Asbestos Exposure among Mitering Workers

The objectives are to compare the airborne asbestos concentrations resulted from mitering of abestos cement roof sheets by a high-speed motor and a hand saw, and to monitor whether other workers near the test sites are vulnerable to the fibers exceeding the occupational exposure limit. Four test cases were carried out and altogether 7 personal and 4 area air samples were collected. The NIOSH method 7400 was employed for the air samplings and analysis. Using the phase contrast microscopy, fiber counting was conducted under Rule A. The study showed that the fiber concentration medians for personal air samples gathered from the two tools were 4.11 fibers/cc (ranged: 1.33-12.41 fibers/cc) and 0.13 fibers/cc (ranged: 0.01-5.00 fibers/cc) respectively. The median for the area samples was 0.59 fibers/cc (ranged: 0.14-3.32 fibers/cc). Comparing each study case, the concentration level caused by the high-speed motor saw was more than twice that of the hand saw. According to the area samples, the workers nearby the test site are at risk from high exposure to asbestos.

Evaluation of MTBE Exposure, Knowledge and Practice about Methyl Tertiary - Butyl Ether among Traffic Policemen in Bangkok

The aim of this study was to assess the levels of exposure to methyl tertiary-butyl ether (MTBE) in traffic policemen in Bangkok metropolitan area by using personal air sampling, biological monitoring (blood and urine) including questionnaire about knowledge. The subjects of this study consisted of 61 traffic policemen and 24 office workers as controls. The MTBE in airborne was measured throughout the work with a diffusion passive monitor attached on the breathing zone of each subject. The urine and the blood samples were taken after the work. The MTBE in airborne was analyzed by gas chromatography equipped with FID and the biological (blood and urine) samples were done by one with headspace. The geometric mean of MTBE in airborne was 33.0 ppb among the traffic policemen and significantly higher than one among the controls (21.1 ppb). In addition, this study showed that the traffic policemen had significantly higher concentrations of MTBE in blood than the controls. The subjects had little knowledge about the hazard of exposure to MTBE. From these results, we can emphasize that traffic policemen are exposed to MTBE and they should get occupational health education and use suitable personal protective equipment.