A cross-sectional study concerning working conditions and the fatigue complaints of assembly line workers employed in two different electronic factories (A and B) in Vietnam was conducted from August to September 1994. While general working conditions, such as noise, dust, heat and lighting, were worse in Factory B, the prevalence rate of the subjective fatigue after working time was significantly higher among workers in Factory A. Fatigue symptoms in category I (Drowsiness and dullness) were particularly apparent among workers in Factory A. More interestingly, one-third of workers in Factory A complained of stiff shoulders and low back pain. Our field observation results suggest that the ergonomic inappropriateness of the assembly line in Factory A, may be causing a high rate of subjective fatigue among workers.
The purpose of this study was to evaluate the health hazards of firefighters after fighting a department store fire which lasted for 40 hours. Respiratory symptoms of 168 firefighters were collected and the pulmonary functions of 149 firefighters were measured by spirometer two days after fighting the fire and compared to 32 controls. The principal symptoms manifested by firefighters were burning eyes and mucous membrane irritation. Cross-sectional study of the pulmonary functions showed that FEV1.0, FEV1.0/FVC and the flow rates (MMF, FEF25%, and FEF75%) in smoking exposed firefighters were significantly lower than those in smoking controls. However, only FEV1.0 (%) was significantly lower in nonsmoking exposed firefighters than in nonsmoking controls. Both FVC and FEV1.0 showed a declining trend with the duration of fire fighting. This study provides further evidence that firefighters are exposed to irritants during fighting a fire. Exposure to the combustion products could lead to pulmonary function defects, especially in smoking firefighters.
A direct on-filter method in infrared spectrophotometry was investigated for the quantitative analysis of respirable cristobalite. A polypropylene membrane filter was employed for this analysis, because the membrane filter has high transparency and no interference peak in the spectral range to be used (750-250cm-1). Linear relation between the sample weight and peak height (absorbance) for three specific peaks at 620, 385 and 300cm-1 of cristobalite were confirmed over the range from 45 to 1, 000μg/cm2 for 620 cm-1 peak and 45-2, 380μg/cm2 for 385 and 300cm-1 peaks. The variation of absorbance with the difference of particle size was smaller in filter sample than in potassium bromide pellet sample. As a conclusion, this direct on-filter method can be used for quantitative analysis of cristobalite in airborne dust in working environment.
An intervention study has been conducted in chrysotile asbestos milling processes with an interval of one year. The ‘Membrane Filter Method’ adopted in the former study for fiber concentration estimation has been followed in the present study, to estimate the environmental samples under the same experimental conditions. Though very high fiber levels compared to the prescribed permissible limit in India, have also been obtained in this study, a general reduction trend in the values of mills common to the both studies are observed. A further suitable control measure has been recommended in the paper to reduce fiber levels in the milling processes.
A modest assessment of noise was made in Calcutta Metro, India's first ever underground tube rail system, to examine if the range of noise levels present could endanger the hearing sensitivity of workers for the Metro. Sound measuring instruments of a sound level meter, an octave band analyzer, and a sound level calibrator were used for measuring the sound pressure levels in platforms of three stations: Esplanade, Kalighat and Tollygunge. The results indicated that the averaged A-weighted SPLs in these stations were in the range of 84-87dBA. In the coaches of the moving train the Leq values ranged 92-99dBA and LNP 105-117dBA, all exceeding the safe limit of day time noise exposure of 55dBA5) and 85dBA of ACGIH4). The SPLs at 4, 000Hz in the coaches were also in excess of safe exposure limit of 79dB6). The findings thus posed a potential threat to the workers.
The time of onset and magnitude of cold-induced vasodilatation (CIVD) in six older men (62-70 years) were compared with those of seven younger men (20-29 years) by using a modified local cold tolerance test. This test consisted of a 10-min immersion of the left middle finger in cold water at 10°C, and was substituted for a conventional test (30-min immersion in ice water at 0°C). Vasodilatation occurred significantly later in the older group, and the magnitude of their response was significantly lower during the immersion. No vasodilatation occurred in two of the older men. As the finger skin temperature before the test was not significantly different between the two age groups, the difference of CIVD response in the two age groups was thought to reflect the age-related changes of peripheral vascular reactivity to a local cold stimulus. Considering the fact that no subjects complained a great deal of cold pain during the immersion, our modified local cold tolerance test seems to be a useful method for detecting the age-related degradation of local cold tolerance and peripheral vascular reactivity in older workers.
To obtain a reference value for delta-aminolevulinic acid in plasma (ALA-P), we determined ALA-P levels in 141 subjects (105 males and 36 females) without occupational exposure to lead. The distribution of ALA-P levels in males can be regarded to follow log-normal distribution and the geometric mean was 8.7μg/l with 95% confidence interval of 6.0-12.5μg/l. These data would be useful as a baseline for evaluating the relationship between ALA and its biological effects.