خيارات البحث
النتائج 1251 - 1260 من 1,310
Pesticide removal from waste spray-tank water by organoclay adsorption after field application to vineyards النص الكامل
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 [-]Cultural heritage: a potential pollution source in museum النص الكامل
2011
Lee, CheolMin | Kim, YoonShin | Nagajyothi, P. C. | Thammalangsy, Soulighothai | Goung, Sun Ju Nam
Introduction The purposes of this study, as part of research projects for establishing the preservation environment of domestic cultural properties, are to identify the hazardous environmental factors which have a possibility to cause damages on long-term preservation of cultural heritage within the museum exhibition halls and the storages area, and to provide the basic data for the future establishment of preservation environment. Materials and methods The temperature (23.5 and 20.6°C,) relative humidity (52.1% and 55.4%), PM10 (31.5 and 18.9 μg/m3), CO2 (472.7 and 526.8 ppm), HCHO (20.8 and 34.0 μg/m3), CO (0.3 and 0.3 ppm), NO2 (0.012 and 0.004 ppm), TVOCs (493.6 and 788.9 μg/m3), O3 (0.003 and 0.002 ppm), Rn (0.7 and 1.5 pCi/L), and SO2 (0.003 and 0.002 ppm) as chemical factors, and airborne bacteria and fungi as biological factors, were selected for this research subjects of hazardous environmental factors, which were the subjects of the study conducted by the National Research Institute of Cultural Heritage from 2006 to 2008, and the subjects of related domestic researches performed in fragments. Results and discussion The concentration distributions of selected hazardous environmental factors in a museum environment were calculated by using the inverse variance weighted average in meta-analysis, and the concentration distributions possibly emerging in a museum exhibition halls and storages were computed through Monte Carlo simulation in order to minimize the uncertainty that can be caused from meagerness of related domestic researches.
اظهر المزيد [+] اقل [-]The effect of paraoxon on spermatogenesis in Dugesia gonocephala from the Chilean Altiplano: proliferation and apoptosis النص الكامل
2011
Rodríguez, Hector Hernan | Espinoza-Navarro, Omar | Silva, Ivan | Needham, Douglas | Castro, María Eugenia | Sarabia, Luis | Inostroza, Juan | Jimenez, Leonella
Introduction and aims The Chilean Altiplano ecosystem is conserved free from contaminants and pollutants because of the absence of major local human activities such as agriculture or other industries. We studied the effects of paraoxon on proliferation and apoptosis of testicular cells during active spermatogenesis in Dugesia gonocephala collected from a pristine river (Guacollo) in the Altiplano region nearby Visviri town, Chile. Materials and methods Adult planarians were incubated in varying concentrations of paraoxon (0.8, 0.4, 0.04, 0.004, and 0.0004 mM) for 4 h. After 3 h of incubation, bromodeoxyuridine (BrdU) was added. Effects on cell proliferation (BrdU) and apoptosis (Apaf-1) were determined by immunohistochemistry. Results Paraoxon concentrations of 0.4 and 0.8 mM caused 100% mortality in the respective treatment groups. The lowest tested concentration (0.0004 mM) caused a significant increase on cell proliferation in the seminiferous tubules, as well as an increase in the number of apoptotic cells. All other tested concentrations significantly inhibited cell proliferation and induced apoptosis. Conclusions Paraoxon inhibits DNA synthesis and induces apoptosis during spermatogenesis in adult planarians from a high-altitude, pollution-free environment. This could suggest its use as a biosensor or biomarker for contamination with agro pesticides.
اظهر المزيد [+] اقل [-]Trace element concentrations from lichen transplants in Pretoria, South Africa النص الكامل
2011
Olowoyo, Joshua Oluwole | van Heerden, E. | Fischer, J. L.
Purpose The purpose of this study was to assess the level and possible sources of trace elements in Tshwane metropolis using transplanted lichen thallus of Parmelia sulcata with a view to evaluating the ability of this lichen species to monitor air pollutants from a perceived polluted environment. Methods Samples of the lichen thalli were transplanted into ten different sites and covered with a net. Samples were exposed for 3 months. Concentrations of ten trace elements were determined with the use of inductively coupled plasma mass spectrometry. Results A significant difference was observed in the values of elemental concentration in lichen from unpolluted area and those transplanted to all the sites (p < 0.01). Variations in values of trace elements recorded in lichen transplant from different sites were also statistically significant (p < 0.01). The high traffic sites showed significantly higher elemental concentrations, particularly for Pb, Zn, and Cu than the industrial and residential areas (p < 0.05). Conclusion Trends in the trace element values from different sites suggested that the elements might have come from anthropogenic sources.
اظهر المزيد [+] اقل [-]Fine particulate phase PAHs in ambient atmosphere of Chennai metropolitan city, India النص الكامل
2011
Mohanraj, Rangaswamy | Solaraj, Govindaraj | Dhanakumar, Selvaraj
Background Airborne fine particulates (PM 2.5) and its associated polycyclic aromatic hydrocarbons (PAHs) are reportedly hazardous in urban environment due to the presence of multiple emission sources. Methods In this study, fine particulates collected from fourth largest metropolitan city of India, Chennai, were extracted and analyzed for 11 PAHs by high-performance liquid chromatography equipped with a fluorescence detector. Results PM 2.5 values varied between 27.2 and 190.2 μg/m³, while average concentration of particle-associated PAHs determined was in the range from 325.7 to 790.8 ng/m³, which signaled an alarming pollution level in Chennai. Conclusions Factor analysis suggested vehicular emissions inclusive of petrol- and diesel-driven engines as probable sources.
اظهر المزيد [+] اقل [-]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 [-]Bioremediation and reclamation of soil contaminated with petroleum oil hydrocarbons by exogenously seeded bacterial consortium: a pilot-scale study النص الكامل
2011
Mukherjee, Ashis K | Bordoloi, Naba K
Purpose Spillage of petroleum hydrocarbons causes significant environmental pollution. Bioremediation is an effective process to remediate petroleum oil contaminant from the ecosystem. The aim of the present study was to reclaim a petroleum oil-contaminated soil which was unsuitable for the cultivation of crop plants by using petroleum oil hydrocarbon-degrading microbial consortium. Materials and methods Bacterial consortium consisting of Bacillus subtilis DM-04 and Pseudomonas aeruginosa M and NM strains were seeded to 20% (v/w) petroleum oil-contaminated soil, and bioremediation experiment was carried out for 180 days under laboratory condition. The kinetics of hydrocarbon degradation was analyzed using biochemical and gas chromatographic (GC) techniques. The ecotoxicity of the elutriates obtained from petroleum oil-contaminated soil before and post-treatment with microbial consortium was tested on germination and growth of Bengal gram (Cicer aretinum) and green gram (Phaseolus mungo) seeds. Results Bacterial consortium showed a significant reduction in total petroleum hydrocarbon level in contaminated soil (76% degradation) as compared to the control soil (3.6% degradation) 180 days post-inoculation. The GC analysis confirmed that bacterial consortium was more effective in degrading the alkane fraction compared to aromatic fraction of crude petroleum oil hydrocarbons in soil. The nitrogen, sulfur, and oxygen compounds fraction was least degraded. The reclaimed soil supported the germination and growth of crop plants (C. aretinum and P. mungo). In contrast, seeds could not be germinated in petroleum oil-contaminated soil. Conclusions The present study reinforces the application of bacterial consortium rather than individual bacterium for the effective bioremediation and reclamation of soil contaminated with petroleum oil.
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 النص الكامل
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 [-]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 [-]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.
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