Occupational exposure to trichloroethylene (TRI) was studied by analysis of environmental air and urine from 49 workers operating in a special printing house on glass. For the measurement of environmental concentration of TRI (Cenv), the ambient air was sampled using personal passive dosimeters. The activated charcoal was desorbed with carbon disulfide and injected into a gascromatograph-mass spectrometer (GC-MSD). The biological monitoring of exposed workers was conducted by determining the concentration of TRI in urine (Curine). Urine concentration of TRI was determined by headspace analysis using GC-MSD. Significant correlation was found between the environmental TRI concentration and urinary TRI concentration. The use of a regression equation between Curine (μg/l) and Cenv (mg/m3) (Curine = 0.081 × Cenv + 4.27) resulted in a value of Curine corresponding to Threshold Limit Value-Time Weighted Average (TLV-TWA) exposure value (269 mg/m3) of 26.0 μg/L.
Toluene is an ototoxic organic solvent widely used in industry and could be a cause of sleep apnea. Acute toluene administration in rats induces an increase in the number of neural cells immunostained for mu-opioid receptors in several brainstem nuclei, such as the inferior colliculus, dorsal and lateral periaqueductal gray and dorsal raphe, without changes in the superior colliculus and the interpeduncular and lateral reticular nuclei. These data suggest that mu-opioid receptors could be involved in toluene-induced neurotoxic effects on the physiological regulation of breathing during sleep, and auditive function.
Mancozeb, a fungicide of ethylenebisdithiocarbamate group was orally administered at doses of 500, 600, 700 and 800 mg/kg body weight/day to normal virgin rats of Wistar strain for 30 days. The vaginal smear and body weight of the rats were recorded daily and rats were sacrificed on 31st day. Estrous cycle was effected by showing a significant decrease in the number of estrous cycle, duration of proestrus, estrus and metestrus with concomitant significant increase in the duration of diestrus in all the mancozeb treated groups when compared with controls. There were a significant decrease in the number of healthy follicles and a significant increase in the number of atretic follicles in all the mancozeb treated groups when compared with controls. The histologic observation of the ovary revealed the presence of less number of corpora lutea and the size of the ovary was also reduced in high doses of mancozeb treated rats. There was a significant increase in the thyroid weight in all the mancozeb treated rats except in 500 mg/kg/d. In rats treated with 500 mg/kg/d showed a significant increase in the level of total lipids in the liver. In rats treated with 600 mg/kg/d mancozeb showed a significant decrease in the levels of glycogen and total lipids in the uterus and total lipids in the liver. In rats treated with 700 mg/kg/d showed a significant decrease in the levels of protein in ovary, glycogen, total lipids, phospholipids and neutral lipids in the uterus and a significant increase in the levels of phospholipids, neutral lipids in the ovary and total lipids, phospholipids and neutral lipids in the liver. In rats treated with 800 mg/kg/d showed a significant decrease in the levels of protein and glycogen in the ovary and protein, glycogen, total lipids, phospholipids and neutral lipids in the uterus and a significant increase in the levels of total lipids, phospholipids and neutral lipids in the ovary and liver when compared with controls. These observed effect of mancozeb on the estrous cycle, follicles and biochemical constituents may be due to imbalance in the hormone or toxic effect.
It was concluded that there was sufficient evidence about a possible link between long working hours particularly exceeding 50 a week and the risk of significant health outcomes, including cardiovascular disease from literature review by Spurgeon et al.. This study was conducted to find out the single effect of regular overtime work on the cardiovascular functions through objective biological indices such as blood pressure or heart rate variability. We conducted a field survey of 238 male engineers who were working at the department of research & development of three electronics manufacturing companies in S. Korea. The field survey consisted of (1) self-report questionnaire (working hours and health conditions, and fatigue) and (2) measurements of blood pressure and heart rate variability. By multivariate analyses we could show the relationship between overtime work and some cardiovascular functions after controlling the effects of major confounders such as age and sleeping hours, which were pointed out by Iwasaki et al. (1998) and Sasaki et al. (1999). Especially, low frequency component (power in the low frequency range, 0.04-0.15 Hz) of the heart rate variability during work might be used as early objective biological indices for chronic effect of regular overtime work on cardiovascular functions. However, we should confirm those effect through the well-designed prospective study.
Presuming that overtime work may associate with chronic fatigue and then decrease cardiovascular function, this report was prepared to find out the definite positive relationship between long working hours and subjective fatigue complaints. We analysed the data of a field survey of 238 men who were working at the department of research & development of three electronics manufacturing companies in S. Korea. The field survey consisted of self-report questionnaires on the working hours, health conditions, and fatigue. For data analysis, the subjects were divided into 3 groups on the criteria of 60 and 70 working hours per week: less longer (LLWH), longer (LWH), and more longer (MLWH) working hour groups. We compared the age-adjusted mean % scores of fatigue complaints among LLWH, LWH, and MLWH. The rate of complaints of subjective fatigue before going to work for LWH and MLWH tended to be significantly higher than those for LLWH. Hence, we conclude that the questionnaire on the subjective fatigue complaints is a good screening tool for early detection of cumulative fatigue due to chronic job stress such as long working hours.
Recently, ISO has defined the guidelines for the evaluation of the measurement and exposure limits of hand-transmitted vibrations at the handle of hand-held portable power tools. In a measurement of vibrations at pneumatic impact wrenches that tighten and remove screws. ISO 8862-7 standard: 19971) and ISO 5349 standard: 19862) are set as international standards. In order to make an exact measurement of the quantities of vibrations exposed to the hand-arm system of a human body, ISO 8662-7 gives specifications to a measurement device and a loading device. As to a measurement device, for instance, the mass, installation method etc. of transducers and mechanical filters are defined. In addition, it specifies with each tolerance the working conditions of a pneumatic tool, the number of revolutions of socket in a loading device, the feed force, the number of subjects, and such an evaluation method as how to decide a declaration value of vibrations. These specifications give toolmakers a comparative measurement of vibration values of their tools before shipment. Meanwhile, although the measurement condition described in ISO8662-7: 1997 is that skilled operators conduct vibration measurement, no provisions as to operators are made in detail. Hence, this study focuses its concern on ambiguous work experience years in measuring vibrations of the tools in conformity with ISO 8662-7, and hereby the effect of years of work experience upon measurement values is considered and at the same time a knowledge of how to select operators is made clear.
Isocyanates are very useful chemicals, and these are important for our daily life. Various products, especially urethane resin, are made from these chemicals. There is no substitute for isocyanates at the present. Isocyanates are patent agents to provoke immunological responses. This article deals with the case reports of hypersensitivity pneumonitis (HP) induced by isocyanates in Japan. It is said that HP is one of the rare diseases induced by isocyanate with very low frequency so far in the world. Certainly there are rare cases of isocyanate-HP also in Japan, but these are the cases only in large enterprises that pay attention to their working places. In Japan, there are several cases of isocyanate-induced HP, which happened in minor enterprises such as those with less than 50 workers. In clinical appearance, there are few conflicts with Western studies. The best choice for sensitized people is isolation from working places. It is important for the workers to understand the diseases. In these days, several tests for diagnosis are developed. It is indispensable to put these tests for prevention of these diseases and improvement of their working places.
To assess high-level low frequency noise in the working environment, adverse extra-aural effects caused by the noise should be taken into account. The human body vibration induced by low frequency noise, 'noise-induced vibration', was measured on the body surface and the equalacceleration level contours of the vibration were tentatively estimated. With these contours, we can predict the magnitude of noise-induced vibration at every measuring position on the body surface. This is helpful in relating the total dosage of low frequency noise with the physical symptoms caused by the noise. But some important points in the contours remain to be investigated and improved. When these points are dealt with, the equal-acceleration level contours will be useful for assessing high-level low frequency noise in the working environment from the standpoint of predicting the adverse extra-aural effects.