Kunio Hara

Urinary bisphenol A and plasma hormone concentrations in male workers exposed to bisphenol A diglycidyl ether and mixed organic solvents

Aims: To evaluate effects of exposure to bisphenol A diglycidyl ether (BADGE) on urinary excretion of bisphenol A, and plasma gonadotrophic hormones and testosterone in male epoxy resin sprayers. Methods: Cross sectional study of 42 workers whose job was to spray epoxy resin hardening agents including BADGE and mixed organic solvents, and 42 matched control workers without BADGE use in the same machine plants. Results: Concentrations of urinary bisphenol A were higher in the epoxy resin sprayers (median 1.06 μmol/mol creatinine) compared with the controls (median 0.52 μmol/mol creatinine). Urinary metabolite concentrations of organic solvents used were all higher in the epoxy resin workers compared with the controls. Endocrinological examination showed different concentrations of follicle stimulating hormone (FSH) between the epoxy sprayers (median 5.3 mIU/ml) and the controls (median 7.6 mIU/ml). FSH showed a mild correlation with urinary bisphenol A, but not with the metabolites of organic solvents. Luteinising hormone and free testosterone concentrations did not differ between the two groups. Conclusion: BADGE may generate bisphenol A endogenously. Results suggest that bisphenol A may disrupt secretion of gonadotrophic hormones in men. The clinical significance of endocrine disrupting effects by bisphenol A should be further investigated in male workers exposed to bisphenol A.

Urinary 1-hydroxypyrene levels of garbage collectors with low-level exposure to polycyclic aromatic hydrocarbons

Because garbage collectors work in the street, they are exposed to polycyclic aromatic hydrocarbons (PAHs) in motor vehicle exhaust gas as they work. Urinary 1-hydroxypyrene (1-OH-pyrene) began to be used as a biological monitoring index for human exposure to high concentrations of PAHs. The objective of this study was to examine the applicability of urinary 1-OH-pyrene as a biological monitoring index for human low-level PAH exposure, such as the PAH exposure experienced while working in the street. The subjects were fifteen male garbage collectors. We measured individual exposure to PAHs, urinary 1-OH-pyrene concentrations and urinary cotinine concentrations. Individual air samplers were attached to the collar of the clothing of five workers to capture PAHs. Urine samples were collected before work, around noon and after finishing the days work. In all, five PAH samples and 45 urine samples were collected. As control data, we analyzed the urinary 1-OH-pyrene and urinary cotinine levels of six smoking and four non-smoking control subjects who were not occupationally exposed to PAHs. The benzo[a]pyrene level in the air sampled for 5-6 h was 2.5-10.5 ng/m3, and the pyrene level as 10.3-70.3 ng/m3. These levels were similar to those in the vicinity of streets in Japan. A positive correlation between total PAH levels and the pyrene levels was observed. The average urinary 1-OH-pyrene level of the smokers was 0.21 +/- 0.13 mumol/mol creatinine, vs. 0.15 +/- 0.11 mumol/mol creatinine in the non-smokers. The urinary 1-OH-pyrene level obtained in this study was slightly higher than in the control group. No correlation was found between pyrene exposure and the urinary 1-OH-pyrene level of the five workers who wore the personal samplers. A significant positive correlation was observed between the urinary 1-OH-pyrene level and urinary cotinine level of the smokers. A significant positive correlation was also observed between the urinary 1-OH-pyrene and urinary cotinine levels of the control group smokers. In conclusion, urinary 1-OH-pyrene is not applicable for biological monitoring of extremely low levels of exposure to PAHs, as in the case of working in the street. Caution is required to exclude the effects of smoking when evaluating PAH exposure.

Cytochrome P450 1B1 mRNA levels in peripheral blood cells and exposure to polycyclic aromatic hydrocarbons in Chinese coke oven workers.

Cytochrome P450 1B1 (CYP1B1) is induced through the Ah receptor and is involved in the activation of polycyclic aromatic hydrocarbons (PAHs). To determine the validity of a quantitative analysis of CYP1B1 mRNA in peripheral human blood cells for the estimation of PAH exposure, a real-time quantitative polymerase chain reaction method was used to measure the relative levels of CYP1B1 mRNA in 37 Chinese coke oven workers and 13 control workers. A large inter-individual difference in the levels was observed. The average level of the CYP1B1 mRNA in workers at the top work site, where the PAH exposure level from the coke ovens was highest, was significantly higher than in workers at the middle site (P<0.01) or the controls (P=0.02). A non-significant positive correlation was found between the CYP1B1 mRNA levels and urinary 1-hydroxypyrene (R=0.22, P=0.13), and a significant correlation between these mRNA levels and urinary cotinine (R=0.33, P=0.02). It was interesting that a significant positive correlation between CYP1B1 mRNA and 1-hydroxypyrene was observed in subjects with the Leu/Leu type of CYP1B1 Leu432Val polymorphism (R=0.33, P=0.02, n=38) and a non-significant correlation in subjects with the Leu/Val and Val/Val types (R=-0.36, P=0.25, n=12), although the number of subjects in this strata analysis was small. Our preliminary study suggests that PAH exposure in coke ovens and smoking maybe associated with CYP1B1 mRNA levels in peripheral blood cells although mRNA is generally unstable and could be expressed following exposure to other agents.

Acute pulmonary injury due to exposure to a high concentration of trichloroethylene vapor.

Department of International Medical Cooperation, Graduate School of Medical Science, Kumamoto University, Division of Pulmonary Medicine, National Hospital Organization, Kumamoto Medical Center, Department of Environmental Medicine, Kurume University School of Medicine, Section of Pathology, Shin-Koga Hospital, Emergency and Critical Care Medical Center, Kurume University Hospital and First Department of Internal Medicine, Kurume University School of Medicine, Japan

Considering the effects of ambient particulate matter on the lung function of motorcycle taxi drivers in Bangkok, Thailand

ABSTRACT The motorcycle taxi drivers of Bangkok have been heavily exposed to high concentrations of PM10 (particulate matter with an aerodynamic diameter ≤10 μm), and the impact of this on their lungs has been neither documented nor studied. This study examines the association between exposure to PM10 and lung function decline among motorcycle taxi drivers. A cross-sectional study was conducted in Bangkok between two groups: a subject group of motorcycle taxi drivers and control group of enclosed vehicle taxi drivers. The findings of the Thailand Pollution Control Department were used to estimate the annual ambient PM10 concentration levels in the metropolis. Pulmonary functions of motorcycle taxi drivers and enclosed vehicle taxi drivers were measured and compared using the Mann-Whitney test. Multiple linear regression analysis was applied to estimate the effects of PM10 exposure on the lung function of motorcycle taxi drivers. A total of 1283 motorcycle taxi drivers and 600 taxi drivers were investigated. The mean forced expiratory volume in 1 sec/forced vital capacity (FEV1/FVC) of the motorcycle taxi drivers was significantly lower than that of the taxi drivers (P < 0.001). The mean FEV1/FVC of motorcycle taxi drivers exposed to ≥50 µg/m3 PM10 was statistically lower (−2.82%; 95% confidence interval [CI]: −4.54% to −1.09%) and the mean % vital capacity (%VC) of those exposed to 40–49.9 µg/m3 PM10 was statistically lower than that of motorcycle taxi drivers exposed to <30 µg/m3 PM10 (−3.33%; 95% CI: −5.79% to −0.87%). Motorcycle taxi drivers were directly exposed to air pollution in their working environment. As a result, their lung function might decrease more than that of enclosed vehicle taxi drivers. With the possible exposure to ≥50 µg/m3 PM10, the vehicular emission standards should be vigorously enforced. Further investigation is warranted to clarify the effect of lung dysfunction on the work and lifestyle of motorcycle taxi drivers. Implications: Motorcycle taxi drivers are directly exposed to air pollution in their work environment; therefore, their lung function might decrease more than that of enclosed vehicle taxi drivers, especially when exposed to ≥50 µg/m3 PM10. World Health Organization (WHO) vehicular emission standards should be recognized and eventually enforced.

Difference in concentration trends of airborne particulate matter during rush hour on weekdays and Sundays in Tokyo, Japan

Suspended particulate matter (SPM) and fine particulate matter (less than or equal to 2.5 μm: PM2.5) have generally been decreasing for the last decade in Tokyo, Japan. To elucidate the major cause of this decrease, the authors investigated the different trends of airborne particulates (both SPM and PM2.5 concentrations) by evaluating comparisons based on the location of the monitoring stations (roadside vs. ambient), days of the week (weekdays vs. Sundays), and daily fluctuation patterns (2002 vs. 2010). Hourly mean SPM and PM2.5 concentrations were obtained at four monitoring stations (two roadside stations, two ambient stations) in Tokyo, Japan. Annual mean concentrations of each day of the week and of each hour of the day from 2002 to 2010 were calculated. The results showed that (1) the daily differences in annual mean concentration decreased only at the two roadside monitoring stations; (2) the high hourly mean concentrations observed on weekdays during the daily rush hour at the two roadside monitoring stations observed in 2002 diminished in 2010; (3) the SPM concentration that decreased the most since 2002 was the PM2.5 concentration; and (4) the fluctuation of hourly concentrations during weekdays at the two roadside monitoring stations decreased. A decreasing trend of airborne particulates during the daily rush hour in Tokyo, Japan, was observed at the roadside monitoring stations on weekdays since 2002. The decreasing PM2.5 concentration resulted in this decreasing trend of airborne particulate concentrations during the daily rush hours on weekdays, which indicates fewer emissions were produced by diesel vehicles. Implications The authors compared the trends of SPM and PM2.5 in Tokyo by location (roadside vs. ambient), days of the week (weekdays vs. Sundays), and daily fluctuation patterns (2002 vs. 2010). The high hourly mean concentrations observed at the roadside location during rush hour on weekdays in 2002 diminished in 2010. The SPM concentration that decreased during rush hour the most was the PM2.5 concentration. This significant decrease in the PM2.5 concentration resulted in the general decreasing trend of SPM concentrations during the rush hours on weekdays, which indicates fewer emissions were produced from diesel vehicles.

Occupational Exposure Limits of lead, dimethylamine, n-butyl-2,3-epoxypropyl ether, and 2-ethyl-1-hexanol and carcinogenicity and occupational sensitizer classification.

The Committee for Recommendation of Occupational Exposure Limits, Japan Society for Occupational Health Kenichi Azuma, Ginji Endo, Yoko Endo, Kunio Hara, Koji Harada, Hajime Hori, Seichi Horie, Hyogo Horiguchi, Masayoshi Ichiba, Gaku Ichihara, Masayuki Ikeda, Tatsuya Ishitake, Akiyoshi Ito, Satoko Iwasawa, Michihiro Kamijima, Kanae Karita, Toshio Kawai, Toshihiro Kawamoto, Akio Koizumi, Shinji Kumagai, Yukinori Kusaka, Muneyuki Miyagawa, Yasuo Morimoto, Kasuke Nagano, Tamie Nasu, Tetsuo Nomiyama, Kazuyuki Omae, Kazuhiro Sato, Hirokazu Okuda, Haruhiko Sakurai, Tomotaka Sobue, Yasushi Suwazono, Toru Takebayashi, Tatsuya Takeshita, Akito Takeuchi, Masatoshi Tanaka, Shigeru Tanaka, Teruomi Tsukahara, Masashi Tsunoda, Susumu Ueno, Yuko Yamano, Takenori Yamauchi and Eiji Yano

Occupational exposure limits for ethylene glycol monobutyl ether, isoprene, isopropyl acetate and propyleneimine, and classifications on carcinogenicity, occupational sensitizer and reproductive toxicant

The Committee for Recommendation of Occupational Exposure Limits, Japan Society for Occupational Health Kenichi Azuma, Ginji Endo, Yoko Endo, Tetsuhito Fukushima, Kunio Hara, Hajime Hori, Seichi Horie, Hyogo Horiguchi, Masayoshi Ichiba, Gaku Ichihara, Masayuki Ikeda, Tatsuya Ishitake, Akiyoshi Ito, Yuki Ito, Satoko Iwasawa, Michihiro Kamijima, Kanae Karita, Takahiko Katoh, Toshio Kawai, Toshihiro Kawamoto, Reiko Kishi, Shinji Kumagai, Yukinori Kusaka, Akiko Matsumoto, Muneyuki Miyagawa, Hiroyuki Miyauchi, Yasuo Morimoto, Kasuke Nagano, Hisao Naito, Tamie Nakajima, Tetsuo Nomiyama, Hirokazu Okuda, Kazuyuki Omae, Haruhiko Sakurai, Kazuhiro Sato, Tomotaka Sobue, Yasushi Suwazono, Toru Takebayashi, Tatsuya Takeshita, Akito Takeuchi, Ayano Takeuchi, Masatoshi Tanaka, Shigeru Tanaka, Teruomi Tsukahara, Masashi Tsunoda, Susumu Ueno, Jun Ueyama, Yumi Umeda, Yuko Yamano, Takenori Yamauchi and Eiji Yano

Occupational dust exposure and prevalence of respiratory symptoms among conduit repair workers

The amount of water supply in Japan was 16 billion ton as of 1989. Water from rivers and other sources is purified, sterilized and then supplied to the residents through conduits. When conduits are accidentally damaged, they must be repaired by the workers of the Waterworks Bureau of the local government. In this task, the workers are exposed to airborne dust which develops while digging and filling the ground and cutting the conduit and the concrete covering the road. The purpose of the present study was to estimate the airborne dust exposure level among the workers and to investigate its effect on their respiratory organs. First, we measured the total dust exposure concentration of 20 conduit repair workers and the total dust concentration in 10 office rooms. Second, we conducted a self-administered questionnaire survey to estimate the prevalence of respiratory symptoms among the employees of 119 Waterworks Bureaus. The subjects of the analysis were 322 conduit repair workers and as their controls 345 clerical/engineering workers. The results can be summarized as follows: 1) The average daily total dust exposure while repairing conduits ranged from 0.27 to 5.05 mg/m3 (mean = 0.91 mg/m3), while that while exchanging water meters from 0.23 to 0.52 mg/m3 (mean 0.41 mg/m3). These values were 4.6 and 2.1 fold higher than the total dust concentration in office rooms (mean = 0.20 mg/m3). 2) With the use of fluorescent X-ray method, iron and aluminum were detected in all samples collected while repairing conduits and the intensity of X-ray increased with increase in weight of collected dust. Iron exposure concentration ranged from 0.006 to 0.095 mg/m3, which is much higher than the levels in the air in urban areas. Iron and aluminum could not be detected by fluorescent X-ray method in most of the samples collected in office rooms. These findings indicate that the main element in the dust collected while repairing conduits is soil, while that in office rooms is tobacco smoke. 3) Among the smokers, the prevalence of cough and phlegm was significantly higher in conduit repair workers than in clerical/engineering workers. A similar tendency was observed among ex-smokers and non-smokers, but the difference was not significant.