The temperature dependence of the emission of perchloroethylene from dry cleaned fabrics

A study was conducted to evaluate the emission of perchloroethylene (tetrachloroethylene) from freshly dry cleaned fabrics using small environmental test chambers. The temperature dependence of the release of perchloroethylene was evaluated over a temperature range of 20 to 45 degrees C. A linear relation exists between the logarithm of perchloroethylene retention time (tau) and the reciprocal of the absolute temperature (1/T). The temperature dependence of the retention time can be expressed as tau = 2.36 x 10(-16)e13,892/T and 8.38 x 10(-9)e8766/T sec for 100% wool and 55% polyester/45% wool fabrics, respectively. These results indicate that "airing out" freshly dry cleaned fabrics at temperatures near 20 degrees C for short time periods (e.g., 5 hr) will not appreciably reduce the total emissions of perchloroethylene.     

Residual tetrachloroethylene in dry-cleaned clothes

A large amount of residual tetrachloroethylene (TCE), up to 13.6 mg/g, was found in dry-cleaned clothes. The amounts varied among dry-cleaning establishments as well as with the type of fiber. The causes of these variations are discussed. Air TCE concentrations in the closed environment of dry-cleaning outlets were elevated: the highest reading was 4.8 mg/m3. The expired air of outlet employees also showed an increased level of TCE (average, 36.9 micrograms/m3). Increased air contamination from TCE released from dry-cleaned clothes was also observed in the home of a consumer. To reduce environmental contamination from TCE released from any of these sources, the amount of residual TCE in dry-cleaned clothes should be minimized.     

Occupational exposures to new dry cleaning solvents: High-flashpoint hydrocarbons and butylal

The dry cleaning industry is moving away from using perchloroethylene. Occupational exposures to two alternative dry cleaning solvents, butylal and high-flashpoint hydrocarbons, have not been well characterized. We evaluated four dry cleaning shops that used these alternative solvents. The shops were staffed by Korean- and Cantonese-speaking owners, and Korean-, Cantonese-, and Spanish-speaking employees. Because most workers had limited English proficiency we used language services in our evaluations. In two shops we collected personal and area air samples for butylal. We also collected air samples for formaldehyde and butanol, potential hydrolysis products of butylal. Because there are no occupational exposure limits for butylal, we assessed employee health risks using control banding tools. In the remaining two shops we collected personal and area air samples for high-flashpoint hydrocarbon solvents.

In all shops the highest personal airborne exposures occurred when workers loaded and unloaded the dry cleaning machines and pressed dry cleaned fabrics. The air concentrations of formaldehyde and butanol in the butylal shops were well below occupational exposure limits. Likewise, the air concentrations of high-flashpoint hydrocarbons were also well below occupational exposure limits. However, we saw potential skin exposures to these chemicals. We provided recommendations on appropriate work practices and the selection and use of personal protective equipment. These recommendations were consistent with those derived using control banding tools for butylal. However, there is insufficient toxicological and health information to determine the safety of butylal in occupational settings. Independent evaluation of the toxicological properties of these alternative dry cleaning solvents, especially butylal, is urgently needed.     

Rapid method of calculating the heat resistance of clothes using programmable microcomputers]

Microcomputer calculation of the heat resistance of clothes gives the current data for the wide range of air speed. Programme is based on the equation, summarizing the number of standard clothing layers. Other methods (using of dummies, trials on humans) were analysed and the results identical to the suggested method were obtained.     

关于Meta-分析在医学领域的争鸣

Ｍｅｔａ－分析是对具有相同研究目的的多个独立研究结果进行系统合并和综合分析的一种研究方法［１］。Ｍｅｔａ－分析最初应用于教育学、心理学等社会科学领域［２］,７０年代引入到医学领域,８０年代后期取得了很大进展,由仅应用于临床随机试验发展到可用于任何试验研究和非试验研究［３］,但对于其定义、应用及方法学方面尚存在许多争议,现就这一问题综述如下。一、关于Ｍｅｔａ－分析的定义：不同的学者对Ｍｅｔａ－分析定义的描述不尽一致。英国心理学家Ｇｌａｓｓ［４］首先为其下了定义：“Ｍｅｔａ－分析是以综合研究结果为目…     

Psychological methods in the evaluation of neurotoxic effects of organic solvents]

Organic solvents comprise a large and heterogenous group of chemical compounds and mixtures, largely belonging to volatile hydrocarbons. They are widely used in various industries. Long-term exposure to organic solvents as a cause of the central nervous system impairement has been subject of extensive epidemiological and clinical studies for years, especially in Scandinavia, but often with inconsistent results. In 1985 the World Health Organization published the criteria for the evaluation of neurotoxic effects of solvents that are now commonly accepted. The present paper provides a short review of the current state of knowledge in the field emphasizing the role of neuropsychological methods in assessing solvent toxicity.     

Subjective symptoms and blood findings in painters exposed to organic solvents]

Subjective symptoms and blood findings were studied in 16 construction workers and 30 vehicle repairmen using organic solvent and compared to 30 workers who were not exposed to organic solvents. A statistically significant increase was observed in the prevalence of subjective symptoms, serum phospholipid, lipoprotein fraction and IgE in construction workers and vehicle repairmen. A statistically significant decrease in neutrophils function was observed in construction workers.     

Exposure to solvents and tardy epilepsy: 2 clinical cases]

Organic solvents (OS) are widely used in industry and craft work. The neurotoxic effects of OS are well known in occupational exposure occurring in poor industrial hygiene conditions. There has been interest recently in a possible epileptogenic effect of OS exposure. Two cases are reported of late onset epilepsy observed in workers heavily exposed to OS. Case 1 was a 27-year-old male painter employed in a car body repair workshop. Solvent exposure was high for a few months because after his regular work, the man continued working as a car body painter in his own private concern. After a period of weakness and headache, probably indicating an excessive solvent absorption, he suffered two generalized paroxysmal seizures during sleep which necessitated hospitalization and continuous treatment with barbiturates. Case 2 was a 44-year-old male painter in a road advertising billboard factory who was continuously exposed to OS. Ten years previously he had been exposed to accidental massive inhalation of solvent vapours while opening a drum of solvents for coloured paint. Acute solvent poisoning followed and seven weeks later he suffered several epileptic episodes associated with typical EEG alterations; for many years, however, treatment was ineffective. In both cases there was neither a history of neurologic disease nor any other neurologic dysfunctions and the results of comprehensive neuroradiological studies were normal. Evidence exists of a chronological connection between high exposure to paint solvents and clinical evidence of late onset epilepsy, but it is not possible to identify a definite causal relationship.(ABSTRACT TRUNCATED AT 250 WORDS)     

Investigation of health effects associated with solvents used in dry cleaning workplace (report 1). Tetrachloroethylene concentration in working environment

Tetrachloroethylene (TCE) level in the working environment was measured at five dry cleaning workplaces. Time weighted average (TWA) concentration of TCE collected using an activated charcoal badge were 2.3-19.1 ppm in summer and 1.3-56.9 ppm in winter. TCE level in the work place measured during the work process showed that when the dry cleaning machine was opened to remove clothes, TCE ranged from 63.2 to 85.6 ppm and while the machine was operating ranged from 50.8 to 143 ppm. TCE levels at the middle of the cleaning cycle ranged horizontally from 0.5 to 11.0 ppm (mean 3.0 ppm, 12 sampling points) in summer and from 7.7 to 85.3 ppm (mean 28.0 ppm. 12 sampling points) in winter. The values varied according to the location of the sampling point. In the living area adjacent to the workplace, TCE was found to be at the same level as the workplace. Therefore in order to prevent other family members from being affected it is recommended that the workplace be separated from the residence.     

骨科手术铅衣消毒干预措施的研究

目的探讨针对骨科手术铅衣消毒采取的干预措施效果。方法调查某骨专科医院干预措施实施前后手术室铅衣清洁消毒效果和铅衣的使用情况,并对调查结果进行比较。结果干预前、干预三个月后以及干预半年后分别调查铅衣手术488、499、487例,铅衣使用次数分别为1 840、1 901、1 801次。干预前及干预三个月后,发现有可见血渍的铅衣百分率分别为12.55%和0.26%,差异有统计学意义(χ~2=238.99,P=0.00);干预实施半年后有可见血渍的铅衣百分率为0.11%,与干预三个月后相比无统计学差异(χ~2=1.13,P=0.29)。干预前及干预三个月后,铅衣表面菌落数合格率分别为72.34%和89.16%,差异有统计学意义(χ~2=171.24,P=0.00);干预实施半年后铅衣表面菌落数合格率为90.62%,与干预三个月后相比无统计学差异(χ~2=2.14,P=0.14)。干预前及干预三个月后,铅衣的重复使用率分别为19.29%和9.84%,差异有统计学意义(χ~2=70.08,P=0.00);干预实施半年后铅衣的重复使用率为6.22%,与干预三个月后相比差异有统计学意义(χ~2=16.31,P=0.00)。结论针对骨科手术铅衣消毒的干预措施能有效提高铅衣的清洁度,并且干预措施的持续效果较好。     

Evaluation of individual exposure to organic solvents using a portable VOC monitor]

Analysis by gas chromatograph after collection of personal samples is the most common method of evaluating individuals' exposures to organic solvents. This method provides us time-weighted averages (TWA) only, and does not measure fluctuating concentrations of organic solvents. A portable VOC monitor is widely used as a rapid screening instrument for volatile organic compounds (VOCs) in houses, schools, etc. The VOC monitor equipped with a photoionization detector can measure real-time concentrations of VOCs. In this study, the author investigated whether the VOC monitor can evaluate individuals' exposures to organic solvents. First, standard organic solvent gases were prepared and the gas concentrations were measured by a passive air sampler and the VOC monitor. Correction factors (CF) were obtained for the response of the isobutylene calibrated VOC monitor to equal concentrations of the organic solvents. Methyl ethyl ketone's CF was 0.5952, toluene's CF was 0.4418, and N,N-dimethylformamide's CF was 0.9017. Then, a mixed standard organic solvents gas was prepared and the gas concentration was measured by both methods. A significant correlation between both methods was obtained (p < 0.001). Subsequently, 37 male workers in a synthetic-leather factory were examined for solvent exposure using both the VOC and a passive sampler, Similar results were obtained by both methods (p < 0.001). Real-time data can be obtained using the VOC monitor and high exposure tasks can be identified. The VOC monitor will be useful for reducing occupational exposure. Since the VOC monitor provides detailed data of individuals' exposures to organic solvents.