خيارات البحث
النتائج 1221 - 1230 من 1,273
PM₁₀ source apportionment in the surroundings of the San Vicente del Raspeig cement plant complex in southeastern Spain
2011
Yubero, Eduardo | Carratalá, Adoración | Crespo, Javier | Nicolas, Jose | Santacatalina, Milagros | Nava, Silvia | Lucarelli, Franco | Chiari, Massimo
INTRODUCTION: The concentrations of trace metals, ionic species, and carbonaceous components in PM₁₀ (particulate matter with aerodynamic diameters smaller than 10 µm) were measured from samples collected near an industrial complex, primarily composed of cement plants, in southeastern Spain, from September 2005 to August 2006. MATERIALS AND METHODS: Positive matrix factorization and conditional probability function were applied to this data set to identify different types of sources. RESULTS: Six significant sources were identified: crustal matter, traffic, aged sea salt, industrial emissions, secondary aerosol, and sea salt. The difficulty of separating anthropogenic sources from those of natural origin is highlighted in this study; in particular, the crustal source can be connected with both natural (African outbreaks, wind resuspension) and man-made emissions, like fugitive emissions in an industrial environment.
اظهر المزيد [+] اقل [-]Chlorpyrifos degradation by the cyanobacterium Synechocystis sp. strain PUPCCC 64
2011
Singh, D. P. | Khattar, J. I. S. | Nadda, J. | Singh, Y. | Garg, A. | Kaura, Ainna. | Gulati, A.
BACKGROUND, AIM, AND SCOPE: Indiscriminate use of insecticides leads to environmental problems and poses a great threat to beneficial microorganisms. The aim of the present work was to study chlorpyrifos degradation by a rice field cyanobacterium Synechocystis sp. strain PUPCCC 64 so that the organism is able to reduce insecticide pollution in situ. MATERIAL AND METHODS: The unicellular cyanobacterium isolated and purified from a rice field was identified by partial 16S rRNA gene sequence as Synechocystis sp. strain PUPCCC 64. Tolerance limit of the organism was determined by studying its growth in graded concentrations (2.5–20 mg/L) of chlorpyrifos. Chlorpyrifos removal was studied by its depletion from the insecticide supplemented growth medium, and its biodegradation products were identified in the cell extract, biomass wash, and growth medium. RESULTS AND DISCUSSION: The organism tolerated chlorpyrifos up to 15 mg/L. Major fraction of chlorpyrifos was removed by the organism during the first day followed by slow uptake. Biomass, pH, and temperature influenced the insecticide removal and the organism exhibited maximum chlorpyrifos removal at 100 mg protein/L biomass, pH 7.0, and 30°C. The cyanobacterium metabolized chlorpyrifos producing a number of degradation products as evidenced by GC-MS chromatogram. One of the degradation products was identified as 3,5,6-trichloro-2-pyridinol. CONCLUSION AND RECOMMENDATIONS: Present study reports the biodegradation of chlorpyrifos by Synechocystis sp. Biodegradation of the insecticide by the cyanobacterium is significant as it can be biologically removed from the environment. The cyanobacterium may be used for bioremediation of chlorpyrifos-contaminated soils.
اظهر المزيد [+] اقل [-]Pesticide removal from waste spray-tank water by organoclay adsorption after field application to vineyards
2011
Suciu, Nicoleta A. | Ferrari, Tommaso | Ferrari, Federico | Trevisan, Marco | Capri, Ettore
PURPOSE: The main objective of this work was to develop and test a pilot scheme for decontaminating pesticide-containing water derived from pesticide mixtures used to protect vineyards, in which the scheme comprises adsorption by an organoclay and includes a system where an enhanced or rapid microbial degradation of the adsorbed residues can occur. METHODS: In laboratory experiments, the Freundlich adsorption coefficients of formulations of two fungicides, penconazole and cyazofamid, onto the organoclay Cloisite 20 A were measured in order to predict the efficiency of this organoclay in removing these fungicides from the waste spray-tank water. Subsequently, the adsorption tests were repeated in the pilot system in order to test the practical operation of the depuration scheme. RESULTS: The adsorption tests with the pilot system show 96% removal of both fungicides over a few hours, similar to the efficiency of removal predicted from the laboratory adsorption tests. The formulation type may influence the efficiency of clay recovered after adsorption. Regarding the waste disposal, for instance, the organoclay composted after the treatment, cyazofamid showed significant dissipation after 90 days, whereas the dissipation of penconazole was negligible. CONCLUSION: The depuration scheme developed showed to be efficient for decontaminating pesticide-containing water derived from vineyards, but additional treatments for the adsorbed residues still appear to be necessary for persistent pesticides. However, future decontamination research should be attempted for water contaminated with pesticides containing antifoaming agents in their formulations, in which case the present pilot system could not be applied.
اظهر المزيد [+] اقل [-]Still present after all these years: persistence plus potential toxicity raise questions about the use of atrazine
2011
As one of the worlds' most heavily applied herbicides, atrazine is still a matter of controversy. Since it is regularly found in ground and drinking water, as well as in sea water and the ice of remote areas, it has become the subject of continuous concern due to its potential endocrine and carcinogenic activity. Current findings prove long-held suspicions that this compound persists for decades in soil. Due to the high amount applied annually all over the world, the soil burden of this compound is considered to be tremendous, representing a potential long-term threat to the environment. The persistence of chemicals such as atrazine has long been underestimated: Do we need to reconsider the environmental risk?
اظهر المزيد [+] اقل [-]Characterization of dioxin-like contamination in soil and sediments from the “hot spot” area of petrochemical plant in Pancevo (Serbia)
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 [-]Influence of hydraulic retention time in a two-phase upflow anaerobic sludge blanket reactor treating textile dyeing effluent using sago effluent as the co-substrate
2011
Senthilkumar, M. | Gnanapragasam, G. | Arutchelvan, V. | Nagarajan, S.
Purpose Textile dyeing and sago industries are the most polluting industries in South India, especially in industrial cities like Salem, Tamil Nadu, where textile dyeing and sago industries are clumped together geographically. Conventional physicochemical treatment followed by biological processes for the effluent generated from these industries are ineffective, costlier and produce huge quantities of hazardous sludge and harmful by-products which requires further treatment and safe disposal. Hence, the development of an alternative treatment method will become important. The main objective of this investigation is to establish a sustainable biotreatment technology for the treatment of textile dyeing effluent using sago effluent as co-substrate in a two-phase upflow anaerobic sludge blanket (UASB) reactor. Methods In this study, influence of hydraulic retention time (HRT) in a two-phase UASB reactor treating textile dyeing effluent using sago effluent as co-substrate was investigated with different HRTs (36, 30, 24 and 18 h) with an optimum mixing ratio of 70:30 (sago to textile dye wastewaters). Results The results revealed that the HRT had a high influence on the chemical oxygen demand (COD) and colour removal. The maximum COD removal efficiency of 39.4% and 88.5% and colour removal efficiency of 43.7% and 84.4% in the acidogenic and methanogenic reactors, respectively was achieved at 24 h of HRT. The biogas production was 312 L/day. Conclusion The biphasic UASB reactor could be a very feasible alternative, cost-effective, eco-friendly and sustainable treatment system for textile dyeing effluent with sago effluent as a co-substrate.
اظهر المزيد [+] اقل [-]Degradative fate of 3-chlorocarbazole and 3,6-dichlorocarbazole in soil
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 [-]Phytoremediation of a sulphonated azo dye Green HE4B by Glandularia pulchella (Sweet) Tronc. (Moss Verbena)
2011
Kabra, Akhil N. | Khandare, Rahul V. | Kurade, Mayur B. | Govindwar, Sanjay P.
PURPOSE: The dyes and dye stuffs present in effluents released from textile dyeing industries are potentially mutagenic and carcinogenic. Phytoremediation technology can be used for remediating sites contaminated with such textile dyeing effluents. The purpose of the work was to explore the potential of Glandularia pulchella (Sweet) Tronc. to decolorize different textile dyes, textile dyeing effluent, and synthetic mixture of dyes. METHODS: Enzymatic analysis of the plant roots was performed before and after decolorization of dye Green HE4B. Analysis of the metabolites of Green HE4B degradation was done using UV–Vis spectroscopy, high-performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FTIR), and gas chromatography–mass spectroscopy (GC-MS). The ability of the plant to decolorize and detoxify a textile dyeing effluent and a synthetic mixture of dyes was studied by a determination of the American Dye Manufacturer’s Institute (ADMI), biological oxygen demand (BOD), and chemical oxygen demand (COD). Phytotoxicity studies were performed. RESULT: Induction of the activities of lignin peroxidase, laccase, tyrosinase, and 2,6-dichlorophenol indophenol reductase was obtained, suggesting their involvement in the dye degradation. UV–Vis spectroscopy, HPLC, and FTIR analysis confirmed the degradation of the dye. Three metabolites of the dye degradation were identified, namely, 1-(4-methylphenyl)-2-{7-[(Z)-phenyldiazenyl] naphthalen-2-yl} diazene; 7,8-diamino-2-(phenyldiazenyl) naphthalen-1-ol; and (Z)-1,1′-naphthalene-2,7-diylbis (phenyldiazene) using GC-MS. ADMI, BOD, and COD values were reduced. The non-toxic nature of the metabolites of Green HE4B degradation was revealed by phytotoxicity studies. CONCLUSION: This study explored the phytoremediation ability of G. pulchella (Sweet) Tronc. in degrading Green HE4B into non-toxic metabolites.
اظهر المزيد [+] اقل [-]Spectrofluorimetric study of the ageing of mixtions used in the gildings of mediaeval wall paintings
2011
Mounier, Aurélie | Belin, Colette | Daniel, Floréal
Introduction In the Middle Ages, we could find gildings on mural paintings. Gold, silver or tin leaves were applied according to distemper or mixtion technique. For the first one, a binder as glue is necessary, and for the second, a lipidic binder is used to stick the metallic leaf. Studies of gildings materials characterization show that the mixtion technique, with a mordant, is the most common. Linseed oil seems to be the binder used. It is always mixed with a siccative agent as lead. Because of bad conditions of conservation, the gildings do not resist anymore, only remain traces of metal or the adhesive under-layer. Thanks to the binder fluorescence, we can nowadays detect ancient gildings. Objective The purpose of this paper is to study the degradation of the linseed oil, generally mixed with lead white to give a mordant for the metallic leaf, by spectrofluorimetry. Materials and methods To understand in situ fluorescence, gildings recreations, linseed oil and lead white are aged in hygro-thermal and ultraviolet (UV) light (313 nm) climatic rooms and under UV irradiation. Irradiation wavelengths are chosen according to the maximum of absorption of linseed oil and the bibliography (296, 313 and 366 nm = mercury bands). Results In comparison with results (in situ UV lamp, spectrofluorimetry), excitation wavelength chosen is 366 nm. Irradiations at 366 nm of linseed oil and linseed oil mixed with lead white show the most degrading effect in the fluorescence to the big wavelength. Lead white plays an important siccative role; it increases the intensity fluorescence and accelerates the drying of linseed oil. This study also allows to show that 366 nm wavelength is good for the in situ observation.
اظهر المزيد [+] اقل [-]Investigation of ZnO nanoparticles' ecotoxicological effects towards different soil organisms
2011
Manzo, Sonia | Rocco, Annamaria | Carotenuto, Rita | De Luca Picione, Fabiano | Miglietta, Maria Lucia | Rametta, Gabriella | Di Francia, G (Girolamo)
Introduction Nanomaterials have widespread applications in several industrial sectors. ZnO nanoparticles (NPs) are among the most commonly used metal oxide NPs in personal care products, coating and paints. However, their potential toxicological impact on the environment is largely unexplored. Materials and methods The aim of this work was to evaluate whether ZnO nanoparticles exert toxic and genotoxic effects upon terrestrial organisms: plants (Lepidium sativum, Vicia faba), crustaceans (Heterocyipris incongruens), insects (Folsomia candida). To achieve this purpose, organisms pertaining to different trophic levels of the soil ecosystem have been exposed to ZnO NPs. In parallel, the selected soil organisms have been exposed to the same amount of Zn in its ionic form (Zn²⁺) and the effects have been compared. Results The most conspicuous effect, among the test battery organisms, was obtained with the ostracod H. incongruens, which was observed to be the most sensitive organism to ZnO NPs. The root elongation of L. sativum was also mainly affected by exposure to ZnO NPs with respect to ZnCl₂, while collembolan reproduction test produced similar results for both Zn compounds. Slight genotoxic effects with V. faba micronucleus test were observed with both soils. Conclusion Nanostructured ZnO seems to exert a higher toxic effect in insoluble form towards different terrestrial organisms with respect to similar amounts of zinc in ionic form.
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