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Relationship between blood antioxidants and occupational exposure to polycyclic aromatic hydrocarbons in coke oven workers.

BACKGROUND: We investigated if blood Cu++/Zn++ superoxide dismutase, glutathione peroxidase, and catalase activities are increased and total plasma antioxidant concentration is decreased in coke oven workers exposed to polycyclic aromatic hydrocarbons. METHODS: Ninety-six coke oven workers participated in the study. Nonexposed workers (n = 105) were randomly sampled among power plant workers in the same age range. The examination included a questionnaire on health status, occupational history, smoking, and dietary habits. Blood samples completed the examination. Coke oven workers were classified into low-, middle-, and high-exposure groups based on the benzo[a]pyrene (B[a]P) air concentrations and were further classified into the categories "topside" and "non-topside," according to their proximity to the ovens. RESULTS: Erythrocyte glutathione peroxidase activity increased with age (r = 0.18, P = 0.061) in power plant workers, whereas plasma glutathione peroxidase activity decreased with age (r = -0.18, P = 0.068) and erythrocyte glutathione peroxidase activity was inversely correlated with the number of cigarettes per day (r = -0.28, P = 0.08) in coke oven workers. Comparison of blood antioxidant enzyme activities and total plasma antioxidant concentration between coke oven and power plant workers showed that erythrocyte glutathione peroxidase activity was significantly lower in coke oven workers, even after adjustment for potential confounding factors. No differences were found either in other blood antioxidant enzyme activities or in total plasma antioxidant concentration between coke oven and power plant workers. Moreover, no trends toward decreased glutathione peroxidase activity among the three subgroups of B[a]P exposure were observed, and no differences either in blood antioxidant enzyme activities or in total plasma antioxidant concentration between the two groups of job categories were found. CONCLUSIONS: Production of reactive oxygen species seems not to be increased in coke oven workers.

Adult↗

Aromatic and polycyclic hydrocarbons in air and their urinary metabolites in coke plant workers.

This study describes the exposure of coke plant workers to hydrocarbons. Aromatic hydrocarbons (AHs) and polycyclic aromatic hydrocarbons (PAHs) in the breathing zone air and their oxygenated metabolites in the urine of coke plant workers are qualitatively and quantitatively determined. Concentrations of benzene, toluene, naphthalene, m + p-xylene, o-xylene and 14 different PAHs were measured at the different workplaces by personal air sampling. O-cresol, 1- and 2-naphthol, methylhippuric acid, and 1-hydroxypyrene were determined in hydrolyzed urine of workers collected after the work shift. The gas chromatography-mass spectrometry (GC/MS) method was applied to identify AHs in air and in urine samples. Time-weighted values of exposure to aromatic hydrocarbons at a coke plant were: benzene (0.06-9.82 mg/m3), toluene (0.05-4.71 mg/m3), naphthalene (0.01-3.28 mg/m3), o-xylene (0.01-1.76 mg/m3) and m + p-xylene (0.01-2.62 mg/m3). At the coke batteries, the total concentration of PAHs ranged from 7.27 to 21.92 micrograms/m3. At the sorting department, the total concentration of PAHs were about half this value. Concentration of the urinary metabolites (naphthols and methylhippuric acid) detected in workers at the tar distillation department are three times higher than those for the coke batteries and sorting department workers. A correlation between inhaled toluene, naphthalene, xylene, and urinary excretion of metabolites has been found. Time-weighted average concentrations of AHs in the breathing zone air show that exposure levels of the workers are rather low in comparison to exposure limits. The 1-hydroxypyrene concentration is below 24.75 mumol/mol creatinine. The GC/MS analysis reveals the presence of AHs, mainly benzene and naphthalene homologues. It has been found that coke plant workers are simultaneously exposed to the mixture of aromatic and polycyclic hydrocarbons present in the breathing zone air of a coke plant. Exposure levels are significantly influenced by job categories. Compounds identified in the urine appear to be the products of the hydroxylation of AHs present in the air as well as unmetabolized hydrocarbons.

Adult↗

Adsorption removal of pollutants by active cokes produced from sludge in the energy recycle process of wastes.

This study proposes a recycling system of sludge into active cokes and the fundamental examinations for the application were carried out. In the system, active cokes were produced by carbonizing pellets of sludge in a steam stream. Pyrolysis gas yielded by carbonization can be available to a fuel for a steam generation boiler. The exhaust heat from the boiler is used sequentially for drying of sludge. The active cokes are applied to the adsorbent for dioxin removal in exhaust gas from incinerators of wastes, or for purification of gas obtained in a gasification process of wastes, particularly removal of H2S. The used adsorbent is not recycled, but incinerated in the furnace without a desorption process to decompose adsorbed dioxin or to oxidize H2S for a sequential desulfurization process of SO2. Dry pellets of sludge were carbonized in a quartz tube reactor under various atmospheres. The micro pore structure and the adsorption performance of the cokes produced without activation process were examined. The micro pore structure was influenced by the temperature, the sort of flow gas (N2, CO2 and steam) and carbonization time, and the active cokes produced under the condition of the temperature 823 K for 60 min in the steam atmosphere had a largest specific surface area in the diameter less than 5 nm. The amount of benzene adsorption as an alternative substance of dioxin into the active cokes had a similar quality to a commercial active char produced from coal if it was evaluated by adsorption per a unit specific surface area. This fundamental knowledge must be reflected to an optimum design for development of a simple continuous process to produce the active cokes by a fluidized bed type of the carbonization furnace.

Adsorption↗

Associations between XRCC1 and ERCC2 polymorphisms and DNA damage in peripheral blood lymphocyte among coke oven workers.

A wide variety of base damages and single-strand breaks formed by reactive oxygen species during metabolic activation of polycyclic aromatic hydrocarbons (PAHs) have been recognized to be involved in PAH carcinogenesis. In this study, alkaline comet assay was used to detect the DNA damage in peripheral blood lymphocytes among 143 coke-oven workers and 50 non-coke-oven workers, and the effects of genetic polymorphisms of XRCC1 and ERCC2 genes on DNA damage were evaluated. The olive tail moment was significantly higher in coke-oven workers than in non-coke-oven workers (2.6, 95% CI=2.1-3.3 versus 1.0, 95% CI=0.8-1.2, p<0.01), and significant correlation between ln-transformed urinary 1-OHP and ln-transformed olive tail moment was found in total population (n=193, Pearson's r=0.393, p<0.001) and in coke-oven workers (n=143, Pearson's r=0.224, p=0.007). The olive tail moment was significantly higher in coke-oven workers with GA genotype of G27466A polymorphism of XRCC1 than those with GG genotype (4.6, 95% CI=2.5-8.7 versus 2.4, 95% CI=1.9-2.9, p<0.01 with adjustment for covariates). No significant associations between C26304T, G28152A and G36189A polymorphisms of XRCC1 and G23591A and A35931C polymorphisms of ERCC2 and olive tail moment were found in both groups. The study showed that the alkaline comet assay is a suitable biomarker in the detection of DNA damage among coke-oven workers and it suggested that the A allele of G27466A polymorphism of XRCC1 may be associated with decreased DNA repair capacity toward PAH-induced base damage and strand breaks.

Adult↗

Elevated serum liver enzymes in coke oven and by-product workers.

Coke oven and by-product workers are potentially exposed to coke oven emissions (COE), which contain hundreds of chemicals and are primarily composed of polycyclic aromatic hydrocarbons (PAH) and volatile organic compounds. Some of these compounds are hepatotoxins. The objective of this study was to examine the relationship between work in coke oven and by-product plants and serum activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), the most commonly performed liver-function tests. The exposed group was composed of current workers who had been employed at least 3 months in the two coke-operation work areas, including one coke oven plant and one by-product plant (Area I: n = 117; Area II: n = 96) of a large steel company in Taiwan. Control subjects (Area III: n = 131), not visiting either coke-operation area in the last 3 months, were collected from the administrative and nonproduction areas in the same company. PAH exposure, as a surrogate of COE, was measured monthly by PM-10 size-selective high-volume-area air samplers in or around these three areas between June and December 1990, as well as between November 1992 and June 1993. The mean total respiratory particulate PAH exposure levels (< 10 microns) between November 1992 and June 1993 in Area I, II, and III were 6.8 x 10(3), 2.1 x 10(3), and 6.5 x 10(1) ng/m3, respectively. AST, ALT, and hepatitis B surface antigen tests were performed in 1994. Workers who showed either AST or ALT levels greater than reference levels (abnormal > 25 IU/L) were regarded as showing "elevated liver enzyme levels." Workers in Area I had AST levels that were 17% higher (95% confidence interval [CI], 3% to 32%]) and ALT levels that were 35% higher (95% CI, 10% to 65%)] than those in Area III after controlling for appropriate confounders. The adjusted odds ratio (Area I vs Area III) for elevated liver enzymes was 4.4 (95% CI, 1.5 to 13.4). In addition, coke oven (n = 91) and by-product workers (n = 26) from Area I had ALT levels 37% and 45% higher, respectively, compared with control subjects from Area III, after adjusting for appropriate confounders. Similar effects are also seen for AST. Workers in Area II had slightly, but not significantly, elevated AST and ALT levels. These results indicate that workers most heavily exposed to COE exhibit elevated aminotransferase levels.

Adult↗

Is living near a coking works harmful to health? A study of industrial air pollution.

OBJECTIVE: To determine whether there was excess ill health in people living near a coking works, and if so whether it was related to exposure to coking works' emissions. DESIGN: Populations varying in proximity to the coking works were compared with control populations. Health data were correlated with available environmental data. METHODS: Analysis of routinely collected mortality, cancer registration, and birth statistics; community survey using self completed postal questionnaires; retrospective analysis of general practice (GP) records; tests of respiratory function; and analysis of available environmental data. MAIN RESULTS: Study and control populations were comparable in terms of response rates, gender, and most socioeconomic indicators. For adults, age standardised mortality and cancer rates of the population closest to the coking works were comparable with those for the district as a whole. Gender ratios, birthweight, and stillbirth rates were comparable in the study and control populations. For several indicators of respiratory health including cough, sinus trouble, glue ear, and wheeze (but not for asthma and chronic bronchitis) there was a gradient of self reported ill health, with the highest prevalence in areas closest to the works. For example, sinus trouble was reported by 20% of adults and 13% of children in the area closest to the works compared with 13% and 6% respectively in the control area. GP consultations for respiratory disorders increased when pollution (measured by SO2 levels) was high: annual consultation rates per 1000 varied from 752 in the top group of daily pollution levels to 424 in the bottom group. Analysis of locally collected smoke and SO2 data indicated that SO2 concentrations were highest closest to the works and, after closure of the coking works, the number of days on which SO2 and smoke levels exceeded 100 micrograms/m3 and 90 micrograms/m3, respectively, fell steeply. CONCLUSION: Routinely available indicators failed to provide convincing evidence that the coking works had harmed health. Self report and GP consultations indicated that respiratory ill health in the people living close to the works was worse than expected. Some of the excess probably resulted from exposure to coking works emissions. The health effects of relatively low level but intermittently high air pollution from a point source may be subtle, contributing to respiratory morbidity, but not apparent in analysis of routine health indicators.

Adolescent↗

Evaluation of biomarkers in plasma, blood, and urine samples from coke oven workers: significance of exposure to polycyclic aromatic hydrocarbons.

OBJECTIVE: The aim was to assess the significance of two biomarkers; antibody to benzo(a)pyrene DNA adducts and concentration of hydroxyethylvaline haemoglobin adducts in samples from a well studied group of coke oven workers. As a measure of exposure we have used 1-hydroxypyrene in urine. METHODS: Urine and blood samples were collected from coke oven workers and a control group. Samples from coke oven plant workers were collected in January and June. 1-Hydroxypyrene was measured in urine by high performance liquid chromatography (HPLC), antibodies to benzo(a)pyrene DNA adducts were measured by ELISA and hydroxyethylvaline haemoglobin adducts were measured by gas chromatography-mass spectrometry (GC-MS). RESULTS: Mean urinary 1-hydroxypyrene in samples from coke oven workers varied from 1.11 to 5.53 umol/mol creatinine and 0.14 umol/mol creatinine in the control group. Workers at the top side had the highest values of urinary 1-hydroxypyrene. Antibody to benzo(a)pyrene DNA adducts did not correlate with either 1-hydroxypyrene nor length of work at the coke oven plant. But antibody concentration in samples collected in January was predictive of the concentration in samples collected in June. A small non-significant increase in hydroxyethylvaline haemoglobin adducts was found in samples from coke oven workers relative to the control group when comparing smokers and nonsmokers separately. CONCLUSION: 1-Hydroxypyrene correlates well with exposure groups based on job description. Antibodies to benzo(a)-pyrene DNA adducts was related to people and not exposure. Work at a coke oven plant might lead to increased hydroxyethylvaline haemoglobin adducts.

Adult↗

[Study on co-pyrolysis of coking-coal, plastic and dust].

The co-pyrolysis processes of different proportions of coking-coal, plastic, metallurgical dust (MD) were investigated using thermal analyzer (Setaram Labsys) under a neutral atmosphere of N2 at the sweep rate of 30 mL/min, the linear heating rate and the final pyrolysis temperature were 5 degrees C/min and 1000 degrees C respectively in this study. The experimental results indicated that both the pyrolysis process of coking-coal and that of plastic were radical mechanism. In other word, within the relatively lower temperature range, a large amount of radicals were generated during their pyrolysis processes and stabilized through the intra-radical rearrangement reactions or inter-radical combination reactions. This means that sulfur containing in coal and plastic tends to formed gaseous sulfides, such as H2S, COS, CS2, etc. When co-existing with MD, these sulfides will react with metal oxides containing in MD to form metal sulfide with high stability and the cleaner coke oven gas (COG) were obtained. Within higher temperature interval of 500 degrees C-1000 degrees C, some of the gaseous products after pyrolysis (e.g. H2, CO and C) reinforce the reduction atmosphere that the coking reaction system needs and accelerate the reduction of metal oxides in MD and gasification of metal, which were conductive to the effective removal of sulfur in coke. Therefore, it is definitely feasible to adding waste plastic and MD into coking-coal to remove the sulfur in COG and coke simultaneously.

Coke↗

[Preliminary study on naphthalene-metabolites-albumin adduct as an exposure biomarker for coke oven workers].

OBJECTIVE: To study albumin adduct with naphthalene metabolites, namely 1,2-naphthoquinone (1,2-NPQ) and 1,4-naphthoquinone (1,4-NPQ), as a potential biomarker for intermediate/long-term exposure to polycyclic aromatic hydrocarbons (PAH) in coke oven workers. METHODS: Twenty-eight coke oven workers and 22 control workers were recruited from a cokery. Spot urine and venous blood samples were collected from the workers after four continuously working days and personal information was obtained by questionnaire. Plasma albumin adduct was detected with gas chromatography-mass spectrometry. RESULTS: Albumin adduct with 1,2- & 1,4-NPQ (1,2-NPQ and 1,4-NPQ), respectively, were detected in all coke oven workers and controls. Median plasma level of 1,2-NPQ-Alb in coke oven workers was significantly higher than that in controls (76.6 pmol/g vs. 44.9 pmol/g, P < 0.01). However, there was no significant difference in plasma median level of 1,4-NPQ-Alb between the two groups (48.6 pmol/g vs. 44.2 pmol/g, P > 0.05). Plasma level of 1,2-NPQ-Alb was significantly higher than that of 1,4-NPQ-Alb in coke oven workers. Urine levels of naphthalene, 1-naphthol, 2-naphthol and 1-pyrenol in coke oven workers correlated significantly with their plasma level of 1,2-NPQ-Alb (Pearson coefficient of correlation greater than 0.371, P < 0.01), but did not do significantly with 1,4-NPQ-Alb. CONCLUSION: Plasma level of 1,2-NPQ-Alb could effectively reflect their magnitude of personal internal dose of exposure to air PAH, so it could be used as a potential biomarker to evaluate their intermediate/long-term exposure to PAH in coke oven workers.

Air Pollutants, Occupational↗

[Analysis of serum glutathione S-transferase and urinary 8-hydroxy-2-deoxyguanosine in coke oven workers].

OBJECTIVE: To investigate the application of serum glutathione S-transferase (GST) and urinary 8-hydroxy-2-deoxyguanosine (8-OHdG) as the monitoring biomarkers for coke oven workers exposed to polycyclic aromatic hydrocarbons (PAHs). METHODS: 47 male coke oven workers and 31 male control workers were investigated. Urinary 8-OHdG and serum GST were analyzed using high performance liquid chromatography (HPLC) with electrochemical detection and test kit. Urinary 1-hydroxypyrene (1-OHP) as internal exposure of PAHs was also determined simultaneously by alkaline hydrolysis and HPLC. RESULTS: The values of urinary 1-OHP, serum GST and urinary 8-OHdG were reported as median with interquartile range (P(25)-P(75)). Urinary 1-OHP [5.7 (1.4-12.0) micromol/mol Cr], serum GST [22.1 (14.9-31.2) U/ml], and urinary 8-OHdG [1.9 (1.4-15.4) micromol/mol Cr] in coke oven workers were significantly higher than in control workers [3.0 (0.5-6.4) micromol/mol Cr (P < 0.05), 13.1 (9.5-16.7) U/ml (P < 0.01), and 1.3 (1.0-4.0) micromol/mol Cr (P < 0.05) respectively]. Categorizing by smoking status, significant differences in urinary 1-OHP and serum GST were found only in smokers among coke oven workers compared to control workers (P < 0.01), and 8-OHdG levels only in non-smokers (P < 0.01). Additionally, there was significant correlation between urinary 1-OHP and serum GST activity (r(s) = 0.31, P < 0.01, n = 78). The multiple logistic regression analysis showed that coke oven workers were at the higher risk of having GST activities above 16.7 U/ml (OR = 13.2) and 8-OHdG levels above 1.8 micromol/mol creatinine (OR = 4.4). High body mass index was an independent factor to affect urinary 8-OHdG levels. CONCLUSIONS: The elevated serum GST activities and increased oxidative DNA damage were found in the coke oven workers. Occupational exposure and smoking interact on each other. Serum GST may be used as a biomarker for assessing the exposure of PAHs. Assay of urinary 8-OHdG may be useful for evaluating the risk of lung cancer in coke oven workers.

8-Hydroxy-2'-Deoxyguanosine↗

[Effect of new technologies in the coke industry on aromatic polycyclic hydrocarbon concentrations in the ambient air].

Concentractions of aerosols, amount of polycyclic hydrocarbons, in terms of soluble in benzene fraction and benzo(a)pyrene concentration were determined in coking plant air. Air was sampled on the roofs of modern coke batteries and on old-type batteries prior to, and following, modernization and major reapir. Aerosols were determined by passing 10--100 m3 of air through a 26 X 18.5 cm filter. After a weight determination of aerosol content the filter was subjected to benzene extraction and aromatic polycyclic hydrocarbons were isolated from the extract, using thin-layer chromatography. Quantitative determination of these hydrocarbons was done using ultraviolet spectrophotometry. Results of determinations on work-posts in modern and old-type coke batteries prior to, and following, modernization were comapred. Average concentrations of aerosols in the air, amounts of polycyclic hydrocarbons soluble in benzene and concentration of benzo(a)pyrene determined on the roofs of old coke batteries before modernization were as follows: 11.26 mg/m3, 6.37 ug/m3 and 112.28 mg/m3, and after modernization: 0.88 mg/m3, 0.25 mg/m3 and 1.29 ug/m3, respectively. On the roofs of modern high chamber coke batteries average concentrations of aerosols, polycyclic hydrocarbons--benzo(a)pyrene amounts were: 4.21 mg/m3, 0.79 mg/m3 and 5.72 ug/m3, respectively. The results clearly demonstrate that work conditions in modernized coking plants are much better than those in old non-modernized coking plants.

Air Pollutants↗

GSTM1 null genotype as a risk factor for anti-BPDE-DNA adduct formation in mononuclear white blood cells of coke-oven workers.

The influence of the genetic deletion polymorphism of glutathione S-transferase micro 1 (GSTM1 *0/*0) on levels of anti (+/-)-r-7,t-8-dihydroxy-t-9,10-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene (anti-BPDE-DNA) adduct in the peripheral blood lymphocyte plus monocyte fraction (LMF) of coke-oven workers was investigated. A total of 95 male Polish coke-oven workers (60% current smokers) from two different plants comprised the sample population. Polycyclic aromatic hydrocarbons (PAH) exposure was assessed by means of the individual post-shift urinary excretion of 1-pyrenol (mean +/- S.D.: 6.93 +/- 7.20 micromol/mol creatinine; 70% of the subjects exceeded the proposed biological exposure index (BEI) 2.28 micromol/mol creatinine). Anti-BPDE-DNA adduct levels were detected by high performance liquid chromatography (HPLC)/fluorescence analysis of the anti-BPDE tetrol I-1 released after acid hydrolysis of DNA samples. Genotypes were determined by polymerase chain reaction (PCR) on the genomic DNA of each subject. Coke-oven workers without active GSTM1 (GSTM1 *0/*0, 33%) had significantly higher adduct levels than those with active GSTM1 (GSTM1*1/*1 and *1/*0) (5.90 +/- 5.59 versus 3.25 +/- 2.01 adducts/10(8) bases, Mann-Whitney U-test, z = 2.53, P = 0.011), PAH exposure in the two subgroups being similar (7.06 +/- 6.83 versus 6.67 +/- 8.00 1-pyrenol micromol/mol creatinine). The highest number of GSTM1 null subjects (12/23, 39%) belonged to the quartile with the highest adduct levels (i.e., >4.67 adducts/10(8) nucleotides). That is, coke-oven workers with GSTM1 *0/*0 genotype had a significantly higher risk of having high adduct levels than individuals with active GSTM1 genotype (Fisher exact test P = 0.0355; odds ratio (OR) = 4.145, 95% CI 1.0-18.8). Multiple linear regression analysis showed that the increase in anti-BPDE-DNA adduct levels in LMF was significantly related to the high occupational exposure to PAHs (benzo[a]pyrene (BaP)) of coke-oven workers (t = 3.087, P < 0.01) and to the lack of GSTM1 activity (t = 3.512, P < 0.001), rather than to the two other confounding factors of PAH intake, i.e. charcoal-broiled meat consumption and smoking habits. In conclusion, our results indicate the clear influence of the GSTM1 detoxifying genotype on anti-BPDE-DNA adduct formation in the LMF of coke-oven workers. This is invaluable for future environmental-occupational studies using this biomarker of PAH exposure.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

Spatial distribution of coke residues in porous catalyst pellets analyzed by field-cycling relaxometry and parameter imaging.

The distribution of coke residues inside porous catalyst pellets was investigated on the molecular as well as the macroscopic scale. The presence of coke on the pore surface affects the relaxation properties of adsorbed liquid species; these were determined by field-cycling relaxometry for different polar and nonpolar liquids in metal-doped and metal-free catalyst carrier materials. The presence of metal in the Al2O3 matrix had only a minor influence on the dispersion behavior, while the interaction of the adsorbates with the coke layer leads to considerable changes in the relaxation times at low Larmor frequencies. Lowering the temperature to well below the bulk freezing point of dimethyl sulfoxide resulted in a slightly stronger frequency dependence of T1. Not only relaxation times but also the diffusion coefficient is affected by the presence of coke residues in the pores. For macroscopically heterogeneous samples, they offer the possibility to generate maps of the local coke concentration by introducing appropriate filters into NMR imaging sequences. High-temperature regeneration of coked catalysts leads to such heterogeneous distributions which is visualized by T1 parameter imaging.

Adsorption↗

Exposure of coke-oven workers to polycyclic aromatic hydrocarbons based on biological monitoring results.

This study assessed the exposure of coke-oven workers to polycyclic aromatic hydrocarbons (PAH) based on two methods of biological monitoring (urinary mutagenicity by Ames test and urinary 1-hydroxypyrene) and concentrations of benzo(a)pyrene in the air collected by personal sampling. The coke-oven workers were classified into four job categories. There was no significant correlation among three methods applied. According to all methods, the workers most exposed to PAH were those working at the topside area of the coke plant, Coke-oven workers excreted significantly more mutagenic substances and 1-hydroxypyrene (HpU) in urine than the controls. Mutagenic substances in urine of coke-oven workers and the control group were detected only with TA98 after metabolic activation. Median HpU levels of coke-oven workers classified into three job categories (A, B, C) exceeded the biological exposure limit. The effect of smoking on urinary mutagenicity and urinary 1-hydroxypyrene was statistically significant.

Air Pollutants, Occupational↗

Mortality of coke plant workers in The Netherlands.

During the production of coke, large quantities of coke oven gas are emitted. People who work on the top or on the sides of coke ovens are exposed to this oven gas, which contains a range of carcinogenic chemicals. To investigate the cancer risks under these work conditions, a retrospective study was undertaken. In total 11,399 former workers were enrolled in the study. Of these, 5639 had worked in the coke plant for at least six months between 1945 and 1969. The other 5740 had worked in another plant during the same period and formed a non-exposed group for comparison. The study group was followed up until 1984 for mortality. The causes of death were obtained from the Central Bureau of Statistics. Among the coke oven workers significantly higher death rates were found for lung cancer and non-malignant respiratory disease. Mortality in the byproduct section was similar to that expected. Among workers in the tar distillery the rate for lung cancer was higher than expected. The risk for gastric cancer and non-malignant respiratory disease among the workers of the coke shipping department was increased but the SMRs did not reach statistical significance. No data were collected about individual smoking habits or socioeconomic state of the study subjects and the possibility that the risk found could be attributed to these factors cannot be ruled out. It has been stated by other investigators, however, that the effect of not controlling for smoking tends to be modest.

Coke↗

Cross sectional study on lung function of coke oven workers: a lung function surveillance system from 1978 to 1990.

AIMS: To determine the association between lung function of coke oven workers and exposure to coke oven emissions. METHODS: Lung function data and detailed work histories for workers in recovery coke ovens of a steelworks were extracted from a lung function surveillance system. Multiple regressions were employed to determine significant predictors for lung function indices. The first sets of lung function tests for 613 new starters were pooled to assess the selection bias. The last sets of lung function tests for 834 subjects with one or more year of coke oven history were pooled to assess determinants of lung function. RESULTS: Selection bias associated with the recruitment process was not observed among the exposure groups. For subjects with a history of one or more years of coke oven work, each year of working in the most exposed "operation" position was associated with reductions in FEV(1) of around 9 ml (p = 0.006, 95% CI: 3 ml to 16 ml) and in FVC of around 12 ml (p = 0.002, 95% CI: 4 ml to 19 ml). Negative effects of smoking on lung function were also observed. CONCLUSIONS: Exposure to coke oven emissions was found to be associated with lower FEV(1) and FVC. Effects of work exposure on lung function are similar to those found in other studies.

Adolescent↗

Proximity to coke works and hospital admissions for respiratory and cardiovascular disease in England and Wales.

BACKGROUND: The incidence of hospital admissions for respiratory and cardiovascular diseases in areas close to operating coke works in England and Wales was investigated. METHODS: A small area study using distance from source as a proxy for exposure was undertaken in subjects aged 65 or over and children under 5 years within 7.5 km of four coke works (1991 estimated populations 87 760 and 43 932, respectively). The main outcome measures were emergency hospital admissions in 1992/3-1994/5 with a primary diagnosis of coronary heart disease (ICD 410-414), stroke (ICD 431-438), all respiratory diseases (ICD 460-519), chronic obstructive pulmonary disease (ICD 491-492), and asthma (ICD 493) in those aged 65 or over, and all respiratory and asthma admissions in children under 5 years of age. RESULTS: At age 65 or over the combined estimate of relative risk with proximity to coke works (per km) ranged from 0.99 (95% CI 0.90 to 1.09) for chronic obstructive pulmonary disease to 1.03 (95% CI 0.94 to 1.13) for asthma. For children under 5 years the combined estimate of risk was 1.08 (95% CI 0.98 to 1.20) for all respiratory disease and 1.07 (95% CI 0.98 to 1.18) for asthma. There was evidence of significant heterogeneity in risk estimates between coke work groups, especially in children under 5 years (p<0.001 and p=0.004 for respiratory disease and asthma, respectively). For the Teesside coke works in North East England the relative risk with proximity (per km) was 1.09 (95% CI 1.06 to 1.12) for respiratory disease and 1.09 (95% CI 1.04 to 1.15) for asthma. CONCLUSIONS: No evidence overall was found for an association between hospital admissions and living near operational coke works in England and Wales. Trends of a higher risk of hospital admission for respiratory disease and asthma among children with proximity to the Teesside plant require further investigation.

Aged↗

[A study on the relationship between lymphocyte micronucleus rates and blood plasma benzo(a)pyrene levels in coking workers].

OBJECTIVE: To study the relationship between lymphocyte micronucleus rates and blood plasma levels of benzo(a)pyrene [B(a)P] in coking workers. METHODS: One hundred coking workers and 100 unexposed workers were selected, and their lymphocyte micronucleus rates and plasma levels, as well as workplace air concentrations, of B(a)P were determined. RESULTS: It showed that there was significant difference in plasma B(a)P level between coking workers and unexposed workers, and it correlated with air concentration of B(a)P in the workplace. Positive rates of micronucleus and rates of micronucleus lymphocyte were 60% and 1.79per thousand in coking workers and 29% and 1.10per thousand in controls, respectively, with very significantly statistical difference. It also showed that positive micronucleus rate correlated with plasma level of B(a)P in dose-effect pattern. Multivariate analysis showed that factors contributing to positive micronucleus rate ranked in such an order: plasma level of B(a)P, economic status, regularity of their lifestyle and smoking status of the coking workers. CONCLUSION: Accumulation of B(a)P in blood plasma played a major role in the formation of lymphocyte micronucleus. Results of micronucleus test in coking workers could reflect preliminary damage to their health caused by it.

Adult↗