Urinary 1-hydroxypyrene levels in workers exposed to polycyclic aromatic hydrocarbon from rubber wood burning.

BACKGROUND: Urinary 1-hydroxypyrene (1-OHP) was selected as a biomarker of polycyclic aromatic hydrocarbons (PAHs) to explore the accumulation level in the bodies of workers at rubber smoke sheet factories in southern Thailand. METHODS: Spot urine samples were taken from four groups of workers from June 2006 to November 2007. The nonexposure or control groups included habitual cigarette smokers and nonsmokers. The other two groups were workers exposed to particle-bound PAHs from rubber wood smoke and they were nonsmokers. All spot urine samples were analyzed for 1-OHP and creatinine levels. RESULTS: The mean ± standard deviation urinary 1-OHP in the control group of habitual smokers and the nonsmokers was 0.24 ± 0.16 µmol/mol creatinine and not-detected to 0.14 µmol/mol creatinine, respectively. In the workers, the 1-OHP levels on workdays had no significant difference from the 1-OHP levels on the days off. The yearly average 1-OHP level was 0.76 ± 0.41 µmol/mol creatinine whereas the average 1-OHP level during 10 consecutive workdays was 1.06 ± 0.29 µmol/mol creatinine (p > 0.05). CONCLUSION: The urinary 1-OHP levels of workers exposed to PAHs were high. The accumulation of 1-OHP in the body was not clear although the workers had long working hours with few days off during their working experience. Therefore, a regular day off schedule and rotation shift work during high productive RSS should be set for RSS workers.

Noise exposure assessment in a dental school.

OBJECTIVES: This cross-sectional study was performed in the Dental School of Prince of Songkla University to ascertain noise exposure of dentists, dental assistants, and laboratory technicians. A noise spectral analysis was taken to illustrate the spectra of dental devices. METHODS: A noise evaluation was performed to measure the noise level at dental clinics and one dental laboratory from May to December 2010. Noise spectral data of dental devices were taken during dental practices at the dental services clinic and at the dental laboratory. A noise dosimeter was set following the Occupational Safety and Health Administration criteria and then attached to the subjects' collar to record personal noise dose exposure during working periods. RESULTS: The peaks of the noise spectrum of dental instruments were at 1,000, 4,000, and 8,000 Hz which depended on the type of instrument. The differences in working areas and job positions had an influence on the level of noise exposure (p < 0.01). Noise measurement in the personal hearing zone found that the laboratory technicians were exposed to the highest impulsive noise levels (137.1 dBC). The dentists and dental assistants who worked at a pedodontic clinic had the highest percent noise dose (4.60 ± 3.59%). In the working areas, the 8-hour time-weighted average of noise levels ranged between 49.7-58.1 dBA while the noisiest working area was the dental laboratory. CONCLUSION: Dental personnel are exposed to noise intensities lower than occupational exposure limits. Therefore, these dental personnel may not experience a noise-induced hearing loss.

Biomonitoring of heavy metals among nielloware workers in Nakhon Sri Thammarat Province.

OBJECTIVE: To determine lead and mercury concentrations in biological samples from nielloware workers, to describe the association between occupational lifestyle, workposition, work environment, behavioral factors, acute and chronic neurological symptoms, and levels of metals in biological samples. MATERIAL AND METHOD: A cross-sectional study was conducted by interviewing 45 nielloware workers and 45 matched nonexposed persons living in the municipality of Nakhon Si Thammarat Province, Thailand. Blood and urine samples were collected to determine lead and mercury concentrations by atomic absorption spectrophotometer. RESULTS: The blood lead levels (7.30 microg/dl) and urinary mercury levels (3.30 microg/g creatinine) of the nielloware workers were significantly higher than the control group (p < 0.001). Income, working environmental conditions, workposition, duration of work, personal protective equipment (PPE) and personal hygiene, had significant associations with blood lead and urinary mercury levels (p < 0.05). A significant positive correlation was found between income and blood-lead level (r = 0.968, p < 0.001) and urinary-mercury level (r = 0.661, p = 0.004). The nielloware workers developed acute and chronic symptoms, such as headaches, rash, fatigue, tightness in the chest, loss of consciousness, abnormal tiredness and headache at least once a week and those who developed symptoms had significantly higher heavy metal levels than those who did not at p < 0.05. CONCLUSION: The blood lead and urinary mercury levels in nielloware workers were significantly higher than those in the control subjects. The significant associations were found between income, work position, PPE and personal hygiene and blood lead and urinary mercury levels.

Elevated lead contamination in boat-caulkers' homes in southern Thailand.

Surface-wipe lead loading was measured at various locations in the homes of 31 boat-caulkers and 31 location-matched controls to identify factors associated with household lead contamination. Data were obtained by observation checklist and questionnaire. Lead loading was significantly higher in caulkers' than in control households. Median lead loadings (in microg/ft2) of various locations in caulkers' homes were windowsill, 43.9; exterior entrance, 9.5; interior entrance, 21.1; living room floor, 9.8; and bedroom floors 15.6. Corresponding levels in control homes were all less than 0.2 microg/ft2. Regression modeling indicated that lead loading was higher in caulkers' homes that were closer to a boat-yard, in which the caulker had a longer duration of boatyard work, and in which there were no children aged under 6 years resident. Exterior and interior entrance and living room floors had lower lead loading than windowsills. However, bedroom floors had significantly higher lead loading, similar to windowsills.

Construct validity of the Thai version of the job content questionnaire in a large population of heterogeneous occupations.

OBJECTIVE: To test the construct validity of the Thai version of the job content questionnaire (TJCQ). MATERIAL AND METHOD: The present descriptive study recruited 10415 participants from all occupations according to the International Standard Classification of Occupations. The instrument consisted of a 48-item of the job content questionnaire. Eight items newly developed by the authors from in-depth interviews were added. RESULTS: Exploratory factor analysis showed six factor models of work hazards, decision latitude, psychological demand, social support, physical demand, and job security. However, supervisor and co-worker support were not distinguished into two factors and some items distributed differently along the factors extracted. Confirmatory factor analysis supported the construct of six latent factors, although the overall fit was moderately acceptable. Cronbach's alpha coefficients higher than 0.7, supported the internal consistency of TJCQ scales except for job security (0.55). CONCLUSION: These findings suggest that TJCQ is valid and reliable for assessing job stress among Thai populations.

Psychometric properties of the Thai version of the 22-item and 45-item Karasek job content questionnaire.

OBJECTIVES: To evaluate the validity and reliability of the Thai version of the job content questionnaire (TJCQ) both 22-item and 45-item versions. MATERIALS AND METHODS: The study encompassed 10,450 employees in Songkhla province, Thailand. A 45-item job content questionnaire (JCQ) was translated and back translated complying with the JCQ usage policy. TJCQ covers seven scales as follows: psychological demand, decision latitude, supervisor support, coworker support, physical demand, job security and hazard at work. Internal consistency was examined using Cronbach's alpha coefficient. Factor validation was tested using both exploratory and confirmatory factor analysis. RESULTS: Both 22-item and 45-item versions of TJCQ demonstrated acceptable internal consistency in nearly all scales except for psychological demand. The exploratory and confirmatory factor analysis result gave support to 5-factor model in 22-item version and 8-factor model in 45-item version of TJCQ. The psychological demand scale tended to split into two subscales. Other scales were consistent with the expected dimensions though some items extracted differently along the theoretical dimensions. CONCLUSIONS: Our study provided evidence for the reliability and validity of the TJCQ among Thai employees and supported the ongoing debate on multifaceted psychological demand and its complexity, making it feasible to extend the TJCQ beyond its original structure.

Exposure to lead of boatyard workers in southern Thailand.

Lead oxide is used extensively in the construction and repair of wooden boats in Thailand, but the behaviors of boatyard workers that could place them at risk of contamination have not previously been documented. Baseline data on practices and behaviors of boatyard workers and on the level of worker and workplace contamination with lead were therefore collected. Fifty workers in two boatyards participated in this study. Lead exposure of workers was assessed by determining airborne and blood lead levels. A questionnaire was administered to collect information on work history, suspected exogenous lead sources, personal behavior and knowledge about lead. Evidence obtained by the study indicated that safety behavior and personal hygiene were poor--workers used no mask, gloves or hood, wore open sandals, smoked, drank, chewed and ate during work and did not wash their hands before drinking or eating. Some workers had lunch in the working area. The mean personal airborne lead of caulkers (36.4 microg/m3) was higher than that of carpenters (8.3 microg/m3). Forty-eight percent of all workers and 67% of caulkers had a blood lead level (BLL) exceeding 40 microg/dl. Multiple linear regression indicated that blood lead levels of workers were significantly related to job and education level, with significant differences between boatyards. In addition, the potential for "take-home" contamination was high; none of the workers took a shower or changed their clothes prior to going home. These results indicate a problem of lead exposure of sufficient magnitude to be a public health concern.

Work-related respiratory symptoms among cotton-fabric sewing workers.

OBJECTIVES: An inspection of the sewing unit in a 700-bed hospital revealed that workers employed in this unit complained of cough, shortness of breath, and tightness in the chest. The aim of this cross-sectional study was to assess the prevalence of respiratory symptoms in the sewing workers and dust concentration in the workplace. The obtained results were compared with the control group. MATERIALS AND METHODS: The sewing workers (n = 22, including 19 current and 3 former employees) and 22 housekeepers as controls were included in the study. All the participants responded to the respiratory questionnaire and underwent spirometric measurements, skin prick test, chest X-ray, and methacholine inhalation test. Environmental dust was measured using both an air pump and a vertical elutriator. RESULTS: The sewing workers reported more symptoms of phlegm, chest tightness and eye irritation than persons of the control group. Neither clinical investigations nor respiratory disorders under study provided evidence for a significant difference between the sewing workers and the control group. Of the 22 subjects, 2 (9.1%) showed occupational asthma and 4 (18.2%) mucous membrane irritation and organic dust toxic symptoms. The total and respiratory dust was within normal limits, but the dust concentration measured by the elutriator was above the limit value of 0.34 +/- 0.09 mg/m. After ventilation improvements, the dust level decreased to 0.19 +/- 0.06 mg/m. CONCLUSIONS: This study indicated that respiratory and ocular disorders were related to organic dust produced during the sewing process of cotton fabric.