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PubMed1997

Comparison of the mutagenicity of chemical agents released during coke production.

Benzene- and acetone-extracted samples of airborne particulate matter collected in two coke plants were analysed for their content of genotoxic agents (coal tar pitch volatiles (CTPVs), polycyclic aromatic hydrocarbons (PAHs): benzo/a/pyrene, pyrene, dibenzo/a,h/anthracene, anthracene and fluoranthene) following the identification and quantification of the compounds as well as the evaluation of their mutagenic activity using in vitro reverse mutation assay. Results of determinations at the top section of coke batteries were compared. Mean concentrations of total dust, CTPVs and B/a/P were as follows: 2.06 mg/m3, 0.63 micrograms/m3 in plant A, and 2.77 mg/m3, 0.89 mg/m3 and 0.35 micrograms/m3 in plant B, respectively. All the extracts of particulate matter samples increased the induction of bacterial mutation in both +S9 and -S9 tests. The exposures to mutagenic airborne particulate matter were in the range of 98-683 rev./m3 (-S9): 714-2214 rev./m3 (+S9) in plant A, and 21-496 rev./m3 (-S9); 68-850 rev./m3 (+S9) in plant B. The correlation between mutagenic potential and concentrations of tested agents was insignificant. The coke oven emission seemed to be higher in plant A with side charging of coal.

Extraction and Processing Industry↗

PubMed1987

Two-year inhalation toxicity study of petroleum coke in rats and monkeys.

Sprague-Dawley rats and Cynomolgus monkeys were exposed to dust aerosol concentrations (0, 10.2, and 30.7 mg/m3) of micronized delayed process petroleum coke for 6 hr/day, 5 days/week over 2 years. With the exception of pulmonary effects, particularly in the rats, no significant adverse treatment-related effects were observed. Both dust-exposed groups of both species exhibited a gray to black discoloration of the lung, an observation consistent with pulmonary deposition of the coke dust, as well as increased absolute and/or relative lung weight values. The pulmonary histopathology in the monkeys was limited to the deposition and phagocytosis of the test material by pulmonary macrophages. The rats also exhibited these responses, but with concomitant signs of chronic inflammation and focal areas of fibrosis, bronchiolization, sclerosis, squamous alveolar metaplasia, and keratin cyst formation. No difference in the mortality rate was observed between the control and exposed groups of rats. Lastly, no significant increases in chromosomal aberrations were observed in rodents of the 10.2 or 30.7 mg/m3 exposure groups when examined after 5 days, 12 months, and 22 months of exposure.

Animals↗

PubMed2000

Aromatic DNA adducts in coke-oven workers, in relation to exposure, lifestyle and genetic polymorphism of metabolic enzymes.

OBJECTIVE: This study investigates the effect of multiple factors, including exposure to polycyclic aromatic hydrocarbons (PAHs), lifestyle, genetic polymorphism of cytochrome P450 (CYP)1A1, glutathione transferase (GST)M1, GSTP1, N-acetyltransferase (NAT)2 and gene p53, as well as any family history of cancer, on DNA adduct levels in coke-oven workers. METHODS: Sixty-five coke-oven workers employed at the largest iron-steel factory in China were recruited for the study. Personal data were collected at the interview. DNA adduct levels in total white blood cells (WBCs) were detected using 32P-postlabeling techniques. Genetic polymorphisms were analyzed by polymerase chain reaction (PCR) methods. RESULTS: The subjects were divided into low and high exposure groups, according to personal exposure to PAHs. The mean adduct value was 1.57 (range 0.54 to 4.35) per 10(8) nucleotides. A tendency for increased levels of DNA adducts in the high exposure group was observed, compared with the low exposure group (P = 0.07). In the low exposure group, DNA adducts were found to be positively associated with urinary cotinine (r = 0.44, P = 0.01). The rare allele homozygotes of CYP1A1 showed significantly higher DNA adduct levels than those of other CYP1A1 genotypes. Individuals with the NAT2 wild type had significantly increased DNA adduct levels than those with other NAT2 genotypes in the high exposure group. The p53 genetic polymorphism revealed a significantly positive effect on DNA adducts formation. There was a significantly higher adduct level in the subjects with a family history of cancer than those without, in the high exposure category. CONCLUSIONS: Effects of several variables, such as smoking, genetic polymorphism of 2 CYP1A1, NAT2, and gene p53, and a family history of cancer on DNA adduct levels were found, suggesting that these variables should be considered when evaluating the genotoxic effect of occupational exposure to PAHs using WBCs DNA adducts.

Arylamine N-Acetyltransferase↗

PubMed1984

Respiratory impairment in coke oven workers: relationship to work exposure and bronchial inflammation detected by sputum cytology.

Coke oven workers are at excess risk of developing lung cancer and may be at risk for chronic obstructive lung disease (COLD). We have studied 3799 male workers to assess the relationship between the two diseases. Repeated lung function and sputum cytology tests were obtained over a 3-year period. Sputum samples were assessed using standardized methods; in addition to metaplastic and neoplastic changes, we reproducibly assessed the presence and extent of acute and chronic inflammatory changes. Spirometric flow rates (FEV1) were significantly reduced in workers most exposed to coke oven emissions, particularly in those with excessive inflammatory cells and regular metaplasia in sputum. The presence of reactive bronchial epithelial cells and metaplasia were potent predictors of an abnormal FEV1/FVC. Studies like these may offer a means to investigate the relationship between COLD and lung cancer. Such changes in sputum may identify individuals at risk of developing both diseases.

Bronchi↗

PubMed2005

Parallel hybrid modeling methods for a full-scale cokes wastewater treatment plant.

Parallel hybrid modeling methods are applied to a full-scale cokes wastewater treatment plant. Within the hybrid model structure, a mechanistic model specifies the basic dynamics of the relevant process and a non-parametric model compensates for the inaccuracy of the mechanistic model. First, a simplified mechanistic model is developed based on Activated Sludge Model No. 1 and the specific process knowledge of the cokes wastewater treatment process. Then, the mechanistic model is combined with five different non-parametric models--feedforward back-propagation neural network, radial basis function network, linear partial least squares (PLS), quadratic PLS and neural network PLS (NNPLS)--in parallel configuration. These models are identified with the same data obtained from the plant operation to predict dynamic behavior of the process. The performance of each parallel hybrid model is compared based on their ease of model building, prediction accuracy and interpretability. For this application, the parallel hybrid model with NNPLS as non-parametric model gives better performance than other parallel hybrid models. In addition, the NNPLS model is used to analyze the behavior of the operation data in the reduced space and allows for fault detection and isolation.

Bioreactors↗

PubMed2005

Immobilization and encapsulation during vitrification of incineration ashes in a coke bed furnace.

A real-scale coke bed furnace system has been successfully applied to vitrify the incineration ashes into glassy slags. The object of this research was to evaluate the effect of the system on the immobilization of metal species in the slag. Ashes and slag specimens were tested to identify their metal phase distribution following a sequential extraction procedure. The mobility of Al, Ca, Cd, Cr, Mg, Mn and Pb was noticeably reduced by vitrification. An important implication is the reduction of Cr(6+) to Cr(3+) along with its immobilization with this coke bed furnace. The Ni and Zn contents were relatively low in slag, indicating that their availability of mobile phases in ashes was reduced during vitrification. The XRD analyses identified the major crystalline phase in slag as åkermanite, which is inert and helpful in metal immobilization. The phase distribution analysis also contributed to verify that the incorporation of Ca and Mg enhanced the encapsulation in the slag matrix. The low oxygen content in slag made the structure of silicate resistant to the proton-promoted attack and also enhanced the mobility reduction of matrix elements (Ca, Mg and Al) in the moderately reducible phase and also contributed to the immobilization of other metal species. However, the properties of slag also deserve further studies to ensure its long-term stability and safety.

Carbon↗

PubMed2006

Instability of biological nitrogen removal in a cokes wastewater treatment facility during summer.

Failure in nitrogen removal of cokes wastewater occurs occasionally during summer season (38 degrees C) due to the instability of nitrification process. The objective of this study was to examine why the nitrification process is unstable especially in summer. Various parameters such as pH, temperature, nutrients and pollutants were examined in batch experiments using activated sludge and wastewater obtained from a full-scale cokes wastewater treatment facility. Batch experiments showed that nitrification rate of the activated sludge was faster in summer (38 degrees C) than in spring or autumn (29 degrees C) and the toxic effects of cyanide, phenol and thiocyanate on nitrification were reduced with increasing temperature. Meanwhile, experiment using continuous reactor showed that the reduction rate in nitrification efficiency was higher at 38 degrees C than at 29 degrees C. In conclusion, the instability of full-scale nitrification process in summer might be mainly due to washing out of nitrifiers by fast growth of competitive microorganisms at higher temperature under increased concentrations of phenol and thiocyanate.

Biodegradation, Environmental↗

PubMed2003

Determination of polycyclic aromatic hydrocarbons in urine of coke oven workers by headspace solid phase microextraction and gas chromatography-mass spectrometry.

Polycyclic aromatic hydrocarbons (PAHs) represent a complex mixture of toxic compounds that are ubiquitous in the environment. We investigated the utility of head space-solid phase microextraction (HS-SPME) to measure the following surrogate PAHs in urine: naphthalene (NAP), phenanthrene (PHE), pyrene (PYR), and benzo(a)pyrene (BAP), representing classes of 2-, 3-, 4- and 5-ring compounds, respectively. We then applied the method to urine from 28 coke oven workers (median levels (microg/l) were: NAP=3.65, PHE=1.51, PYR=0.003, BAP not detected) and 22 controls (median (microg/l) NAP=0.859, PHE=0.062, PYR=0.001, BAP not detected). Urinary levels of NAP, PHE, and PYR were all associated with exposure category (controls, side- and bottom-workers, and top-workers) but not with smoking status. Strong correlations were observed between urinary levels of NAP, PHE, and PYR in coke-oven workers. Our results indicate that unmetabolized 2-, 3- and 4-ring PAHs can be measured in urine by HS-SPME. Such measurements can be used to investigate the uptake and metabolism of complex PAH mixtures in humans.

Adolescent↗

PubMed1998

Glutathione S-transferase M1 and P1 genotypes and urinary excretion of 1-hydroxypyrene in coke oven workers.

The objective of this study was to analyze the effect of the GSTM1 and GSTP1 genotypes on urinary 1-hydroxypyrene, a biomarker for exposure to polycyclic aromatic hydrocarbon. Urine samples were collected from coke oven workers at two time points (from 66 and 46 workers, respectively) and 1-hydroxypyrene was quantitated by HPLC chromatography. The genotype of GSTM1 and GSTP1 was determined by a PCR methods discriminating between GSTM1 present or absent and three different alleles for GSTP1. The mean value of urinary 1-hydroxypyrene was higher at both time points in coke oven workers with GSTM1 gene present compared to workers having the GSTM1 null genotype, but this difference was not statistically significant. The GSTM1 and GSTP1 genotypes were not significant parameters in a multiple regression analysis with urinary 1-hydroxypyrene as the dependent variable and with GSTM1, GSTP1, exposure group and smoking habit as explanatory variables. The biomarker 1-hydroxypyrene is not or only marginally influenced by the GSTM1 genotype. No systematic influence of the GSTP1 genotypes was found.

Adult↗

PubMed1998

Determination of HPRT mutant frequency and molecular analysis of T-lymphocyte mutants derived from coke-oven workers.

We measured the frequency of mutant (MF) lymphocytes at the hprt locus in a population of 43 coke-oven workers exposed to PAH and in a group of 26 non-exposed workers. A non-significant increase in MF in the exposed group (19.0 +/- 16.3) compared to the non-exposed group (15.8 +/- 14.6) was observed. Moreover, when we considered smoking habits for the overall population, the MF values were higher, although not significantly, in smokers than in non-smokers. For some T-cell mutant clone structural alterations, splicing and coding errors were detected by PCR-based methods. We analysed 161 HPRT- clones, derived from exposed and non-exposed workers by multiplex-PCR and 56 HPRT- clones by reverse transcriptase-PCR. Overall, the percentages of the different types of gene alterations were similar in exposed and non-exposed subjects. Only the frequency of splice mutations in mutant clones derived from coke-oven workers was higher (22%) than in non-exposed donors (11%).

Adult↗

PubMed1998

DNA adduct formation in mammalian cell cultures by polycyclic aromatic hydrocarbons (PAH) and nitro-PAH in coke oven emission extract.

Mammalian cells in culture were used to study the genotoxic potential of coke oven emissions constituting a complex mixture of chemicals. For this purpose, particle extracts and some polycyclic aromatic and nitroaromatic hydrocarbons (PAH and nitro-PAH) occurring in these mixtures were assayed for DNA adduct formation using the -postlabeling technique. In primary cultures of rat hepatocytes, benzo[a]pyrene (B[a]P), benz[a]anthracene (B[a]A) and benzo[b]fluoranthene (B[k]F) caused DNA adduct levels in the range of 1 adduct/108 nucleotides. 4-Nitropyrene (4-NP), 6-nitrochrysene (6-NC), 3-nitrofluoranthene (3-NF) caused DNA adduct levels that were by one to two orders of magnitude higher. The crude particle extract and its fractions differing in acidity and polarity induced the formation of DNA reactive material within diagonal radioactive zones (DRZ) on the autoradiograms. On a weight base, the neutral aromatic fraction contributed by more than 80% to the total adduct level in hepatocytes. To examine whether the PAH- and nitro-PAH-DNA derived adducts can be further differentiated, hepatocyte cultures were preincubated with 2,3,7,8-tetrachloro-p-dioxin (TCDD) to induce the activity of cytochrome P450 1A1. TCDD pretreatment strongly increased the levels of PAH-DNA adducts, whereas, the levels of nitro-PAH adducts were markedly decreased. NCI-H322 cells, a human lung tumor cell line derived from Clara cells, exhibited PAH-DNA adduct levels between 10 and 100, and nitro-PAH-DNA adducts at levels between 0.2 to about 30 adducts per 108 nucleotides, respectively. In contrast to hepatocytes, incubations with extractable organic matter (EOM) and the neutral aromatic EOM fraction displayed several distinct spots in the chromatograms of NCI-H322 cells. The major spot was assigned by cochromatography to be identical with the major DNA adduct formed by incubation with B[a]P alone. In V79NH cells, a Chinese hamster lung cell line expressing nitro-PAH activating enzymes, but virtually no cytochrome P450 activity, PAH-derived DNA adducts were not detectable. Nitro-PAH-derived DNA adducts, however, were formed at levels between 10 and 300 adducts/108 nucleotides. The slightly and the moderately polar EOM fraction caused the formation of distinct adduct spots suggesting the occurrence of nitro-PAH in these fractions. GC/MS analyses revealed the presence of twelve PAH in the aromatic fraction, at a total amount of about 10% (w/w), and of four nitro-PAH in the slightly polar and the acidic fraction amounting to about 0.2% (w/w). In conclusion, our results indicate that PAH and nitro-PAH contribute to the genotoxicity of coke oven emissions. Using DNA adduct analysis in rat hepatocytes (+/-pretreatment with TCDD) and in NCI-H322 and in V79NH cells offers a promising approach to determine the genotoxic activity of PAH and nitro-PAH in any complex environmental samples.

Air Pollutants↗

PubMed2005

Phenanthrene and pyrene sorption and intraparticle diffusion in polyoxymethylene, coke, and activated carbon.

We report sorption isotherms and uptake kinetics for phenanthrene and pyrene with three organic model sorbents: polyoxymethylene (POM), coke, and activated carbon. We combine batch equilibration and kinetic experiments with the direct observation of the long-term diffusion of phenanthrene and pyrene as measured within cross-sectioned particles using microprobe laser-desorption laser-ionization mass spectroscopy (muL2MS). For POM pellets, the intraparticle concentration profiles predicted from kinetic batch experiments and a polymer diffusion model with spherical geometry are in agreement with the independent muL2MS measurements. For coke particles, the apparent diffusivities decreased with smaller particle size. These trends in diffusivities were described by a sorption-retarded pore diffusion model with a particle-size-dependent solid-water partitioning coefficient obtained from apparent equilibrium observed in the kinetic batch studies. For activated carbon, the muL2MS measurements showed faster radial diffusion of phenanthrene and pyrene into the particle interior than predicted from diffusion models based on a single sorption domain and diffusivity. A branched pore kinetic model, comprising polycyclic aromatic hydrocarbon (PAH) macropore diffusion with kinetic exchange of PAH between macroporous and microporous domains, fits the experimental observations better. Because of parallel macro- and microdiffusion processes, nonlinear sorption isotherms, and a concentration-dependent diffusivity, it is not possible to make independent parameter estimations for intraparticle diffusion in activated carbon using our present procedures.

Adsorption↗

PubMed2005

Influence of O2 and H2O on carbothermal reduction of SO2 by oil-sand fluid coke.

To develop a new process for removing high-concentration SO2 from industrial flue gases, the carbothermal reduction of SO2 by oil-sand fluid coke at 700 degrees C was investigated by varying the inlet concentration of either O2 or H2O. Concentrations of O2 and H2O ranged from 0 to 20% and from 0 to 30%, respectively, in a stream of SO2 (18%) with the balance helium. Addition of O2 and H2O was found to enhance SO2 reduction. The enhancement was attributed to the reducing gases, CO and H2, produced by solid-gas reactions between carbon and O2 or H2O. The effects of O2 and H2O on sulfur yield, however, were bifacial: adding O2 and/or H2O increased the sulfur yield when SO2 conversion was incomplete, otherwise, it decreased the sulfur yield through the formation of sulfides such as H2S. The results of a thermodynamic analysis were in a good agreementwith the experimental results, suggesting that gas-solid reactions were slow enough to allow gas-phase equilibrium. This study indicates that carbon, such as oil-sand fluid coke, can be utilized to remove SO2 in flue gases containing O2/H2O and to convert it to elemental sulfur.

Air Pollution↗

PubMed2006

Dispersion modeling of polycyclic aromatic hydrocarbons from combustion of biomass and fossil fuels and production of coke in Tianjin, China.

A USEPA, procedure, ISCLT3 (Industrial Source Complex Long-Term), was applied to model the spatial distribution of polycyclic aromatic hydrocarbons (PAHs) emitted from various sources including coal, petroleum, natural gas, and biomass into the atmosphere of Tianjin, China. Benzo[a]pyrene equivalent concentrations (BaPeq) were calculated for risk assessment. Model results were provisionally validated for concentrations and profiles based on the observed data at two monitoring stations. The dominant emission sources in the area were domestic coal combustion, coke production, and biomass burning. Mainly because of the difference in the emission heights, the contributions of various sources to the average concentrations at receptors differ from proportions emitted. The shares of domestic coal increased from approximately 43% at the sources to 56% at the receptors, while the contributions of coking industry decreased from approximately 23% at the sources to 7% at the receptors. The spatial distributions of gaseous and particulate PAHs were similar, with higher concentrations occurring within urban districts because of domestic coal combustion. With relatively smaller contributions, the other minor sources had limited influences on the overall spatial distribution. The calculated average BaPeq value in air was 2.54 +/- 2.87 ng/m3 on an annual basis. Although only 2.3% of the area in Tianjin exceeded the national standard of 10 ng/m3, 41% of the entire population lives within this area.

Air Movements↗

PubMed1975

Analytical methods used in a study of coke oven effluent.

In a coke oven study conducted by NIOSH, selected chemical analyses of airborne particulates, vapors, and metals in the emissions from five coke ovens were done. Eight sampling procedures and seven analytical techniques were used to analyze samples collected for the study. Six of the analytical methods used are discussed.

Air Pollution↗

PubMedDate not supplied

Occupational exposure to coke oven emissions from 1979-1983.

Breathing zone samples of benzene soluble fraction of total particulate matter (BSFTPM) were obtained for coke oven workers at a selected steel plant from 1979-1983. Analysis of the 1622 samples, collected for compliance with the 1976 OSHA coke oven emissions standard, indicated that there were significant differences in exposures to BSFTPM among the following variables: job classifications, batteries where the employees were stationed, shifts during the work day, and years and quarters of the year when samples were collected. In comparison to studies conducted prior to 1976, exposures to BSFTPM in the current study are consistently lower for every job classification. However, even in 1983, a large percentage of the workers in many of the sampled job classifications had BSFTPM concentrations that were above 0.150 mg/m3, indicating that current engineering controls and work practices are not sufficient to provide exposure levels below the recommended standard.

Air Pollutants, Occupational↗

PubMed1995

Urinary excretion of mutagens in coke oven workers.

The influence of occupational exposure to polycyclic aromatic hydrocarbons (PAHs) on urinary mutagenic activity was assessed in 75 coke oven workers, using a highly sensitive bacterial mutagen technique (extraction with C18 resin and liquid micro-preincubation test on strain TA98 of Salmonella typhimurium in the presence of metabolizing and deconjugating enzymes). Exposure to PAHs was assessed according to the urinary excretion of 1-pyrenol; the main confounding factors were checked by the number of cigarettes smoked per day and the levels of nicotine and its metabolites in urine, or by ascertaining whether recommended dietary restrictions had been followed. Of the 20 urine samples which turned out to be positive (producing at least double the number of spontaneous revertants), 19 (95%) belonged to smokers. Only one non-smoker had obvious urinary mutagenic activity, and was highly exposed occupationally to PAHs (urinary 1-pyrenol of 3.930 mumol/mol of creatinine). Of the five urine samples from subjects who had not followed the recommended diet, two (40%) were clearly mutagenic. Multiple regression analysis (n = 67) showed that the presence of samples positive for urinary mutagenic activity depended only on smoking habits, if this confounding factor was assessed according to the number of cigarettes smoked per day, while the significant influence of exposure to PAH could be shown when the confounding factor was objectively estimated according to the urinary levels of nicotine and its metabolites. Assessment of the mutagenic potency of urinary extracts (net revertants/mmol creatinine) confirmed the strong influence of smoking habits on urinary mutagenic activity (all smokers 2156 +/- 2691 versus non-smokers 939 +/- 947 net revertants/mmol creatinine; Mann-Whitney test: P < 0.01). In smokers highly exposed to PAHs, greater excretion of mutagens with respect to low-exposure smokers was revealed (3548 +/- 4009 versus 1552 +/- 1227 net revertants/mmol creatinine; Mann-Whitney test: P < 0.01). Multiple regression analysis showed that the mutagenic potency of urinary extracts of coke oven workers depended on exposure to PAHs, tobacco smoking habits, and consumption of fried, grilled or barbecued meat. Increased urinary mutagenic activity strengthens epidemiological evidence of the increased risk of renal and urinary tract tumours in these workers. The presence of mutagenic metabolites in urine as a result of occupational exposure to PAH may be demonstrated only by using highly sensitive techniques for assessing urinary mutagenic activity in studies which include careful checking of the main confounding factors.

Coke↗

PubMed1996

GSTM1 and NAT2 genotypes and urinary mutagens in coke oven workers.

The influence of the metabolic genotypes GSTM1 and NAT2 on the urinary excretion of mutagens in 46 coke oven workers (27 of them smokers) was studied. Exposure to polycyclic aromatic hydrocarbons (PAH) was estimated from urinary 1-pyrenol levels, which varied from 0.23 to 5.59 micromol/mol creatinine. Fourteen urine samples (30.4%), all but one belonging to smokers, were positive for mutagenic activity (i.e. at least one of the assayed doses was able to double the number of spontaneous revertants). Nine of the urine-positive subjects were both GSTM1-null and NAT2-ss (64.3%), while the same combination of genotypes was found in nine out of 31 urine-negative subjects (29.0%) (P < 0.05). Significantly more smoking workers with the genotype combination GSTM1-null/NAT2-ss showed positive urine mutagenicity than the other subjects (75.0 versus 28.6%, P < 0.05). Smokers with the slow acetylator genotype showed a significantly higher frequency of positive urine samples than smoking fast acetylators (64.7 versus 22.2%, P < 0.05). Our results suggest that smoking coke oven workers with genotypes unfavourable for detoxification of aromatic amines (NAT2-ss) and PAH (GSTM1-null) may have an increased risk of developing bladder cancer.

Arylamine N-Acetyltransferase↗