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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.
Background. The Thai government has been developing its Eastern Economic Corridor (EEC), which spans three provinces, with the aim of improving connections with other Asian nations. Since this strategic development, the number of trucks, private car, and passenger car registrations have continued to grow, with a corresponding increase in related to benzene, toluene, ethylbenzene, and xylene (BTEX). Objectives. This study aims to compare the levels of trans, trans-muconic acid (t, t MA); toluene (TU); mandelic acid (MA); and methyl hippuric acid (MHA) in the urine of gas station employees, considering demographic and occupational factors. Material and methods. These employees worked either near or away from the fuel dispenser, and there 100 people in each group. Data were collected using interviews and testing environmental air and urine samples for benzene, toluene, ethyl benzene, and xylene (BTEX). Results. The results showed that BTEX concentrations were just detectable in all 200 cases (100%). The mean (±SD) urine level of t, t MA was 449.28 (±213.32) μg/g creatinine, while the median (min-max) was 428.23 (95.58-1202.56) μg/g creatinine. The mean TU was 0.011 (0.001) mg/L, while the median (min-max) was 0.011 (0.010-0.013) mg/L. MA levels were higher inside the pollution control zone than they were outside the zone (p=.009). Employees who practiced poor personal hygiene had relatively high urinary toluene and MHA levels (p=.009) and those who did not wear personal protective equipment (PPE) had relatively high MA levels (p=.040). Conclusion. The results of this study revealed statistically significant biomarkers influencing the levels of t, t MA; TU; MA; and MHA in urine. The recommendations of this study are that employers should provide their employees with suitable PPE, check regularly to ensure that it is worn, and strongly encourage employees to take care of their sanitation. Employees should take appropriate breaks and days off to minimize their exposure to BTEX.
This paper concerns quality assurance of arsenic determination in urine using the graphite furnace AAS method after toluene extraction. Obtained analytical results are used for validation and quality assurance purposes. The investigated urine samples were acquired from the workers of a large coal-fired Slovak power plant. In the proposed analytical method the following metrological characteristics were calculated: trueness, precision, recovery, the limit of detection and the limit of quantification. The method was satisfactorily used in the intercomparison test. The proposed method is suggested for utilisation in the assessment of occupational or environmental exposure to inorganic arsenic.
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.
Przebadano wpływ skojarzonego działania alkoholu etylowego z benzenem i ksylenem na przebieg wydalania kwasu benzoesowego u szczurów po kontrolowanym narażeniu drogą oddechową.
Przebadano wydalanie kwasu trichlorooctowego i trichloroetanolu u szczurów poddanych pięciodniowym ekspozycjom na sam trichloroetylen (TRI) lub łącznie z toluenem po jednoczesnym podaniu etanolu. Wykazano, że oba związki zmieniają wydalanie głównych metabolitów trichloroetylenu.
Przebadano wpływ skojarzonego działania alkoholu etylowego z benzenem i toluenem na wydalanie kwasu metylobenzoesowego u szczurów po kontrolowanym narażeniu drogą inhalacyjną.
Oceniono wpływ alkoholu etylowego i kofeiny na wydalanie fenolu, kwasu benzoesowego i kwasu metylobenzoesowego - metabolitów stanowiących podstawę testów wykorzystywanych w biologiczym monitoringu narażenia na benzen, toluen i ksylen w warunkach przemysłowych.
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