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1.
The present study assesses the impact of coal mining on surface and groundwater resources of Korba Coalfield, Central India. Accordingly, water samples collected from various sources are analyzed for major ions, trace elements, and other mine effluent parameters. Results show that the groundwater samples are slightly acidic, whereas river water and mine water samples are mildly alkaline. Elevated concentrations of Ca2+, Na+, HCO3 ?, and SO4 2? alongside the molar ratios (Ca2++Mg2+)/(SO4 2?+HCO3 ?) <1 and Na+/Cl? >1 suggest that silicate weathering (water-rock interaction) coupled with ion exchange are dominant solute acquisition processes controlling the chemistry of groundwater in the study area. The overall hydrogeochemistry of the area is dominated by two major hydrogeochemical facies (i.e., Ca–Cl–SO4 and Ca–HCO3). Analysis of groundwater and river water quality index (GRWQI) elucidates that majority (82%) of samples are of “excellent” to “good” category, and the remaining 12% are of “poor” quality. Similarly, the effluent water quality index (EWQI) indicates that 6 out of 8 samples belong to excellent quality. Concentration of trace element constituents such as As, Zn, Cu, Cr, and Cd is found to be well within the stipulated limits for potable use, except for Fe, Mn, and Pb. Suitability of water samples for irrigation purpose, established using standard tools like Wilcox and USSL diagrams, reveal “excellent to permissible” category for majority of the samples. The present study also substantiates the effectiveness of the measures implemented for the treatment of mine effluent water.  相似文献   

2.
Laboratory batch sorption and column transport experiments were performed on heterogeneous alluvial soils with a wide range of physical characteristics from wells that are located in the region between Mogan Lake and Eymir Lake, Gölba??, Ankara. The mean values for the K d of Cu were found to be highest in clay (32550.350 L/kg) and lowest in loamy sand (18170.76 L/kg). The minimum and maximum sorption capacity values (mean values) for Zn were found to be in clay (10985.148 mg/kg) and in silty loam (8597.14 mg/kg) units, respectively. Similarly, the minimum and maximum values for Mn were found in loamy sand (4908.695 mg/kg) and clay (7587.391 mg/kg) units. The non-linear least-squares optimization code “CXTFIT” was used to determine transport parameter values by curve-fitting. The results of the column experiments demonstrate dispersivity values within the range of 0.024–1.13 cm for soil samples.  相似文献   

3.
The Lower Jurassic section at Makhtesh Ramon, in the northeastern Negev of Israel, comprises a sequence of fluviatile sediments of laterite composition. Post-depositional chemical weathering has resulted in marked facies changes whereby the clastic sequence passes laterally into high-alumina flint clays and bauxites (Goldbery, 1979). A geochemical and mineralogical investigation was initiated on 216 samples from several key sections of the facies change to obtain a more refined definition of the diagenetic overprint, to reconstruct the history of chemical weathering and finally to recognize the parent material of the unaltered laterite sediments.Results are presented herein on major and trace-element composition, normative mineralogical composition, kaolinite crystallinity and porosity and density measurements. Kaolinite crystallinity values proved to be a good indicator of intensity of leaching, showing a marked decline in ordering with increase of diagenetic reorganization. On the basis of mineralogical parameters it was possible to subdivide the section of flint clays and bauxites, generated under karstic conditions, into four units. Bivariate plots of Al2O3 vs. several elements within the section, plotted into four distinctive fields coinciding with the subdivision. Enrichment/depletion ratios, calculated from the element concentrations within these flint clays against element concentrations of the clastic parent material of the karstic infill, led to the reconstruction of a multi-cyclic leaching event, whose “signature” is left in each of the four units. At least 3 individual episodes of leaching, related to a rising water table and punctuated by “still-stands” could be recognized.Zr/TiO2: Nb/Y plots of stable elements, using the diagram of Floyd and Winchester (1978) for determination of source rocks, indicated a rhyolite or alkaline rhyolite provenance for the clastic laterite detritus.  相似文献   

4.
Capturing CO2 from point sources and storing it in geologic formations is a potential option for allaying the CO2 level in the atmosphere. In order to evaluate the effect of geological storage of CO2 on rock-water interaction, batch experiments were performed on sandstone samples taken from the Altmark reservoir, Germany, under in situ conditions of 125 °C and 50 bar CO2 partial pressure. Two sets of experiments were performed on pulverized sample material placed inside a closed batch reactor in (a) CO2 saturated and (b) CO2 free environment for 5, 9 and 14 days. A 3M NaCl brine was used in both cases to mimic the reservoir formation water. For the “CO2 free” environment, Ar was used as a pressure medium. The sandstone was mainly composed of quartz, feldspars, anhydrite, calcite, illite and chlorite minerals. Chemical analyses of the liquid phase suggested dissolution of both calcite and anhydrite in both cases. However, dissolution of calcite was more pronounced in the presence of CO2. In addition, the presence of CO2 enhanced dissolution of feldspar minerals. Solid phase analysis by X-ray diffraction and Mössbauer spectroscopy did not show any secondary mineral precipitation. Moreover, Mössbauer analysis did not show any evidence of significant changes in redox conditions. Calculations of total dissolved solids’ concentrations indicated that the extent of mineral dissolution was enhanced by a factor of approximately 1.5 during the injection of CO2, which might improve the injectivity and storage capacity of the targeted reservoir. The experimental data provide a basis for numerical simulations to evaluate the effect of injected CO2 on long-term geochemical alteration at reservoir scale.  相似文献   

5.
Rare-earth elements in samples of geological interest were separated from other elements and concentrated onto ion-exchange membrane through ion-exchange procedures. The membrane was then used to determine the REE by X-ray fluorescence spectrography. In comparison with the traditional “thick-specimen” approach, the requirement of sample (REE oxides) in this method was reduced from 10 to 1 mg. Variable-internal-standard-quantification method was adopted to determine the relative concentrations of REE collected on the membrane. The area density of the sample was controlled at about 0.0003 g/cm2, so that the matrix effect could be eliminated to a satisfactory extent. Interference calibration between the spectro-lines and the background determination was also improved, with the detection limit reaching 2.5×10?6g.  相似文献   

6.
《Applied Geochemistry》2006,21(9):1498-1521
A baseline determination of CO2 and CH4 fluxes and soil gas concentrations of CO2 and CH4 was made over the Teapot Dome oil field in the Naval Petroleum Reserve No. 3 (NPR-3) in Wyoming, USA. This was done in anticipation of experimentation with CO2 sequestration in the Pennsylvanian Tensleep Sandstone underlying the field at a depth of 1680 m.The baseline data were collected during the winter, 2004 in order to minimize near-surface biological activity in the soil profile. The baseline data were used to select anomalous locations that may be the result of seeping thermogenic gas, along with background locations. Five 10-m holes were drilled, 3 of which had anomalous gas microseepage, and 2 were characterized as “background.” These were equipped for nested gas sampling at depths of 10-, 5-, 3-, 2-, and 1-m depths. Methane concentrations as high as 170,000 ppmv (17%) were found, along with high concentrations of C2H6, C3H8, n-C4H10, and i-C4H10. Much smaller concentrations of C2H4 and C3H6 were observed indicating the beginning of hydrocarbon oxidation in the anomalous holes. The anomalous 10-m holes also had high concentrations of isotopically enriched CO2, indicating the oxidation of hydrocarbons. Concentrations of the gases decreased upward, as expected, indicating oxidation and transport into the atmosphere. The ancient source of the gases was confirmed by 14C determinations on CO2, with radiocarbon ages approaching 38 ka within 5 m of the surface.Modeling was used to analyze the distribution of hydrocarbons in the anomalous and background 10-m holes. Diffusion alone was not sufficient to account for the hydrocarbon concentration distributions, however the data could be fit with the addition of a consumptive reaction. First-order rate constants for methanotrophic oxidation were obtained by inverse modeling. High rates of oxidation were found, particularly near the surface in the anomalous 10-m holes, demonstrating the effectiveness of the process in the attenuation of CH4 microseepage. The results also demonstrate the importance of CH4 measurements in the planning of a monitoring and verification program for geological CO2 sequestration in sites with significant remaining hydrocarbons (i.e. spent oil reservoirs).  相似文献   

7.
Active and abandoned mine activities constitute the sources of deterioration of water and soil quality in many parts of the world, particularly in the African Copperbelt regions. The accumulation in soils and the release of toxic substances into the aquatic ecosystem can lead to water resources pollution and may place aquatic organisms and human health at risk. In this study, the impact of past mining activity (i.e., abandoned mine) on aquatic ecosystems has been studied using ICP-MS analysis for trace metals and Rare Earth Elements (REE) in sediment samples from Lubumbashi River (RL) and Tshamilemba Canal (CT), Katanga, Democratic Republic of the Congo (DRC). Soil samples from surrounding CT were collected to evaluate trace metal and REE concentrations and their spatial distribution. The extent of trace metal contamination compared to the background area was assessed by Enrichment Factor (EF) and Geoaccumulation Index (Igeo). Additionally, the trace metal concentrations probable effect levels (PELs) for their potential environmental impact was achieved by comparing the trace metal concentrations in the sediment/soil samples with the Sediment Quality Guidelines (SQGs). Spearman's Rank-order correlation was used to identify the source and origin of contaminants. The results highlighted high concentrations of trace metals in surface sediments of CT reaching the values of 40152, 15586, 610, 10322, 60704 and 15152 mg kg−1 for Cu, Co, Zn, Pb, Fe and Mn, respectively. In the RL, the concentrations reached the values of 24093, 2046, 5463, 3340, 68290 and 769 mg kg−1 for Cu, Co, Zn, Pb, Fe and Mn, respectively. The ΣREE varied from 66 to 218 and 142–331 mg kg−1 for CT and RL, respectively. The soil samples are characterized by variable levels of trace metals. The EF analysis showed “extremely severe enrichment” for Cu and Co. However, no enrichment was observed for REE. Except for Mo, Th, U, Eu, Mo, Ho and Tm for which Igeo is classified as “moderately polluted and/or unpolluted”, all elements in different sites are classified in the class 6, “extremely polluted”. The trace metal concentrations in all sampling sites largely exceeded the SQGs and the PELs for the Protection of Aquatic Life recommendation. Cu and Co had positive correlation coefficient values (r = 0.741, P < 0.05, n = 14). This research presents useful tools for the evaluation of water contamination in abandoned and active mining areas.  相似文献   

8.
Olivine crystals from two mantle nodules in kimberlites (pipe Udachnaya and pipe Obnazennaya, Yakutiya, Siberia) were investigated using EMP, TEM, AEM and FTIR techniques to determine the mode of hydrogen occurrence in olivine. Olivine contains three types of nanometer-sized inclusions: “large” inclusions of hexagonal-like shape up to several hundred nm in size (1), lamellar defects (2) and small inclusions of hexagon-like shape up to several 10?nm in size (3). Lamellar defects and small inclusions are considered to be a “hydrous” olivine. All three types of inclusions contain OH? or water, but they are different with respect to their phase composition. In “large” inclusions (1) hydrous magnesium silicates, such as serpentine?+?talc (“kerolite”?) and 10-Å phase?+?talc were identified. Lamellar defects (2) and small inclusions (3) are depleted in Mg and Fe compared to the olivine matrix, while the silica content is the same as that of olivine. Modulations in the periodicity of the olivine structure are observed in SAED patterns and HREM images of (2) and (3). The superperiodicity can be referred to OH?-bearing point defect ordering in the olivine structure. If this is the case, the material of both lamellar defects and small inclusions can be assumed to be a “hydrous olivine” Mg2– x v x SiO4H2 x with a cation-deficient olivine crystal structure. Thus, both an extrinsic mode of hydrogen occurrence in olivine, such as nanometer-sized inclusions of OH?-bearing magnesium silicates, and an intrinsic mode of hydrogen incorporation into the olivine structure, such as “hydrous olivine” in itself, were found. The data obtained here show that the OH absorption bands observed in olivine spectra at 3704(3717) and 3683(3688) cm?1 can be unambiguously identified with serpentine; the band at 3677(3676) cm?1 can be associated with talc. The absorption bands observed at 3591 and 3660?cm?1 in olivine match those of the 10-Å phase at 3594, 3662 and 3666?cm?1.  相似文献   

9.
Utilization of wood bottom ash as fertilizer additive contributes to the return of valuable nutrients to agricultural soils, especially when no artificial mineral fertilizer is being used. In general, wood combustion ash is enriched in calcium and potash, and may also contain elevated amounts of zinc, but the concentrations of these elements depend on tree species, part of the tree, harvest season and local soil type. In this study, bottom ash samples from eight different agricultural wood species from Cameroon, Africa were investigated by using X-ray diffraction and atomic absorption spectroscopy to determine the refractory components and the concentrations of selected heavy metals and arsenic. Results show calcite, potassium salts, periclase and quartz as major components. These phase contents were used to calculate major element concentrations, which were subsequently validated by X-ray-fluorescence analysis. The chemical compositions varied within the range of common compositions of wood ashes. Six of the ashes reached sufficient concentrations of calcium to be defined as a “calcium fertilizer”. Pb contents are most variable, ranging from 0.03 to 21.1 mg/kg. Concentrations of Ni, Cu, Zn, Cd, Pb, and As are all lower than the strictest limit concentrations required for wood ash fertilizers and therefore, the studied wood ashes can be used without environmental concern.  相似文献   

10.
This paper presents new major and trace element data from 150 garnet xenocrysts from the V. Grib kimberlite pipe located in the central part of the Arkhangelsk diamondiferous province (ADP). Based on the concentrations of Cr2O3, CaO, TiO2 and rare earth elements (REE) the garnets were divided into seven groups: (1) lherzolitic “depleted” garnets (“Lz 1”), (2) lherzolitic garnets with normal REE patterns (“Lz 2”), (3) lherzolitic garnets with weakly sinusoidal REE patterns (“Lz 3”), (4) lherzolitic garnets with strongly sinusoidal REE patterns (“Lz 4”), (5) harzburgitic garnets with sinusoidal REE patterns (“Hz”), (6) wehrlitic garnets with weakly sinusoidal REE patterns (“W”), (7) garnets of megacryst paragenesis with normal REE patterns (“Meg”). Detailed mineralogical and geochemical garnet studies and modeling results suggest several stages of mantle metasomatism influenced by carbonatite and silicate melts. Carbonatitic metasomatism at the first stage resulted in refertilization of the lithospheric mantle, which is evidenced by a nearly vertical CaO-Cr2O3 trend from harzburgitic (“Hz”) to lherzolitic (“Lz 4”) garnet composition. Harzburgitic garnets (“Hz”) have probably been formed by interactions between carbonatite melts and exsolved garnets in high-degree melt extraction residues. At the second stage of metasomatism, garnets with weakly sinusoidal REE patterns (“Lz 3”, “W”) were affected by a silicate melt possessing a REE composition similar to that of ADP alkaline mica-poor picrites. At the last stage, the garnets interacted with basaltic melts, which resulted in the decrease CaO-Cr2O3 trend of “Lz 2” garnet composition. Cr-poor garnets of megacryst paragenesis (“Meg”) could crystallize directly from the silicate melt which has a REE composition close to that of ADP alkaline mica-poor picrites. P-T estimates of the garnet xenocrysts indicate that the interval of ～60–110 km of the lithospheric mantle beneath the V. Grib pipe was predominantly affected by the silicate melts, whereas the lithospheric mantle deeper than 150 km was influenced by the carbonatite melts.  相似文献   

11.
The wreck U Pezzo, excavated within the Saint Florent Gulf in northern Corsica was identified as the pink, Saint Etienne, a merchant ship which sank on January 31, 1769. In order to determine the composition of organic materials used to coat the hull or to waterproof different parts of the pink, a study of several samples, using molecular biomarker and carbon isotopic analysis, was initiated. The results revealed that the remarkable yellow coat, covering the outside planks of the ship’s bottom under the water line, is composed of sulfur, tallow (of ox and not of cetacean origin) and black pitch which corresponds to a mixture called “couroi” or “stuff”. Onboard ropes had been submitted to a tarring treatment with pitch. Hairs mixed with pitch were identified in samples collected between the two layers of the hull or under the sheathing planking. The study also provides a key model for weathering of pitch, as different degrees of degradation were found between the surface and the heart of several samples. Accordingly, molecular parameters for alteration were proposed. Furthermore novel mixed esters between terpenic and diterpenic alcohols and the free major fatty acids (C14:0, C16:0, C18:0) were detected in the yellow coat.  相似文献   

12.
The content and distribution of mercury in Holocene–Upper Pleistocene turbidites, hemipelagic sediments intercalating therein, as well as basement basalts are studied. Samples of sediments were taken from the core of Holes 858A, 858B, 858C, 858D, and 858F. Basalt samples were taken from Holes 858F and 858G drilled during Leg 139 ODP in the Middle Valley (Juan de Fuca Ridge) in the Dead Dog hydrothermal field with a high heat flow (4–20 W/m2) and numerous vents with temperature ranging from 234 to 276°C. Samples of sediments and basalts with the background Hg content were taken from the core of Holes 855A, 855C, and 855D are located beyond the hydrothermal system in the base of the fault scarp on the eastern Middle Valley. In rocks, the content of Hg and its occurrence form were determined by the atomic absorption spectrometry with thermal atomization method; the chemical composition, by the XFA and ICP-MS methods. Sections of the sedimentary cover and basalt basement are marked by an alternation of “layer cake” type units with low and high contents of Hg. Mercury occurs in rocks in the physically adsorbed and mineral forms. The Hg concentration in some parts of the sedimentary section is anomalously high: up to 9696 ppb in Hole 858B and 7260 ppb in Hole 858C. In metalliferous sediments, the Hg content is 3130 ppb. Its maximum content (up to 23200 ppb) is recorded in basalts.  相似文献   

13.
Regional study on the impact of variations in input rainfall over groundwater quality and its suitability for utilitarian purposes is essential for its extraction and management. Water chemistry from 456 observations wells for 2007–2011 period in hard rock Basaltic terrain of Upper Godavari basin is supported with 8 field samples (in 2014) in this analysis. Based on mean annual rainfall (MAR), four narrow climatic zones are identified in the basin, defined as “humid” (MAR > 1600 mm), “sub-humid” (1600–1000 mm), “semi-arid” (1000–600 mm), and “arid” (MAR < 600 mm). NICB ratio (<±10%), and anionic percentages demarcated the polluted areas from rest “good data”, composing of 1818 samples. Hydrochemical facies are studied using Piper diagram, secondary alkalinity exceeded 50% and not one cation–anion pair exceeded 50%, and silicate–carbonate plot, arid zone nearer to silicate pole indicated the dominance of SiO2 in Ca/Na vs Mg/Na plot. These geochemical variations emphasize a detailed study on role of climatic gradient on groundwater suitability for different purposes, for groundwater extraction, and its management. Suitability of groundwater for drinking based on water quality indices (WQI) indicated 98% of the samples as suitable (WQI < 50%). TDS in humid zone is 150–500 and 500–1000 mg/L in rest of the zones with ～68% in permissible range, 15% as hard water (TDS > 600 mg/L) and not acceptable for drinking. Suitability of groundwater for irrigation is studied using sodium percentage (Na %), Wilcox diagram, sodium absorption ratio (SAR), US salinity diagram, residual sodium carbonate (RSC), permeability index (PI), Kelly’s ratio (KR), ancd magnesium absorption ratio (MgAR). Na % in four zones is < 60% and permissible for irrigation. Very few water samples fall in “doubtful to unsuitable” and “unsuitable” category of Wilcox diagram. Region is observed to have SAR < 6, indicating that water would not cause any problem to the soil and crop. Humid and sub-humid zones belonged to C1S1 and C2S1 categories (low and medium sodium), while semi-arid extended to C3S1 category (salinity hazard zone) in US salinity plot. RSC for all the three zones ranged from 1 to 1.5 meq/L, with 90–95% of the area safe for irrigation. Out of 1818 samples, 1129 belonged to class 2 of PI classification (PI ranging from 25 to 75%) while rest 689 samples had PI >75% (class 1). KR varied from 0.05 to 12.81, with 70–80% of the area having KR < 1. MgAR ratio ranged from 67% to 96%, with sub-humid, humid zones having higher Mg concentrations (increased salinity). Thus, 90% of the samples indicated non-alkaline water with 1% of normal alkalinity. Hence, the current study systematically analyzed the effect of precipitation and geology on groundwater quality and on its usability for various purposes. This stepwise procedure categorized the regions, and the same can be adopted for any regional hydrogeochemical studies.  相似文献   

14.
Human health is strongly influenced by water quality which is threatened by the poor quality of polluted groundwater. In this study, the groundwater quality and its suitability for drinking have been studied in Lenjanat plain aquifer, Iran. Fifty-nine groundwater samples from study area were evaluated based on WHO and Iranian standards for drinking water. Groundwater samples from selected monitoring sources were sampled seasonally during 2009–2010. Physical and chemical parameters of groundwater such as electrical conductivity, pH, total dissolved solids, Ca2+, Na+, K+, Mg2+, HCO3 ?, SO4 2?, Cl?, F? and NO3 ? were determined. During the water quality index calculating process, the weight of each parameter is usually given by experts according to their practical experience, which is subjective, so much useful and valuable information about the water quality gets lost. In order to avoid personal judgments about the weight of parameters, an information entropy method was used to assign weight to each parameter. Calculation of entropy weighted water quality index (EWQI) for groundwater samples showed that in the wet season, over 57 and 74 % of samples were in the range of “excellent” to “medium” quality based on WHO and Iranian standards, respectively. Due to groundwater quality reduction during dry season, 42 and 62 % of samples were in the range of “excellent” to “medium” quality based on WHO and Iranian standards, respectively. The results indicate that application of the EWQI is very useful to help the public and decision-makers will be able to identify and to evaluate groundwater quality in Lenjanat, Iran.  相似文献   

15.
An assessment was carried out on the pollution impact potentials of drilling waste generated from wells X and Y in “Eden Field,” offshore Niger Delta. Eleven samples each were collected from well X (8 treated and 3 untreated cuttings) and well Y (6 treated cuttings and 5 spent muds). The samples were subjected to three separate analyses, namely, oil-on-cutting analysis using Dean and Stark reflux method, heavy metal analysis using atomic absorption spectrophotometer (Unicam 929), and toxicity test analysis using bioassay procedure on test organisms such as Desmoscaris trispinosa and Palaemonetes africanus all in attempt to detect their pollution potential. The results showed that the oil-on-cutting analysis for the well X samples was between 15.8 and 17.5 % for unwashed cuttings and between 4.6 and 5.1 % for washed cuttings, while that for well Y samples was between 3.49 and 4.27 % for washed cuttings and 1.69 to 2.59 % for the drill mud samples. The heavy metal analysis on the wells X and Y samples showed absence of mercury, cadmium concentration ranged from 0.52 to 0.99 mg/kg for well X and from 0.69 to 0.78 mg/kg for well Y samples. The result of the toxicity test of samples from well X on D. trispinosa showed that 96-h LC50 occurred at 9800 to 10,900 mg/l for the washed drill cutting and 6200 to 6700 mg/l for the unwashed drill cuttings. On the other hand, the toxicity test on P. africanus indicated more resistant to the toxicity of the drill cuttings as 96-h LC50 was achieved at higher concentrations. At 96-h exposure, the concentration that killed 50 % of the test organism (LC50) occurred at 14,000 to 16,900 mg/l for the washed cuttings and 10,300 to 11,350 mg/l for the unwashed cuttings. Similarly, the 96-h LC50 was achieved on washed drill cuttings from well Y at concentrations of 9800 to 10,400 mg/l using D. tripinosa and 11,600 to 17,200 mg/l using P. africanus. The study has shown that oil-on-cutting content, heavy metal concentrations, and toxicity level did not indicate any major risk to the environment as the treatment and cleaning of the drilling wastes on the rig helped in reducing the concentration of all the contaminants in compliance with the regulatory limits.  相似文献   

16.
In the area surrounding the El Teniente giant porphyry copper deposit, eight soil sites were sampled at three depth levels in the summer 2004. The sites were selected for their theoretical potential of being influenced by past SO2 emissions from the smelter and/or seepage from a now idle tailings impoundment. The soil mineralogy, grain size distribution, total organic matter contents, major element composition, cation exchange capacity, and Cu, Mo, Pb, Zn, As and SO4 2− concentrations were determined for all samples after nitric acid extraction and separate leaches by ammonium acetate (pH 7) and sodium acetate (pH 5). For water rinses, only Cu could be determined with the analytical set-up used. Cu and SO4 2− enrichment in topsoils was found at six sites either downwind from the smelter or within the combined influence of the smelter and the tailings impoundment. Both elements were released partially by ammonium and sodium acetate extractions. Due to the scarce background trace element concentrations of soil and rock outside the immediate mine area, assessment of trace element mobility for Mo, Zn, Pb and As was difficult. Arsenic was found to be concentrated in soil horizons with high smectite and/or organic matter contents. Mo appears to be linked to the presence of windblown tailings sediment in the soils. Mobilization of Mo, Zn, and As for the acetate extractions was minimal or below the detection limits for the AAS technique used. The presence of windblown tailings is considered to be an additional impact on the soils in the foothills of the El Teniente compound, together with the potential of acidity surges and Cu mobilization in topsoils after rainfalls. Two sites located at the western limit of the former SO2 saturated zone with strongly zeolitized soils and underlying rock did not show any Cu or SO4 2− enrichment in the topsoils, and remaining total trace element concentrations were below the known regional background levels.  相似文献   

17.
Near-infrared (NIR) absorption bands related to total water (4000 and 7050 cm−1), OH groups (4500 cm−1) and molecular H2O (5200 cm−1) were studied in two polymerised glasses, a synthetic albitic composition and a natural obsidian. The water contents of the glasses were determined using Karl Fischer titration. Molar absorption coefficients were calculated for each of the bands using albitic glasses containing between 0.54 and 9.16 wt.% H2O and rhyolitic glasses containing between 0.97 and 9.20 wt.% H2O. Different combinations of baseline type and intensity measure (peak height/area) for the combination bands at 4500 and 5200 cm−1 were used to investigate the effect of evaluation procedure on calculated hydrous species concentrations. Total water contents calculated using each of the baseline/molar absorption coefficient combinations agree to within 5.8% relative for rhyolitic and 6.5% relative for albitic glasses (maximum absolute differences of 0.08 and 0.15 wt.% H2O, respectively). In glasses with water contents >1 wt.%, calculated hydrous species concentrations vary by up to 17% relative for OH and 11% relative for H2O (maximum absolute differences of 0.33 and 0.43 wt.% H2O, respectively). This variation in calculated species concentrations is typically greater in rhyolitic glasses than albitic. In situ, micro-FTIR analysis at 300 and 100 K was used to investigate the effect of varying temperature on the NIR spectra of the glasses. The linear and integral molar absorption coefficients for each of the bands were recalculated from the 100 K spectra, and were found to vary systematically from the 300 K values. Linear molar absorption coefficients for the 4000 and 7050 cm−1 bands decrease by 16–20% and integral molar absorption coefficients by up to 30%. Depending on glass composition and baseline type, the integral molar absorption coefficients for the absorption bands related to OH groups and molecular H2O change by up to −5.8 and +7.4%, respectively, while linear molar absorption coefficients show less variation, with a maximum change of ∼4%. Using the new molar absorption coefficients for the combination bands to calculate species concentrations at 100 K, the maximum change in species concentration is 0.08 wt.% H2O, compared with 0.39 wt.% which would be calculated if constant values were assumed for the combination band molar absorption coefficients. Almost all the changes in the spectra can therefore be interpreted in terms of changing molar absorption coefficient, rather than interconversion between hydrous species. Received: 17 December 1998 / Revised, accepted 8 July 1999  相似文献   

18.
Some 150 white K-micas from the Central Alps were analysed for their polymorph and phengite content. Pre-Alpine white K-micas and those belonging to the Meso-Alpine Lepontine Metamorphic “High” show exclusively the 2M1 polymorph. The 3T structural form, on the other hand, has been found in one third of the white K-micas formed during the Alpine regional metamorphism. In most cases this trigonal structure coexists with varying amounts of the 2M1 form. The 3T distribution pattern suggests that this polymorph originated during the Eo-Alpine high-pressure/“low temperature” metamorphism. Provided this interpretation is correct, the sporadic occurrence of this polymorph within the Meso-Alpine staurolite zone may be used as a tracer for the Eo-Alpine metamorphism. The following improved correlation between the (060, 331) reflections of 2M1 white K-micas and the RM-content (= 2Fe2O3+FeO+MgO in molar proportions), based on 24 micas from granitoid rocks, is presented: d(060, 331)= 1.498+0.082 RM. The phengite content of Alpine white K-micas belonging to the assemblage muscovite-biotite-K-feldspar-quartz was estimated from RM values or derived from chemical analyses and was found to be clearly related to metamorphic grade. Phengite-rich micas were formed during the Eo-Alpine high-P/“ low-T” metamorphism while aluminous muscovite was found within the Meso-Alpine thermal high of the Lepontine gneiss area. White K-micas from areas which underwent both the Eo-Alpine and the Meso-Alpine metamorphism display variable phengite contents. Although these micas show Tertiary Rb-Sr and K-Ar ages, the variable phengite content presumably reflects conditions during the Eo-Alpine high-P/“low-T” metamorphism. This interpretation implies that the cations occupying the interlayer positions are more easily equilibrated than those in octahedral and tetrahedral structural sites. A compilation of 3T white K-mica occurrences described in the literature is given in the appendix.  相似文献   

19.
Dynamics of heavy metals in the surface sediments of Mahanadi river estuarine system were studied for three different seasons. This study demonstrates that the relative abundance of these metals follows in the order of Fe > Mn > Zn > Pb > Cr > Ni ≥ Co > Cu > Cd. The spatial pattern of heavy metals supported by enrichment ratio data, suggests their anthropogenic sources possibly from various industrial wastes and municipal wastes as well as agricultural runoff. The metal concentrations in estuarine sediments are relatively higher than in the river due to adsorption/accumulation of metals on sediments during saline mixing, while there is a decreasing trend of heavy metal concentrations towards the marine side. The temporal variations for metals, such as Fe, Mn, Zn, Ni and Pb exhibit higher values during monsoon season, which are related to agricultural runoff. Higher elemental concentrations are observed during pre-monsoon season for these above metals (except Ni) at the polluted stations and for metals, such as Cr, Co and Cd at all sites, which demonstrate the intensity of anthropogenic contribution. R-mode factor analysis reveals that “Fe–Mn oxy hydroxide”, “organic matter”, “CaCO3”, and “textural variables” factors are the major controlling geochemical factors for the enrichment of heavy metals in river estuarine sediment and their seasonal variations, though their intensities were different for different seasons. The relationships among the stations are highlighted by cluster analysis, represented in dendrograms to categorize different contributing sites for the enrichment of heavy metals in the river estuarine system.  相似文献   

20.
A stepwise extraction technique, based on that of Beletskaya (1972), has been aplied to sedimentary rock samples of variable grain size and maturity from a Neogene sequence in the Pannonian Basin (S.E. Hungary). The resulting chloroform extracts, claimed by Beletskaya (1978) to sample “open” and mineralogically “closed” pores, have been analysed by gas chromatography and gas chromatography-mass spectrometry. Differences in the concentrations of the two extracts and the concentrations of their hydrocarbon fractions, and in the distributions of n-alkanes and steroid hydrocarbons suggest that either the “open” pores are impregnated with mature oil which has migrated from depth, or that movement of organic material from the “closed” to “open” pores occurs with considerable fractionation based on both polarity and molecular size. The implications of these differences for source rock-oil correlation studies are discussed and an assessment of mechanisms for primary migration is given.  相似文献   

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