsaturated zone and of shallow groundwaters in semi-arid regions, can be used to determine not only the present-day direct recharge component, but also a recharge chronology of immediate historic times, which may be important in the estimation of long-term water resources. (author)

Expected Geochemical and Mineralogical Properties of Meteorites from Mercury: Inferences from Messenger Data

Science.gov (United States)

McCubbin, F. M.; McCoy, T. J.

2016-01-01

Meteorites from the Moon, Mars, and many types of asteroid bodies have been identified among our global inventory of meteorites, however samples of Mercury and Venus have not been identified. The absence of mercurian and venusian meteorites could be attributed to an inability to recognize them in our collections due to a paucity of geochemical information for Venus and Mercury. In the case of mercurian meteorites, this possibility is further supported by dynamical calculations that suggest mercurian meteorites should be present on Earth at a factor of 2-3 less than meteorites from Mars [1]. In the present study, we focus on the putative mineralogy of mercurian meteorites using data obtained from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, which has provided us with our first quantitative constraints on the geochemistry of planet Mercury. We have used the MESSENGER data to compile a list of mineralogical and geochemical characteristics that a meteorite from Mercury is likely to exhibit.

Extension of the EQ3/6 computer codes to geochemical modeling of brines

Energy Technology Data Exchange (ETDEWEB)

Jackson, K.J.; Wolery, T.J.

1984-10-23

Recent modifications to the EQ3/6 geochemical modeling software package provide for the use of Pitzer's equations to calculate the activity coefficients of aqueous species and the activity of water. These changes extend the range of solute concentrations over which the codes can be used to dependably calculate equilibria in geochemical systems, and permit the inclusion of ion pairs, complexes, and undissociated acids and bases as explicit component species in the Pitzer model. Comparisons of calculations made by the EQ3NR and EQ6 compuer codes with experimental data confirm that the modifications not only allow the codes to accurately evaluate activity coefficients in concentrated solutions, but also permit prediction of solubility limits of evaporite minerals in brines at 25/sup 0/C and elevated temperatures. Calculations for a few salts can be made at temperatures up to approx. 300/sup 0/C, but the temperature range for most electrolytes is constrained by the availability of requisite data to values less than or equal to 100/sup 0/C. The implementation of Pitzer's equations in EQ3/6 allows application of these codes to problems involving calculation of geochemical equilibria in brines; such as evaluation of the chemical environment which might be anticipated for nuclear waste canisters located in a salt repository. 26 references, 3 figures, 1 table.

Sulfur isotopes as a tracer for biogenic sulfate reduction in natural environments: A link between modern and ancient ecosystems. Geologica Ultraiectina (316)

NARCIS (Netherlands)

Stam, M.C.

2010-01-01

Sulfur isotopes have been widely used to trace the activity of sulfate reducing prokaryotes in modern and ancient geochemical settings and to estimate the role of this microbial metabolism in global sulfur cycling. Extensive pure culture data provide detailed insight into cellular mechanisms

Kinetic and thermodynamic modelling of geochemical effects of a nuclear waste storage in granitic environment

International Nuclear Information System (INIS)

Made, B.; Fritz, B.

1993-01-01

In the world, various experimental sites are selected to study the behavior of different types of source rocks under nuclear waste storage influence. The surrounding rock tested to receive the waste storage must be a stable geological formation. In France, four geological formations are preselected for the feasibility study of repository for spent nuclear fuel at long term: shale, salt, clay and granite. At present time, numerous studies are carried out in Europe (Germany, Belgium, Sweden, Switzerland, United-Kingdom...), in North America (U.S.A. and Canada) and in Japan. Water-rock interactions control the most of rock transformations near the surface of the earth. The rock forming minerals react with the aqueous solutions, the primary minerals dissolution releases ionic species in solution and secondary minerals precipitate if equilibrium or oversaturation is reached. The weathering processes (hydrothermal or not) are always very complicated thus, geochemical codes has been developed to simulate the water-rock interactions. The first generation of codes is based on purely thermodynamic laws without reference to the time dependence of chemical reactions and then the dissolution path calculation refer to the irreversible dissolution of reactants and reversible precipitation of products ([1] to [4]). The system evolution is followed according to the reaction progress ξ which has been introduced in chemical system by Gibbs. Since few years, the experimental studies on the kinetics of minerals dissolution have allowed to take into account of dissolution rates data for the major minerals (silicates, carbonates...). More recently, a new geochemical codes generation appears based on thermodynamic potential and kinetic laws ([5] to [8]). The system evolution is followed according to the reaction time. (authors). 8 figs., 4 tabs., 24 refs

Geochemical behavior under tropical weathering of the Barama-Mazaruni greenstone belt at Omai gold mine, Guiana Shield

Energy Technology Data Exchange (ETDEWEB)

Voicu, G. [Universite du Quebec a Montreal (Canada). Dept. des Sciences de la Terre et de l' Atmosphere; Omai Gold Mines, Georgetown (Guyana); Bardoux, M. [Universite du Quebec a Montreal (Canada). Dept. des Sciences de la Terre et de l' Atmosphere

2002-07-01

Mineralogical, petrographical, and geochemical studies of the weathering profile have been carried out at Omai Au mine, Guyana. The area is underlain by felsic to mafic volcanic and sedimentary rocks of the Barama-Mazaruni Supergroup, part of the Paleoproterozoic greenstone belts of the Guiana Shield. Tropical rainy climate has favoured extensive lateritization processes and formation of a deeply weathered regolith. The top of the weathering profile consists of lateritic gravel or is masked by the Pleistocene continental-deltaic Berbice Formation. Mineralogical composition of regolith consists mainly of kaolinite, goethite and quark, and subordinately sericite, feldspar, hematite, pyrite, smectite, heavy minerals, and uncommon mineral phases (nacrite, ephesite, corrensite, guyanaite). A specific feature of the weathering profile at Omai is the preservation of fresh hydrothermal pyrite in the saprolith horizon. Chemical changes during the weathering processes depend on various physicochemical and structural parameters. Consequently, the depth should not be the principal criterion for comparison purposes of the geochemical behavior within the weathering profile, but rather an index that measures the degree of supergene alteration that has affected each analyzed sample, independently of the depth of sampling. Thus, the mineralogical index of alteration (MIA) can provide more accurate information about the behavior of major and trace elements in regolith as opposed to unweathered bedrock. It can also aid in establishing a quantitative relationship between intensity of weathering and mobility (leaching or accumulation) of each element in each analyzed sample. At Omai, some major and trace elements that are commonly considered as immobile (ex: TiO{sub 2}, Zr, etc.) during weathering could become mobile in several rock types and cannot be used to calculate the mass and volume balance. In addition, due to higher ''immobile element'' ratios, the

Geochemical and geo-electrical study of mud pools at the Mutnovsky volcano (South Kamchatka, Russia): Behavior of elements, structures of feeding channels and a model of origin

International Nuclear Information System (INIS)

Bessonova, E.P.; Bortnikova, S.B.; Gora, M.P.; Manstein, Yu.A.; Shevko, A.Ya.; Panin, G.L.; Manstein, A.K.

2012-01-01

This study presents data on the geochemical composition of boiling mud pools at the Mutnovsky volcano. The physicochemical characteristics of the pools and the concentrations of major, minor and trace elements in pool solutions vary widely. A comparison of the geochemical compositions of host rocks and solutions indicates that leaching from rocks is not the only source of chemicals in thermal solutions. Geophysical studies reveal the inner structure of thermal fields, which reflect the shapes of the underground reservoirs and feed channels. Using geophysical methods (electrical resistivity tomography and frequency domain investigations), it was shown that the vertical structure and complex geochemical zonation of the feed channels leads to a high contrast in the compositions of the mud solutions. These findings answer questions about the origin and composition of surface manifestations. To elucidate the mechanisms of solution formation, an attempt was made to describe the magmatic fluid evolution and the resulting mixing of waters by physical and mathematical models. The model illustrates fluid migration from a magma chamber to the surface. It is shown that the formation of brines corresponding to the mud pool composition is possible during secondary boiling.

Sharp fronts within geochemical transport problems

International Nuclear Information System (INIS)

Grindrod, P.

1995-01-01

The authors consider some reactive geochemical transport problems in groundwater systems. When incoming fluid is in disequilibrium with the mineralogy sharp transition fronts may develop. They show that this is a generic property for a class of systems where the timescales associated with reaction and diffusion phenomena are much shorter than those associated with advective transport. Such multiple timescale problems are relevant to a variety of processes in natural systems: mathematically methods of singular perturbation theory reduce the dimension of the problems to be solved locally. Furthermore, they consider how spatial heterogeneous mineralogy can impact upon the propagation of sharp geochemical fronts. The authors developed an asymptotic approach in which they solve equations for the evolving geometry of the front and indicate how the non-smooth perturbations due to natural heterogeneity of the mineralogy on underlying ground water flow field are balanced against the smoothing effect of diffusion/dispersive processes. Fronts are curvature damped, and the results here indicate the generic nature of separate front propagation within both model (idealized) and natural (heterogeneous) geochemical systems

Lead distribution in coastal and estuarine sediments around India

Digital Repository Service at National Institute of Oceanography (India)

Chakraborty, S.; Chakraborty, P.; Nath, B.N.

. Trace element geochemical associations in the Arabian Gulf. Mar. Pollut. Bull. 17, 353–356. doi:10.1016/0025-326X(86)90247-X Achyuthan, H., Richardmohan, D., Srinivasalu, S., 2002a. Trace metals concentrations in the sediment cores of estuary... in the coastal sediment of chennai coast. IIOAB J. 3, 12–18. Ray, A.K., Tripathy, S.C., Patra, S., Sarma, V. V, 2006. Assessment of Godavari estuarine mangrove ecosystem through trace metal studies. Environ. Int. 32, 219–223. Reddy, M.S., Basha, S., Sravan...

Geochemical modeling and assessment of leaching from carbonated municipal solid waste incinerator (MSWI) fly ash.

Science.gov (United States)

Wang, Lei; Chen, Qi; Jamro, Imtiaz Ali; Li, Rundong; Li, Yanlong; Li, Shaobai; Luan, Jingde

2016-06-01

Municipal solid waste incinerator (MSWI) fly ashes are characterized by high calcium oxide (CaO) content. Carbon dioxide (CO2) adsorption by MSWI fly ash was discussed based on thermogravimetry (TG)/differential thermal analysis (DTA), minerology analysis, and adapting the Stenoir equation. TG/DTA analysis showed that the weight gain of the fly ash below 440 °C was as high as 5.70 %. An adapted Stenoir equation for MSWI fly ash was discussed. The chloride in MSWI fly ash has a major impact on CO2 adsorption by MSWI fly ash or air pollution control (APC) residues. Geochemical modeling of the critical trace elements copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), and antimony (Sb) before and after carbonation was performed using a thermodynamic equilibrium model for solubility and a surface complexation model for metal sorption. Leaching of critical trace elements was generally found to be strongly dependent on the degree of carbonation attained, and their solubility appeared to be controlled by several minerals. Adsorption on ferrum (Fe) and aluminum (Al) colloids was also responsible for removal of the trace elements Cd, Pb, and Sb. We used Hakanson's potential ecological risk index (HPERI) to evaluate the risk of trace element leaching in general. The results demonstrate that the ecological risk showed a V-shaped dependency on pH; the optimum pH of the carbonated fly ash was found to be 10.3-11, resulting from the optimum carbonation (liquid-to-solid (L/S) ratio = 0.25, carbonation duration = ∼30-48 h). The dataset and modeling results presented here provide a contribution to assessing the leaching behavior of MSWI fly ash under a wide range of conditions.

Geochemical effects of CO2 sequestration in sandstones under simulated in situ conditions of deep saline aquifers

International Nuclear Information System (INIS)

Wigand, M.; Carey, J.W.; Schuett, H.; Spangenberg, E.; Erzinger, J.

2008-01-01

The geochemical effects of brine and supercritical CO 2 (SCCO 2 ) on reservoir rocks from deep (1500-2000 m) saline aquifers were examined via experimental simulation at in situ conditions. Dry sandstone samples were mounted in a triaxial cell and autoclave system, evacuated, and saturated with 1 M NaCl solution. The brine-rock system was allowed to react at 30 MPa confining pressure, 15 MPa pore fluid pressure, and 60 deg. C while SCCO 2 was injected at a pressure gradient of 1-2 MPa. The experiment was conducted for a period of 1496 h, during which fluids were periodically sampled and analyzed. The pH measured in partially degassed fluid samples at 25 deg. C decreased from a starting value of 7.0-4.3 (9 days) and finally 5.1 after saturation with SCCO 2 . Fluid analyses indicate that most of the major (e.g. Ca, Mg, Fe, Mn) and trace elements (e.g. Sr, Ba, Pb) of the sandstone increase in concentration during the reaction with brine and SCCO 2 . These results are supported by scanning electron microscopy which indicates dissolution of dolomite cement, K-feldspar, and albite. In addition to dissolution reactions the formation of montmorillonite was observed. By adjusting surface area and reaction rates of dissolution and precipitation, geochemical modeling of the experiments could reproduce long-term trends in solution chemistry and indicated limited rates of dissolution as the system remained strongly undersaturated with most minerals, including carbonates. The geochemical models could not account for decreases in concentration of some elements, changes in solution composition resulting from changes in imposed pressure gradient, and the observed Ca/Mg and Si/Al ratios in solution

Dynamics of submarine groundwater discharge and associated fluxes of dissolved nutrients, carbon, and trace gases to the coastal zone (Okatee River estuary, South Carolina)

Science.gov (United States)

Porubsky, W.P.; Weston, N.B.; Moore, W.S.; Ruppel, C.; Joye, S.B.

2014-01-01

Multiple techniques, including thermal infrared aerial remote sensing, geophysical and geological data, geochemical characterization and radium isotopes, were used to evaluate the role of groundwater as a source of dissolved nutrients, carbon, and trace gases to the Okatee River estuary, South Carolina. Thermal infrared aerial remote sensing surveys illustrated the presence of multiple submarine groundwater discharge sites in Okatee headwaters. Significant relationships were observed between groundwater geochemical constituents and 226Ra activity in groundwater with higher 226Ra activity correlated to higher concentrations of organics, dissolved inorganic carbon, nutrients, and trace gases to the Okatee system. A system-level radium mass balance confirmed a substantial submarine groundwater discharge contribution of these constituents to the Okatee River. Diffusive benthic flux measurements and potential denitrification rate assays tracked the fate of constituents in creek bank sediments. Diffusive benthic fluxes were substantially lower than calculated radium-based submarine groundwater discharge inputs, showing that advection of groundwater-derived nutrients dominated fluxes in the system. While a considerable potential for denitrification in tidal creek bank sediments was noted, in situ denitrification rates were nitrate-limited, making intertidal sediments an inefficient nitrogen sink in this system. Groundwater geochemical data indicated significant differences in groundwater chemical composition and radium activity ratios between the eastern and western sides of the river; these likely arose from the distinct hydrological regimes observed in each area. Groundwater from the western side of the Okatee headwaters was characterized by higher concentrations of dissolved organic and inorganic carbon, dissolved organic nitrogen, inorganic nutrients and reduced metabolites and trace gases, i.e. methane and nitrous oxide, than groundwater from the eastern side

A >100 Ma Mantle Geochemical Record: Retiring Mantle Plumes may be Premature

Science.gov (United States)

Konter, J. G.; Hanan, B. B.; Blichert-Toft, J.; Koppers, A. A.; Plank, T.; Staudigel, H.

2006-12-01

Hotspot volcanism has long been attributed to mantle plumes, but in recent years suggestions have been made that plate tectonic processes, such as extension, can account for all hotspot tracks. This explanation involves a profoundly less dynamic lower mantle, which justifies a critical evaluation before the plume model is dismissed. Such an evaluation has to involve a wide range of geochemical, geological, and geophysical techniques, broadly investigating the products of volcanism as well as the underlying lithosphere and mantle. We argue here that the combined geological record and geochemistry of intraplate volcanoes holds some important clues that help us decide between models of plume-like upwelling versus passive upwelling with lithospheric extension. The best of these integrated datasets can be obtained from the long seamount chains in the Pacific Ocean. A new combined dataset of trace element and isotopic compositions, along with modern 40Ar/39Ar ages from seamounts in the Gilbert Ridge, Tokelau chain, and West Pacific Seamount Province (WPSP) provides a record of current to Cretaceous volcanism in the South Pacific. We have reconstructed the eruptive locations of the seamounts using a range of absolute plate motion models, including some models with hotspot motion and others that use the Indo-Atlantic hotspot reference frame. Our results show that the backtracked locations consistently form clusters (300km radius) around the active ends of the Macdonald, Rurutu and Rarotonga hotspot chains, while closely matching their distinct C-HIMU and C-EM1 signatures. The oldest WPSP seamounts (older than 100 Ma) form the only exception and backtrack, with larger uncertainty, to north of Rarotonga. Therefore, the mantle currently underlying the Cook-Austral islands has produced volcanoes in three geochemically distinct areas for at least 100 m.y. Furthermore, we find the shortest mantle residence time, 0.6 Ga, for a source of mixed recycled DMM and an EM1-like

ACTRIS Aerosol, Clouds and Trace Gases Research Infrastructure

Science.gov (United States)

Pappalardo, Gelsomina

2018-04-01

The Aerosols, Clouds and Trace gases Research Infrastructure (ACTRIS) is a distributed infrastructure dedicated to high-quality observation of aerosols, clouds, trace gases and exploration of their interactions. It will deliver precision data, services and procedures regarding the 4D variability of clouds, short-lived atmospheric species and the physical, optical and chemical properties of aerosols to improve the current capacity to analyse, understand and predict past, current and future evolution of the atmospheric environment.

Metal and trace element assessment of sediments from Guarapiranga reservoir, Sao Paulo State, by neutron activation analysis

International Nuclear Information System (INIS)

Guimaraes, Guilherme M.; Favaro, Deborah I.T.; Franklin, Robson L.; Ferreira, Francisco J.; Bevilacqua, Jose E.

2009-01-01

Guarapiranga Reservoir is extremely important due to the fact that it is one of the main water reservoirs for South America's largest city, Sao Paulo, Brazil. Guarapiranga Basin is located within the Metropolitan Region of Sao Paulo - RMSP, and occupies an area of approximately 630 km 2 , and the reservoir itself is located in the northern part of the basin occupying approximately 26 km 2 . This reservoir is characterized by environmental impacts from urban invasion, industrial and sewage wastes, all of which seriously affect its water quality. Due to its vulnerability CETESB (Environmental Control Agency of the Sao Paulo State) regularly monitors the contamination levels of waters and once a year sediment samples. In order to better understand geochemical and environmental processes and their possible changes due to anthropogenic activities trace metals analyses and their distribution in sediments are commonly undertaken. The present study reports results concerning the distribution of some major (Fe, K and Na), trace (As, Ba, Br, Co, Cr, Cs, Hf, Hg, Rb, Sb, Sc, Ta, Tb, Th, U and Zn) and rare earth (Ce, Eu, La, Lu, Nd, Sm, Tb and Yb) elements in sediments from the Guarapiranga Reservoir. Multielementar analysis was carried out by instrumental neutron activation analysis (INAA). Multielemental concentrations in the sediment samples were compared to NASC (North American Shale Composite) values. The concentration values for metals As, Cr and Zn in the sediment samples were compared to the Canadian Council of Minister of the Environment (CCME) oriented values (TEL and PEL values) and adopted by CETESB. (author)

Petrographic And Geochemical Relationships And Environmentally Significant Trace Element Contents Of Miocene Coals in The Çayirli (Erzincan) Area, Eastern Anatolia, Turkey

Science.gov (United States)

Yalcin Erik, Nazan

2014-05-01

This study has done related to the petrographic, coal-quality and the environmental influences of the Çayırlı coal field in the Eastern Anatolia. The region is one of the best examples of a continental collision zone in the world and located in a North-south converging collision zone between the Eurasian and the Arabian Plates. The geological units on the North of the basin are the peridotites and on the South, the Upper Triassic to Lower Cretaceous limestone. Tertiary sedimentary units also occupy a significant part of the geological features. Lower Miocene sediments include recifal limestone, marls, green clay and coal seams. The Çayırlı mining area in Eastern Anatolia region, contains these Miocene aged coals. These coals is characterized by high vitrinite and inertinite and low liptinite contents. The coals are Bituminous coal rank, with vitrinite reflectance ranging from 0.53 to 0.58%. Chemically, the coal in this study is characterised by low moisture, ash yield and sulfur content. The Çayırlı coal consist mainly of SiO2 and CaO, with secondary Fe2O3, Al2O3, and minor proportions of TiO2, P2O5 and other oxides. Several trace elements of environmental concern namely As, U and Be in Çayırlı coal are above the world averages, while Ni and Pb concentrations are less than the world average. However, As, Co, Cr, Ni, Pb, U and V contents of this coal are below Turkish averages. It can clearly observed that the concentration of the elements is highest in the high ash coal levels. Among the potentially hazardous trace elements, Be, Co, Ni, Se and U may be of little or no health and environmental concerns, wheras As, Pb, Sb, and Th require further examination for their potential health and environmental concerns. These properties may be related to evaluation of the coal forming environment from more reducing contitions in a marine influenced lower delta plain environment for investigated coals. On the basis of analytical data, there is no possibility that

Indian deepsea environment experiment (index): Achievements and applications

Digital Repository Service at National Institute of Oceanography (India)

Sharma, R.

impact experiment. Evaluation of impact of simulated disturbance in the benthic environment shows vertical mixing of sediment, lateral distribution of particles, changes in geochemical and biochemical conditions as well as reduction in biomass...

Robust statistics and geochemical data analysis

International Nuclear Information System (INIS)

Di, Z.

1987-01-01

Advantages of robust procedures over ordinary least-squares procedures in geochemical data analysis is demonstrated using NURE data from the Hot Springs Quadrangle, South Dakota, USA. Robust principal components analysis with 5% multivariate trimming successfully guarded the analysis against perturbations by outliers and increased the number of interpretable factors. Regression with SINE estimates significantly increased the goodness-of-fit of the regression and improved the correspondence of delineated anomalies with known uranium prospects. Because of the ubiquitous existence of outliers in geochemical data, robust statistical procedures are suggested as routine procedures to replace ordinary least-squares procedures

Coupling of transport and geochemical models

International Nuclear Information System (INIS)

Noy, D.J.

1985-01-01

This contract stipulated separate pieces of work to consider mass transport in the far-field of a repository, and more detailed geochemical modelling of the groundwater in the near-field. It was envisaged that the far-field problem would be tackled by numerical solutions to the classical advection-diffusion equation obtained by the finite element method. For the near-field problem the feasibility of coupling existing geochemical equilibrium codes to the three dimensional groundwater flow codes was to be investigated. This report is divided into two sections with one part devoted to each aspect of this contract. (author)

Integrated geophysical-geochemical methods for archaeological prospecting

OpenAIRE

Persson, Kjell

2005-01-01

A great number of field measurements with different methods and instruments were conducted in attempts to develop a method for an optimal combination of various geochemical and geophysical methods in archaeological prospecting. The research presented in this thesis focuses on a study of how different anthropogenic changes in the ground can be detected by geochemical and geophysical mapping and how the results can be presented. A six-year pilot project, Svealand in Vendel and Viking periods (S...

Tracing the sources of stream sediments by Pb isotopes and trace elements

International Nuclear Information System (INIS)

Kyung-Seok Ko; Jae Gon Kim; Kyoochul Ha; Kil Yong Lee

2012-01-01

The objective of this research is to trace the sources of stream sediments in a small watershed influenced by anthropogenic and lithogenic origins identified by the spatial distributions and temporal variations of stream sediments using geochemical interpretation of the stable and radiogenic isotopes, major components, and heavy metals data and principal component analysis. To know the effects of both present and past mining, the stream sediments were sampled at the stream tributaries and sediment coring work. The spatial distributions of heavy metals clearly showed the effects of Cu and Pb-Zn mineralization zones at the site. Anthropogenic Pb was elevated at the downstream area by the stream sediments due to an active quarry. The results of principal components analysis also represent the effects of the stream sediments origins, including anthropogenic wastes and the active quarry and lithogenic sediment. Anomalous Cu, indicating the effect of past Guryong mining, was identified at the deep core sediments of 1.80-5.05 m depth. The influence of active quarry was shown in the recently deposited sediments of 210 Pb and stable Pb and Sr isotopes. This study suggests that the chemical studies using radiogenic and stable isotopes and heavy metals and multivariate statistical method are useful tools to discriminate the sources of stream sediments with different origins. (author)

Retention/sorption and geochemical modelling

Energy Technology Data Exchange (ETDEWEB)

Arcos, D.; Grandia, F.; Domenech, C. [Enviros Spain, S.L., Barcelona (Spain); SCK-CEN, Mol (Belgium); Sellin, P. [SKB - Swedish Nuclear Fuel and Waste Management, SE, Stockholm (Sweden); Hunter, F.M.I.; Bate, F.; Heath, T.G.; Hoch, A. [Serco Assurance, Oxfordshire (United Kingdom); Werme, L.O. [SKB - Svensk Karnbranslehantering AB, Stockholm (Sweden); Bruggeman, C.; Maes, I.A.; Breynaert, E.; Vancluysen, J. [Leuven Katholieke Univ., Lab. for Colloid Chemistry (Belgium); Montavon, G.; Guo, Z. [Ecole des Mines, 44 - Nantes (France); Riebe, B.; Bunnenberg, C.; Meleshyn, A. [Leibniz Univ. Hannover, Zentrum fur Strahlenschutz und Radiookologie, Hannover (Germany); Dultz, S. [Leibniz Univ. Hannover, Institut fur Bodenkunde, Hannover (Germany)

2007-07-01

This session gathers 4 articles dealing with: the long-term geochemical evolution of the near field of a KBS-3 HLNW repository: insights from reactive transport modelling (D. Arcos, F. Grandia, C. Domenech, P. Sellin); the investigation of iron transport into bentonite from anaerobically corroding steel: a geochemical modelling study (F.M.I. Hunter, F. Bate, T.G. Heath, A. Hoch, L.O. Werme); SeO{sub 3}{sup 2-} adsorption on conditioned Na-illite: XAS spectroscopy, kinetics, surface complexation model and influence of compaction (C. Bruggeman, A. Maes, G. Montavon, E. Breynaert, Z. Guo, J. Vancluysen); the influence of temperature and gamma-irradiation on the anion sorption capacity of modified bentonites (B. Riebe, C. Bunnenberg, A. Meleshyn, S. Dultz)

Geochemical prospect ion results of Treinta y Tres aerial photo

International Nuclear Information System (INIS)

Zeegers, H.; Bonnefoy, D.; Garau, M.; Spangenberg, J.

1981-01-01

This report shows the geochemical prospect ion results carried out within the framework of the multielemental geochemical strategy. The samples were studied by e spectrometry in the laboratories of Orleans.

The corrosion of depleted uranium in terrestrial and marine environments.

Science.gov (United States)

Toque, C; Milodowski, A E; Baker, A C

2014-02-01

Depleted Uranium alloyed with titanium is used in armour penetrating munitions that have been fired in a number of conflict zones and testing ranges including the UK ranges at Kirkcudbright and Eskmeals. The study presented here evaluates the corrosion of DU alloy cylinders in soil on these two UK ranges and in the adjacent marine environment of the Solway Firth. The estimated mean initial corrosion rates and times for complete corrosion range from 0.13 to 1.9 g cm(-2) y(-1) and 2.5-48 years respectively depending on the particular physical and geochemical environment. The marine environment at the experimental site was very turbulent. This may have caused the scouring of corrosion products and given rise to a different geochemical environment from that which could be easily duplicated in laboratory experiments. The rate of mass loss was found to vary through time in one soil environment and this is hypothesised to be due to pitting increasing the surface area, followed by a build up of corrosion products inhibiting further corrosion. This indicates that early time measurements of mass loss or corrosion rate may be poor indicators of late time corrosion behaviour, potentially giving rise to incorrect estimates of time to complete corrosion. The DU alloy placed in apparently the same geochemical environment, for the same period of time, can experience very different amounts of corrosion and mass loss, indicating that even small variations in the corrosion environment can have a significant effect. These effects are more significant than other experimental errors and variations in initial surface area. Copyright © 2013. Published by Elsevier Ltd.

From trace chemistry to single atom chemistry

International Nuclear Information System (INIS)

Adloff, J.P.

1993-01-01

Hot atom chemistry in the vast majority of experimental works deals with the trace amount of radioactive matters. Accordingly, the concept of trace chemistry is at the heart of hot atom chemistry. Some aspects of the chemistry at trace scale and at subtrace scale are presented together with the related problems of speciation and the complication which may arise due to the formation of radio colloids. The examples of 127 I(n,γ) 128 I and 132 Te (β - ) 132 I are shown, and the method based on radioactivity was used. The procedure of separating the elements in pitchblende is shown as the example of the chemistry of traces. 13 27 Al+ 2 4 He→ 0 1 n+ 15 30 P and 15 30 P→ 14 30 Si+e + +V are shown, and how to recognize the presence of radioactive colloids is explained. The formation of radiocolloids is by the sorption of a trace radioelement on pre-existing colloidal impurity or the self-condensation of monomeric species. The temporal parameters of the nature of reactions at trace concentration are listed. The examples of Class A and Class B reactions are shown. The kinetics of reactions at trace level, radon concentration, anthropogenic Pu and natural Pu in environment, the behavior of Pu atoms and so on are described. (K.I.)

Trace conditioning in insects-keep the trace!

Science.gov (United States)

Dylla, Kristina V; Galili, Dana S; Szyszka, Paul; Lüdke, Alja

2013-01-01

Trace conditioning is a form of associative learning that can be induced by presenting a conditioned stimulus (CS) and an unconditioned stimulus (US) following each other, but separated by a temporal gap. This gap distinguishes trace conditioning from classical delay conditioning, where the CS and US overlap. To bridge the temporal gap between both stimuli and to form an association between CS and US in trace conditioning, the brain must keep a neural representation of the CS after its termination-a stimulus trace. Behavioral and physiological studies on trace and delay conditioning revealed similarities between the two forms of learning, like similar memory decay and similar odor identity perception in invertebrates. On the other hand differences were reported also, like the requirement of distinct brain structures in vertebrates or disparities in molecular mechanisms in both vertebrates and invertebrates. For example, in commonly used vertebrate conditioning paradigms the hippocampus is necessary for trace but not for delay conditioning, and Drosophila delay conditioning requires the Rutabaga adenylyl cyclase (Rut-AC), which is dispensable in trace conditioning. It is still unknown how the brain encodes CS traces and how they are associated with a US in trace conditioning. Insects serve as powerful models to address the mechanisms underlying trace conditioning, due to their simple brain anatomy, behavioral accessibility and established methods of genetic interference. In this review we summarize the recent progress in insect trace conditioning on the behavioral and physiological level and emphasize similarities and differences compared to delay conditioning. Moreover, we examine proposed molecular and computational models and reassess different experimental approaches used for trace conditioning.

The loading history of trace metals and nutrients in Altata-Ensenada del Pabellon, lagoon complex, northwestern Mexico

International Nuclear Information System (INIS)

Ruiz-Fernandez, A.C.; Paez-Osuna, F.; Soto-Jimenez, M.; Hillaire-Marcel, C.; Ghaleb, B.

2003-01-01

This paper summarizes the geochemical investigations about the origin and loading history of some trace metals (Ag, Cu and Zn) and nutrients (N and P) in the coastal lagoon complex of Altata-Ensenada del Pabellon, Mexico, by using the radioactive chronometers 210 Pb and 228 Th and the stable isotopes of C and N. The examination of sediment cores collected at different locations in the lagoon system identified a slight enrichment in metals and nutrients in some points, which was mainly associated to organic matter accumulation. Stable C and N isotope ratios revealed wastewater inputs to the lagoon system and the 210 Pb geochronology showed that anthropogenic impact started 50 years ago, with the beginning of the agriculture development and the associated urban growth of the surrounding area. Several atypical 210 Pb and 228 Th/ 232 Th profiles demonstrated that biological and physical disturbances are common phenomena in these environments, that frequently mask the pollution records; and therefore, considering that the contaminated sediments at some locations in the lagoon system are frequently resuspended and re-oxygenated, the pollutants will continue to be easily remobilized in the food chain

The use of some geochemical methods in evaporation pond reclamation assessments

International Nuclear Information System (INIS)

Thimm, H. F.; Siebert, L. D.

1998-01-01

Certain geochemical techniques, such as complete inorganic identification, rare earth fingerprints, and the use of chondrite plots that may be used over and above CCME (Canadian Council of Ministers of the Environment) standards in the reclamation of evaporation ponds, are described. These techniques permit the separation of contaminant elements that occur naturally beyond provincial or CCME standards. They also permit conclusions to be drawn about soil stratification around the lagoons. The methods are less costly yet more effective than conventional assessment methods. Use of these techniques is illustrated with an example from an Alberta gas plant. 7 refs., 6 tabs., 5 figs

Geochemical nature of sub-ridge mantle and opening dynamics of the South China Sea

Science.gov (United States)

Zhang, Guo-Liang; Luo, Qing; Zhao, Jian; Jackson, Matthew G.; Guo, Li-Shuang; Zhong, Li-Feng

2018-05-01

The Indian-type mantle (i.e., above the north hemisphere reference line on the plot of 208Pb/204Pb vs. 206Pb/204Pb) has been considered as a "Southern Hemisphere" geochemical signature, whose origin remains enigmatic. The South China Sea is an extensional basin formed after rifting of the Euro-Asia continent in the Northern Hemisphere, however, the geochemical nature of the igneous crust remains unexplored. For the first time, IODP Expedition 349 has recovered seafloor basalts covered by the thick sediments in the Southwest sub-basin (Sites U1433 and U1434) and the East sub-basin (Site U1431). The Southwest sub-basin consists of enriched (E)-MORB type basalts, and the East sub-basin consists of both normal (N)-MORB-type and E-MORB-type basalts based on trace element compositions. The basalts of the two sub-basins are Indian-type MORBs based on Sr-Nd-Pb-Hf isotope compositions, and the Southwest sub-basin basalts show isotopic compositions (i.e., 206Pb/204Pb of 17.59-17.89) distinctly different from the East sub-basin (i.e., 206Pb/204Pb of 18.38-18.57), suggesting a sub-basin scale mantle compositional heterogeneity and different histories of mantle compositional evolution. Two different enriched mantle end-members (EM1 and EM2) are responsible for the genesis of the Indian-type mantle in the South China Sea. We have modeled the influences of Hainan mantle plume and lower continental crust based on Sr-Nd-Pb-Hf isotope compositions. The results indicate that the influence of Hainan plume can explain the elevated 206Pb/204Pb of the East sub-basin basalts, and the recycling of lower continental crust can explain the low 206Pb/204Pb of the Southwest sub-basin basalts. Based on the strong geochemical imprints of Hainan plume in the ridge magmatism, we propose that the Hainan plume might have promoted the opening of the South China Sea, during which the Hainan plume contributed enriched component to the sub-ridge mantle and caused thermal erosion and return of lower

Clean laboratories and clean rooms for analysis of radionuclides and trace elements

International Nuclear Information System (INIS)

2003-01-01

requirements are summarized of clean laboratory environments, for construction materials as well as for materials used during routine analysis, maintenance, and pitfalls in the analysis of radionuclides and elements at trace- and ultra trace levels. Current methodologies and practices are described for planning the installation of a clean environment as well as protocols for maximizing the benefit-to-cost ratio and for achieving QA/QC. Special emphasis is given to the analysis of radionuclides, and measurement of trace, minor and major elements using nuclear and related analytical techniques such as NAA and XRF. Also included are papers contributed by experts from India, the Netherlands, the United States of America and the IAEA Laboratories, Seibersdorf

Identification of magnetic particulates in road dust accumulated on roadside snow using magnetic, geochemical and micro-morphological analyses

International Nuclear Information System (INIS)

Bucko, Michal S.; Magiera, Tadeusz; Johanson, Bo; Petrovsky, Eduard; Pesonen, Lauri J.

2011-01-01

The aim of this study is to test the applicability of snow surveying in the collection and detailed characterization of vehicle-derived magnetic particles. Road dust extracted from snow, collected near a busy urban highway and a low traffic road in a rural environment (southern Finland), was studied using magnetic, geochemical and micro-morphological analyses. Significant differences in horizontal distribution of mass specific magnetic susceptibility (χ) were noticed for both roads. Multi-domain (MD) magnetite was identified as the primary magnetic mineral. Scanning electron microscope (SEM) analyses of road dust from both roads revealed: (1) angular-shaped particles (diameter ∼1-300 μm) mostly composed of Fe, Cr and Ni, derived from circulation of motor vehicles and (2) iron-rich spherules (d ∼ 2-70 μm). Tungsten-rich particles (d < 2 μm), derived from tyre stud abrasion were also identified. Additionally, a decreasing trend in χ and selected trace elements was observed with increasing distance from the road edge. - Highlights: → Snow surveying is an effective method in studies of vehicle-derived particles. → Multi-domain (MD) magnetite was identified as the primary magnetic mineral. → Particles mostly composed of Fe, Cr and Ni were identified in the roadside snow. → Snow located near the road is contaminated by heavy metals. - Snow surveying is an effective method in detailed studies of vehicle-derived magnetic particles.

Geochemical behaviour of natural uranium-series nuclides in geological formation

International Nuclear Information System (INIS)

Yamakawa, Minoru

1991-01-01

Recent research and investigation show that the Tono uranium deposit and its natural uranium-series nuclides have been preserved, without any significant changes like re-migration or reconcentration, throughout geological events such as upheaval-submergence, marine transgression-regression, and faulting which can readily change geological, hydrogeological, and geochemical conditions. This situation might have come about as a result of being kept in a geometrical closure system, with reducing and milk alkalic geochemical conditions, from the hydrogeological and geochemical point of view. (author)

ACTRIS Aerosol, Clouds and Trace Gases Research Infrastructure

Directory of Open Access Journals (Sweden)

Pappalardo Gelsomina

2018-01-01

Full Text Available The Aerosols, Clouds and Trace gases Research Infrastructure (ACTRIS is a distributed infrastructure dedicated to high-quality observation of aerosols, clouds, trace gases and exploration of their interactions. It will deliver precision data, services and procedures regarding the 4D variability of clouds, short-lived atmospheric species and the physical, optical and chemical properties of aerosols to improve the current capacity to analyse, understand and predict past, current and future evolution of the atmospheric environment.

Subduction recycling of continental sediments and the origin of geochemically enriched reservoirs in the deep mantle

Energy Technology Data Exchange (ETDEWEB)

Rapp, R.P.; Irifune, T.; Shimizu, N.; Nishiyama, N.; Norman, M.D.; Inoue, T. (Ehime U); (WHOI); (UC); (ANU)

2008-10-08

Isotopic and trace element geochemical studies of ocean island basalts (OIBs) have for many years been used to infer the presence of long-lived ({approx} 1-2 Ga old) compositional heterogeneities in the deep mantle related to recycling of crustal lithologies and marine and terrigenous sediments via subduction [e.g., Zindler, A., Hart, S.R., 1986. Chemical geodynamics. Annu. Rev. Earth Planet. Sci. 14, 493-571; Weaver, B.L., 1991. The origin of ocean island basalt end-member compositions: trace element and isotopic constraints. Earth Planet. Sci. Lett. 104, 381-397; Chauvel, C., Hofmann, A.W., Vidal, P., 1992. HIMU-EM: the French Polynesian connection. Earth Planet. Sci. Lett. 110, 99-119; Hofmann, A.W., 1997. Mantle geochemistry: the message from oceanic volcanism. Nature 385, 219-229; Willbold, M., Stracke, A., 2006. Trace element composition of mantle end-members: Implications for recycling of oceanic and upper and lower continental crust. Geochem. Geophys. Geosyst. Q04004. 7, doi:10.1029/2005GC001005]. In particular, models for the EM-1 type ('enriched mantle') OIB reservoir have invoked the presence of subducted, continental-derived sediment to explain high {sup 87}Sr/{sup 86}Sr ratios, low {sup 143}Nd/{sup 144}Nd and {sup 206}Pb/{sup 204}Pb ratios, and extreme enrichments in incompatible elements observed in OIB lavas from, for example, the Pitcairn Island group in the South Pacific [Woodhead, J.D., McCulloch, M.T., 1989; Woodhead, J.D., Devey, C.W., 1993. Geochemistry of the Pitcairn seamounts, I: source character and temporal trends. Earth Planet. Sci. Lett. 116, 81-99; Eisele, J., Sharma, M., Galer, S.J.G., Blichert-Toft, J., Devey, C.W., Hofmann, A.W., 2002. The role of sediment recycling in EM-1 inferred from Os, Pb, Hf, Nd, Sr isotope and trace element systematics of the Pitcairn hotspot. Earth Planet. Sci. Lett. 196, 197-212]. More recently, ultrapotassic, mantle-derived lavas (lamproites) from Gaussberg, Antarctica have been interpreted as

Geochemical and biogeochemical investigations in national parks [Badania geochemiczne i biogeochemiczne w parkach narodowych

Science.gov (United States)

Migaszewski, Z.M.; Lamothe, P.J.; Crock, J.G.

1998-01-01

National parks hold a key position among nature protection areas including a diversity of resources - natural, cultural, recreational and scenic. These "inviolable sanctuaries" are simultaneosuly ecologic knots and pristine nature refuges due to the presence of a number of unique plant and animal species. These species make up a natural gene bank. Classically, the level of biologic degradation in national parks is determined on the basis of qualitative and quantitative studies of plant bioindicators. Their scope encompasses phytosociologic survey the purpose of which is to identify floral assemblages with a detailed list of species to record future changes in their number. The best biomonitors of air quality are epiphytic lichens, ground mosses and conifers. Geochemical and biogeochemical investigations are widely performed in the U.S.A. to evaluate the degree of pollution in the nature protection areas including national parks (Gough et al., 1988a, b; Crock et al., 1992a, 1993; Jackson et al., 1995). Variability of element concentrations in soils and plants is assessed by using unbalanced, nested analysis-of-variance (ANOVA). It enables obtaining important statistical information with a minimum number of samples. In some cases a combined grid and barbell sampling design is applied (Jackson et al., 1995). In specific mountainous parks a method of 2-3 transects parallel to the extent of range (crest) is recommended. To determine the impact of a single pollution source on a given park, traverse sampling beginning near the emitter is used (Crock et al., 1992, 1993). The obtained results are a "snapshot" of chemical composition of soils and plant bioindicators that can be a reference for any future changes in the concentration level of chemical elements and organics. In addition, baseline element and organics composition of the media mentioned above can be compared with that obtained for geochemical atlases of polluted urban and industrial areas. Geochemical and

A geochemical and geochronological section through the Eastern Aegean

Science.gov (United States)

Boehm, Katharina; Kuiper, Klaudia; Vroon, Pieter; Wijbrans, Jan

2017-04-01

The convergence of Africa and Eurasia and the subduction of a oceanic lithosphere of narrow basins between Gondwana terranes has controlled the geological evolution of the Eastern Mediterranean region since the Cretaceous. This resulted in back-arc extension and lithospheric thinning caused by slab roll-back together with the westward extrusion of Anatolia, in the southwards retreat and stepwise development of the subduction system and also in a low velocity seismic anomaly gap between the Cyprus and Hellenic slab and other slab segments. However, the exact timing of all these events in the Eastern Mediterranean region is still a matter of debate, and the purpose of this study is therefore to disentangle when terrains collided and slab detached in the last 30Ma. In a N-S transect magmatic rocks of the Aegean plate are studied, including volcanics from the islands Nisyros, Kos, Patmos, Chios, Lesbos and Samothraki. Major- and trace elements as well as Sr-Nd-Hf-Pb-O isotopes are used to interpret the different features of the Aegean subduction zone. With this geochemical approach the extend of upwelling hot asthenospheric material from the slab tear can be traced in the recent to Eocene volcanic rocks. The volcanic rocks give a wide scatter in classification diagrams and pose for example the question how the sodium rich volcanic products of Patmos can be explained. On the other hand Chios seems to play a key role around 15 Ma years in a phase of relatively low volcanic activity. To get a reliable timeline of the subduction in the Aegean since the Eocene we are aiming to tie our chemical and isotopic data to parallel obtained geochronological ages. New 40Ar/39Ar data will allow us to get the needed resolution for this time span and material.

Geochemical prospecting for thorium and uranium deposits

International Nuclear Information System (INIS)

Boyle, R.W.

1982-01-01

The basic purpose of this book is to present an analysis of the various geochemical methods applicable in the search for all types of thorium and uranium deposits. The general chemistry and geochemistry of thorium and uranium are briefly described in the opening chapter, and this is followed by a chapter on the deposits of the two elements with emphasis on their indicator (pathfinder) elements and on the primary and secondary dispersion characteristics of thorium and uranium in the vicinity of their deposits. The next seven chapters form the main part of the book and describe geochemical prospecting for thorium and uranium, stressing selection of areas in which to prospect, radiometric surveys, analytical geochemical surveys based on rocks (lithochemical surveys), unconsolidated materials (pedochemical surveys), natural waters and sediments (hydrochemical surveys), biological materials (biogeochemical surveys), gases (atmochemical surveys), and miscellaneous methods. A final brief chapter reviews radiometric and analytical methods for the detection and estimation of thorium and uranium. (Auth.)

Heavy metals and related trace elements

International Nuclear Information System (INIS)

Leland, H.V.; Luoma, S.N.; Wilkes, D.J.

1977-01-01

A review is given of heavy metals and related trace elements in the aquatic environment. Other reviews and bibliographies are cited, dealing with the metabolism and transport of metal ions and with the toxic effects of stable and radioactive trace metals on aquatic organisms. The sources of trace elements in natural waters are discussed. It is suggested that atmospheric inputs of several trace metals comprise sizable fractions of total inputs to the Great Lakes and continental shelf waters. Information on stack emissions of trace elements from a coal-fired steam plant was used to estimate the likely range of air concentrations and inputs to a forested watershed in Tennessee. Some basic concepts of cycling of elements through aquatic communities were examined, such as the Pb, Mn and Zn concentrations in sediment and estuarine plants and animals colonizing dredge-spoil disposal areas. The use of plants as biological indicators of trace element contamination was outlined, as well as bioaccumulation in aquatic fauna. The effects of environmental factors on the kinetics of element exchange were noted, for example the influx rates of Cs 137 in tubificid worms, and Co 60 and Zn 65 in shrimp were shown to be temperature dependent. The toxicity of heavy metals on aquatic fauna was discussed, such as the histopathological lesions in the kidney and liver of fishes caused by heavy metals, and the effects of Hg and Cu on the olfactory response of rainbow trout

Holocene geochemical footprint from Semi-arid alpine wetlands in southern Spain

Science.gov (United States)

García-Alix, Antonio; Jiménez-Espejo, Francisco J.; Jiménez-Moreno, Gonzalo; Toney, Jaime L.; Ramos-Román, María J.; Camuera, Jon; Anderson, R. Scott; Delgado-Huertas, Antonio; Martínez-Ruiz, Francisca; Queralt, Ignasi

2018-02-01

Here we provide the geochemical dataset that our research group has collected after 10 years of investigation in the Sierra Nevada National Park in southern Spain. These data come from Holocene sedimentary records from four alpine sites (ranging from ˜2500 to ˜3000 masl): two peatlands and two shallow lakes. Different kinds of organic and inorganic analyses have been conducted. The organic matter in the bulk sediment was characterised using elemental measurements and isotope-ratio mass spectrometry (EA-IRMS). Leaf waxes in the sediment were investigated by means of chromatography with flame-ionization detection and mass spectrometry (GC-FID, GC-MS). Major, minor and trace elements of the sediments were analysed with atomic absorption (AAS), inductively coupled plasma mass spectrometry (ICP-MS), as well as X-ray scanning fluorescence. These data can be reused by environmental researchers and soil and land managers of the Sierra Nevada National Park and similar regions to identify the effect of natural climate change, overprinted by human impact, as well as to project new management policies in similar protected areas.

Geochemical characterization of critical dust source regions in the American West

Science.gov (United States)

Aarons, Sarah M.; Blakowski, Molly A.; Aciego, Sarah M.; Stevenson, Emily I.; Sims, Kenneth W. W.; Scott, Sean R.; Aarons, Charles

2017-10-01

The generation, transport, and deposition of mineral dust are detectable in paleoclimate records from land, ocean, and ice, providing valuable insight into earth surface conditions and cycles on a range of timescales. Dust deposited in marine and terrestrial ecosystems can provide critical nutrients to nutrient-limited ecosystems, and variations in dust provenance can indicate changes in dust production, sources and transport pathways as a function of climate variability and land use change. Thus, temporal changes in locations of dust source areas and transport pathways have implications for understanding interactions between mineral dust, global climate, and biogeochemical cycles. This work characterizes dust from areas in the American West known for dust events and/or affected by increasing human settlement and livestock grazing during the last 150 years. Dust generation and uplift from these dust source areas depends on climate and land use practices, and the relative contribution of dust has likely changed since the expansion of industrialization and agriculture into the western United States. We present elemental and isotopic analysis of 28 potential dust source area samples analyzed using Thermal Ionization Mass Spectrometry (TIMS) for 87Sr/86Sr and 143Nd/144Nd composition and Multi-Collector Inductively Coupled Plasma Mass Spectrometer (MC-ICPMS) for 176Hf/177Hf composition, and ICPMS for major and trace element concentrations. We find significant variability in the Sr, Nd, and Hf isotope compositions of potential source areas of dust throughout western North America, ranging from 87Sr/86Sr = 0.703699 to 0.740236, εNd = -26.6 to 2.4, and εHf = -21.7 to -0.1. We also report differences in the trace metal and phosphorus concentrations in the geologic provinces sampled. This research provides an important resource for the geochemical tracing of dust sources and sinks in western North America, and will aid in modeling the biogeochemical impacts of increased

Role of Mineral Deposits in Global Geochemical Cycles

Science.gov (United States)

Kesler, S.; Wilkinson, B.

2009-12-01

Mineral deposits represent the most extreme degree of natural concentration for most elements and their formation and destruction are important parts of global geochemical cycles. Quantitative estimates of the role that mineral deposits play in these geochemical cycles has been limited, however, by the lack of information on actual amounts of elements that are concentrated in these deposits, and their rates of formation and destruction at geologic time scales. Recent use of a “tectonic diffusion” model for porphyry copper deposits, the most important source of world copper, in conjunction with estimates of their copper content (Kesler and Wilkinson, 2008), allows an assessment of the role of copper deposits in Earth’s global copper cycles. These results indicate that ~4.5*10^8 Gg of Cu have been concentrated in porphyry copper deposits through Phanerozoic time, that deposits containing ~2.8*10^8 Gg of Cu have been removed by uplift and erosion over the same time period, and that deposits containing ~1.7*10^8 Gg remain in Earth’s crust. If styles of formation and destruction of other copper-bearing mineral deposits are similar, then all crustal deposits contain ~3*10^8 Gg of copper. This constitutes about 0.03% of the copper that resides in crustal rocks and provides a first-ever estimate of the rate at which natural geochemical cycles produce the extreme concentrations that constitute mineral deposits. Another ~8*10^8 Gg of copper have been destroyed during the uplift and erosion of mineral deposits over Phanerozoic time, a flux amounting to an annual contribution of about 1.5 Gg of copper to the near-surface environment. This amount is similar in magnitude to copper released by volcanic outgassing, but only ~2.5% of the 56 Gg of copper estimated to be released annually by weathering of average crustal rocks (Rauch and Graedel, 2007). The amount of copper removed from mineral deposits by mining, 1.1*10^4 Gg/year, is much larger than any natural

Uranium, thorium and trace elements in geologic occurrences as analogues of nuclear waste repository conditions

International Nuclear Information System (INIS)

Wollenberg, H.A.; Brookins, D.G.; Cohen, L.H.; Flexser, S.; Abashian, M.; Murphy, M.; Williams, A.E.

1984-01-01

Contact zones between intrusive rocks and tuff, basalt, salt and granitic rock were investigated as possible analogues of nuclear waste repository conditions. Results of detailed studies of contacts between quartz monzonite of Laramide age, intrusive into Precambrian gneiss, and a Tertiary monzonite-tuff contact zone indicate that uranium, thorium and other trace elements have not migrated significantly from the more radioactive instrusives into the country rock. Similar observations resulted from preliminary investigations of a rhyodacite dike cutting basalt of the Columbia River plateau and a kimberlitic dike cutting bedded salt of the Salina basin. This lack of radionuclide migration occurred in hydrologic and thermal conditions comparable to, or more severe than those expected in nuclear waste repository environments and over time periods of the order of concern for waste repositories. Attention is now directed to investigation of active hydrothermal systems in candidate repository rock types, and in this regard a preliminary set of samples has been obtained from a core hole intersecting basalt underlying the Newberry caldera, Oregon, where temperatures presently range from 100 to 265 0 C. Results of mineralogical and geochemical investigations of this core should indicate the alteration mineralogy and behavior of radioelements in conditions analogous to those in the near field of a repository in basalt

Concerning initial and secondary character of radionuclide distribution in elementary landscape geochemical systems

Science.gov (United States)

Korobova, Elena; Romanov, Sergey

2017-04-01

study confirms that Cs-137 as a label helps to trace processes and patterns of chemical elements' migration on the level of ELGS that are numerously reproduced elsewhere in natural systems. The study is aimed at and believed to provide solution for a number of important problems related to generation and evolution of soil structure, spatial redistribution of fertilizers and pesticides, other important processes of matter redistribution on the level of local LGS. References Korobova E.M., Korovaykov P.A., 1990. Landscape and geochemical approach to drawing up a soil distribution profile for Chernobyl radionuclides in distant areas //Seminar "Comparative assessment of the environmental impact of radionuclides released during three major nuclear accidents: Kyshtum, Windscale, Chernobyl". V. 1. Luxembourg, 309-327. Linnik V.G., 2008. Landscape differentiation of technogenic radionuclides: geoinformation systems and models. Thesis. Moscow: Moscow State University, 42 p. Romanov S.L., 1989. Principles of formation of radionuclide dispersion and concentration fields // Abstracts of the All-Union Conference "Principles and methods of landscape geochemical studies of radionuclide migration". Moscow: Vernadsky Institute, p. 46. Shcheglov A.I., Tsvetnova O.B., KlyashtorinA.L., 2001. Biogeochemical migration of technogenic radionuclides in forest ecosystems. Moscow: Nauka, 235 p.

Detailed geochemical survey for east-central Minnesota, geology and geochemistry of selected uranium targets

International Nuclear Information System (INIS)

Morey, G.B.; Lively, R.S.

1980-01-01

Results of a detailed geochemical survey of approximately 6820 km 2 in parts of Aitkin, Carlton, Kanabec, and Pine Counties, east-central Minnesota are reported. Geochemical data are presented for 883 groundwater samples and 200 bedrock samples. Although all of the groundwaters in the study area have similar major-element concentrations and therefore presumably a common ancestry, small differences in the minor-element concentrations serve to characterize various aquifers, both in the Quaternary deposits and in the bedrock. All of the aquifers locally yield waters having statistically anomalous concentrations of uranium or radon, but these anomalies are spatially coincident only in a few places and particularly in three geologic environments considered favorable for uranium mineralization. These include the following: (1) Thomson Formation near the unconformably overlying Fond du Lac Formation, (2) Hinckley Sandstone near a major fault system, and (3) Denham Formation near the unconformity with the McGrath Gneiss, particularly where these rocks are faulted and overlain by the Fond du Lac Formation. One additional uranium environment characterized by thin laminae of uraniferous apatite was located in the Thomson Formation during outcrop reconnaissance and sampling. The coincidence of this and other anomalously high uranium values in the bedrock with specific uranium and radon anomalies in the groundwater confirms the usefulness of the hydrogeochemical data to uranium exploration in this glaciated terrane

Statistical interpretation of geochemical data

International Nuclear Information System (INIS)

Carambula, M.

1990-01-01

Statistical results have been obtained from a geochemical research from the following four aerial photographies Zapican, Carape, Las Canias, Alferez. They have been studied 3020 samples in total, to 22 chemical elements using plasma emission spectrometry methods.

Use of geochemical signatures, including rare earth elements, in mosses and lichens to assess spatial integration and the influence of forest environment

Science.gov (United States)

Gandois, L.; Agnan, Y.; Leblond, S.; Séjalon-Delmas, N.; Le Roux, G.; Probst, A.

2014-10-01

In order to assess the influence of local environment and spatial integration of Trace Metals (TM) by biomonitors, Al, As, Cd, Cr, Cs, Cu, Fe, Mn, Ni, Pb, Sb, Sn, V and Zn and some rare earth element (REE) concentrations have been measured in lichens and mosses collected in three French forest sites located in three distinct mountainous areas, as well as in the local soil and bedrock, and in both bulk deposition (BD) and throughfall (TF). Similar enrichment factors (EF) were calculated using lichens and mosses and local bedrock for most elements, except for Cs, Mn, Ni, Pb, and Cu which were significantly (KW, p leaching (Mn), direct uptake (Ni), or dry deposition dissolution (Pb, Cu, Cs).

Tracking riverborne sediment and contaminants in Commencement Bay, Washington, using geochemical signatures

Science.gov (United States)

Takesue, Renee K.; Conn, Kathleen E.; Dinicola, Richard S.

2017-09-29

Large rivers carry terrestrial sediment, contaminants, and other materials to the coastal zone where they can affect marine biogeochemical cycles and ecosystems. This U.S. Geological Survey study combined river and marine sediment geochemistry and organic contaminant analyses to identify riverborne sediment and associated contaminants at shoreline sites in Commencement Bay, Puget Sound, Washington, that could be used by adult forage fish and other marine organisms. Geochemical signatures distinguished the fine fraction (contaminants were measured in surface sediment did not have measurable 7Be activities in that layer, so their contaminant assemblages were attributed to sources from previous years. Concentrations of organic contaminants (the most common of which were polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and fecal sterols) were higher in the contaminants in marine rather than river sediment, indicates that riverborne sediment-bound contaminants are retained in shallow marine habitats of Commencement Bay. The retention of earlier inputs complicates efforts to identify recent inputs and sources. Understanding modern sources and fates of riverborne sediment and contaminants and their potential ecological impacts will therefore require a suite of targeted geochemical studies in such marine depositional environments.

Regional geochemical maps of uranium in Northern Scotland. Environmental and economic considerations

International Nuclear Information System (INIS)

Plant, J.

1978-01-01

The Institute of Geological Studies geochemical mapping programme is outlined. The natural levels of uranium in rocks, soils and waters are discussed. Some practical details of geochemical mapping are given. Applications of geochemical maps of uranium in Scotland are considered: economic applications and medical geography and agriculture. A list of 38 references is appended. (U.K.)

Uranium geochemical exploration in northwestern Luzon

International Nuclear Information System (INIS)

Santos, G. Jr.; Fernandez, L.; Ogena, M.; Tauli, G.

1980-01-01

A reconnaissance geochemical stream water and sediment survey which was conducted in northwestern Luzon was able to detect ten (10) uranium anomalous areas. These anomalous areas are located along a north-south trending zone of Miocene marine clastics and sedimentary rocks with tuffaceous sediment intercalations. In general, northwest Luzon has low radioactivity except for two anomalous areas which have 3 to 6 times background radioactivity. Radon anomalies occur in sparsely scattered locations. The anomalous zones appear to be related to major north-south faults and secondary northeast-southwest trending structures. Geochemical correlations between uranium and other elements such as copper, lead, zinc, manganese, silver, cobalt and nickel are generally very poor. (author)

Trace elements from the Central Pacific Mexican Shelf: Geochemical associations and anthropogenic influences

Science.gov (United States)

Marmolejo-Rodríguez, A. J.; Morales-Blake, A. R.; González-Chavarín, I.; Hernández-Becerril, D.; Alonso-Rodríguez, R.; Rodríguez-Palacio, M. C.; Sánchez-González, A.; Magallanes-Ordóñez, V. R.

2017-11-01

Baselines for major and trace elements were determined from surface sediment samples from sites located along the Central Pacific Mexican Shelf (CPMS; 16.7-20.45° N). This study area is next to the biggest harbours in Mexico, for example touristic (Puerto Vallarta and Acapulco), touristic and industrial (Manzanillo), and industrial harbours (Lázaro Cárdenas). The industrial harbours have been expanding, transporting tonnes of materials to Asia and North and South America. Oceanographic campaigns were conducted to obtain sediment from depths ranging from 56 to 159 m. The grain size was predominately fine fraction (determined for the sediments. Arsenic is enriched in the CPMS; the Normalized Enrichment Factor average (NEFAV) for As is NEFAV = 8 ± 7. However the ratio between As and Cs indicates a natural origin in the most of the sites. Cadmium, Mo, and Ag were significantly correlated with Corg enhanced precipitation of sulfide-reactive metals. Moreover, an anthropogenic influence was detected for Hg (NEFAV = 4.3 ± 1.5) and Ag (NEFAV = 8.5 ± 2.6) in the shelf near the heavily industrialized harbour of Lázaro Cárdenas.

Geochemical Investigation of the Arbuckle-Simpson Aquifer, South-Central Oklahoma, 2004-06

Science.gov (United States)

Christenson, Scott; Hunt, Andrew G.; Parkhurst, David L.

2009-01-01

A geochemical reconnaissance investigation of the Arbuckle-Simpson aquifer in south-central Oklahoma was initiated in 2004 to characterize the ground-water quality at an aquifer scale, to describe the chemical evolution of ground water as it flows from recharge areas to discharge in wells and springs, and to determine the residence time of ground water in the aquifer. Thirty-six water samples were collected from 32 wells and springs distributed across the aquifer for chemical analysis of major ions, trace elements, isotopes of oxygen and hydrogen, dissolved gases, and age-dating tracers. In general, the waters from wells and springs in the Arbuckle-Simpson aquifer are chemically suitable for all regulated uses, such as public supplies. Dissolved solids concentrations are low, with a median of 347 milligrams per liter (mg/L). Two domestic wells produced water with nitrate concentrations that exceeded the U.S. Environmental Protection Agency's nitrate maximum contaminant level (MCL) of 10 mg/L. Samples from two wells in the confined part of the aquifer exceeded the secondary maximum contaminant level (SMCL) for chloride of 250 mg/L and the SMCL of 500 mg/L for dissolved solids. Water samples from these two wells are not representative of water samples from the other wells and springs completed in the unconfined part of the aquifer. No other water samples from the Arbuckle-Simpson geochemical reconnaissance exceeded MCLs or SMCLs, although not every chemical constituent for which the U.S. Environmental Protection Agency has established a MCL or SMCL was analyzed as part of the Arbuckle-Simpson geochemical investigation. The major ion chemistry of 34 of the 36 samples indicates the water is a calcium bicarbonate or calcium magnesium bicarbonate water type. Calcium bicarbonate water type is found in the western part of the aquifer, which is predominantly limestone. Calcium magnesium bicarbonate water is found in the eastern part of the aquifer, which is predominantly a

Trace conditioning in insects – Keep the trace!

Directory of Open Access Journals (Sweden)

Kristina V Dylla

2013-08-01

Full Text Available Trace conditioning is a form of associative learning that can be induced by presenting a conditioned stimulus (CS and an unconditioned stimulus (US following each other, but separated by a temporal gap. This gap distinguishes trace conditioning from classical delay conditioning, where the CS and US overlap. To bridge the temporal gap between both stimuli and to form an association between CS and US in trace conditioning, the brain must keep a neural representation of the CS after its termination – a stimulus trace. Behavioral and physiological studies on trace and delay conditioning revealed similarities between the two forms of learning, like similar memory decay and similar odor identity perception in invertebrates. On the other hand differences were reported also, like the requirement of distinct brain structures in vertebrates or disparities in molecular mechanisms in both vertebrates and invertebrates. For example, in commonly used vertebrate conditioning paradigms the hippocampus is necessary for trace but not for delay conditioning, and Drosophila delay conditioning requires the Rutabaga adenylyl cyclase, which is dispensable in trace conditioning. It is still unknown how the brain encodes CS traces and how they are associated with a US in trace conditioning. Insects serve as powerful models to address the mechanisms underlying trace conditioning, due to their simple brain anatomy, behavioral accessibility and established methods of genetic interference. In this review we summarize the recent progress in insect trace conditioning on the behavioral and physiological level and emphasize similarities and differences compared to delay conditioning. Moreover, we examine proposed molecular and computational models and reassess different experimental approaches used for trace conditioning.

Geochemistry of trace elements and Sr- Nd isotopes of foraminifera shell from the Okinawa Trough

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

Trace elemental associations and Sr - Nd isotopic compositions are of important to recognition of biogenic material from mixed marine sediments. The foraminifera shell from the Okinawa Trough strongly enrichesSr, P, Mn andBa, enriches Li, U, Th, Sc, Co, Cu, Pb, Zn, Cr, Rb, Y, Sb and light rare earth elements, slightly enriches V, Ga, Zr, Nb, Cd and middle rare earth elements,is short of Mo, In, Sn, Cs, Hf, Ta, W, Ti, Bi and heavy rare earth elements. The mechanism of elemental enrichment in forminifera is the concentrations of trace elements in sea water and selective absorption of trace elements during foraminifera living, as well as the geochemical affinity between major elements and trace elements. The REE (rare earth elements) partition pattern of foraminifera shell of the Okinawa Trough shows enrichment of middle rare earth elements with slightly negative Ce anomaly,which are different from those of foraminifera of the Pacific Ocean. The Sr, Nd isotopic ratios of the Okinawa Trough foraminifera are 0.709 769 and 0.512 162, respectively, which are different not only from those of oceanic water, but also from those of river water of China's Mainland, the former is slightly higher than those of oceanic water, but much lower than those of river water; the latter is slightly lower than those of oceanic water, but higher than those of river water, demonstrating that the Okinawa Trough sea water has been influenced by river water of China's Mainland.

Trace Elements in Teeth by ICPMS

International Nuclear Information System (INIS)

Zahran, N.F.; Helal, A.I.; Amr, M.A.; Amr, M.A.; Al-saad, K.A.

2008-01-01

Teeth are reported to be suitable indicators of trace element exposure from environment and nutritional status. Inductively coupled plasma mass spectrometry (ICP-MS) is used to compare the trace element content of children's primary teeth and adult teeth. Primary teeth are collected from 28 children and 42 adult from non-industrial City. The data are assessed statistically using t-tests. The adult teeth contained significantly greater concentrations of Na, Mg, Al, Fe, Ni, Cu, Sr, Cd, Ba, Pb and U and significantly less Mn, Co, As, Se, Mo and Bi than the children teeth. Additional measurements on adult teeth pulps are performed. Comparison between trace element concentrations in health and caries teeth pulps show that the mean concentrations of Na, Al, K, Cr, Mn, Co, Cu, Zn, Mo, Ag, Bi and U are lower in caries than healthy teeth pulps. On the other hand, the mean concentrations of Mg, Cd and Pb are higher in caries samples than healthy teeth pulps

Urban farming as a possible source of trace metals in human diets

Directory of Open Access Journals (Sweden)

Joshua O. Olowoyo

2016-02-01

Full Text Available Rapid industrialisation and urbanisation have greatly increased the concentrations of trace metals as pollutants in the urban environment. These pollutants (trace metals are more likely to have an adverse effect on peri-urban agriculture which is now becoming a permanent feature of the landscape of many urban cities in the world. This review reports on the concentrations of trace metals in crops, including leafy vegetables harvested from different urban areas, thus highlighting the presence of trace metals in leafy vegetables. Various pathways of uptake of trace metals by leafy vegetables, such as the foliar and roots, and possible health risks associated with urban faming are discussed and various morphological and physiological impacts of trace metals in leafy vegetables are described. Defensive mechanisms and positive aspects of trace metals in plants are also highlighted.

Geochemical site-selection criteria for HLW repositories in Europe and North America

International Nuclear Information System (INIS)

Savage, David; Arthur, Randolph C.; Sasamoto, Hiroshi; Shibata, Masahiro; Yui, Mikazu

2000-01-01

Geochemical as well as socio-economic issues associated with the selection of potential sites to host a high-level nuclear waste repository have received considerable attention in repository programs in Europe (Belgium, Finland, France, Germany, Spain, Sweden, Switzerland and the U.K.) and North America (Canada and the United States). The objective of the present study is to summarize this international experience with particular emphasis on geochemical properties that factor into the adopted site-selection strategies. Results indicate that the geochemical properties of a site play a subordinate role, at best, to other geotechnical properties in the international site-selection approaches. In countries where geochemical properties are acknowledged in the site-selection approach, requirements are stated qualitatively and tend to focus on associated impacts on the stability of the engineered barrier system and on radionuclide transport. Site geochemical properties that are likely to control the long-term stability of geochemical conditions and radionuclide migration behavior are unspecified, however. This non-prescriptive approach may be reasonable for purposes of screening among potential sites, but a better understanding of site properties that are most important in controlling the long-term geochemical evolution of the site over a range of possible scenarios would enable the potential sites to be ranked in terms of their suitability to host a repository. (author)

Geochemical criteria for reservoir quality variations in chalk from the North Sea

International Nuclear Information System (INIS)

Kunzendorf, H.; Soerensen, P.

1989-12-01

The influence of chalk geochemistry on petrophysical parameters determining porosity and permeability is investigated. The central well TWB-8 and eastern marginal well E-lx of the North Sea Tyra gas field were chosen. Drill core sections of Upper Maastrichtian and Danian chalk were selected. Chemical data on chalk samples were gathered by using X-ray fluorescence and instrumental neutron activation. Geochemical data are compared with the well-logging results. Geophysical logging suggests that there is reduced porosity in the Danian reservoir units LDP and UDT in both wells. The chalk drill core samples from the section with reduced porosity also show a lower Ca content. A high Si content is observed in these samples and a number of trace elements in chalk show a similar distribution with depth. Reservoir porosity may be estimated from the Si content of chalk. Chalk permeability may also be elements Al, Fe and Sc show the same trends as that for Si. Diagenetic changes in chalk also include clay minerals. The gas zone in TWB-8 is characterized by low contents of Na and Cl, i.e. lower water saturation is indicated. Low concentrations of rare earths in all chalk samples show a shale-normalized pattern that is characteristic of marine sediments laid down under oxic conditions. Some changes that occur with depth in the Ce anomaly may indicate a slight change in the depositional environment. The content of manganese continuously decreases with depth, from Danian (about 2000 ppm) to Maastrichtian strata (less than 200 ppm). In this respect, no other chemical element in chalk correlates with Mn. There is no indication as to which mineral or mineral phase one is likely to find in the element. (AB) 14 tabs., 49 ills., 147 refs

Atmospheric trace metal concentrations in Suspended Particulate ...

African Journals Online (AJOL)

The air particulate samples were collected from the kitchens, living rooms and outdoor environment of five households in the community. The quantification of the trace metals was done using Atomic Absorption spectrometry method, employing HNO based wet digestion. High baseline concentration of SPMwere obtained ...

Improved backward ray tracing with stochastic sampling

Science.gov (United States)

Ryu, Seung Taek; Yoon, Kyung-Hyun

1999-03-01

This paper presents a new technique that enhances the diffuse interreflection with the concepts of backward ray tracing. In this research, we have modeled the diffuse rays with the following conditions. First, as the reflection from the diffuse surfaces occurs in all directions, it is impossible to trace all of the reflected rays. We confined the diffuse rays by sampling the spherical angle out of the reflected rays around the normal vector. Second, the traveled distance of reflected energy from the diffuse surface differs according to the object's property, and has a comparatively short reflection distance. Considering the fact that the rays created on the diffuse surfaces affect relatively small area, it is very inefficient to trace all of the sampled diffused rays. Therefore, we set a fixed distance as the critical distance and all the rays beyond this distance are ignored. The result of this research is that as the improved backward ray tracing can model the illumination effects such as the color bleeding effects, we can replace the radiosity algorithm under the limited environment.

Mobilization of Trace Metals in an Experimental Carbon Sequestration Scenario

Science.gov (United States)

Marcon, V.; Kaszuba, J. P.

2012-12-01

Mobilizing trace metals with injection of supercritical CO2 into deep saline aquifers is a concern for geologic carbon sequestration. The potential for leakage from these systems requires an understanding of how injection reservoirs interact with the overlying potable aquifers. Hydrothermal experiments were performed to evaluate metal mobilization and mechanisms of release in a carbonate storage reservoir and at the caprock-reservoir boundary. Experiments react synthetic Desert Creek limestone and/or Gothic Shale, formations in the Paradox Basin, Utah, with brine that is close to equilibrium with these rocks. A reaction temperature of 1600C accelerates the reaction kinetics without changing in-situ water-rock reactions. The experiments were allowed to reach steady state before injecting CO2. Changes in major and trace element water chemistry, dissolved carbon and sulfide, and pH were tracked throughout the experiments. CO2 injection decreases the pH by 1 to 2 units; concomitant mineral dissolution produces elevated Ba, Cu, Fe, Pb, and Zn concentrations in the brine. Concentrations subsequently decrease to approximately steady state values after 120-330 hours, likely due to mineral precipitation as seen in SEM images and predicted by geochemical modeling. In experiments that emulate the caprock-reservoir boundary, final Fe (0.7ppb), an element of secondary concern for the EPA, and Pb (0.05ppb) concentrations exceed EPA limits, whereas Ba (0.140ppb), Cu (48ppb), and Zn (433ppb) values remain below EPA limits. In experiments that simulate deeper reservoir conditions, away from the caprock boundary, final Fe (3.5ppb) and Pb (0.017ppb) values indicate less mobilization than seen at the caprock-reservoir boundary, but values still exceed EPA limits. Barium concentrations always remain below the EPA limit of 2ppb, but are more readily mobilized in experiments replicating deeper reservoir conditions. In both systems, transition elements Cd, Cr, Cu, Pb and Zn behave in a

Searching for traces of life in subglacial Lake Vostok (Antarctica) in terms of forward contamination: the lessons for exploration of icy environments on Mars

Science.gov (United States)

Bulat, S. A.; Alekhina, I. A.; Lipenkov, V. Ya.; Petit, J.-R.

Bacterial 16S ribosomal gene analysis guarded by criteria for trace DNA analysis and Ancient DNA research clearly testifies for the very low biomass in accretion ice from giant subglacial Lake Vostok buried beneath 4-km thick East Antarctic ice sheet. It seems that the accretion ice is essentially germ-free indicating that the water body should also be hosting a highly sparse life, if any, unless the lake water lost its biological contents during accretion process. Due to this the search for life in Lake Vostok is constrained by a high chance of contamination similar to forward-contamination upon searching for life on Mars and other icy planets. Of 16 bacterial phylotypes initially recovered from the accretion ice the only one was kept with confident relevance to the lake environment while 15 others were presumed to be contaminants on the basis of indexing contaminant criteria developed for Lake Vostok and similar icy environments. The current way to avoid contamination appears to use stringent ice chemistry-based decontamination procedures and comprehensive biological controls including establishment of contemporary contaminant database as a prerequisite to identify and categorize sources of contaminants. More challenge would be to advance cleanliness and sterilization approaches and procedures in order to achieve and measure the level of cleanliness appropriate for tools exploring environments like Lake Vostok. As a guide for searching for life in (sub)glacial environments on Earth or Mars and Jovian's Europa our recommendations can be summarized as follows: (i) apply stringent ice decontamination procedures to meet chemistry and trace DNA analysis standards, (ii) document biological contents of various environments including humans in contact with ice samples (development of contaminant database), (iii) ensure in using relevant methods to cover both known and expected biodiversity and (iv) verify microbial findings through their possible metabolic profiles

Geochemical reversals within the lower 100 m of the Palisades sill, New Jersey

Science.gov (United States)

Gorring, Matthew L.; Naslund, H. R.

1995-03-01

Transects through the lower part of the Palisades sill were made at Fort Lee and Alpine, New Jersey in order to characterize the petrologic signature of previously proposed “reversals” in the normal, tholeiitic differentiation trend. Petrographic and geochemical data include: (1) modal and grain size analyses, (2) bulk rock major and trace element concentrations by DCP-AES, and (3) augite, orthopyroxene, magnetite, and olivine compositions by electron microprobe analysis. Anomalous horizons, defined by increased bulk rock Mg?, Cr, Ni, and Co concentrations and abrupt modal and grain-size changes, occur at 10 m (the well known olivine zone), 27 m, 45 m, and 95 m above the basal contact. Thermal models coupled with estimates of the emplacement rate and total magma volume indicate that the olivine zone (OZ) is an early-stage feature, related to the emplacement of initial magma into the Palisades chamber. Stoke’s Law calculations indicate that the settling velocity of average-sized olivine crystals in a high-titanium, quartz-normative (HTQ) magma is too slow for significant gravity settling to have occurred prior to the solidification of the basal 20 m of the sill. It is suggested that the OZ resulted from the emplacement of a heterogeneous initial magma from a compositionally stratified, sub-Palisades storage chamber located within the upper crust; however, heterogeneity may have been derived directly from the mantle or during rapid ascent. Geochemical models indicate that the OZ contains accumulated olivine that is not in cotectic (or constant) proportions with the other cumulus phases, suggesting a mechanical sorting process. Magma chamber recharge is proposed to have occurred at the 27 m and 45 m levels, when a slightly more-primitive HTQ magma was injected into the Palisades sill cha- mber. Zones of elevated Mg? and Cr, 6 to 10 m thick, at these two horizons may indicate the thickness of the hybrid magma formed by the mixing of these two compositions

The corrosion of depleted uranium in terrestrial and marine environments

International Nuclear Information System (INIS)

Toque, C.; Milodowski, A.E.; Baker, A.C.

2014-01-01

Depleted Uranium alloyed with titanium is used in armour penetrating munitions that have been fired in a number of conflict zones and testing ranges including the UK ranges at Kirkcudbright and Eskmeals. The study presented here evaluates the corrosion of DU alloy cylinders in soil on these two UK ranges and in the adjacent marine environment of the Solway Firth. The estimated mean initial corrosion rates and times for complete corrosion range from 0.13 to 1.9 g cm −2 y −1 and 2.5–48 years respectively depending on the particular physical and geochemical environment. The marine environment at the experimental site was very turbulent. This may have caused the scouring of corrosion products and given rise to a different geochemical environment from that which could be easily duplicated in laboratory experiments. The rate of mass loss was found to vary through time in one soil environment and this is hypothesised to be due to pitting increasing the surface area, followed by a build up of corrosion products inhibiting further corrosion. This indicates that early time measurements of mass loss or corrosion rate may be poor indicators of late time corrosion behaviour, potentially giving rise to incorrect estimates of time to complete corrosion. The DU alloy placed in apparently the same geochemical environment, for the same period of time, can experience very different amounts of corrosion and mass loss, indicating that even small variations in the corrosion environment can have a significant effect. These effects are more significant than other experimental errors and variations in initial surface area. -- Highlights: ► In-situ experiments were conducted to evaluate corrosion rates of depleted uranium. ► Samples were corroded in marine sediments, open sea water and two terrestrial soils. ► The depleted uranium titanium alloy corroded fastest in the marine environments. ► Rates of mass loss can vary through time if corrosion products are not removed. �

Trace Elements in Marine Sediment and Organisms in the Gulf of Thailand

Science.gov (United States)

Worakhunpiset, Suwalee

2018-01-01

This review summarizes the findings from studies of trace element levels in marine sediment and organisms in the Gulf of Thailand. Spatial and temporal variations in trace element concentrations were observed. Although trace element contamination levels were low, the increased urbanization and agricultural and industrial activities may adversely affect ecosystems and human health. The periodic monitoring of marine environments is recommended in order to minimize human health risks from the consumption of contaminated marine organisms. PMID:29677146

Leave no trace in the outdoors

Science.gov (United States)

Marion, Jeffrey L.

2014-01-01

The essential guide for enjoying the outdoors without harming the environment. - Details the seven core principles of Leave No Trace ethics and practices - Covers hiking, campfires, food storage, and personal hygiene - Endorsed by the USDI National Park Service, Bureau of Land Management, Fish & Wildlife Service, U.S. Geological Survey, and the USDA Forest Service

Temporally rendered automatic cloud extraction (TRACE) system

Science.gov (United States)

Bodrero, Dennis M.; Yale, James G.; Davis, Roger E.; Rollins, John M.

1999-10-01

Smoke/obscurant testing requires that 2D cloud extent be extracted from visible and thermal imagery. These data are used alone or in combination with 2D data from other aspects to make 3D calculations of cloud properties, including dimensions, volume, centroid, travel, and uniformity. Determining cloud extent from imagery has historically been a time-consuming manual process. To reduce time and cost associated with smoke/obscurant data processing, automated methods to extract cloud extent from imagery were investigated. The TRACE system described in this paper was developed and implemented at U.S. Army Dugway Proving Ground, UT by the Science and Technology Corporation--Acuity Imaging Incorporated team with Small Business Innovation Research funding. TRACE uses dynamic background subtraction and 3D fast Fourier transform as primary methods to discriminate the smoke/obscurant cloud from the background. TRACE has been designed to run on a PC-based platform using Windows. The PC-Windows environment was chosen for portability, to give TRACE the maximum flexibility in terms of its interaction with peripheral hardware devices such as video capture boards, removable media drives, network cards, and digital video interfaces. Video for Windows provides all of the necessary tools for the development of the video capture utility in TRACE and allows for interchangeability of video capture boards without any software changes. TRACE is designed to take advantage of future upgrades in all aspects of its component hardware. A comparison of cloud extent determined by TRACE with manual method is included in this paper.

Raw material variability as archaeological tools: Preliminary results from a geochemical study of the basalt vessel workshop at Iron Age Tel Hazor, Israel

Directory of Open Access Journals (Sweden)

Tatjana Gluhak

2016-10-01

Full Text Available The discovery of a basalt vessel workshop at Tel Hazor, one of the most important Iron Age sites in the Near East, marks a turning point in our understanding of stone artifact production and distribution during the1st millennium BCE. It offers a rare opportunity to characterize ancient raw material sources, production sites, and study production, trade and distribution systems. The basalt vessel workshop, the only one of its kind in the Levant, produced large quantities of bowl preforms and production waste. To better understand the production and distribution systems behind this specialized production center, in 2011 we initiated a focused geochemical project that concentrated on the products of this unique workshop.  We measured the major and trace element composition of 44 unfinished basalt vessels from the workshop and other contexts at Hazor, and can demonstrate that the majority of these objects were derived from one specific, geochemically well-constrained, basaltic rock source. Only a few bowls clearly deviate from this geochemical composition and were produced using raw material from other sources. Thus, we believe that one major quarry existed that supplied the Hazor workshop with the majority of the basaltic raw material. The products from this specific extraction site provide us with a “Hazor reference group” that can be used to test whether or not finished vessels from Hazor and contemporary sites were produced in the Hazor workshop.

Trace element geochemistry and mineralogy of coal from Samaleswari open cast coal block (S-OCB), Eastern India

Science.gov (United States)

Saha, Debasree; Chatterjee, Debashis; Chakravarty, Sanchita; Mazumder, Madhurina

2018-04-01

Coal samples of Samaleswari open cast coal block (S-OCB) are high ash (Aad, mean value 35.43%) and low sulphur content (St, on dry basis, mean value 0.91% analysis. The work is further supported by the use of chemical fractionation experiment that reveals the multi mode of occurrence of several environmentally concern and interested trace elements (Sb, As, Be, Cd, Cr, Co, Cu, Pb, Mn, Ni, Zn). Among the analysed trace elements Co, Mn and Zn have major silicate association along with significant carbonate/oxide/monosulfide association. Whereas As, Cd, Cu, Pb and Ni have dominant pyritic association with notable silicate and carbonate/oxide/monosulfide association. The rest three elements (Sb, Be, Cr) have principally organic association with minor silicate and carbonate/oxide/monosulfide association. The stratigraphic variation of organo-mineral matrix content and detrital-authigenic mineral ratio are primarily related to coal rank. Geochemical character of coal also reflects a light towards proper utilisation of S-OCB coal from technical and environmental view point.

Geochemical Distribution of Lead and Chromium in River Getsi-Kano

African Journals Online (AJOL)

Geochemical forms of lead (Pb) and Chromium (Cr) from the sediment of River Getsi Kano-Nigeria were determined using Atomic Absorption spectrometer for eighteen months. Apart from determination of the metals in water, geochemical forms of the metals were also evaluated into five fractions. Exchangeable, bound to ...

The Geochemical Databases GEOROC and GeoReM - What's New?

Science.gov (United States)

Sarbas, B.; Jochum, K. P.; Nohl, U.; Weis, U.

2017-12-01

The geochemical databases GEOROC (http: georoc.mpch-mainz.gwdg.de) and GeoReM (http: georem.mpch-mainz.gwdg.de) are maintained by the Max Planck Institute for Chemistry in Mainz, Germany. Both online databases became crucial tools for geoscientists from different research areas. They are regularly upgraded by new tools and new data from recent publications obtained from a wide range of international journals. GEOROC is a collection of published analyses of volcanic rocks and mantle xenoliths. Since recently, data for plutonic rocks are added. The analyses include major and trace element concentrations, radiogenic and non-radiogenic isotope ratios as well as analytical ages for whole rocks, glasses, minerals and inclusions. Samples come from eleven geological settings and span the whole geological age scale from Archean to Recent. Metadata include, among others, geographic location, rock class and rock type, geological age, degree of alteration, analytical method, laboratory, and reference. The GEOROC web page allows selection of samples by geological setting, geography, chemical criteria, rock or sample name, and bibliographic criteria. In addition, it provides a large number of precompiled files for individual locations, minerals and rock classes. GeoReM is a database collecting information about reference materials of geological and environmental interest, such as rock powders, synthetic and natural glasses as well as mineral, isotopic, biological, river water and seawater reference materials. It contains published data and compilation values (major and trace element concentrations and mass fractions, radiogenic and stable isotope ratios). Metadata comprise, among others, uncertainty, analytical method and laboratory. Reference materials are important for calibration, method validation, quality control and to establish metrological traceability. GeoReM offers six different search strategies: samples or materials (published values), samples (GeoReM preferred

Chemical and geochemical composition of spring-summer Arctic aerosol collected at Ny Alesund, Svalbard Islands.

Science.gov (United States)

Udisti, Roberto; Becagli, Silvia; Caiazzo, Laura; Cappelletti, David; Giardi, Fabio; Grotti, Marco; Lucarelli, Franco; Moroni, Beatrice; Nava, Silvia; Severi, Mirko; Traversi, Rita

2017-04-01

Since March 2010, spring-summer (usually March - September) campaigns were continuously carried out at the Italian Gruvebadet Observatory, Ny Alesund, Svalbard Island. Aerosol was sampled by PM10 (daily) and 4-stage (4-day resolution) collector devices and size distribution was evaluated at 10 min resolution in the range 10 nm - 20 um (106 size classes by a TSI SMPS-APS integrated system). Six-year (2010-2015) PM10 and size-segregated (>10, 10-2.5, 2.5-1, metal content (major and trace metals, including Rare Earth Elements - REEs, by PIXE and ICP-MS), Pb isotopic composition (by ICP-MS) and Elemental and Organic Carbon (EC-OC) concentrations. The data set was elaborated by multi-parametric statistical analysis (Positive Matrix Factorization - PMF), in order to identifying and quantifying the contribution of the main anthropic and natural aerosol sources. Particular attention was spent in evaluating the anthropic contribution of nss-sulphate, nitrate, EC and heavy metals during the Arctic Haze in spring. The isotopic composition of Pb was used in identifying the source areas (North America, Greenland, North Europe, Siberia, Iceland) of anthropic emissions as a function of seasonality (different atmospheric circulation pathway). Crustal metals and, especially, REEs anomalies (with respect to the Chondrite-normalized profile) allowed characterizing the dust emissions from their Potential Source Areas (PSA). Biogenic markers (especially methane sulfonic acid - MSA - and bio-nss-sulphate) was used to obtain relevant information about the relationship between marine biogenic activity (primary productivity) and sea ice coverage and atmospheric conditions (irradiance, temperature, circulation pathways). The seasonal pattern of the nitrate deposition was also investigated. Chemical and geochemical measurements were compared with high-resolution size distribution and back-trajectory cluster analysis in order to understand the seasonal pattern of the contributions of long

Geochemical prospecting in Guiana

International Nuclear Information System (INIS)

Coulomb, R.

1957-01-01

During the last few years geochemical prospecting techniques have become common usage in the field of mineral deposit prospecting. The real scope of these methods lies in their use in the prospecting of large areas. The most promising use of the geochemistry and hydro-geochemistry of uranium is in heavily forested tropical territories, with few outcrops, where radiometry is strongly handicapped. (author) [fr

ARTEAM - Advanced ray tracing with earth atmospheric models

NARCIS (Netherlands)

Kunz, G.J.; Moerman, M.M.; Eijk, A.M.J. van

2002-01-01

The Advanced Ray Tracing with Earth Atmospheric Models (ARTEAM) aims at a description of the electro-optical propagation environment in the marine atmospheric surface layer. For given meteorological conditions, the model evaluates height- and range-resolved transmission losses, refraction and

Sequential Extractions and Toxicity Potential of Trace Metals Absorbed into Airborne Particles in an Urban Atmosphere of Southwestern Nigeria

Directory of Open Access Journals (Sweden)

Emmanuel Gbenga Olumayede

2018-01-01

Full Text Available The paper investigates the hypothesis that biotoxicities of trace metals depend not only on the concentration as expressed by the total amount, but also on their geochemical fractions and bioavailability. Airborne particles were collected using SKC Air Check XR 5000 high volume Sampler at a human breathing height of 1.5–2.0 meters, during the dry season months from November 2014 to March 2015 at different locations in Akure (7°10′N and 5°15′E. The geochemical-based sequential extractions were performed on the particles using a series of increasingly stringent solutions selected to extract metals (Cd, Cu, Cr, Ni, Pb, Zn, and Mn into four operational geochemical phases—exchangeable, reducible, organic, and residual—and then quantified using an Atomic Absorption Spectrophotometer. The results showed metals concentration of order Pb > Cr > Cd > Zn > Ni > Cu > Mn. However, most metals in the samples exist in nonmobile fractions: exchangeable (6.43–16.2%, reducible (32.58–47.39%, organic (4.73–9.88%, and residual (18.28–27.53%. The pollution indices show ingestion as the leading route of metal exposure, with noncarcinogenic (HQ and cancer risk (HI for humans in the area being higher than 1.0 × 10−4, indicating a health threat.

Geochemical element mobility during the history of a Paleo-proterozoic clastic sedimentary basin, the Athabasca Basin (Saskatchewan, Canada)

International Nuclear Information System (INIS)

Kister, Philippe

2003-01-01

In order to understand the mechanisms of migration and deposition of ore elements, it is essential to determine the timing, source, and destination of the geochemical element mass transfers and/or transportation on a scale encompassing the great sedimentary basins. The purpose of this study is to trace and to date the element migrations that occurred during the history of a Paleo-proterozoic clastic sedimentary basin, the Athabasca Basin, which hosts the world's largest and richest uranium deposits. As this geological environment was proved to be efficient to preserve high grade ore deposits for over more than one billion years, it provides an opportunity to study some natural analogues of deep geological nuclear waste storage. Five research topics were studied: 3D modelling of the distribution of normative minerals and trace elements on a basin-wide scale; U-Pb and Rb-Sr systematics; average chemical age estimation; thermodynamic modelling of the major mineralogical assemblages; U-Pb geochronology of uranium oxides. Some elements have remained immobile (Zr) since their initial sedimentary deposition, or were transferred from one phase to another (Al, Th). Other elements have been transported during fluid flow events that occurred: (1) on a basin wide scale during diagenesis (REE, Y, Sr, Fe), (2) at the unconformity and in the vicinity of the fault zones that represent preferential fluid flow pathways between the basement and the sandstone cover (U, Ni, As, B, Mg, K, Fe, Sr, REE), (3) during the late fault reactivation events associated with the basin uplift (U, Pb, Ni, S, Sr, REE). The successive tectonic events related to the geodynamical context that lead to the formation of these high-grade U concentrations (1460 Ma, 1335 Ma and 1275 Ma in the McArthur River deposit), did not however systematically occur in the whole basin (1275 Ma only at Shea Creek). The exceptionally high grade and tonnages of some deposits seem to be related to a larger number of U

Summary report on geochemical barrier special study

International Nuclear Information System (INIS)

1988-12-01

Long-term management of uranium mill tailings must provide assurance that soluble contaminants will not migrate beyond the Point of Compliance. Conventional management alternatives provide containment through the use of physical barriers which are designed to prevent migration of water through the tailings pile. An alternative is to geochemically modify the tailings to immobilize the contaminants. This investigation examined three potential geochemical modifiers to determine their ability to immobilize inorganic groundwater contaminants found in uranium mill tailings. These modifiers were hydrated lime (Ca(OH) 2 ), limestone (CaCO 3 ), and a sphaegnum peat moss. This investigation focused on both the geochemical interactions between the tailings and the modifiers, and the effects the modifiers had on the physical strength of the tailings. The geochemical investigations began with characterization of the tailings by X-ray diffraction and scanning electron microscopy. This was followed by batch leaching experiments in which various concentrations of each modifier were added to tailings in shaker flasks and allowed to come to equilibrium. Finally, column experiments were conducted to simulate flow through a tailings pile. The results show that all of the modifiers were at least moderately effective at immobilizing most of the groundwater contaminants of concern at uranium mill tailings sites. Hydrated lime was able to achieve 90 percent concentration reduction of arsenic, cadmium, selenium, uranium, and sulfate when added at a two percent concentration. Limestone was somewhat less effective and peat removed greater than 90 percent of arsenic, lead, uranium, and sulfate at a one percent concentration. The column tests showed that kinetic and/or mass transfer limitations are important and that sufficient time must be allowed for the immobilization reactions to occur

Proceedings of 2. Brazilian Geochemical Congress

International Nuclear Information System (INIS)

1989-01-01

Some works about geochemistry are presented, including themes about geochemical exploration, lithogeochemistry and isotope geochemistry, environmental geochemistry, analytical geochemistry, geochemistry of carbonatites and rare earth elements and organic geochemistry. (C.G.C.) [pt

Trace element mapping of two Pyrenean chert deposits (SW Europe) by PIXE

Energy Technology Data Exchange (ETDEWEB)

Sánchez de la Torre, Marta, E-mail: marta.sanchez-de-la-torre@u-bordeaux-montaigne.fr [IRAMAT-CRP2A (UMR 5060), CNRS/Université Bordeaux Montaigne, Maison de l’Archéologie, Esplanade des Antilles, 33607 Pessac Cedex (France); SERP-Universitat de Barcelona, Montalegre St 6-8, 08001 Barcelona (Spain); Angyal, Anikó; Kertész, Zsófia [MTA Atomki, Institute for Nuclear Research, Hungarian Academy of Sciences, H-4026 Debrecen (Hungary); Dubernet, Stéphan; Le Bourdonnec, François-Xavier [IRAMAT-CRP2A (UMR 5060), CNRS/Université Bordeaux Montaigne, Maison de l’Archéologie, Esplanade des Antilles, 33607 Pessac Cedex (France); Csedreki, László; Furu, Enikő; Papp, Enikő; Szoboszlai, Zoltán; Szikszai, Zita [MTA Atomki, Institute for Nuclear Research, Hungarian Academy of Sciences, H-4026 Debrecen (Hungary)

2017-06-01

The geochemical character of two chert formations from the Pyrenean mountain range (SW Europe) was established by PIXE analyses. While it was not possible to distinguish the formations through reference to major and minor elements, some variations were revealed at the trace elemental level. In order to determine if these elements are associated with the Si matrix or to the contents of a specific inclusion, elemental maps were acquired and the elemental composition of the identified inclusions were also determined. As a result, Sr, Ni and Zn are better represented in Montgaillard samples while Y, Hf, W and Zr are typical of Montsaunès cherts. Thanks to elemental maps it has been possible to determine that most of these characteristic elements are usually related to a specific inclusion content.

Geochemical modelling. Pt.1, Pt.2

International Nuclear Information System (INIS)

Skytte Jensen, B.; Jensen, H.; Pearson, F.J.

1992-01-01

This work is carried out under cost-sharing contract with the European Atomic Energy Community in the framework of its fourth research programme on radioactive waste management and radioactive waste storage. This final report is subdivided into two parts. In the first part, JENSEN, a computer code for the computation of chemical equilibria in aqueous systems, describes the structure, function and use of a new geochemical computer program intended for PC's. The program, which is written in Turbo Pascal, version 4, is fundamentally similar to most other geochemical programs, but combines in one program several of the merits these programs have. The intention has been to make an advanced program, which also should be user friendly and fast, and to attain this several new algorithms have been developed and implemented. The program has a built-in database mainly based on the CHEMVAL compilation containing data for 395 soluble species and 149 minerals. The program can find equilibria in the presence of all or some of these soluble species, under conditions or fixed or floating pH and / or Redox potential. The program by itself eliminates a bad guess of a candidate for precipitation. In the present version, the program can identify which minerals and how much of them there will be formed when equilibrium is established. In the second part, LITTLE JOE, an expert system to support geochemical modelling, describes the construction of a minor expert system for use in the evaluation of analytical data for the composition of ground waters from limestone formation. Although the example given is rather limited in scope, the application of the expert system for the evaluation of the analytical data clearly demonstrates the mature expert knowledge imbedded in the system which is contrasted with the uncritical acceptance of analytical or theoretical data. With the overall neglect of ion-exchange and the formation of solid solutions in geochemical calculations, geochemistry is

Geochemical modelling of groundwater evolution using chemical equilibrium codes

International Nuclear Information System (INIS)

Pitkaenen, P.; Pirhonen, V.

1991-01-01

Geochemical equilibrium codes are a modern tool in studying interaction between groundwater and solid phases. The most common used programs and application subjects are shortly presented in this article. The main emphasis is laid on the approach method of using calculated results in evaluating groundwater evolution in hydrogeological system. At present in geochemical equilibrium modelling also kinetic as well as hydrologic constrains along a flow path are taken into consideration

Geochemical and Pb, Sr, and O isotopic study of the Tiva Canyon Tuff and Topopah Spring Tuff, Yucca Mountain, Nye County, Nevada

International Nuclear Information System (INIS)

Neymark, L.A.; Marshall, B.D.; Kwak, L.M.; Futa, Kiyoto; Mahan, S.A.

1995-01-01

Yucca Mountain is currently being studied as a potential site for an underground repository for high-level radioactive waste. One aspect of the site characterization studies is an evaluation o the resource potential at Yucca Mountain. Geochemical and isotopic signatures of past alteration of the welded tuffs that underlie Yucca Mountain provide a means of assessing the probability of hydrothermal ore deposits being present within Yucca Mountain. In this preliminary report, geochemical and isotopic measurements of altered Tiva Canyon Tuff and Topopah Spring Tuff collected from fault zones exposed on the east flank of Yucca Mountain and from one drill core are compared to their unaltered equivalents sampled both in outcrop and drill core. The geochemistry and isotopic compositions of unaltered Tiva Canyon Tuff and Topopah Spring Tuff (high-silica rhyolite portions) are fairly uniform; these data provide a good baseline for comparisons with the altered samples. Geochemical analyses indicate that the brecciated tuffs are characterized by addition of calcium carbonate and opaline silica; this resulted in additions of calcium and strontium,increases in oxygen-18 content, and some redistribution of trace elements. After leaching the samples to remove authigenic carbonate, no differences in strontium or lead isotope compositions between altered and unaltered sections were observed. These data show that although localized alteration of the tuffs has occurred and affected their geochemistry, there is no indication of additions of exotic components. The lack of evidence for exotic strontium and lead in the most severely altered tuff samples at Yucca Mountain strongly implies a similar lack of exotic base or precious metals

Review of geochemical measurement techniques for a nuclear waste repository in bedded salt

International Nuclear Information System (INIS)

Knauss, K.G.; Steinborn, T.L.

1980-01-01

A broad, general review is presented of geochemical measurement techniques that can provide data necessary for site selection and repository effectiveness assessment for a radioactive waste repository in bedded salt. The available measurement techniques are organized according to the parameter measured. The list of geochemical parameters include all those measurable geochemical properties of a sample whole values determine the geochemical characteristics or behavior of the system. For each technique, remarks are made pertaining to the operating principles of the measurement instrument and the purpose for which the technique is used. Attention is drawn to areas where further research and development are needed

Behaviour of nature and technogenic radioisotopes in buried geochemical barriers

International Nuclear Information System (INIS)

Kuznetsov, V.A.; Onoshko, M.P.; Generalova, V.A.

1998-01-01

Behaviour of potassium 40, radium 226, thorium 232, strontium 90 and cesium 137 on geochemical barriers connected with buried soils and cut-off meander sediments of the Holocene age of the Sozh river valley are examined. Some sides of the barrier geochemical structure caused by syngeneic and epigenetic processes have been taken into consideration

Radionuclide behavior at underground environment

International Nuclear Information System (INIS)

Hahn, Phil Soo; Park, Chung Kyun; Keum, Dong Kwon; Cho, Young Hwan; Kang, Moon Ja; Baik, Min Hoon; Hahn, Kyung Won; Park, Hyun Soo

2003-04-01

This study of radionuclide behavior at underground environment has been carried out as a part of the study of high-level waste disposal technology development. Therefore, the main objectives of this project are constructing a data-base and producing data for the safety assessment of a high-level radioactive waste, and verification of the objectivity of the assessment through characterization of the geochemical processes and experimental validation of the radionuclide migration. This project is composed of 6 subjects such as data production required for safety assessments, sorption properties and mechanisms, nuclide migration in the fractured rock, colloid formation and migration, nuclide speciation in deep geological environments, and total evaluation of geochemical behaviors considering multi-factors. The various results from the this project can be applicable to the preliminary safety and performance assessments of the established disposal concept for a future high-level radioactive waste repository. Providing required data and technical basis for assessment methodologies could be a direct application of the results. In a long-term view, the results can also be utilized as a technical background for the establishment of government policy for high-level radioactive waste disposal

Geochemical patterns in soils of the karst region, Croatia

Science.gov (United States)

Prohic, E.; Hausberger, G.; Davis, J.C.

1997-01-01

Soil samples were collected at 420 locations in a 5-km grid pattern in the Istria and Gorski Kotar areas of Croatia, and on the Croatian islands of Cres, Rab and Krk, in order to relate geochemical variation in the soils to underlying differences in geology, bedrock lithology, soil type, environment and natural versus anthropogenic influences. Specific objectives included assessment of possible agricultural and industrial sources of contamination, especially from airborne effluent emitted by a local power plant. The study also tested the adequacy of a fixed-depth soil sampling procedure developed for meager karstic soils. Although 40 geochemical variables were analyzed, only 15 elements and 5 radionuclides are common to all the sample locations. These elements can be divided into three groups: (1) those of mostly anthropogenic origin -Pb, V, Cu and Cr; (2) those of mixed origin - radionuclides and Zn; and (3) those of mostly geogene origin -Ba, Sr, Ti, Al, Na, Ca, Mg, Fe, Mn, Ni and Co. Variation in Pb shows a strong correlation with the pattern of road traffic in Istria. The distributions of Ca, Na and Mg in the flysch basins of southern Istria and Slovenia are clearly distinguishable from the distributions of these elements in the surrounding carbonate terrains, a consequence of differences in bedrock permeability, type of drainage and pH. The spatial pattern of Cs from the Chernobyl nuclear power plant accident reflects almost exclusively the precipitation in Istria during the days immediately after the explosion. ?? 1997 Elsevier Science B.V.

Heavy metal and trace elements in riparian vegetation and macrophytes associated with lacustrine systems in Northern Patagonia Andean Range.

Science.gov (United States)

Juárez, Andrea; Arribére, María A; Arcagni, Marina; Williams, Natalia; Rizzo, Andrea; Ribeiro Guevara, Sergio

2016-09-01

Vegetation associated with lacustrine systems in Northern Patagonia was studied for heavy metal and trace element contents, regarding their elemental contribution to these aquatic ecosystems. The research focused on native species and exotic vascular plant Salix spp. potential for absorbing heavy metals and trace elements. The native species studied were riparian Amomyrtus luma, Austrocedrus chilensis, Chusquea culeou, Desfontainia fulgens, Escallonia rubra, Gaultheria mucronata, Lomatia hirsuta, Luma apiculata, Maytenus boaria, Myrceugenia exsucca, Nothofagus antarctica, Nothofagus dombeyi, Schinus patagonicus, and Weinmannia trichosperma, and macrophytes Hydrocotyle chamaemorus, Isöetes chubutiana, Galium sp., Myriophyllum quitense, Nitella sp. (algae), Potamogeton linguatus, Ranunculus sp., and Schoenoplectus californicus. Fresh leaves were analyzed as well as leaves decomposing within the aquatic bodies, collected from lakes Futalaufquen and Rivadavia (Los Alerces National Park), and lakes Moreno and Nahuel Huapi (Nahuel Huapi National Park). The elements studied were heavy metals Ag, As, Cd, Hg, and U, major elements Ca, K, and Fe, and trace elements Ba, Br, Co, Cr, Cs, Hf, Na, Rb, Se, Sr, and Zn. Geochemical tracers La and Sm were also determined to evaluate contamination of the biological tissues by geological particulate (sediment, soil, dust) and to implement concentration corrections.

Geochemical patterns and microbial contribution to iron plaque formation in the rice plant rhizosphere

Science.gov (United States)

Maisch, Markus; Murata, Chihiro; Unger, Julia; Kappler, Andreas; Schmidt, Caroline

2015-04-01

Rice is the major food source for more than half of the world population and 80 percent of the worldwide rice cultivation is performed on water logged paddy soils. The establishment of reducing conditions in the soil and across the soil-water interface not only stimulates the microbial production and release of the greenhouse gas methane. These settings also create optimal conditions for microbial iron(III) reduction and therefore saturate the system with reduced ferrous iron. Through the reduction and dissolution of ferric minerals that are characterized by their high surface activity, sorbed nutrients and contaminants (e.g. arsenic) will be mobilized and are thus available for uptake by plants. Rice plants have evolved a strategy to release oxygen from their roots in order to prevent iron toxification in highly ferrous environments. The release of oxygen to the reduced paddy soil causes ferric iron plaque formation on the rice roots and finally increases the sorption capacity for toxic metals. To this date the geochemical and microbiological processes that control the formation of iron plaque are not deciphered. It has been hypothesized that iron(II)-oxidizing bacteria play a potential role in the iron(III) mineral formation along the roots. However, not much is known about the actual processes, mineral products, and geochemical gradients that establish within the rhizosphere. In the present study we have developed a growth set-up that allows the co-cultivation of rice plants and iron(II)-oxidizing bacteria, as well as the visual observation and in situ measurement of geochemical parameters. Oxygen and dissolved iron(II) gradients have been measured using microelectrodes and show geochemical hot spots that offer optimal growth conditions for microaerophilic iron(II) oxidizers. First mineral identification attempts of iron plaque have been performed using Mössbauer spectroscopy and microscopy. The obtained results on mineraology and crystallinity have been

GEOBASI: The geochemical Database of Tuscany Region (Italy

Directory of Open Access Journals (Sweden)

Brunella Raco

2015-03-01

Full Text Available In this study the new Regional Geochemical Database (RGDB, called GEOBASI, is presented and illustrated in the framework of a joint collaboration among the three Tuscan universities (Florence, Pisa and Siena, CNR-IGG (Institute of Geosciences and Earth Resources of Pisa, ARPAT (Regional Agency for the Environmental Protection, LAMMA (Environmental Modelling and Monitoring Laboratory for Sustainable Development Consortium and S.I.R.A. (Territorial and Environmental Informative System of Tuscany. The database has permitted the construction of a repository where the geochemical information (compositional and isotopic has been stored in a structured way so that it can be available for different groups of users (e.g. institutional, public and private companies. The information contained in the database can in fact be downloaded freely and queried to correlate geochemistry to other non compositional variables. The first phase of the project was aimed at promoting the use of the geochemical data already available from previous investigations through a powerful Web-GIS interface to implement the exploratory statistics graphical-numerical tools used to: 1 analyse the spatial variability of the investigated context, 2 highlight the geographic location of data pertaining to classes of values or single cases, 3 compare the results of different analytical methodologies applied to the determination of the same element and/or chemical species, 4 extract the geochemical data related to specific monitoring plans and/or geographical areas, and finally 5 recover information about data below the detection limit to understand their impact on the behaviour of the investigated variable. Developments of this project will be focused on the definition of rules and standardized methods in a way that external users could also interactively pursue the RGDB. Furthermore, a detailed investigation of the Scarlino-Follonica plain will permit the improvement and test of

Geochemical Anomalies in the Sediments of Lake Druksiai

International Nuclear Information System (INIS)

Kleinas, A.

1999-01-01

In order to evaluate the impact of Ignalina Nuclear Power Plant (NPP) on natural processes in Lake Druksiai and accumulation of pollutants, in 19931997, carrying on the state scientific program, the Marine Geochemistry Division of the Institute of Geography performed lithological geochemical mapping of lake bottom sediments on a scale of 1 .50 000. The results obtained enabled to distinguish zones of higher anthropogenous geochemical load, where geochemical anomalies of pollutants, including oil hydrocarbons and heavy metals, had been taken into account. Applying concentration coefficients for oil hydrocarbons and heavy metals (Cr, Cu, Ni, Pb, and Zn) and their natural background, the attempt was made to differentiate natural and technogenous components in the geochemical anomalies As expected, the finer sediments -aleurite-pelite mud - showed amounts of oil hydrocarbons and heavy metals being 12.1 times higher than in fine sand - the most coarse of the sediments studied Sediments with organic mater exceeding 20% contained 11.7 times more pollutants than those with organic matter below 1 .5%. Calculations of concentration coefficients (CC) showed no elements in no stations exceeded 10 - the sediments did not reach the category of high pollution However, in many sites, the coefficients exceeded values of 1-2, thus, showing sediments attributable to the categories of weakly polluted or just polluted. Mapping model done by GIS methods (by superimposing schemes of pollutant CCs distribution in the lake and summing them) for geochemical anomalies two derivative map-schemes were obtained for oil hydrocarbons and heavy metals. They showed that clean sediments cover just 24.75% (according to the pollutant background for soil types) and 12.35% (according to the organic matter background for its amount intervals) lake bottom area. Zones slightly polluted by an element at least cover 69.7 and 80.29% of lake area, correspondingly; whereas zones slightly polluted by all

Effect of source integration on the geochemical fluxes from springs

International Nuclear Information System (INIS)

Frisbee, Marty D.; Phillips, Fred M.; White, Art F.; Campbell, Andrew R.; Liu, Fengjing

2013-01-01

Geochemical fluxes from watersheds are typically defined using mass-balance methods that essentially lump all weathering processes operative in a watershed into a single flux of solute mass measured in streamflow at the watershed outlet. However, it is important that we understand how weathering processes in different hydrological zones of a watershed (i.e., surface, unsaturated, and saturated zones) contribute to the total geochemical flux from the watershed. This capability will improve understanding of how geochemical fluxes from these different zones may change in response to climate change. Here, the geochemical flux from weathering processes occurring solely in the saturated zone is investigated. This task, however, remains exceedingly difficult due to the sparsity of subsurface sampling points, especially in large, remote, and/or undeveloped watersheds. In such cases, springflow is often assumed to be a proxy for groundwater (defined as water residing in fully saturated geologic formations). However, springflow generation may integrate different sources of water including, but not limited to, groundwater. The authors’ hypothesis is that long-term estimates of geochemical fluxes from groundwater using springflow proxies will be too large due to the integrative nature of springflow generation. Two conceptual models of springflow generation are tested using endmember mixing analyses (EMMA) on observations of spring chemistries and stable isotopic compositions in a large alpine watershed in the San Juan Mountains of southwestern Colorado. In the “total springflow” conceptual model, springflow is assumed to be 100% groundwater. In the “fractional springflow” conceptual model, springflow is assumed to be an integration of different sources of water (e.g., groundwater, unsaturated flow, preferential flow in the soil, etc.) and groundwater is only a fractional component. The results indicate that groundwater contributions in springflow range from 2% to 100

Drowning in Geochemical Data: The Good, the bad, and the Ugly

Science.gov (United States)

Hofmann, A. W.; Goldstein, S. L.

2008-12-01

Geochemical databases are placing unprecedented amounts of geochemical data at the fingertips of professionals and students. How these data are being used is taking an increasingly important role in shaping our thinking about the Earth. Databases have helped to expose (and eventually kill?) some long- cherished myths, such as the idea of the well-homogenized upper-mantle reservoir, and and they have made geochemical data accessible to geophysicists and enabled them to look at geochemistry with fresh eyes, leading to genuinely new insights. Yet, their very accessibility also makes them "dangerous tools" in the hands of the inexperienced. Statistical treatment of masses of geochemical data without, or with excessive, filtering can yield all sorts of "answers" we would probably be better off without. Data that are severely flawed (due to alteration or poor analytical quality, errors in published data, or errors during data entry) might not be easily identified by, say, a geodynamicist. Other dangers stem from overrepresentation of over-sampled locations and the general, but faulty, assumption of random sampling of the Earth. We will show examples where raw downloads of data from databases without extensive screening can yield data collections where the garbage swamps the useful information. We will also show impressive but meaningless correlations, e.g. upper-mantle temperature versus atmospheric temperature. The lesson is that screening is necessary. On the other hand, sound database compilations now demonstrate that average incompatible-element concentrations in global MORB are two to five times higher than published estimates. This fundamentally changes 30-year-old geochemical mass balance estimates of the mantle. OIBs are fundamentally similar to MORBs but are isotopically shifted, on average, to more "enriched" values. Mantle geochemistry is now fully consistent with dynamic models of "whole-mantle" circulation, with the likely exception of a relatively small

Olfactory memory traces in Drosophila

OpenAIRE

Berry, Jacob; Krause, William C.; Davis, Ronald L.

2008-01-01

In Drosophila the fruit fly, coincident exposure to an odor and an aversive electric shock can produce robust behavioral memory. This behavioral memory is thought to be regulated by cellular memory traces within the central nervous system of the fly. These molecular, physiological or structural changes in neurons, induced by pairing odor and shock, regulate behavior by altering the neurons’ response to the learned environment. Recently, novel in vivo functional imaging techniques have allowed...

Past 140-year environmental record in the northern South China Sea: Evidence from coral skeletal trace metal variations

International Nuclear Information System (INIS)

Song, Yinxian; Yu, Kefu; Zhao, Jianxin; Feng, Yuexing; Shi, Qi; Zhang, Huiling; Ayoko, Godwin A.; Frost, Ray L.

2014-01-01

About 140-year changes in the trace metals in Porites coral samples from two locations in the northern South China Sea were investigated. Results of PCA analyses suggest that near the coast, terrestrial input impacted behavior of trace metals by 28.4%, impact of Sea Surface Temperature (SST) was 19.0%, contribution of war and infrastructure were 14.4% and 15.6% respectively. But for a location in the open sea, contribution of War and SST reached 33.2% and 16.5%, while activities of infrastructure and guano exploration reached 13.2% and 14.7%. While the spatiotemporal change model of Cu, Cd and Pb in seawater of the north area of South China Sea during 1986–1997 were reconstructed. It was found that in the sea area Cu and Cd contaminations were distributed near the coast while areas around Sanya, Hainan had high Pb levels because of the well-developed tourism related activities. -- Highlights: • Geochemical behaviors of trace elements in corals from South China Sea were investigated. • Terrestrial input, SST, war and infrastructure explain about 77.4% of elements behaviors in coral. • Changes of trace elements in coral of Xisha Islands were mainly impacted by local activities. • Spatial change of elements in seawater by was evaluated in 1986–1997 using distribution coefficient K D of coral. -- 140-year changes in the trace metals in corals from South China Sea were investigated. The spatiotemporal change model of the metals in seawater was reconstructed using coral record

Parametrization of environment by geochemistry of the varved clastic and bio- chemogenic lake sediments

Science.gov (United States)

Kalugin, Ivan; Darin, Andrey; Babich, Valery; Markovich, Tatiana; Meydan, Feray

2017-04-01

As it well known, recent quantitative estimations of high-resolution environmental variability are based on geochemical records in lake sediments. Naturally, annually laminated sediments (varves) are the best objects for paleoclimatic study, because they allow to investigate seasonal variability for understanding long-term environmental pattern. Also, varved sediments seem to be applied as the model for identification of element-indicators for non-laminated sediments. The XRF scanner on Synchrotron Radiation provides big geochemical dataset for next mathematic treatment, including time series construction. XRF scanning realizes rapid and non-destructive determinations more than 30 trace elements in a range of concentration from 1 up to 10000 ppm in annual layers. That makes sedimentary cores comparable with tree-rings. Geochemical and physicochemical investigation of lake sediments provides basic information to identify geochemical signals with paleoclimate. In general, sediment consists of mineral component, organics and carbonates. The proportions between these components are affected by environmental parameters, because measured element content or their combinations show correlation with meteodata on instrumental time interval. That allows applying geochemical variability to reconstruct the environmental parameters in the form of time series. The proportions between main components are controlled by temperature, atmospheric precipitation, water salinity and other external forcings. So, layered structure of lake bottom sediments and detectable elements content variability both represent a continuous record of environmental history. Element composition and it's climatic response. Bottom sediments represent conditions of physical weathering, temperate bioproductivity and aridity, which concern to mountain lakes within extra tropical zone. The numerical values of the parameters can be computed by software of physical-chemical modeling for gas+water+rock multisystems

Geochemical Investigation of Clay Minerals in Marte, Borno State, Nigeria

Directory of Open Access Journals (Sweden)

F. D. Adams

2017-10-01

Full Text Available Clay deposit collected from various locations in Marte (Northern Borno, were studied to determine their physical and chemical characteristics in order to evaluate their suitability for industrial uses. Major and trace element analyses were carried out on clay samples using Inductively Couple Plasma-Optical Emission Spectrometry (ICP-OES and X- Ray Fluorescence (XRF. The result of the chemical analysis of the ten (10 samples collected showed significant amounts of SiO2 and Al2O3. Silica content ranges from 51.48 to 62.44 % while alumina varies from 12.49 to 19.00 %. The calcium oxide ranges from 1.17 to 3.39 %, Na2O ranges from 1.1 to 8.61 %, K2O from 1.54 to 3.66 %, MgO varies from 0.04 to0.14 %, Fe2O3 varies from 0.3 to 2.7 % and MnO ranges from 0.01 to 1.03 %. The result showed that the clays are mainly smectite with quartz and felspar as the main non-clay minerals. Generally, the geochemical results of the samples do not meet the standard for industrial utilization when compared to the Industrial specifications. However, for industrial utilization, some of the clay samples may be used after necessary beneficiations.

Well sediments: a medium for geochemical prospecting, an example from the Nisa region, Portugal

NARCIS (Netherlands)

Vriend, S.P.; Dekkers, M.J.; Janssen, M.A.; Commandeur, J.

1991-01-01

Vriend, S.P., Dekkers, M.J.. Janssen, M.A. and Commandeur, J., 1991. Well sediments: a medium for geochemical prospecting, an example from the Nisa region. Portugal. In: A.W. Rose and P.M. Taufen I Editors). Geochemical Exploration ! 989. J. Geochem. Expior., 4 ! : ! 5 I- 167. Tile potential of

Geochemical stratigraphy of two regolith cores from the Central Highlands of the moon

Science.gov (United States)

Korotev, R. L.

1991-01-01

High-resolution concentration profiles are presented for 20-22 chemical elements in the under 1-mm grain-size fractions of 60001-7 and 60009/10. Emphasis is placed on the stratigraphic features of the cores, and the fresh results are compared with those of previous petrographic and geochemical studies. For elements associated with major mineral phases, the variations in concentration in both cores exceed that observed in some 40 samples of surface and trench soils. Most of the variation in lithophile element concentrations at depths of 18 to 21 cm results from the mixing of two components - oil that is relatively mafic and rich in incompatible trace elements (ITEs), and coarse-grained anorthosite. The linearity of mixing lines on two-element concentration plots argues that the relative abundances of these various subcomponents are sufficiently uniform from sample to sample and from region to region in the core that the mixture behaves effectively as a single component. Soils at depths of 52-55 cm exhibit very low concentrations of ITEs.

Geochemical composition of permafrost-affected soils around the town Tiksi, Northern Yakutia, Russia

Science.gov (United States)

Antcibor, Iuliia; Eschenbach, Annette; Pfeiffer, Eva-Maria

2014-05-01

Northeastern Siberia represents an area remote from evident anthropogenic trace metal sources. However, a risk of airborne pollution by trace metals from anthropogenic sources connected to the settlements exists. The largest of these are the settlements Tiksi (71° 42' 55.6" N, 128° 48' 46.3" E) and Kyusyur (70° 45' 41.7" N, 127° 23' 04.7" E). The area of Tiksi is located between the Lena River and the Kharaulach River mouths. It covers parts of Primorsky Ridge and Kharaulach Mountains which are a part of the Verkhoyansk Range. The objective of this study was to investigate features of the spatial element distribution in representative landscape-geochemical units of the Tiksi area and to identify whether local pollution from the settlement takes place. The physical and chemical properties of soils were accessed at three sites located radially in the immediate vicinity to the town Tiksi and one control site remote 10 km south from the settlement. The elements measured were As, Cd, Co, Cu, Fe, Mn, Ni, Pb, and Zn in soils. Differences in the element content were found for various relief forms (depressions, slopes, and elevations). The coefficient of soil buffer capacity (Bf) for the surface soil horizons in depressions was the highest (Bf > 40 %) for the majority of elements indicating their intensive accumulation there. In the surface soil horizons of elevated landscape forms the coefficient, by contrast showed low to very low soil buffer capacity to accumulate metals (0 % acid-base barriers. No significant difference in metal distribution among studied sites was revealed, except for the western site which was characterized by the highest median Ni concentration. The data suggest that ecological impacts at the studied sites were low except for one site north to Tiksi where signs of local pollution probably as a result of local emissions of fuel and mining operations were detected. Keywords: Trace metals; Russian Arctic; Northeastern Siberia; Permafrost

Validation of the WATEQ4 geochemical model for uranium

International Nuclear Information System (INIS)

Krupka, K.M.; Jenne, E.A.; Deutsch, W.J.

1983-09-01

As part of the Geochemical Modeling and Nuclide/Rock/Groundwater Interactions Studies Program, a study was conducted to partially validate the WATEQ4 aqueous speciation-solubility geochemical model for uranium. The solubility controls determined with the WATEQ4 geochemical model were in excellent agreement with those laboratory studies in which the solids schoepite [UO 2 (OH) 2 . H 2 O], UO 2 (OH) 2 , and rutherfordine ((UO 2 CO 3 ) were identified as actual solubility controls for uranium. The results of modeling solution analyses from laboratory studies of uranyl phosphate solids, however, identified possible errors in the characterization of solids in the original solubility experiments. As part of this study, significant deficiencies in the WATEQ4 thermodynamic data base for uranium solutes and solids were corrected. Revisions included recalculation of selected uranium reactions. Additionally, thermodynamic data for the hydroxyl complexes of U(VI), including anionic (VI) species, were evaluated (to the extent permitted by the available data). Vanadium reactions were also added to the thermodynamic data base because uranium-vanadium solids can exist in natural ground-water systems. This study is only a partial validation of the WATEQ4 geochemical model because the available laboratory solubility studies do not cover the range of solid phases, alkaline pH values, and concentrations of inorganic complexing ligands needed to evaluate the potential solubility of uranium in ground waters associated with various proposed nuclear waste repositories. Further validation of this or other geochemical models for uranium will require careful determinations of uraninite solubility over the pH range of 7 to 10 under highly reducing conditions and of uranyl hydroxide and phosphate solubilities over the pH range of 7 to 10 under oxygenated conditions

Behaviour of transuranic nuclides in coastal environment

International Nuclear Information System (INIS)

Pillai, K.C.; Mathew, E.; Matkar, V.M.; Dey, N.N.; Abani, M.C.; Chhapgar, B.F.; Mullay, C.D.

1982-01-01

In view of the nuclear technological developments, the potential for contamination of marine environment with transuranic nuclides has increased. In this context it is necessary to know not only the current levels of these artificial nuclides but there is also a need to understand the physico-chemical, biological and geochemical behaviour of transuranics to evaluate their significance in the marine environment. Studies on these aspects have been carried out in the coastal environment of the west coast of India, near Bombay. The results obtained and conclusions drawn from the various investigations carried out are given in this document

Geochemical signature of land-based activities in Caribbean coral surface samples

Science.gov (United States)

Prouty, N.G.; Hughen, K.A.; Carilli, J.

2008-01-01

Anthropogenic threats, such as increased sedimentation, agrochemical run-off, coastal development, tourism, and overfishing, are of great concern to the Mesoamerican Caribbean Reef System (MACR). Trace metals in corals can be used to quantify and monitor the impact of these land-based activities. Surface coral samples from the MACR were investigated for trace metal signatures resulting from relative differences in water quality. Samples were analyzed at three spatial scales (colony, reef, and regional) as part of a hierarchical multi-scale survey. A primary goal of the paper is to elucidate the extrapolation of information between fine-scale variation at the colony or reef scale and broad-scale patterns at the regional scale. Of the 18 metals measured, five yielded statistical differences at the colony and/or reef scale, suggesting fine-scale spatial heterogeneity not conducive to regional interpretation. Five metals yielded a statistical difference at the regional scale with an absence of a statistical difference at either the colony or reef scale. These metals are barium (Ba), manganese (Mn), chromium (Cr), copper (Cu), and antimony (Sb). The most robust geochemical indicators of land-based activities are coral Ba and Mn concentrations, which are elevated in samples from the southern region of the Gulf of Honduras relative to those from the Turneffe Islands. These findings are consistent with the occurrence of the most significant watersheds in the MACR from southern Belize to Honduras, which contribute sediment-laden freshwater to the coastal zone primarily as a result of human alteration to the landscape (e.g., deforestation and agricultural practices). Elevated levels of Cu and Sb were found in samples from Honduras and may be linked to industrial shipping activities where copper-antimony additives are commonly used in antifouling paints. Results from this study strongly demonstrate the impact of terrestrial runoff and anthropogenic activities on coastal water

Organic geochemical investigation and coal-bed methane characteristics of the Guasare coals (Paso Diablo mine, western Venezuela)

Science.gov (United States)

Quintero, K.; Martinez, M.; Hackley, P.; Marquez, G.; Garban, G.; Esteves, I.; Escobar, M.

2011-01-01

The aim of this work was to carry out a geochemical study of channel samples collected from six coal beds in the Marcelina Formation (Zulia State, western Venezuela) and to determine experimentally the gas content of the coals from the Paso Diablo mine. Organic geochemical analyses by gas chromatography-mass spectrometry and isotopic analyses on-line in coalbed gas samples were performed. The results suggest that the Guasare coals were deposited in a continental environment under highly dysoxic and low salinity conditions. The non-detection of 18??(H)-oleanane does not preclude that the organic facies that gave rise to the coals were dominated by angiosperms. In addition, the presence of the sesquiterpenoid cadalene may indicate the subordinate contribution of gymnosperms (conifers) in the Paleocene Guasare mire. The average coalbed gas content obtained was 0.6 cm3/g. ??13C and D values indicate that thermogenic gas is prevalent in the studied coals. Copyright ?? Taylor & Francis Group, LLC.

Geochemical Triggers of Arsenic Mobilization during Managed Aquifer Recharge.

Science.gov (United States)

Fakhreddine, Sarah; Dittmar, Jessica; Phipps, Don; Dadakis, Jason; Fendorf, Scott

2015-07-07

Mobilization of arsenic and other trace metal contaminants during managed aquifer recharge (MAR) poses a challenge to maintaining local groundwater quality and to ensuring the viability of aquifer storage and recovery techniques. Arsenic release from sediments into solution has occurred during purified recycled water recharge of shallow aquifers within Orange County, CA. Accordingly, we examine the geochemical processes controlling As desorption and mobilization from shallow, aerated sediments underlying MAR infiltration basins. Further, we conducted a series of batch and column experiments to evaluate recharge water chemistries that minimize the propensity of As desorption from the aquifer sediments. Within the shallow Orange County Groundwater Basin sediments, the divalent cations Ca(2+) and Mg(2+) are critical for limiting arsenic desorption; they promote As (as arsenate) adsorption to the phyllosilicate clay minerals of the aquifer. While native groundwater contains adequate concentrations of dissolved Ca(2+) and Mg(2+), these cations are not present at sufficient concentrations during recharge of highly purified recycled water. Subsequently, the absence of dissolved Ca(2+) and Mg(2+) displaces As from the sediments into solution. Increasing the dosages of common water treatment amendments including quicklime (Ca(OH)2) and dolomitic lime (CaO·MgO) provides recharge water with higher concentrations of Ca(2+) and Mg(2+) ions and subsequently decreases the release of As during infiltration.

Snowmelt induced hydrologic perturbations drive dynamic microbiological and geochemical behaviors across a shallow riparian aquifer

Directory of Open Access Journals (Sweden)

Robert eDanczak

2016-05-01

Full Text Available Shallow riparian aquifers represent hotspots of biogeochemical activity in the arid western US. While these environments provide extensive ecosystem services, little is known of how natural environmental perturbations influence subsurface microbial communities and associated biogeochemical processes. Over a six-month period we tracked the annual snowmelt-driven incursion of groundwater into the vadose zone of an aquifer adjacent to the Colorado River, leading to increased dissolved oxygen (DO concentrations in the normally suboxic saturated zone. Strong biogeochemical heterogeneity was measured across the site, with abiotic reactions between DO and sulfide minerals driving rapid DO consumption and mobilization of redox active species in reduced aquifer regions. Conversely, extensive DO increases were detected in less reduced sediments. 16S rRNA gene surveys tracked microbial community composition within the aquifer, revealing strong correlations between increases in putative oxygen-utilizing chemolithoautotrophs and heterotrophs and rising DO concentrations. The gradual return to suboxic aquifer conditions favored increasing abundances of 16S rRNA sequences matching members of the Microgenomates (OP11 and Parcubacteria (OD1 that have been strongly implicated in fermentative processes. Microbial community stability measurements indicated that deeper aquifer locations were relatively less affected by geochemical perturbations, while communities in shallower locations exhibited the greatest change. Reactive transport modeling of the geochemical and microbiological results supported field observations, suggesting that a predictive framework can be applied to develop a greater understanding of such environments.

Snowmelt induced hydrologic perturbations drive dynamic microbiological and geochemical behaviors across a shallow riparian aquifer

Science.gov (United States)

Danczak, Robert; Yabusaki, Steven; Williams, Kenneth; Fang, Yilin; Hobson, Chad; Wilkins, Michael

2016-05-01

Shallow riparian aquifers represent hotspots of biogeochemical activity in the arid western US. While these environments provide extensive ecosystem services, little is known of how natural environmental perturbations influence subsurface microbial communities and associated biogeochemical processes. Over a six-month period we tracked the annual snowmelt-driven incursion of groundwater into the vadose zone of an aquifer adjacent to the Colorado River, leading to increased dissolved oxygen (DO) concentrations in the normally suboxic saturated zone. Strong biogeochemical heterogeneity was measured across the site, with abiotic reactions between DO and sulfide minerals driving rapid DO consumption and mobilization of redox active species in reduced aquifer regions. Conversely, extensive DO increases were detected in less reduced sediments. 16S rRNA gene surveys tracked microbial community composition within the aquifer, revealing strong correlations between increases in putative oxygen-utilizing chemolithoautotrophs and heterotrophs and rising DO concentrations. The gradual return to suboxic aquifer conditions favored increasing abundances of 16S rRNA sequences matching members of the Microgenomates (OP11) and Parcubacteria (OD1) that have been strongly implicated in fermentative processes. Microbial community stability measurements indicated that deeper aquifer locations were relatively less affected by geochemical perturbations, while communities in shallower locations exhibited the greatest change. Reactive transport modeling of the geochemical and microbiological results supported field observations, suggesting that a predictive framework can be applied to develop a greater understanding of such environments.

Development of a method for the classification of geochemical data quality

International Nuclear Information System (INIS)

Sugita, Kenichirou

2005-03-01

This report describes the development of a method for the classification of geochemical data quality. The project had four tasks: (1) review of quality information; (2) development of Evidence Support Logic (ESL) models; (3) development of rules for choosing parameter values; (4) classification of existing data. During H15, JNC developed a preliminary system for classifying groundwater chemical data according to its quality. This system gives a very general indication of data quality, but has a number of limitations. Notably, it is based on adding together scores for individual quality indicators, so that high scores given by some indicators tend to compensate for low scores given by other indicators. Additionally, the system does not distinguish between cases where data quality is poor and cases where data quality is unknown. A further limitation is that the system is based on only a small number of the quality indicators that could be used. By using ESL to develop a new system for classifying geochemical data quality, these limitations can be avoided. This methodology involves weighing evidence for and against a particular hypothesis being true or reliable. Varied evidence, which may be quantitative or qualitative, can be evaluated in an integrated fashion. A process model is constructed to link a hypothesis of interest to evidence corresponding to observations and quantitative data, usually via intermediate processes. An arithmetical approach is then used to propagate evidence through the model. Thus, the approach does not rely on simple addition of quality scores for individual parameters. In this project, evidence for and evidence against the hypothesis that groundwater chemical data represent in-situ conditions are evaluated independently. Both kinds of evidence are represented using numerical scales from 0 to 1. Lack of information about data quality is then represented by 1 - evidence for - evidence against. In this way the situation where the available

Kriging - a challenge in geochemical mapping

Czech Academy of Sciences Publication Activity Database

Štojdl, J.; Matys Grygar, Tomáš; Elznicová, J.; Popelka, J.; Váchová, T.; Hošek, Michal

2017-01-01

Roč. 19, APR (2017) ISSN 1607-7962. [EGU General Assembly 2017. 23.04.2017-28.04.2017, Vienna] Institutional support: RVO:61388980 Keywords : kriging * geochemical mapping Subject RIV: DD - Geochemistry http://meetingorganizer.copernicus.org/EGU2017/EGU2017-3615.pdf

Status report on geochemical modelling

International Nuclear Information System (INIS)

Read, D.

1991-12-01

This report describes the findings of a review undertaken on behalf of the project management group of the programme 'Endlagersicherheit in der Nachbetriebsphase' based at GSF-IfT (Forschungszentrum fuer Umwelt und Gesundheit - Institut fuer Tieflagerung) to establish the current status of research into the simulation of geochemical processes relevant to radiological assessment. The review is intended to contribute to Stage 1 of a strategy formulated to enhance the use of geochemical models in Germany. Emphasis has been placed on processes deemed to be of greatest relevance to performance assessment for a HLW-repository in a salt dome principally, speciation-solubility in high salinity solutions, complexation by natural organics and generation-transport of colloids. For each of these and other topics covered, a summary is given of fundamental concepts, theoretical representations and their limitations, highlighting, where appropriate, the advantages and disadvantages of alternative approaches. The availability of data to quantify any given representation is addressed, taking into account the need for information at elevated temperatures and pressures. Mass transfer is considered in terms of aqueous, particulate and gas-mediated transport, respectively. (orig.) [de

Transport and fate of ammonium and its impact on uranium and other trace elements at a former uranium mill tailing site

International Nuclear Information System (INIS)

Miao, Ziheng; Akyol, Hakan N.; McMillan, Andrew L.; Brusseau, Mark L.

2013-01-01

Highlights: • Nitrification of ammonium evidenced by stable isotopes of nitrate at a mining site. • Concentrations of uranium and other trace elements related to ammonium conc. • Observed impact of ammonium on redox, pH, and possibly complexation. • Proposed impact of transformation of NO 3 and NH 4 on trace elements. - Abstract: The remediation of ammonium-containing groundwater discharged from uranium mill tailing sites is a difficult problem facing the mining industry. The Monument Valley site is a former uranium mining site in the southwest US with both ammonium and nitrate contamination of groundwater. In this study, samples collected from 14 selected wells were analyzed for major cations and anions, trace elements, and isotopic composition of ammonium and nitrate. In addition, geochemical data from the U.S. Department of Energy (DOE) database were analyzed. Results showing oxic redox conditions and correspondence of isotopic compositions of ammonium and nitrate confirmed the natural attenuation of ammonium via nitrification. Moreover, it was observed that ammonium concentration within the plume area is closely related to concentrations of uranium and a series of other trace elements including chromium, selenium, vanadium, iron, and manganese. It is hypothesized that ammonium–nitrate transformation processes influence the disposition of the trace elements through mediation of redox potential, pH, and possibly aqueous complexation and solid-phase sorption. Despite the generally relatively low concentrations of trace elements present in groundwater, their transport and fate may be influenced by remediation of ammonium or nitrate at the site

The two-layer geochemical structure of modern biogeochemical provinces and its significance for spatially adequate ecological evaluations and decisions

Science.gov (United States)

Korobova, Elena; Romanov, Sergey

2014-05-01

Contamination of the environment has reached such a scale that ecogeochemical situation in any area can be interpreted now as a result of the combined effect of natural and anthropogenic factors. The areas that appear uncomfortable for a long stay can have natural and anthropogenic genesis, but the spatial structure of such biogeochemical provinces is in any case formed of a combination of natural and technogenic fields of chemical elements. Features of structural organization and the difference in factors and specific time of their formation allow their separation on one hand and help in identification of areas with different ecological risks due to overlay of the two structures on the other. Geochemistry of soil cover reflects the long-term result of the naturally balanced biogeochemical cycles, therefore the soil geochemical maps of the undisturbed areas may serve the basis for evaluation of the natural geochemical background with due regard to the main factors of geochemical differentiation in biosphere. Purposeful and incidental technogenic concentrations and dispersions of chemical elements of specific (mainly mono- or polycentric) structure are also fixed in soils that serve as secondary sources of contamination of the vegetation cover and local food chains. Overlay of the two structures forms specific heterogeneity of modern biogeochemical provinces with different risk for particular groups of people, animals and plants adapted to specific natural geochemical background within particular concentration interval. The developed approach is believed to be helpful for biogeochemical regionalizing of modern biosphere (noosphere) and for spatially adequate ecogeochemical evaluation of the environment and landuse decisions. It allows production of a set of applied geochemical maps such as: 1) health risk due to chemical elements deficiency and technogenic contamination accounting of possible additive effects; 2) adequate soil fertilization and melioration with due

Comparison study of RNAA and ICP-MS for the determination of ultra-traces of Th and U in geological and cosmochemical samples

International Nuclear Information System (INIS)

Chai, J.; Oura, Y.; Ebihara, M.

2003-01-01

In order to determine thorium and uranium traces in geochemical and cosmochemical samples, we developed an ICP-MS procedure, in which an anion-exchange step was introduced after sample digestion to separate major matrix elements, leading to decrease the dilution factor and increase the sensitivity for Th and U. The ICP-MS procedure was compared to the RNAA procedure which we recently developed for the same purpose. Both ICP-MS and RNAA procedures developed were found to yield similar detection limits (sub ppb) for Th and U. (author)

Application of micro-PIXE analysis to investigate trace elements in deciduous teeth enamel

International Nuclear Information System (INIS)

Igari, K.; Takahashi, A.; Ando, H.

2010-01-01

The early life environment has widespread consequences for later health and disease. To prevent the disease in later life, the assessment of fetal environment is very important. In Japan, birthweight has fallen rapidly during recent two decades. The reduction of birthweight represents reduced fetal nutrition. Deciduous tooth enamel contains pre- and postnatal enamel and its chemical composition reflects the status of metabolism of trace elements during formation period. Deciduous tooth enamel is considered to be a suitable indicator of trace elements exposure in utero. We applied micro-PIXE analysis to investigate the trace elemental content in deciduous tooth enamel. Two deciduous canines from one healthy Japanese boy were used for this study. The enamel section including pre- and postnatal enamel was prepared for micro-PIXE analysis. Five trace elements (Na, Mg, Cl, Zn, and Sr) were detected in the scanning area of tooth. The distribution profiles of 5 elements were obtained as X-ray maps. The distribution profiles of zinc and chlorine were specific, and showed higher concentration in surface enamel. No elements showed different profiles of X-ray maps between pre- and postnatal enamel in this sample. The results of this study suggested that micro-PIXE analysis would be able to estimate the trace elements in prenatal and postnatal enamel, respectively. (author)

trace metals in selected fish species from lakes awassa and ziway

African Journals Online (AJOL)

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were collected from six sampling stations in Lakes Awassa and Ziway, Ethiopia. The edible ... Concentrations of trace elements in the fishes ranged (µg element/g dry mass): Zn. 23.04–30.92; Fe ...... water and soil sediments from some fishponds. Int. J. Environ. ... radioactive contaminants in the aquatic environ- ment and ...

Trace analysis of actinides in the environment using resonance ionization mass spectrometry

International Nuclear Information System (INIS)

Raeder, Sebastian

2011-01-01

In this work the resonant ionization of neutral atoms using laser radiation was applied and optimized for ultra-trace analysis of the actinides thorium, uranium, neptunium and plutonium. The sensitive detection of these actinides is a challange for the monitoring and quantification of radioactive releases from nuclear facilities. Using resonance ionization spectroscopy combined with a newly developed quadrupole-mass-spectrometer, numerous energy levels in the atomic structure of these actinides could be identified. With this knowledge efficient excitation schemes for the mentioned actinides could be identified and characterised. The applied in-source-ionization ensures for a high detection efficiency due to the good overlap of laser radiation with the atomic beam and allows therefore for a low sample consumption which is required for the analysis of radio nuclides. The selective excitation processes in the resonant ionization method supresses unwanted contaminations and was optimized for analytical detection of ultra-trace amounts in environmental samples as well as for determination of isotopic compositions. The efficient in-source-ionization combined with high power pulsed laser radiation allows for detections efficiency up to 1%. For plutonium detection limits in the range of 10 4 -10 5 atoms could be demonstrated for synthetic samples as well as for first environmental samples. The usage of narrow bandwidth continuous wave lasers in combination with a transversal overlap of the laser radiation and the free propagating atomic beam enable for resolving individual isotopic shifts of the resonant transitions. This results in a high selectivity against dominant neighboring isotopes but with a significant loss in detection efficiency. For the ultra-trace isotope 236 U a detection limit down to 10 -9 for the isotope ratio N ( 236 U)/N ( 238 U) could be determined.

Geochemical evidence for waning magmatism and polycyclic volcanism at Crater Flat, Nevada

International Nuclear Information System (INIS)

Perry, F.V.; Crowe, B.M.

1992-01-01

This paper reports that petrologic and geochemical studies of basaltic rocks in the Yucca Mountain region are currently focused on understanding the evolution of volcanism in the Crater Flat volcanic field and the mechanisms of polycyclic volcanic field and the mechanisms of polycyclic volcanism at the Lathrop Wells volcanic center, the youngest center in the Crater Flat volcanic field. Geochemical and petrologic data indicate that the magma chambers which supplied the volcanic centers at Crater Flat became situated at greater crustal depths as the field evolved. Deep magma chambers may be related to a waning magma flux that was unable to sustain upper crustal magma conduits and chambers. Geochemical data from the Lathrop Wells volcanic center indicate that eruptive units identified from field and geomorphic relationships are geochemically distinct. The geochemical variations cannot be explained by fractional crystallization of a single magma batch, indicating that several magma batches were involved in the formation of the Lathrop Wells center. Considering the low magma flux in the Yucca Mountain region in the Quaternary, the probability of several magma batches erupting essentially simultaneously at Lathrop Wells is considered remote

Importance of inorganic geochemical characteristics on assessment of shale gas potential in the Devonian Horn River Formation of western Canada

Science.gov (United States)

Hong, Sung Kyung; Shinn, Young Jae; Choi, Jiyoung; Lee, Hyun Suk

2017-04-01

The gas generation and storage potentials of shale has mostly been assessed by original TOC (TOCo) and original kerogen type. However, in the Horn River Formation, organic geochemical tools and analysis are barely sufficient for assessing the TOCo and original kerogen type because residual carbon contents represent up to 90% of TOC in shales. Major and trace elements are used as proxies for the bottom water oxygen level, for terrestrial sediment input and for productivity, which is related with variation of kerogen type. By using the inorganic geochemical proxies, we attempt to assess original kerogen type in shale gas formation and suggest its implication for HIo (original Hydrogen Index) estimation. The estimated HIo in this study allows us to calculate a reliable TOCo. These results provide new insights into the accurate estimation of the hydrocarbon potential of shale gas resources. The inorganic geochemical proxies indicate vertical variations of productivity (EX-SiO2 and Baauth), terrestrial sediment input (Al2O3, Zr, Hf, and Nb) and oxygen content in bottom water during deposition (Moauth, Uauth and Th/U), which represent the temporal changes in the mixing ratio between Type II and III kerogens. The Horn River Formation has different HIo values calculated from EX-SiO2 (biogenic origin) and it is ranked by HIo value in descending order: Evie and Muskwa members (500-700 mgHC/gTOC) > middle Otterpark Member (400-500 mgHC/gTOC) > upper Otterpark Member (300-400 mgHC/gTOC) > lower Otterpark Member (200 mgHC/gTOC). Based on the original kerogen type and TOCo, the gas generation and storage potentials of the Evie, middle Otterpark and Muskwa members are higher than those of other members. The source rock potential is excellent for the Evie Member with a remarkable difference between TOCo and measured TOC.

Chemical behaviour of transuranic elements in the natural environment

International Nuclear Information System (INIS)

Kim, J.I.

1991-01-01

The chemical behaviour of transuranic elements in natural aquifer systems is governed by a variety of geochemical reactions, such as dissolution reaction (solubility), hydrolysis, complexation with inorganics or organics, redox reaction, colloid formation, geochemical interaction with surfaces of various minerals, coprecipitation, mineralisation etc. This paper reviews the present state of knowledge on some of these particular reactions. The emphasis is placed on how the individual reactions can be appraised for the long-term prediction of the geochemical behaviour of transuranic elements in the natural environment. Of the various reactions, the primary thermodynamic processes of dissolution of transuranic compounds in aquatic solution, complexation with important anions present in groundwater and colloid generation are discussed with notable examples. Various laser spectroscopy in use for the chemical speciation are mentioned briefly as for their spectroscopic capability as well as applicability. The present review discussion is primarily directed to a better understanding of the migration behaviour of transuranic elements in natural aquifer systems. (author) 100 refs

Oak Ridge Geochemical Reconnaissance Program

International Nuclear Information System (INIS)

Arendt, J.W.

1977-03-01

The Oak Ridge reconnaissance program is responsible for the geochemical survey in a 12-state area covering Texas, Oklahoma, Kansas, Nebraska, South Dakota, North Dakota, Minnesota, Wisconsin, Michigan, Iowa, Indiana, and Illinois as part of the National Uranium Resource Evaluation Program. The program concept is outlined and the planning and organization of the program is discussed

Determination of trace elements: Neutron-activation analysis in geochemistry and cosmochemistry

International Nuclear Information System (INIS)

Kolesov, G.M.

1994-01-01

Geochemistry, like cosmochemistry, open-quotes studies chemical elements hor-ellipsis of the crust and hor-ellipsis the Earth hor-ellipsis their history, their distribution hor-ellipsis their genetic hor-ellipsis connectionsclose quotes and is based on data on the abundance and distribution of elements obtained by various analytical methods. Neutron-activation analysis (NAA) plays a particular role in this respect. This is due to its high sensitivity (detection limit as small as 10 -14 g), which makes possible the use of samples of arbitrary mass, and also due to the possibility of obtaining information about composition without destruction of the object, conserving, if required, the unique material under investigation. Of the most interest are the data on the contents for a number of trace elements (at a level of 10 -7 - 10 -4 %), among which are rare-earth elements (REE), U, Th, Zr, Hf, Ta, W, Ga, Ni, Rb, Cs, platinum-group metals, Ag, Au, etc. These elements are considered as indicators of geochemical processes associated with the genesis and evolution of solar system bodies in early and more recent stages of evolution; they are also used to study processes and phenomena at zone boundaries: river-sea, ocean-atmosphere, and so on. The aim of this work is to show the capabilities of NAA in the determination of trace elements

Geochemical study of main elements and trace elements in soils of three profiles in the state of Santa Catarina

International Nuclear Information System (INIS)

Santelli, R.E.

1985-01-01

The total concentrations of the main components (Si, Al, Fe, Ca, Mg, Mn, Ti, Na and K) and of nine trace elements (Ba, Co, Cu, La, Li, Mo, Ni, V and Zn are measured. The elements are determined by several atomic absorption and emission spectroscopic methods. Some properties such as granulometry, mineralogy of the clay fraction, organic matter, etc, are studied. (M.J.C.) [pt

Multivariate statistical analysis to characterize/discriminate between anthropogenic and geogenic trace elements occurrence in the Campania Plain, Southern Italy.

Science.gov (United States)

Busico, Gianluigi; Cuoco, Emilio; Kazakis, Nerantzis; Colombani, Nicolò; Mastrocicco, Micòl; Tedesco, Dario; Voudouris, Konstantinos

2018-03-01

Shallow aquifers are the most accessible reservoirs of potable groundwater; nevertheless, they are also prone to various sources of pollution and it is usually difficult to distinguish between human and natural sources at the watershed scale. The area chosen for this study (the Campania Plain) is characterized by high spatial heterogeneities both in geochemical features and in hydraulic properties. Groundwater mineralization is driven by many processes such as, geothermal activity, weathering of volcanic products and intense human activities. In such a landscape, multivariate statistical analysis has been used to differentiate among the main hydrochemical processes occurring in the area, using three different approaches of factor analysis: (i) major elements, (ii) trace elements, (iii) both major and trace elements. The elaboration of the factor analysis approaches has revealed seven distinct hydrogeochemical processes: i) Salinization (Cl - , Na + ); ii) Carbonate rocks dissolution; iii) Anthropogenic inputs (NO 3 - , SO 4 2- , U, V); iv) Reducing conditions (Fe 2+ , Mn 2+ ); v) Heavy metals contamination (Cr and Ni); vi) Geothermal fluids influence (Li + ); and vii) Volcanic products contribution (As, Rb). Results from this study highlight the need to separately apply factor analysis when a large data set of trace elements is available. In fact, the impact of geothermal fluids in the shallow aquifer was identified from the application of the factor analysis using only trace elements. This study also reveals that the factor analysis of major and trace elements can differentiate between anthropogenic and geogenic sources of pollution in intensively exploited aquifers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Speciation and Distribution of Trace Metals and Organic Matter in Marine Lake as In Situ Laboratory

Science.gov (United States)

Mlakar, M.; Fiket, Ž.; Cuculić, V.; Cukrov, N.; Geček, S.

2016-02-01

Marine lakes are unique, isolated marine systems, also recognized as in situ "laboratories" in which geochemical processes on a different scale compared to the open sea, can be observed. Impact of organic matter cycling on distribution of trace metals in the marine lake Mir, located on Dugi Otok Island, in the central part of the eastern Adriatic Sea, was investigated. Intense spatial and seasonal variations of physico-chemical parameters and organic matter concentrations in the water column of the Lake are governed predominantly by natural processes. Enhanced oxygen consumption in the Lake during summer season, high organic carbon concentrations and low redox potential result in occasional occurrence of anoxic conditions in the bottom layers. Speciation modelling showed that dissolved trace metals Cu, Pb and Zn, are mostly bound to organic matter, while Cd, Co and Ni are present predominantly as free ions and inorganic complexes. Trace metals removal from the water column and their retention in the sediment was found to depend on the nature of the relationship between specific metal and high proportion of organic matter (up to 9%) and inorganic phases, Fe-oxyhydroxydes or biogenic calcite. Surrounding karstic background, with occasional occurrences of red soil characterize deposited sediments as coarse grained and carbonate rich, whose elemental composition is affected by bathymetry of the basin and overall biological production.

Groundwater contamination with arsenic and other trace elements in an area of the Pampa, province of Cordoba, Argentina

International Nuclear Information System (INIS)

Nicolli, H.B.; Suriano, J.M.; Gomez Peral, M.A.; Ferpozzi, L.H.; Baleani, O.A.

1989-01-01

A geochemical study of the groundwater of the pampa in the province of Cordoba, Argentina, is reported. Physical-chemical parameters, dissolved solids, and seven trace elements were determined in 60 selected water samples. Systematic and accurate measurements of arsenic, fluorine, and vanadium were performed for the first time. The geographic distribution of the seven trace elements was mapped and its correlation with the anion-cation composition of the water was studied. Eighty-four percent of the water analyzed showed arsenic contents over 0.05 mg/l. The maxima for arsenic, fluorine, vanadium, and uranium contents were found in the western part of the study area, in waters dominated by alkali metal cations. Maximum selenium and antimony contents were found in the eastern part of the areas, whereas molybdenum distribution showed no relationship to the other groups. The movements of the subsoil have disturbed surface and subsurface drainage, thus influencing the water salinity and trace element contents. To investigate the origin of contamination, 54 loess samples were collected at wells in depths ranging from the surface down to the water table. This loess, which has a high proportion of volcanic components, mainly rhyolitic glass, exhibits a chemical composition corresponding to that of a dacite. The loess and volcanic glass show anomalous contents of all contaminant trace elements, mainly arsenic and selenium. For this reason, loess is considered to be the most important source of contamination of this ground water area. 30 refs., 6 figs., 9 tab

Evaluation of urban environment pollution based on the accumulation of macro- and trace elements in epiphytic lichens.

Science.gov (United States)

Parzych, Agnieszka; Astel, Aleksander; Zduńczyk, Anna; Surowiec, Tomasz

2016-01-01

Nitrogen, phosphorus, potassium, magnesium, zinc, nickel, copper, manganese, iron and lead accumulation properties of three epiphytic lichen species (Hypogymnia physodes (L.) Nyl., Parmelia sulcata Taylor and Xanthoria parietina (L.) Th. Fr.) were compared. An assessment of pollution of the municipal environment in Słupsk (Poland) according to macro- and trace elements was also done. Lichen samples were taken in Autumn 2013 from Betula pendula, Fraxinus excelsior, Acer platanoides, A. pseudoplatanus and Populus sp. trees. Sampling stations comprised of house development areas, green urban parks, vicinity of streets with heavy traffic and industrial enterprises. It was found that lichens represent diverse accumulation properties to pollutants according to the species. X. parietina indicated the highest bioaccumulation in relation to N, K, Mg, Zn and Fe, the thalli of H. physodes accumulated the largest amounts of Ni and Pb, while P. sulcata P and Cu. Manganese was accumulated in similar quantities by all species. Evidences acquired by the use of factor analysis proved that pollution in Słupsk municipal environment is a serious issue with three major sources domination: street dust, marine factor and residual oil combustion. The high-risk areas were detected and visualized using surface maps based on Kriging algorithm. It was seen that the highest pollution occurs in the town centre, while the smallest happened on its outskirts and in urban parks.

Mineralogical and geochemical study of contaminated soils on abandoned Sb deposits Dubrava and Poproc

International Nuclear Information System (INIS)

Klimko, T.; Jurkovic, L.

2010-01-01

In this paper we present initial results of mineralogical and geochemical study of secondary mineral phases, often with a high content of Sb and As, resulting from oxidation of sulphide minerals in the soil environment on two, now abandoned Sb deposits. Dubrava deposit is situated on the northern slopes of the Dumbier Low Tatras and Poproc deposit is located in the eastern part of Spis-Gemer Rudohorie. Both studied sites were in the past (second half of 20 th century) significant producers of antimony ore and Dubrava deposit belonged to medium-sized Sb deposits in the world.

Post-depositional redistribution of trace metals in reservoir sediments of a mining/smelting-impacted watershed (the Lot River, SW France)

International Nuclear Information System (INIS)

Audry, Stephane; Grosbois, Cecile; Bril, Hubert; Schaefer, Joerg; Kierczak, Jakub; Blanc, Gerard

2010-01-01

Mining/smelting wastes and reservoir sediment cores from the Lot River watershed were studied using mineralogical (XRD, SEM-EDS, EMPA) and geochemical (redox dynamics, selective extractions) approaches to characterize the main carrier phases of trace metals. These two approaches permitted determining the role of post-depositional redistribution processes in sediments and their effects on the fate and mobility of trace metals. The mining/smelting wastes showed heterogeneous mineral compositions with highly variable contents of trace metals. The main trace metal-bearing phases include spinels affected by secondary processes, silicates and sulfates. The results indicate a clear change in the chemical partitioning of trace metals between the reservoir sediments upstream and downstream of the mining/smelting activities, with the downstream sediments showing a 2-fold to 5-fold greater contribution of the oxidizable fraction. This increase was ascribed to stronger post-depositional redistribution of trace metals related to intense early diagenetic processes, including dissolution of trace metal-bearing phases and precipitation of authigenic sulfide phases through organic matter (OM) mineralization. This redistribution is due to high inputs (derived from mining/smelting waste weathering) at the water-sediment interface of (i) dissolved SO 4 promoting more efficient OM mineralization, and (ii) highly reactive trace metal-bearing particles. As a result, the main trace metal-bearing phases in the downstream sediments are represented by Zn- and Fe-sulfides, with minor occurrence of detrital zincian spinels, sulfates and Fe-oxyhydroxides. Sequestration of trace metals in sulfides at depth in reservoir sediments does not represent long term sequestration owing to possible resuspension of anoxic sediments by natural (floods) and/or anthropogenic (dredging, dam flush) events that might promote trace metal mobilization through sulfide oxidation. It is estimated that, during a major

Beliefs about emotional residue: the idea that emotions leave a trace in the physical environment.

Science.gov (United States)

Savani, Krishna; Kumar, Satishchandra; Naidu, N V R; Dweck, Carol S

2011-10-01

Drawing upon the literatures on beliefs about magical contagion and property transmission, we examined people's belief in a novel mechanism of human-to-human contagion, emotional residue. This is the lay belief that people's emotions leave traces in the physical environment, which can later influence others or be sensed by others. Studies 1-4 demonstrated that Indians are more likely than Americans to endorse a lay theory of emotions as substances that move in and out of the body, and to claim that they can sense emotional residue. However, when the belief in emotional residue is measured implicitly, both Indians and American believe to a similar extent that emotional residue influences the moods and behaviors of those who come into contact with it (Studies 5-7). Both Indians and Americans also believe that closer relationships and a larger number of people yield more detectable residue (Study 8). Finally, Study 9 demonstrated that beliefs about emotional residue can influence people's behaviors. Together, these finding suggest that emotional residue is likely to be an intuitive concept, one that people in different cultures acquire even without explicit instruction. 2011 APA, all rights reserved

Correlation of trace element content in air particulates with solar meteorological data in the atmosphere of Athens

International Nuclear Information System (INIS)

Kanias, G.D.; Grimanis, A.P.; Viras, L.G.

2003-01-01

Relation between the trace element content in air particulates and solar meteorological data in the atmospheric environment of Athens, Greece, was studied. For this purpose, Sm, Br, As, Na, K, La, Ce, Cr, Ag, Sc, Fe, Zn, Co, Sb, Th were determined by INAA in respirable aerosols collected during winter 1993-1994. The results showed that the average cloudiness, sunshine, and the total solar radiation (sun and sky) on a horizontal surface, (3 variables) have no relation with trace element variation. However, diffuse solar radiation (sun and sky) on a horizontal surface seems to have statistically significant relationship with some of the trace element variation. It forms a single component with some trace elements after the application of the factor analysis. The increase of the same solar variable in the Athens City center, is one of the factors which cannot permit the emission of trace elements in the atmospheric environment from dust soil and car tires. (author)

Mineralogical, geochemical and hydrocarbon potential of subsurface Cretaceous shales, Northern Western Desert, Egypt

Directory of Open Access Journals (Sweden)

D.A. Mousa

2014-03-01

Full Text Available Twenty four Cretaceous shale core samples of Gibb Afia-1, Betty-1, Salam-1X and Mersa Matruh-1 wells were mineralogically and geochemically studied using XRD, XRF and Rock Eval Pyrolysis. Kaolinite, smectite and illite are the main clay minerals in addition to rare chlorite, while the non-clay minerals include quartz, calcite, dolomite and rare siderite. The shales were derived through intensive chemical weathering of mafic basement and older sedimentary rocks. These sediments were deposited in a near-shore shallow marine environment with some terrestrial material input. The shales have poor to fair organic content. It is marginally to rarely mature.

GEOCHEMICAL CONTROLS ON NUCLEAR MAGNETIC RESONANCE MEASUREMENTS

International Nuclear Information System (INIS)

Knight, Rosemary

2008-01-01

Proton nuclear magnetic resonance (NMR) is used in the Earth Sciences as a means of obtaining information about the molecular-scale environment of fluids in porous geological materials. Laboratory experiments were conducted to advance our fundamental understanding of the link between the NMR response and the geochemical properties of geological materials. In the first part of this research project, we studied the impact of both the surface-area-to-volume ratio (S/V) of the pore space and the surface relaxivity on the NMR response of fluids in sand-clay mixtures. This study highlighted the way in which these two parameters control our ability to use NMR measurements to detect and quantify fluid saturation in multiphase saturated systems. The second part of the project was designed to explore the way in which the mineralogic form of iron, as opposed to simply the concentration of iron, affects the surface relaxation rate and, more generally, the NMR response of porous materials. We found that the magnitude of the surface relaxation rate was different for the various iron-oxide minerals because of changes in both the surface-area-to-volume ratio of the pore space, and the surface relaxivity. Of particular significance from this study was the finding of an anomalously large surface relaxivity of magnetite compared to that of the other iron minerals. Differences in the NMR response of iron minerals were seen in column experiments during the reaction of ferrihydrite-coated quartz sand with aqueous Fe(II) solutions to form goethite, lepidocrocite and magnetite; indicating the potential use of NMR as a means of monitoring geochemical reactions. The final part of the research project investigated the impact of heterogeneity, at the pore-scale, on the NMR response. This work highlighted the way in which the geochemistry, by controlling the surface relaxivity, has a significant impact on the link between NMR data and the microgeometry of the pore space.

Analysis on deep metallogenic trace and simulation experiment in xiangshan large-scale volcanic hydrothermal type uranium deposit

International Nuclear Information System (INIS)

Liu Zhengyi; Liu Zhangyue; Wen Zhijian; Du Letian

2010-01-01

Based on series experiments on field geologic analysis, and associated with deep metallogenic trace experiment model transformed from establishment of field deep metallogenic trace model, this paper come to the conclusion that distribution coefficients of U and Th first domestic from the magmatic experiment, and then discuss the geochemical behaviors of U, Th, K during magmatic evolution stage. The experiment shows that close relationship between U and Na during the hydrothermal alteration stage; and relationship between U and K during metallogenic stage, which prove that U and K are incompatible and regularity of variation between K and Na. The conclusion of uranium dissolving ability increased accompany with pressure increasing in basement metamorphic rocks and host rocks, is obtained from this experiment, which indicate a good deep metallogenic prospect. Furthermore, Pb, Sr, Nd, He isotopes show that the volcanic rocks and basement rocks are ore source beds; due to the combined functions of volcanic hydrothermal and mantle ichor, uranium undergo multi-migration and enrichment and finally concentrated to large rich deposit. (authors)

High resolution geochemical proxy record of the last 600yr in a speleothem from the northwest Iberian Peninsula

Science.gov (United States)

Iglesias González, Miguel; Pisonero, Jorge; Cheng, Hai; Edwards, R. Lawrence; Stoll, Heather

2017-04-01

In meteorology and climatology, the instrumental period is the period where we have measured directly by instrumentation, different meteorological data along the surface which allow us to determinate the evolution of the climate during the last 150 years over the world. At the beginning, the density of this data were very low, so we have to wait until the last 75-100 years to have a good network in most of the parts of the surface. This time period is very small if we want to analyze the relationship between geochemical and instrumental variability in any speleothem. So a very high resolution data is needed to determinate the connection between both of them in the instrumental period, to try to determinate de evolution of climate in the last 600 years. Here we present a high resolution speleothem record from a cave located in the middle of the Cantabrian Mountains without any anthropologic influence and with no CO2 seasonal variability. This 600yr stalagmite, dated with U/Th method with a growth rate from 100 to 200 micrometers/yr calculated with Bchron model, provide us accurate information of the climate conditions near the cave. Trace elements are analyzed at 8 micrometers intervals by Laser Ablation ICP-MS which resolves even monthly resolution during the last 600 years with special attention with Sr, Mg, Al and Si. This data, without seasonal variability and with the presence of a river inside the cave, give us very valuable information about the extreme flood events inside the cave during the whole period, which is related with the precipitations and the snow fusion events outside the cave. We identify more extremely flood events during the Little Ice Age than in the last 100yr. As well, we have trace elements data with spatial resolution of 0.2mm analyzed with ICP-AES which allow us to compare the geochemical variability with both technics. We also analyze stable isotope d13C and d18O with a spatial resolution of 0.2mm, so we are able to identify variations

Determination of Geochemical Bio-Signatures in Mars-Like Basaltic Environments

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Karen Olsson-Francis

2017-09-01

Full Text Available Bio-signatures play a central role in determining whether life existed on early Mars. Using a terrestrial basalt as a compositional analog for the martian surface, we applied a combination of experimental microbiology and thermochemical modeling techniques to identify potential geochemical bio-signatures for life on early Mars. Laboratory experiments were used to determine the short-term effects of biota on the dissolution of terrestrial basalt, and the formation of secondary alteration minerals. The chemoorganoheterotrophic bacterium, Burkholderia sp. strain B_33, was grown in a minimal growth medium with and without terrestrial basalt as the sole nutrient source. No growth was detected in the absence of the basalt. In the presence of basalt, during exponential growth, the pH decreased rapidly from pH 7.0 to 3.6 and then gradually increased to a steady-state of equilibrium of between 6.8 and 7.1. Microbial growth coincided with an increase in key elements in the growth medium (Si, K, Ca, Mg, and Fe. Experimental results were compared with theoretical thermochemical modeling to predict growth of secondary alteration minerals, which can be used as bio-signatures, over a geological timescale. We thermochemically modeled the dissolution of the basalt (in the absence of biota in very dilute brine at 25°C, 1 bar; the pH was buffered by the mineral dissolution and precipitation reactions. Preliminary results suggested that at the water to rock ratio of 1 × 107, zeolite, hematite, chlorite, kaolinite, and apatite formed abiotically. The biotic weathering processes were modeled by varying the pH conditions within the model to adjust for biologic influence. The results suggested that, for a basaltic system, the microbially-mediated dissolution of basalt would result in “simpler” secondary alteration, consisting of Fe-hydroxide and kaolinite, under conditions where the abiotic system would also form chlorite. The results from this study demonstrate

Chemical modelling of trace elements in pore water from PFBC residues containing ammonia

International Nuclear Information System (INIS)

Karlsson, L.G.; Brandberg, F.

1993-01-01

Ammonia is added to the PFBC process with the purpose to reduce the emissions of NO x in the stack gases. The design of the system for cleaning the stack gases will lead to an increased adsorption of ammonia and an accumulation of soluble ammonium salts in the cyclone ash from PFBC processes. This can be an environmental problem since the amounts will increase over the coming years and there will be a need to dispose the residues. When infiltrating rainwater penetrates the disposed residues ammonia and ammonium salts result in a contamination of the pore water with ammonia in the disposed residues. This entail the solubility of several trace elements in the residues that form soluble complexes with ammonia will increase and cause an increased contamination of groundwater and surface water. In this study the increased solubilities is calculated for the trace elements cadmium, cobalt, copper, mercury, nickel, silver and zinc in the residues using thermodynamical data. The calculations have been performed with probable solid phases of the trace elements at oxidizing and reducing conditions as a function of pH and at varying concentration of ammonia in the pore water. The thermodynamic calculations have been performed with the geochemical code EQ3NR. The results from the calculations show that as a concentration of 17 mg NH 3 /l in the pore water of the residues increases the solubilities for copper and silver. If the concentration of ammonia increases to 170 mg NH 3 /l will the solubilities increase also for cadmium, nickel and zinc. (12 refs., 39 figs.)

Geochemical Weathering in Glacial and Proglacial Environments

Science.gov (United States)

Tranter, M.

2003-12-01

It seems counterintuitive that chemical erosion in glaciated regions proceeds at rates comparable to those of temperate catchments with comparable specific runoff (Anderson et al., 1997). All the usual factors that are associated with elevated rates of chemical weathering ( Drever, 1988, 1994), such as water, soil, and vegetation, are either entirely absent or absent for much of the year. For example, glaciated regions are largely frozen for significant periods each year, the residence time of liquid water in the catchment is low ( Knight, 1999), there are thin, skeletal soils at best, and vegetation is either absent or limited ( French, 1997). Other chapters in this volume have highlighted how these factors are important in other, more temperate and tropical environments. Even so, chemical erosion rates in glaciated terrain are usually near to or greater than the continental average ( Sharp et al., 1995; Wadham et al., 1997; Hodson et al., 2000). This is because glaciated catchments usually have high specific runoff, there are high concentrations of freshly comminuted rock flour, which is typically silt sized and coated with microparticles, and adsorbed organic matter or surface precipitates that may hinder water-rock interactions are largely absent ( Tranter, 1982). In short, the rapid flow of water over fine-grained, recently crushed, reactive mineral surfaces maximizes both the potential rates of chemical weathering and chemical erosion.A range of both lab- and field-based studies of glacial chemical weathering have been undertaken, mainly on the smaller glaciers of Continental Europe (e.g., Brown et al., 1993a, b), Svalbard (e.g., Hodson et al., 2002), and North America (e.g., Anderson et al., 2000). The field-based studies typically generate hydrographs of glacier runoff, which show a characteristic diurnal cycle during summer in low latitudes ( Figure 1), and more subdued diurnal cycles at high latitudes (Figure 2 and Figure 3). The concentration of ions in

Predicting trace metal solubility and fractionation in Urban soils from isotopic exchangeability

International Nuclear Information System (INIS)

Mao, L.C.; Young, S.D.; Tye, A.M.; Bailey, E.H.

2017-01-01

Metal-salt amended soils (MA, n = 23), and historically-contaminated urban soils from two English cities (Urban, n = 50), were investigated to assess the effects of soil properties and contaminant source on metal lability and solubility. A stable isotope dilution method, with and without a resin purification step, was used to measure the lability of Cd, Cu, Ni, Pb and Zn. For all five metals in MA soils, lability (%E-values) could be reasonably well predicted from soil pH value with a simple logistic equation. However, there was evidence of continuing time-dependent fixation of Cd and Zn in the MA soils, following more than a decade of storage under air-dried conditions, mainly in high pH soils. All five metals in MA soils remained much more labile than in Urban soils, strongly indicating an effect of contaminant source on metal lability in the latter. Metal solubility was predicted for both sets of soil by the geochemical speciation model WHAM-VII, using E-value as an input variable. For soils with low metal solution concentrations, over-estimation of Cd, Ni and Zn solubility was associated with binding to the Fe oxide fraction while accurate prediction of Cu solubility was dependent on humic acid content. Lead solubility was most poorly described, especially in the Urban soils. Generally, slightly poorer estimation of metal solubility was observed in Urban soils, possibly due to a greater incidence of high pH values. The use of isotopically exchangeable metal to predict solubility is appropriate both for historically contaminated soils and where amendment with soluble forms of metal is used, as in toxicological trials. However, the major limitation to predicting solubility may lie with the accuracy of model input variables such as humic acid and Fe oxide contents where there is often a reliance on relatively crude analytical estimations of these variables. Trace metal reactivity in urban soils depends on both soil properties and the original source material

Geochemical methods for identification of formations being prospective for uranium

International Nuclear Information System (INIS)

Zhukova, A.M.; Komarova, N.I.; Spiridonov, A.A.; Shor, G.M.

1985-01-01

Geochemical methods of uranium content evaluation in metamorphic, ultrametamorphic and sedimentary formations are considered. At that, the following four factors are of the highest importance: 1) average uranium content-geochemical background; 2) character of uranium distribution; 3) forms of uranium presence; 4) the value of thorium-uranium ratio. A complex of radiogeochemical criteria, favourable for uranium presence is formulated: high average background content of total and '' mobile''uranium and high value of variation coefficient (80-100% and above); low (approximately one or lower) thorium-uranium ratio; sharp increase in uranium concentration in accessory minerals. Radiogeochemical peculiarities of metamorphic and ultrametamorphic formations prospective for uranium are enumerated. The peculiarities condition specificity of geochemical prospecting methods. Prospecting methods first of all must be directed at the evaluation of radioelement distribution parameters and specification of the forms of their presence

Synthesizing Earth's geochemical data for hydrogeochemical analysis

Science.gov (United States)

Brantley, S. L.; Kubicki, J.; Miller, D.; Richter, D.; Giles, L.; Mitra, P.

2007-12-01

For over 200 years, geochemical, microbiological, and chemical data have been collected to describe the evolution of the surface earth. Many of these measurements are data showing variations in time or in space. To forward predict hydrologic response to changing tectonic, climatic, or anthropogenic forcings requires synthesis of these data and utilization in hydrogeochemical models. Increasingly, scientists are attempting to synthesize such data in order to make predictions for new regions or for future time periods. However, to make such complex geochemical data accessible requires development of sophisticated cyberinfrastructures that both invite uploading as well as usage of data. Two such cyberinfrastructure (CI) initiatives are currently developing, one to invite and promote the use of environmental kinetics data (laboratory time course data) through ChemxSeer, and the other to invite and promote the use of spatially indexed geochemical data for the Earth's Critical Zone through CZEN.org. The vision of these CI initiatives is to provide cyber-enhanced portals that encourage domain scientists to upload their data before publication (in private cyberspace), and to make these data eventually publicly accessible (after an embargo period). If the CI can be made to provide services to the domain specialist - e.g. to provide data analysis services or data comparison services - we envision that scientists will upload data. In addition, the CI can promote the use and comparison of datasets across disciplines. For example, the CI can facilitate the use of spatially indexed geochemical data by scientists more accustomed to dealing with time-course data for hydrologic flow, and can provide user-friendly interfaces with CI established to facilitate the use of hydrologic data. Examples of the usage of synthesized data to predict soil development over the last 13ky and its effects on active hydrological flow boundaries in surficial systems will be discussed for i) a N

Mineralogical and geochemical aspects of nickeliferous laterite of Vermelho region, Serra dos Carajas (State of Para)

International Nuclear Information System (INIS)

Almeida Correa, S.L. de.

1982-01-01

Mineralogical and geochemical studies were carried out on the nickeliferous laterite of Vermelho region (Serra of Carajas, state of Para). A total of 64 samples were analysed by X-ray fluorescence analysis and atomic absorption, spectrophotometry, including bed-rock specimens. The laterite is derived from ultramafic rocks (serpentinites) and there horizons were recognized towards the top: saprolitic horizon with a thickness of more than 4 meters, clay horizon 6,1 meters thick and limonitic horizon with a thickness of 8,3 meters. The process of weathering affected both major and trace elements which were bleached, transported and reprecipitated. This caused variations in the concentration of the elements with depth, except for magnesium which was extensively bleached. Nickel concentrations in the clay horizon probably was a result of ion exchange between smectite and Ni-bearing solutions, the source of this Ni being goethite. Cobalt and zinc were also strongly enriched during the process of laterization, although maximum concentrations of these elements are found in different horizons. (author)

Geochemical evolution of Ngorongoro Caldera, Northern Tanzania: Implications for crust magma interaction

Science.gov (United States)

Mollel, Godwin F.; Swisher, Carl C.; Feigenson, Mark D.; Carr, Michael J.

2008-07-01

Ngorongoro Caldera is the largest and best-preserved of nine Plio-Pleistocene volcanoes that make-up the Ngorongoro Volcanic Highlands (NVH) complex situated at the southern bifurcation of Gregory Rift, part of the East African Rift system of northern Tanzania. We report here, major and trace element abundances, Sr-Nd-Pb isotope analyses and 40Ar/ 39Ar laser incremental-heating and total fusion ages on lava and tephra sampled from stratigraphic sections exposed within the Ngorongoro Caldera. Major and trace elements measured on samples collected from the Ngorongoro Caldera wall indicate a stratified magma chamber whose silicic top and basaltic bottom was inverted by sequential eruptions. Samples from the lower part of the exposed Ngorongoro Caldera wall are high in silica, alkalis and HFSE (High Field Strength Elements). The Zr, Nb and Hf concentrations are highly correlated with each other and decrease up-section, indicative of the extent of magma evolution. Modeling of major, trace as well as Sr, Nd and Pb isotope data suggests that assimilation fractional crystallization processes were essential in producing the observed geochemical variations. The Sr and Nd isotope ratios from the Ngorongoro samples are widely dispersed ( 87Sr/ 86Sr = 0.70405 to 0.70801, 143Nd/ 144Nd = 0.512205 to 0.512623) and Pb isotope ratios are consistent with previous studies: 206Pb/ 204Pb = 18.73 to 19.37, 207Pb/ 204Pb = 15.64 to 15.69, 208Pb/ 204Pb = 39.52 to 39.55. Although Sr isotopic ratios are similar to Oceanic Island Basalt (OIB), the more radiogenic samples ( 87Sr/ 86Sr > 0.705) from the lower part of the section suggest crust-magma interaction; this is supported by Ce/Pb ratios (Ngorongoro Caldera wall section yield 40Ar/ 39Ar ages of 2.25 ± 0.02 Ma to 2.01 ± 0.02 Ma, constraining a duration of volcanism of the order of ~ 240 kyr. These ages suggest correlation of a normal to reverse geomagnetic polarity transition measured in the Ngorongoro Caldera wall section with the ~ 2

Geochemical fingerprints and pebbles zircon geochronology

Indian Academy of Sciences (India)

Home; Journals; Journal of Earth System Science; Volume 125; Issue 7. Geochemical fingerprints and pebbles zircon geochronology: Implications for the provenance and tectonic setting of Lower Cretaceous sediments in the Zhucheng Basin (Jiaodong peninsula, North China). Jin-Long Ni Jun-Lai Liu Xiao-Ling Tang ...

Trace metals concentration assessment in urban particulate matter ...

African Journals Online (AJOL)

This study was conducted to investigate the distribution and correlation of selected trace elements (Ca, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in Yenagoa, Bayelsa State and its environs. Air particulate matter was collected gravimetrically at five stations (using a high volume portable SKC air check MTXSidekickair sampler ...

Trace Metals And Organic Matter Diagenesis At The Oman Margin

Digital Repository Service at National Institute of Oceanography (India)

Alagarsamy, R.

Trace Metals (e.g. Mn and Fe) play an important role as secondary oxidants in the degradation of sedimentary OM under sub-oxic conditions. Hence the remineralisation of organic constituents of sediments in the marine environment may significantly...