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Результаты 321-330 из 447
Evaluation of Pb Phytoremediation Potential in Buddleja asiatica and B. paniculata
2008
Waranusantigul, Piyaporn | Kruatrachue, Maleeya | Pokethitiyook, Prayad | Auesukaree, Choowong
The phytoremediation potential for Pb of Buddleja asiatica (a wild species) and a closely related cultivated species, B. paniculata, was investigated by means of field survey, hydroponic and pot experiments, and field trial experiments. Field surveys showed that B. asiatica had an extraordinary accumulation capacity and tolerance for Pb. Plants grown in soil with 2,369.8-206,152 mg kg⁻¹ total Pb accumulated 1,835.5-4,335.8 mg kg⁻¹ Pb in their shoots. Under hydroponic conditions (10, 20 mg l⁻¹ Pb), both B. asiatica and B. paniculata showed unusually high concentrations of Pb in their roots (12,133-21,667 mg kg⁻¹) and increased biomass production. A pot experiment in a greenhouse without any soil amendments was conducted on three different soils with various Pb contents (10,652, 31,304, 89,083 mg kg⁻¹) for 3 months. The results showed that both species of Buddleja had an increase in the biomass similar to the control plants. There was a slight decrease in survival rates of plants grown in soil with 89,083 mg kg⁻¹ Pb content. A field trial experiment was conducted for 6 months at three sites around the Pb mine area in which plants were provided with Osmocote fertilizer. Both Buddleja species showed 100% survival, increased biomass production and phytoextraction capacity (TF 1.1-2.3) when grown in soil with Pb content of 94,584-101,405 mg kg⁻¹. Plants accumulated 2,273-3,675 mg kg⁻¹ Pb in their shoots. The results suggest these Buddleja plants are suitable for use in the phytoremediation of Pb-contaminated soil.
Показать больше [+] Меньше [-]Judging Fitness for Purpose of a X-ray Fluorescence Based Method Investigating the Vertical Distribution of Metals and Metalloids in Soil Profiles
2008
Morgenstern, Peter | Brüggemann, Lutz | Krüger, Frank | Hofacker, Anke | Wennrich, Rainer
A column of soil, excavated from a contaminated landscape was evaluated by means of X-ray fluorescence analysis. The measurements were intended to assess the vertical distribution of heavy metals and toxic elements in the depth profile. To judge fitness for purpose of the analytical method used the element specific power functions were derived yielding the minimum detectable variations of analyte concentrations refer to the investigated soil profile. The required measurement uncertainty components caused by both the sampling procedure and chemical analysis were empirically estimated using a nested sampling design (duplicate method). For this purpose the full length of the soil core was divided into horizontal layers. From each selected layer (sampling target) two composite samples were taken by simple random sampling to represent the typical composition of the sampling target. The pool of measurement results, obtained for the nested sampling design finally was subjected to variance analysis. The evaluation of the estimated variance components in terms of the percentage of total variance confirmed fitness for purpose for the method used.
Показать больше [+] Меньше [-]Sulphur Isotopes, Trace Elements and Mineral Stability Diagrams of Waters from the Abandoned Fe-Cu Mines of Libiola and Vigonzano (Northern Apennines, Italy)
2008
Cortecci, Gianni | Boschetti, Tiziano | Dinelli, Enrico | Cabella, Roberto
The geochemical characteristics of rills draining pyrite-chalcopyrite tailings impoundments and of bordering streams were investigated at the ophiolite-hosted Libiola and Vigonzano abandoned massive sulphide mines, northern Apennines Italy. Water samples were analysed for major and trace chemical composition, hydrogen and oxygen isotope composition, and sulphur isotope composition of aqueous sulphate. Sulphur isotope composition was determined also for some samples of ore sulphides. At Libiola, the newly acquired chemical results on waters corroborate those from previous investigations, thus providing additional support to existing geochemical models in terms of metal distribution, solid phases precipitation, reaction path modelling and mixing reaction paths, and environmental problems. At Vigonzano, the chemical characteristics of waters are similar to those at Libiola. In both localities, solution-secondary phase equilibria estimated using an updated thermodynamic dataset account for mineralogy in the field, including poorly crystalline phases like jurbanite and hydrowoodwardite. The hydrogen and oxygen isotope composition of waters at Libiola and Vigonzano agrees with their meteoric origin. Acid to neutral mine waters do not show any significant isotope shift with respect to the initial water, in spite of the oxidation of even large amounts of pyrite/chalcopyrite ore. The sulphur isotope composition of aqueous sulphate in mine rills at Libiola (δ ³⁴S = 5.6 to 8.5[per thousand]; mean 6.5[per thousand]) matches that of massive sulphide ore (δ ³⁴S = -0.5 to 6.7[per thousand]; mean 5.8[per thousand]), in keeping with the supergenic origin of the sulphate and related isotope effects in the sulphide oxidation process. Sulphate in mine waters at Vigonzano displays lower δ ³⁴S values in the range 0.6 to 1.5[per thousand]. The δ ³⁴S signature of massive ore specimens is within the range reported for most volcanic-hosted massive sulphide deposits, including Cyprus-type deposits.
Показать больше [+] Меньше [-]Changes in Fatty Acid Composition and Content of Two Plants (Lolium perenne and Trifolium repens) Grown During 6 and 18 Months in a Metal (Pb, Cd, Zn) Contaminated Field
2008
Bidar, G. | Verdin, A. | Garçon, G. | Pruvot, C. | Laruelle, F. | Grandmougin-Ferjani, A. | Douay, F. | Shirali, P.
The aim of this in situ study was to investigate the fatty acid (FA) composition and content in roots and shoots of Lolium perenne and Trifolium repens, grown under heavy metal stress (Cd, Pb, Zn). The composition of FA was quite similar for the two plants and the two organs; main FA were palmitic acid (C16:0), oleic acid (C18:1), linoleic acid (C18:2) and linolenic acid (C18:3). For both plants, the major FA that characterized the roots was C18:2 whereas C18:3 was the prominent FA in shoots. For the first sampling (S1), in the roots of L. perenne and T. repens, polyunsaturated fatty acids (PUFA) were affected by metal contamination while, in the second sampling (S2), PUFA were affected in the shoots of the two plants. This alteration of PUFA was well correlated with the bioaccumulation factor of metals which decreased in roots and increased in shoots with the time. Moreover, a positive correlation was found between the PUFA decrease and the malondialdehyde (MDA) content, indicating the occurrence of a lipid peroxidation induced by the metal stress.
Показать больше [+] Меньше [-]Application of Adjoint-based Forecast Sensitivities to Asian Dust Transport Events in Korea
2008
Kim, Hyun Mee | Kay, Jun Kyung | Jung, Byoung-Joo
Sensitivities of the forecast to changes in the initial state are evaluated for an Asian dust event, which affected the Korean Peninsula on 7 to 9 April 2006, to understand the impact of initial condition uncertainties on the forecast and thence to suggest the sensitive regions for adaptive observations of the Asian dust. To assess the forecast sensitivities, adjoint-based sensitivities were used. Sensitive regions are located over the northwestern part of Mongolia at the initial time, then propagate to Inner Mongolia and Manchuria. Close to the verification time, sensitive regions as determined by adjoint-based forecast sensitivities coincide with the passage of the Asian dust. Forecast error for the atmospheric circulation during the dust event is reduced 57.4% by extracting properly weighted adjoint-based forecast sensitivity perturbations from the initial state, and the correction occurs primarily in the upper troposphere where the forecast error is the largest. The improvement in the overall forecast implies that adjoint-based forecast sensitivities would be beneficial in determining the observational sites and in improving the forecast of Asian dust events. An additional experiment with another Asian dust event confirms the validity of adjoint-based forecast sensitivities to Asian dust events.
Показать больше [+] Меньше [-]Comparison of Microscopic and Macroscopic Modeling Approaches for Subsurface Contaminant Transport
2008
Bagtzoglou, Amvrossios C | Kim, Daehyun (Don)
The practice of contaminant transport and remediation has shown significant progress in recent years. However, despite the significant progress made, remediation efforts are often delayed by extremely long breakthrough curve tails that render efforts to bring the level of contaminants below the regulatory standards inefficient. One hypothesis is that these long tails are due to the reservoir-like slow diffusive processes in soil micropore zones. This study compares the effects of micropores at macroscopic and microscopic levels and establishes a link between these approaches for validation and calibration purposes. The link between macroscopic and microscopic levels is established through comparisons and testing of the two models while incorporating appropriate scale and boundary effects. Despite the differences in conceptual approaches and simulation time, the two approaches rendered meaningful results. The link helps forecast the effects of micropore zone transport processes in the subsurface efficiently and thus allows development of numerical tools that could contribute towards more efficient remediation design.
Показать больше [+] Меньше [-]Novel Mercury Oxidant and Sorbent for Mercury Emissions Control from Coal-fired Power Plants
2008
Lee, Joo-Youp | Ju, Yuhong | Lee, Sang-Sup | Keener, Tim C | Varma, Rajender S
The authors have successfully developed novel efficient and cost-effective sorbent and oxidant for removing mercury from power plant flue gases. These sorbent and oxidant offer great promise for controlling mercury emissions from coal-fired power plants burning a wide range of coals including bituminous, sub-bituminous, and lignite coals. A preliminary analysis from the bench-scale test results shows that this new sorbent will be thermally more stable and cost-effective in comparison with any promoted mercury sorbents currently available in the marketplace. In addition to the sorbent, an excellent elemental mercury (Hg(0)) oxidant has also been developed, and will enable coal-fired power plants equipped with wet scrubbers to simultaneously control their mercury emissions as well as their sulfur oxides emissions. This will work by converting all elemental mercury to an oxidized form which will be removed by the wet scrubber. This will result in significant cost savings for mercury emissions control to the atmosphere, and will help in keeping electric costs low. The sorbent and oxidant will benefit from the utilization of a waste stream from the printed circuit board (PCB) industry, and would thus be environmentally beneficial to both of the utility and electronics industries. The sorbent also demonstrated thermal stability up to 350°C, suggesting a possibility of an application in pulverized coal-fired power plants equipped with hot-side electrostatic precipitators and coal gasification plants.
Показать больше [+] Меньше [-]Use of Sterol and Bile Acid Biomarkers to Identify Domesticated Animal Sources of Fecal Pollution
2008
Tyagi, Punam | Edwards, Dwayne R. | Coyne, Mark S.
The objective of this study was to demonstrate the use of chemical biomarkers (fecal sterols and bile acids) to identify selected sources of fecal pollution in the environment. Fecal sterols and bile acids were determined for pig, horse, cow, and chicken feces. Ten to twenty-six fresh fecal samples were collected for each animal, and the concentrations of fecal sterols (coprostanol, epicoprostanol, cholesterol, cholestanol, stigmastanol, and stigmasterol) and bile acids (lithocholic acid, deoxycholic acid, cholic acid, chenodeoxycholic acid, ursodeoxycholic acid, hyodeoxycholic acid) were determined using a gas chromatography and mass spectrometer (GC-MS) technique. Correlation study was performed among sterol and bile acid variables for selected animals, and a ratio (cholesterol + epicoprostanol)/(deoxycholic acid + chenodeoxycholic acid + hyodeoxycholic acid) has been proposed as an indicator for assessing fecal input. The levels of (cholesterol + epicoprostanol)/(deoxycholic acid + chenodeoxycholic acid + hyodeoxycholic acid) in horse, cow, chicken and pig were observed 3.258 ± 1.191, 1.921 ± 1.006, 1.013 ± 0.726, and 0.205 ± 0.119 respectively and the ratio of horse: cow: chicken: pig was 16: 9: 5: 1. This ratio suggests the potential of sterol and bile acid biomarkers in identifying sources and occurrence of fecal matter. While additional work using polluted water (as opposed to fresh fecal samples) as well as multiple pollution sources are needed to investigate the transport of these biomarkers into water bodies.
Показать больше [+] Меньше [-]Characterization of the Salinisation Processes in Aquifers Using Boron Isotopes; Application to South-Eastern Spain
2008
Morell Evangelista, Ignacio | Pulido Bosch, Antonio | Sánchez-Martos, Francisco | Vallejos, Angela | Daniele, Linda | Molina, Luis | Calaforra, José María | Roig, Antoni Francesc | Renau, Alejandra
Use of δ¹¹B provides a solid tool for discriminating hydrogeochemical processes in complex coastal aquifers. Its efficiency increases markedly when it is applied along with other major or minor constituents. Nevertheless, various factors may affect its interpretation: the presence of clays, which favour adsorption and desorption, the influence of wastewaters, and even the presence of geothermalism. The δ¹¹B has been applied to the study of a series of aquifers in south-eastern Spain: Castell de Ferro (Granada), Campo de Dalías, Lower Andarax and Sorbas (Almería), all of which are complex and heterogeneous. The results obtained demonstrate that the concentration of Br, the SO₄/Cl and Cl/Br ratios are good indicators of marine intrusion. Inland some negative values of δ¹¹B (-16.7 and -8.1[per thousand]) are related to a geothermal influence (34.8 and 51.5°C). The boron solubility is directly related to temperature favours boron mobilization, even from the associated metapelitic deposits. The difference in the boron isotope content in two carbonate units must be caused by the different composition of the carbonate rocks, as well as a long residence time.
Показать больше [+] Меньше [-]Acting Environmentally Proactive in an Emerging Market-Oriented Economy
2008
Constantin, L.-A. | Teodorescu, C | Nicolau, M
As a new member of the European Union (EU), Romania has to align its economy with that of other EU partners, including the addition of a proactive component to environmental protection. This requires the development of a transitive approach capable of overcoming the difficulties of implementing the sustainability paradigm within an emerging market-oriented economy, which despite its progress, is still not fully prepared to understand and accept sustainability. This paper describes such a transition, showing how INCD ECOIND (the main Romanian Research and Development entity in the field of industrial ecology) reshaped its policies to include in current projects developed with Romanian partners the following elements: the Integrated Pollution Prevention and Control (IPPC) Directive, components relating to the REACH Process; the Environmental Management Accounting (EMA) mainframe and assistance in cultivating Corporate Social Responsibility (CSR) as an intrinsic part of modern enterprise. Lessons learned from previous and current projects are presented, underlining the complexity of obstacles met and problem-solving procedures derived and verified in practice.
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