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Anomalous low tropospheric column ozone over Eastern India during the severe drought event of monsoon 2002: a case study النص الكامل
2011
Ghude, Sachin D. | Kulkarni, Santosh H. | Kulkarni, Pavan S. | Kanawade, Vijay P. | Fadnavis, Suvarna | Pokhrel, Samir | Jena, Chinmay | Beig, G. | Bortoli, D.
BACKGROUND, AIM, AND SCOPE: The present study is an attempt to examine some of the probable causes of the unusually low tropospheric column ozone observed over eastern India during the exceptional drought event in July 2002. METHOD: We examined horizontal wind and omega (vertical velocity) anomalies over the Indian region to understand the large-scale dynamical processes which prevailed in July 2002. We also examined anomalies in tropospheric carbon monoxide (CO), an important ozone precursor, and observed low CO mixing ratio in the free troposphere in 2002 over eastern India. RESULTS AND DISCUSSION: It was found that instead of a normal large-scale ascent, the air was descending in the middle and lower troposphere over a vast part of India. This configuration was apparently responsible for the less convective upwelling of precursors and likely caused less photochemical ozone formation in the free troposphere over eastern India in July 2002. CONCLUSION: The insight gained from this case study will hopefully provide a better understanding of the process controlling the distribution of the tropospheric ozone over the Indian region.
اظهر المزيد [+] اقل [-]Natural radionuclides in trees grown on a uranium mill tailings waste pile النص الكامل
2011
Štrok, Marko | Smodiš, B (Borut) | Eler, Klemen
Objective The purpose of the study was to investigate natural radionuclide uptake and allocation by trees. Materials and methods Samples from six Scots pines (P. sylvestris), six Norway spruces (Picea abies) and one sycamore maple (Acer pseudoplatanus) tree, growing on the Boršt uranium mill tailings waste pile in Slovenia were collected. ²³⁸U, ²³⁰Th, ²²⁶Ra and ²¹⁰Pb activity concentrations in wood, shoots and 1-year-old needles or leaves were determined. Particular radionuclides were separated from the samples by appropriate radiochemical procedures and their activity concentrations measured with an alpha spectrometry system. In addition, concentration ratios for different plant parts were calculated. Results and conclusions Results showed that for all radionuclides, the highest activity concentrations were found in foliage, followed by shoots and wood. The activity concentrations in trees were from 0.01 to 5.4 Bq kg⁻¹ for ²³⁸U, 0.03-11.3 Bq kg⁻¹ for ²³⁰Th, 2.7-2,728 Bq kg⁻¹ for ²²⁶Ra and 5.1-321 Bq kg⁻¹ for ²¹⁰Pb. All activity concentrations were calculated on dry weight basis. The calculated concentration ratios were from 1.05E-5 to 5.39E-3 for ²³⁸U, 7.65E-6-2.88E-3 for ²³⁰Th, 3.10E-4-3.16E-1 for ²²⁶Ra and 6.70E-4-4.22E-2 for ²¹⁰Pb.
اظهر المزيد [+] اقل [-]Pharmaceuticals in the environment: an educational perspective النص الكامل
2011
PURPOSE: Pharmaceuticals are an integral part of a dignified life. However, a lack of degradability and threats to the welfare of living beings cause concern due to their emission into the environment. There is also a lack of knowledge about cause and consequence. Therefore, we intend to contribute to the development of educational programmes which should increasingly include the topic ‘pharmaceuticals in the environment’. METHODS: Considering the current literature, we developed a corresponding series of worksheets (Online Resource) and sample solutions on an introductory level and integrated them into our curriculum. RESULTS: The material compiled for the worksheets was arranged in a logical order and considers several subtopics. The worksheets aim to support the examination of related aspects such as environmental effects, emissions, wastewater treatment plants, degradation, degradation by-products, advanced oxidation processes, hydraulic retention times, half-life times, biosolids, exposition pathways, precautionary principle, classification schemes for pharmaceuticals and, related to the structure–activity relationship, the design for degradability. The students managed to work on the tasks in an appropriate manner and received a good overview of the occurrence and fate of pharmaceuticals in the environment. CONCLUSIONS: Tasks that were presented to students regarding the topic ‘pharmaceuticals in the environment’ contributed to a better understanding of the possible risks of medical care on an introductory level. The tasks have been incorporated into a logic series of worksheets (Online Resource) with sample solutions available. Alternatively, the material would be appropriate for the preparation of a corresponding lecture on this topic.
اظهر المزيد [+] اقل [-]Characterization of dioxin-like contamination in soil and sediments from the “hot spot” area of petrochemical plant in Pancevo (Serbia) النص الكامل
2011
Kaisarevic, Sonja | Hilscherova, Klara | Weber, Roland | Sundqvist, Kristina L. | Tysklind, Mats | Voncina, Ernest | Bobic, Stanka | Andric, Nebojsa | Pogrmic-Majkic, Kristina | Vojinović-Miloradov, Mirjana | Giesy, John Paul | Kovačević, Radmila
Purpose Combinatorial bio/chemical approach was applied to investigate dioxin-like contamination of soil and sediment at the petrochemical and organochlorine plant in Pancevo, Serbia, after the destruction of manufacturing facilities that occurred in the spring of 1999 and subsequent remediation actions. Materials and methods Soil samples were analyzed for indicator polychlorinated biphenyls (PCBs) by gas chromatography/electron capture detection (GC/ECD). Prioritized soil sample and sediment samples from the waste water channel were analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). Microethoxyresorufin o-deethylase (Micro-EROD) and H4IIE-luciferase bioassays were used for monitoring of dioxin-like compounds (DLC) and for better characterization of dioxin-like activity of soil samples. Results Bioanalytical results indicated high dioxin-like activity in one localized soil sample, while the chemical analysis confirmed the presence of large quantities of DLC: 3.0 × 10⁵ ng/g d.w. of seven-key PCBs, 8.2 ng/g d.w. of PCDD/Fs, and 3.0 × 10⁵ ng/g d.w. of planar and mono-ortho PCBs. In the sediment, contaminant concentrations were in the range 2-8 ng/g d.w. of PCDD/Fs and 9-20 ng/g d.w. of PCBs. Conclusions This study demonstrates the utility of combined application of bioassays and instrumental analysis, especially for developing and transition country which do not have capacity of the expensive instrumental analysis. The results indicate the high contamination of soil in the area of petrochemical plant, and PCDD/Fs contamination of the sediment from the waste water channel originating from the ethylene dichloride production.
اظهر المزيد [+] اقل [-]Polychlorinated biphenyls in farmed and wild Onchorhynchus kisutch and Onchorhynchus mykiss from the Chilean Patagonia النص الكامل
2011
Montory, Monica | Habit, Evelyn | Bahamonde, Paulina | Fernández, Pilar | Grimalt, Joan O. | Saez, Katia | Rudolph, Ignacio | Barra, Ricardo
Purpose This paper analyses the presence of polychlorinated biphenyls (PCBs) in escaped: farmed and wild salmons in southern Chile, analysing their concentrations and congener profiles in two species (Oncorhynchus kisutch and Oncorhynchus mykiss). Methods Muscle samples from both farmed and escaped fish of two species, O. mykiss (rainbow trout) and O. kisutch (coho salmon), were analysed for PCBs (42 congeners). To differentiate between the wild salmon and the salmon that have escaped from fish farms, the astaxanthin content in the muscular tissue was analysed with a high-performance liquid chromatography -diode array detector method. PCBs were measured by gas chromatography with an electron capture detector. Results The levels of astaxanthin can be used to differentiate between farmed, escaped and wild-borne salmons with statistically different concentrations. When comparing the total PCB concentrations for both trout and salmon samples, it can be determined that a separate analysis for farmed, escaped and wild-borne fish more accurately describes the real differences in the concentrations; these differences are hidden when separate analyses are not performed. The congener profiles are similar in both trout and coho salmon, where the tri-, tetra- and penta-CB congeners are the most abundant. Conclusion This study is the first report of PCBs in wild-borne, farmed and escaped salmons for the Southern Hemisphere, considering that Chile is actually one of the principal world producers of salmon.
اظهر المزيد [+] اقل [-]Degradative fate of 3-chlorocarbazole and 3,6-dichlorocarbazole in soil النص الكامل
2011
Tröbs, Lisa | Henkelmann, Bernhard | Lenoir, Dieter | Reischl, Arthur | Schramm, Karl-Werner
Background, aim, and scope 3-Chlorocarbazole and 3,6-dichlorocarbazole were isolated from Bavarian soils. The stereospecific formation of the isomers of these chlorinated carbazols can be explained by quantum mechanical calculations using the DFT method. It was shown that chlorination of carbazole and 3-chlorocarbazole respectively is preferred via the sigma-complexes 3-chlorocarbazole and 3,6-dichlorocarbazole as the most stable products. The dioxin-like toxicological potential of 3,6-dichlorocarbazole, determined by the Micro-EROD Test, is in the range of some picogram TCDD equivalents per milligram carbazole. The degradative fate of 3-chlorocarbazole and 3,6-dichlorocarbazole was analysed within a long-term study (57 days) in soil. Materials and methods The soil was extracted by ASE (accelerated solvent extraction) and a further clean-up procedure with column chromatography and chromatography with C18-SPE stationary phases. Quantification of 3-chlorocarbazole and 3,6-dichlorocarbazole was performed employing the isotope-dilution method. The samples were measured with high-resolution GC/MS. Results The degradation (ln(c/c₀) vs. time with best-fit line) showed in almost every storage condition a very small degradation (slopes (h⁻¹) in −10⁻⁴ range). However, the decay for the controls were two to three times (−28°C) and six times (with sodium azide) higher, than the decrease of 3-chlorocarbazole and 3,6-dichlorocarbazole in the samples of environmental conditions. Discussion Especially because of the toxicological potential of 3-chlorocarbazole and 3,6-dichlorocarbazole the proven degradative fate is of large interest. The results show that the analysed carbazoles are not readily degradable in this time period. Conclusions The expected results of exponential decay behaviour could not be proven. Recommendation and perspectives Longer-lasting studies are expected to reveal more accurate half-lives, although it has been shown here, that the compounds are not readily degradable in their native soil environment.
اظهر المزيد [+] اقل [-]Toxic effect of tetracycline exposure on growth, antioxidative and genetic indices of wheat (Triticum aestivum L.) النص الكامل
2011
Xie, Xiujie | Zhou, Qixing | Lin, Dasong | Guo, Jianmian | Bao, Yanyu
Introduction More attention has been paid to tetracycline contamination in view of its rapid increasing concentration in the environment. Therefore, it is important to set up rapid, simple, and accurate methods for monitoring tetracycline ecotoxicity. Methods In the present study, a hydroponics experiment was conducted to examine toxic effects of tetracycline at the concentration range of 0.5 to 300 mg L⁻¹ on growth, antioxidative, and genetic indices of wheat (Triticum aestivum L.). Results The results indicated that tetracycline at 0.5-10 mg L⁻¹ could stimulate seed germination, cell mitotic division, and growth of wheat seedlings and did not induce a significant increase in the activity of antioxidative enzymes. However, tetracycline at the high concentrations (10-300 mg L⁻¹) could significantly inhibit these parameters in the concentration-dependent manner, including germination percentage (≥100 mg L⁻¹), shoot height (≥100 mg L⁻¹), root length (≥50 mg L⁻¹), and mitotic index (≥50 mg L⁻¹), and increased the activity of antioxidative enzymes (≥25 mg L⁻¹) in the dose-dependent manner, including superoxide dismutase, catalase, and peroxidase. Tetracycline at 5 mg L⁻¹ and above significantly augmented chromosome aberration frequency and malondialdehyde (MDA) content. On the other hand, MDA has positive correlation with the inhibition rates of seed germination, root length, shoot length, mitotic index, and antioxidative enzyme activities. Conclusion Tetracycline may have potential physiological, biochemical, and genetic toxicity to plant cells, and chromosome aberration and MDA might be sensitive bioindicators for tetracycline contamination than the other plant characteristics.
اظهر المزيد [+] اقل [-]The performance of nature reserves in capturing the biological diversity on Hainan Island, China النص الكامل
2011
Wu, Ruidong | Ma, Guangzhi | Long, Yongcheng | Yu, Jiehua | Li, Shining | Jiang, Haisheng
Purpose The performance of nature reserves depends on the degree to which they represent a region's full biodiversity. Here, we conducted a study on Hainan Island, China, to assess how well Hainan's biodiversity features were captured by existing nature reserves. We also explored the driving forces behind the current protection pattern so as to provide guidelines for improving the island's conservation system. Methods We integrated the information on nature reserves, ecological variables, and human activities into a spatial database, then assessed the performance of nature reserves in representing natural variation, vegetation types, and species, and examined the impacts of human activities and land ownership on the current protection pattern. Results About 8.4% of Hainan Island was protected by nature reserves; the coverage was geographically biased toward its central mountainous areas with higher elevation, rugged terrain, and fertile soils. We found that 60% of the environmental units and 39.4% of the natural vegetation types had more than 10% of their area protected, respectively. Lowlands tended to have higher animal species richness, and the protection for endangered species was less efficient. Nature reserve coverage was negatively correlated with amount of converted habitats, human population density, and road density, and 82.4% of the total reserved area was allocated on state-owned land. Conclusions Nature reserve coverage was not enough to capture lowlands biodiversity features. The current protection pattern was significantly driven by several major conservation targets, human development, planning methods, and land ownership. To improve its conservation system, Hainan should enhance protection in the north and northeast plains and coastal regions, implement systematic planning approaches to define clear visions for guiding future conservation actions, and develop flexible management and funding mechanisms toward sustainable use of natural resources.
اظهر المزيد [+] اقل [-]Statistical analysis and isotherm study of uranium biosorption by Padina sp. algae biomass النص الكامل
2011
Khani, Mohammad Hassan
Introduction The application of response surface methodology is presented for optimizing the removal of U ions from aqueous solutions using Padina sp., a brown marine algal biomass. Methods Box-Wilson central composite design was employed to assess individual and interactive effects of the four main parameters (pH and initial uranium concentration in solutions, contact time and temperature) on uranium uptake. Results and discussion Response surface analysis showed that the data were adequately fitted to second-order polynomial model. Analysis of variance showed a high coefficient of determination value (R ² = 0.9746) and satisfactory second-order regression model was derived. Conclusion The optimum pH and initial uranium concentration in solutions, contact time and temperature were found to be 4.07, 778.48 mg/l, 74.31 min, and 37.47°C, respectively. Maximized uranium uptake was predicted and experimentally validated. The equilibrium data for biosorption of U onto the Padina sp. were well represented by the Langmuir isotherm, giving maximum monolayer adsorption capacity as high as 376.73 mg/g.
اظهر المزيد [+] اقل [-]Remédiation à la pollution par la chlordécone aux Antilles النص الكامل
2011
Jannoyer M. (ed.) | Lordinot J. (ed.) | Quénéhervé P.