The ability of a bubble column reactor (BCR) to biodegrade a mixture of styrene and acetone vapors was evaluated to determine the factors limiting the process efficiency, with a particular emphasis on the presence of degradation intermediates and oxygen levels. The results obtained under varied loadings and ratios were matched with the dissolved oxygen levels and kinetics of oxygen mass transfer, which was assessed by determination of kLa coefficients. A 1.5-L laboratory-scale BCR was operated under a constant air flow of 1.0 L.min-1, using a defined mixed microbial population as a biocatalyst. Maximum values of elimination capacities/maximum overall specific degradation rates of 75.5 gC.m-3.h-1/0.197 gC.gdw-1.h-1, 66.0 gC.m-3.h-1/0.059 gC.gdw-1.h-1, and 45.8 gC.m-3.h-1/0.027 gC.gdw-1.h-1 were observed for styrene/acetone 2:1, styrene-rich and acetone-rich mixtures, respectively, indicating significant substrate interactions and rate limitation by biological factors. The BCR removed both acetone and styrene near-quantitatively up to a relatively high organic load of 50 g.m-3.h-1. From this point, the removal efficiencies declined under increasing loading rates, accompanied by a significant drop in the dissolved oxygen concentration, showing a process transition to oxygen-limited conditions. However, the relatively efficient pollutant removal from air continued, due to significant oxygen mass transfer, up to a threshold loading rate when the accumulation of acetone and degradation intermediates in the aqueous medium became significant. These observations demonstrate that oxygen availability is the limiting factor for efficient pollutant degradation and that accumulation of intermediates may serve as an indicator of oxygen limitation. Microbial (activated sludge) analyses revealed the presence of amoebae and active nematodes that were not affected by variations in operational conditions.

• MeSH
• aceton analýza   MeSH
• aerobióza MeSH
• biodegradace MeSH
• biomasa MeSH
• bioreaktory mikrobiologie   MeSH
• filtrace metody   MeSH
• kinetika MeSH
• látky znečišťující vzduch analýza   MeSH
• odpadní vody mikrobiologie   MeSH
• styren analýza   MeSH
• Publikační typ
• časopisecké články MeSH

Mandelic acid (MA) is an important metabolite of styrene. In humans, measurement of its concentration in urine provides an important assessment of the overall level of styrene exposure in workers of the reinforced plastic manufacturing industry. The aim of our study was to investigate in these workers the relationship between MA concentration and styrene exposure time and intensity as well as its dependence on work occupation. The concentration of MA in the urine samples of 35 employees was analyzed with HPLC (high performance liquid chromatography). Out of 35 workers, 11 performed laminating, 11 milling and finalizing, 6 laying-up and spraying-up, and 7 worked in background support. Urinal samples were obtained twice a day over the course of three weeks, at the beginning and the end of the work shift. We found a significant increase in MA concentrations during a work shift in all tested days (Wilcoxon test p < 0.05). Employees working in elevated atmospheric concentrations of styrene (93.77-159.88 mg/m3) had significantly higher MA concentrations in urine compared to other groups at both the beginning and the end of the shift (Kruskal Wallis test p < 0.001) (p < 0.001). Only samples from laminating workers exceeded the biological limit of MA concentration (640 mg/L) at the end of the shift. Normalisation of MA concentration to body mass index (BMI, normal range: 21.7 +/- 3.2 kg/m2) refined differences within groups (Kruskal-Wallis analysis p < 0.001). The accumulation of MA at the end of the work shift for measured time period was not significant for the measured time period (Friedman analysis p > 0.11). Our results confirmed that MA is a sensitive metabolic marker of styrene exposure without cumulative effect. However, normalization of MA concentrations to BMI can improve the accuracy of styrene exposure estimates in certain groups of employees.

• MeSH
• časové faktory MeSH
• kyseliny mandlové moč   MeSH
• látky znečišťující vzduch v pracovním prostředí analýza   metabolismus   MeSH
• lidé MeSH
• monitorování životního prostředí metody   MeSH
• plastické hmoty MeSH
• pracovní expozice analýza   statistika a číselné údaje   MeSH
• styren analýza   metabolismus   MeSH
• zaměstnání statistika a číselné údaje   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• tabulky MeSH

The study focuses on indoor air quality (microclimate and chemicals) in industrial premises. The health risk is determined. The model is presented for taking into consideration the concentration of chemicals in the air of the work environment and possible negative health effects. Practical examples and the results of measurements of microclimate and chemicals concentration in the workplace air in five industries (mechanical, printing, wood, plastic and clothing industries) are presented. The microclimate is under control except during very hot climate in summer. The chemicals are under control in printing, mechanical (except welding in closed workrooms), and clothing industry. The chemicals are often over the limits in wood processing industry and in some of the premises of plastic (manufacturing of rubber details) industry.

• MeSH
• butanoly analýza   normy   škodlivé účinky   MeSH
• chemický průmysl MeSH
• hodnocení rizik metody   normy   využití   MeSH
• hygiena práce * MeSH
• látky znečišťující vzduch v pracovním prostředí * analýza   normy   MeSH
• lesnictví MeSH
• lidé MeSH
• maximální přípustná koncentrace MeSH
• nebezpečné látky analýza   MeSH
• nemoc vyvolaná prostředím prevence a kontrola   MeSH
• polygrafie MeSH
• pracoviště MeSH
• pracovní expozice * normy   prevence a kontrola   statistika a číselné údaje   škodlivé účinky   MeSH
• prahové limitní hodnoty MeSH
• řízení bezpečnosti * metody   normy   MeSH
• styren analýza   normy   škodlivé účinky   MeSH
• teplota MeSH
• textilní průmysl MeSH
• těžební a zpracovatelský průmysl MeSH
• toluen analýza   normy   škodlivé účinky   MeSH
• vlhkost normy   MeSH
• xyleny analýza   normy   škodlivé účinky   MeSH
• znečištění vzduchu ve vnitřním prostředí * prevence a kontrola   statistika a číselné údaje   MeSH
• Check Tag
• lidé MeSH

Results of a recent molecular epidemiological study of 1,3-butadiene (BD) exposed Czech workers, conducted to compare female to male responses, have confirmed and extended the findings of a previously reported males only study (HEI Research Report 116, 2003). The initial study found that urine concentrations of the metabolites 1,2-dihydroxy-4-(acetyl) butane (M1) and 1-dihydroxy-2-(N-acetylcysteinyl)-3-butene (M2) and blood concentrations of the hemoglobin adducts N-[2-hydroxy-3-butenyl] valine (HB-Val) and N-[2,3,4-trihydroxy-butyl] valine (THB-Val) constitute excellent biomarkers of exposure, both being highly correlated with BD exposure levels, and that GST genotypes modulate at least one metabolic pathway, but that irreversible genotoxic effects such as chromosome aberrations and HPRT gene mutations are neither associated with BD exposure levels nor with worker genotypes (GST [glutathione-S-transferase]-M1, GSTT1, CYP2E1 (5' promoter), CYP2E1 (intron 6), EH [epoxide hydrolase] 113, EH139, ADH [alcohol dehydrogenase]2 and ADH3). The no observed adverse effect level (NOAEL) for chromosome aberrations and HPRT mutations was 1.794 mg/m(3) (0.812 ppm)--the mean exposure level for the highest exposed worker group in this initial study. The second Czech study, reported here, initiated in 2003, included 26 female control workers, 23 female BD exposed workers, 25 male control workers and 30 male BD exposed workers (some repeats from the first study). Multiple external exposure measurements (10 full 8-h shift measures by personal monitoring per worker) over a 4-month period before biological sample collections showed that BD workplace levels were lower than in the first study. Mean 8-h TWA exposure levels were 0.008 mg/m(3) (0.0035 ppm) and 0.397 mg/m(3) (0.180 ppm) for female controls and exposed, respectively, but with individual single 8-h TWA values up to 9.793 mg/m(3) (4.45 ppm) in the exposed group. Mean male 8-h TWA exposure levels were 0.007 mg/m(3) (0.0032 ppm) and 0.808 mg/m(3) (0.370 ppm) for controls and exposed, respectively; however, the individual single 8-h TWA values up to 12.583 mg/m(3) (5.72 ppm) in the exposed group. While the urine metabolite concentrations for both M1 and M2 were elevated in exposed compared to control females, the differences were not significant, possibly due to the relatively low BD exposure levels. For males, with greater BD exposures, the concentrations of both metabolites were significantly elevated in urine from exposed compared to control workers. As in the first study, urine metabolite excretion patterns in both sexes revealed conjugation to be the minor detoxification pathway (yielding the M2 metabolite) but both M1 and M2 concentration values were lower in males in this second study compared to their concentrations in the first, reflecting the lower external exposures of males in this second study compared to the first. Of note, females showed lower concentrations of both M1 and M2 metabolites in the urine per unit of BD exposure than did males while exhibiting the same M1/(M1+M2) ratio, reflecting the same relative utilization of the hydrolytic (producing M1) and the conjugation (producing M2) detoxification pathways as males. Assays for the N,N-(2,3-dihydroxy-1,4-butadyl) valine (pyr-Val) hemoglobin (Hb) adduct, which is specific for the highly genotoxic 1,2,3,4-diepoxybutane (DEB) metabolite of BD, have been conducted on blood samples from all participants in this second Czech study. Any adduct that may have been present was below the limits of quantitation (LOQ) for this assay for all samples, indicating that production of this important BD metabolite in humans is below levels produced in both mice and rats exposed to as little as 1.0 ppm BD by inhalation (J.A. Swenberg, M.G. Bird, R.J. Lewis, Future directions in butadiene risk assessment, Chem. Biol. Int. (2006), this issue). Results of assays for the HB-Val and THB-Val hemoglobin adducts are pending. HPRT mutations, determined by cloning assays, and multiple measures of chromosome level changes (sister-chromatid exchanges [SCE], aberrations determined by conventional methods and FISH) again showed no associations with BD exposures, confirming the findings of the initial study that these irreversible genotoxic changes do not arise in humans occupationally exposed to low levels of BD. Except for lower production of both urine metabolites in females, no female-male differences in response to BD exposures were detected in this study. As in the initial study, there were no significant genotype associations with the irreversible genotoxic endpoints. However, as in the first, differences in the metabolic detoxification of BD as reflected in relative amounts of the M1 and M2 urinary metabolites were associated with genotypes, this time both GST and EH.

• MeSH
• acetylcystein analogy a deriváty   moč   MeSH
• benzen analýza   MeSH
• butadieny aplikace a dávkování   škodlivé účinky   MeSH
• chemický průmysl * MeSH
• chromozomální aberace účinky léků   MeSH
• dospělí MeSH
• genotyp MeSH
• hemoglobiny metabolismus   MeSH
• hypoxanthinfosforibosyltransferasa genetika   MeSH
• lidé MeSH
• molekulární epidemiologie MeSH
• mutace genetika   MeSH
• pohlavní dimorfismus * MeSH
• pracovní expozice škodlivé účinky   statistika a číselné údaje   MeSH
• pracovní síly MeSH
• styren analýza   MeSH
• toluen analýza   MeSH
• výměna sesterských chromatid účinky léků   genetika   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Geografické názvy
• Česká republika MeSH

A multiinstitutional, transitional epidemiologic study was conducted with a worker population in the Czech Republic to evaluate the utility of a continuum of non-disease biological responses as biomarkers of exposure to 1,3-butadiene (BD)* in an industrial setting. The study site included two BD facilities in the Czech Republic. Institutions that collaborated in the study were the University of Vermont (Burlington, Vermont, USA); the Laboratory of Genetic Ecotoxicology (Prague, the Czech Republic); Shell International Chemicals, BV (Amsterdam, The Netherlands); the University of North Carolina at Chapel Hill (Chapel Hill, North Carolina, USA); University of Texas Medical Branch at Galveston (Galveston, Texas, USA); Leiden University (Leiden, The Netherlands); and the Health and Safety Laboratory (Sheffield, United Kingdom). Male volunteer workers (83) participated in the study: 24 were engaged in BD monomer production, 34 in polymerization activities, and 25 plant administrative workers served as unexposed control subjects. The BD concentrations experienced by each exposed worker were measured by personal monitor on approximately ten separate occasions for 8-hour workshifts over a 60-day exposure assessment period before biological samples were collected. Coexposures to styrene, benzene, and toluene were also measured. The administrative control workers were considered to be a homogeneous, unexposed group for whom a series of 28 random BD measurements were taken during the exposure assessment period. Questionnaires were administered in Czech to all participants. At the end of the exposure assessment period, blood and urine samples were collected at the plant; samples were. fractionated, cryopreserved, and kept frozen in Prague until they were shipped to the appropriate laboratories for specific biomarker analysis. The following biomarkers were analyzed: * polymorphisms in genes involved in BD metabolism (Prague and Burlington); * urinary concentrations of 1-hydroxy-2-(N-acetylcysteinyl)-3-butene and 2-hydroxy-1-(N-acetylcysteinyl)-3-butene (M2 [refers to an isomeric mixture of both forms]) (Amsterdam); * urinary concentrations of 1,2-dihydroxy-4-(N-acetylcysteinyl)-butane (M1) (Amsterdam); * concentrations of the hemoglobin (Hb) adducts N-(1-[hydroxymethyl]-2-propenyl)valine and N-(2-hydroxy-3-butenyl)valine (HBVal [refers to an isomeric mixture of both forms]) (Amsterdam); * concentrations of the Hb adduct N-(2,3,4-trihydroxybutyl)valine (THBVal) (Chapel Hill); * T cell mutations in the hypoxanthine phosphoribosyltransferase (HPRT) gene (autoradiographic assay in Galveston with slide review in Burlington; cloning assay in Leiden with mutational spectra determined in Burlington); and * chromosomal aberrations by the conventional method and by fluorescence in situ hybridization [FISH]), and cytogenetic changes (sister chromatid exchanges [SCEs] (Prague). All assay analysts were blinded to worker and sample identity and remained so until all work in that laboratory had been completed and reported. Assay results were sent to the Biometry Facility in Burlington for statistical analyses. Analysis of questionnaire data revealed that the three exposure groups were balanced with respect to age and years of residence in the district, but the control group had significantly more education than the other two groups and included fewer smokers. Group average BD exposures were 0.023 mg/m3 (0.010 ppm) for the control group, 0.642 mg/m3 (0.290 ppm) for the monomer group, and 1.794 mg/m3 (0.812 ppm) for the polymer group; exposure levels showed considerable variability between and within individuals. Styrene exposures were significantly higher in the polymer group than in the other two groups. We found no statistically significant differences in the distributions of metabolic genotypes over the three exposure groups; genotype frequencies were consistent with those previously reported for this ethnic and national population. Although some specific genotypes were associated with quantitative differences in urinary metabolite concentrations or Hb adduct dose-response characteristics, none indicated a heightened susceptibility to BD. Concentrations of both the M2 and M1 urinary metabolites and both the HBVal and THBVal Hb adducts were significantly correlated with group and individual mean BD exposure levels; the Hb adducts were more strongly correlated than the urinary metabolites. By contrast, no significant relations were observed between BD exposures and HPRT gene mutations (whether determined by the auto-radiographic or the cloning method) or any of the cytogenetic biomarkers (whether determined by the conventional method or FISH analysis). Neither the mutational nor the cytogenetic responses showed any association with genotypes. The molecular spectrum of HPRT mutations in BD-exposed workers showed a high frequency of deletions; but the same result was found in the unexposed control subjects, which suggests that these were not due to BD exposure. This lack of association between BD exposures and genetic effects persisted even when control subjects were excluded from the analyses or when we conducted regression analyses of individual workers exposed to different levels of BD.

• MeSH
• benzen analýza   metabolismus   MeSH
• biologické markery analýza   MeSH
• butadieny krev   metabolismus   moč   MeSH
• genotyp MeSH
• hemoglobiny účinky léků   MeSH
• hypoxanthinfosforibosyltransferasa genetika   MeSH
• krysa rodu rattus MeSH
• lidé MeSH
• lymfocyty ultrastruktura   MeSH
• mutace MeSH
• polymorfismus genetický MeSH
• pracovní expozice analýza   statistika a číselné údaje   MeSH
• průmysl MeSH
• styren analýza   metabolismus   MeSH
• toluen analýza   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Research Support, U.S. Gov't, P.H.S. MeSH
• Geografické názvy
• Česká republika MeSH

• MeSH
• biotransformace MeSH
• hippuráty analýza   metabolismus   moč   MeSH
• hygiena práce MeSH
• látky znečišťující vzduch v pracovním prostředí analýza   MeSH
• moč chemie   MeSH
• pracovní expozice analýza   MeSH
• styren analýza   metabolismus   moč   MeSH
• tetrachlorethylen analýza   metabolismus   moč   MeSH
• toluen analýza   metabolismus   moč   MeSH
• trichlorethylen analýza   metabolismus   moč   MeSH
• znečištění vzduchu ve vnitřním prostředí MeSH

• Klíčová slova
• kyselina fenylglyoxylová,
• MeSH
• analýza moči metody   MeSH
• hygiena práce MeSH
• lidé MeSH
• pracovní expozice * analýza   MeSH
• spektrofotometrie metody   MeSH
• styren * analýza   moč   MeSH
• Check Tag
• lidé MeSH

• MeSH
• látky znečišťující vzduch v pracovním prostředí analýza   MeSH
• styren analýza   MeSH

• MeSH
• hygiena práce MeSH
• pracovní expozice MeSH
• styren analýza   škodlivé účinky   MeSH

• MeSH
• experimenty na lidech MeSH
• kreatinin izolace a purifikace   metabolismus   MeSH
• lidé MeSH
• polystyreny analýza   metabolismus   škodlivé účinky   MeSH
• pracovní expozice * analýza   normy   škodlivé účinky   MeSH
• pracovní lékařství metody   MeSH
• statistika jako téma MeSH
• styren * analýza   metabolismus   škodlivé účinky   MeSH
• syntetické pryskyřice analýza   metabolismus   škodlivé účinky   MeSH
• Check Tag
• lidé MeSH