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Monoaromatic pollutants such as benzene, toluene, ethylbenzene and mixture of xylenes are now considered as widespread contaminants of groundwater. In situ bioremediation under natural attenuation or enhanced remediation has been successfully used for removal of organic pollutants, including monoaromatic compounds, from groundwater. Results published indicate that in some sites, intrinsic bioremediation can reduce the monoaromatic compounds content of contaminated water to reach standard levels of potable water. However, engineering bioremediation is faster and more efficient. Also, studies have shown that enhanced anaerobic bioremediation can be applied for many BTEX contaminated groundwaters, as it is simple, applicable and economical.This paper reviews microbiology and metabolism of monoaromatic biodegradation and in situ bioremediation for BTEX removal from groundwater under aerobic and anaerobic conditions. It also discusses the factors affecting and limiting bioremediation processes and interactions between monoaromatic pollutants and other compounds during the remediation processes.
Our objective was the assessment of algal medium harmfulness for in vitro fibroblasts. The algal medium was from Chlorella cultures (Beijerinck 1890) grown in the presence of benzene, which was added before the inoculation of culture. The medium contained, besides the benzene residues, its various metabolites formed during culture, among them phenol and catechol. Its addition to fibroblast cultures resulted in a decrease in their growth intensity and protein content in fibroblasts as well as an increase in DNA content and 14C-thymidine incorporation intensity to fibroblasts. The latter effect was probably connected with the inhibition of cell-division and DNA damage reparations. The obtained results indicate that Chlorella algae, besides other hydrobionts, take part in the forming of the benzene-like pollution toxicity in water habitat.
An inhibition of growth of Chlorella vulgaris, Beijerinck 1980 laboratory cultures carried out under different conditions caused by benzene, phenol and catechol was investigated. Each of the investigated substances was added to the culture medium at 4 or 5 different concentrations, directly before inoculation. The cultures were carried up to the stationary phase of growth. The density of alga cell suspension in the culture medium was determined with the use of a Bürker hemocytometer as well as EC50/96 and EC 50/Tmax values. It was stated that under some conditions it was possible to estimate the toxicity of the investigated substances, either in open cultures (flasks with microbiological corks, type I cultures) or closed (flasks with ground corks, type II cultures), but in this second case with the presence of NaHCO3 as an additional source of C02. The results presented in this paper indicate a relatively high toxicity of benzene and its investigated metabolites, phenol and catechol, as well as its dependence on conditions in the investigated cultures.
We estimated the toxic effect of benzene, phenol, and catechol on the logarithmic phase of growth of Chlorella vulgaris, Beijerinck 1890 cultures; the compounds show various degrees of toxicity to the algae. A concept was developed concerning each compound's toxicity index EC50/(T2-T1) The concept assumes the calculation of the index as well as benzene, phenol, and catechof-ináuced inhibition of test cultures growth f(T2-T1,) in T2-T1, interval which corresponds in our experiment to the logarithmic phase of control culture growth. f(T2-T1,) was proved to remain in linear relation to the initial concentration of the investigated substances in culture medium. Also, it was found that the values of EC50/(T2-T1), calculated by probit methods, are characterized by confidence intervals comparable to those determined for EC50/96 and EC50/Tmax (the indexes were determined at hour 96 and Tmax, respectively)
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Chromosomal aberrations in humans induced by benzene

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Adverse effects associated with occupational exposure to benzene have often been reported in humans. It has been shown, that benzene causes chromosomal aberrations, sister chromatid exchanges and micronuclei in lymphocytes of exposed workers. In addition to evidence by conventional cytogenetic methods, the genotoxic effect of benzene has also been proved by a more specific approach based on fluorescence in situ hybridization with DNA probes. In the present paper, the nature of benzene-induced chromosomal aberrations and supposed consequence on human health is reviewed. The new possibilities in chromosomal alterations identification by molecular cytogenetic methods are also presented.
This paper presents the behaviour of selected. bacteria, the mixture of, and indigenous to municipal sewage microorganisms, in biodegradation of benzene, toluene, o-xylene and p-xylene (BTX). Apart from an expected different behaviour under aerobic and anaerobic conditions the difference in degradation rate obtained for the different microorganisms tested, suppositions on practical application of the results were made. It was found that the mixture of microorganisms present in municipal sewage can be advantageously used in biodegradation of aromatic hydrocarbons under aerobic conditions. Opposite conclusions could be drawn from the experiments performed in anaerobic conditions where selected specific bacteria have been much more active. The observations made, of toluene biosynthesis. under specific anaerobic conditions seem to be totally new and unique.
W pracy przedstawiono test somatycznej mutacji i rekombinacji u muszki owocowej do pomiaru aktywności mutagennej benzenu oraz aldehydów octowego i mrówkowego.
The present paper provides an account of a study on benzene, toluene and xylene degradation by neustonic and planktonic bacteria in lake Jeziorak Mary. Aromatic hydrocarbons were better decomposed by neustonic bacteria than planktonic bacteria. Moreover, the obtained data point to the total number of bacteria and heterotrophic bacteria number being greater in surface microlayer than in subsurface water.
Przebadano wpływ skojarzonego działania alkoholu etylowego z benzenem i ksylenem na przebieg wydalania kwasu benzoesowego u szczurów po kontrolowanym narażeniu drogą oddechową.
Przebadano wpływ trichloroetylenu na wydalanie fenolu u szczurów poddanych łącznym ekspozycjom inhalacyjnym na równo- i różnomolowe mieszaniny benzenu i trichloroetylenu.
Przebadano wpływ mleczka pszczelego i pyłku kwiatowego na przebieg zatrucia benzenem w warunkach kontrolowanej ekspozycji inhalacyjnej.
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