Solvent pollution in shoe factories]

In order to study solvent exposure in shoe factories, 43 kinds of glues and 22 solvent products used in footwear manufacturing were analyzed. A gas chromatographic spectrometric method was used to identify the mixtures of solvents contained in glues and their diluents. Acetone, ethylacetate and cyclohexane were the solvents more frequently found in glues. Cyclohexane represented on average about 40% of the solvent mixture. Methyl ethyl ketone, 3-methylpentane and 2-methylpentane were often present in glues (45-52% of the samples), but only in a few cases were they associated with n-hexane. N-hexane and methylcyclopentane were found in 32% of the glue samples. N-hexane represented 47% of the solvents only in one glue. Most of the glues contained less than 10% n-hexane. Other solvents (dichloropropane, toluene, trichloroethane, butyl acetate, iso-butyl acetate and 2,2-dimethylbutane) were found in few glue samples or in low percentages. The 22 solvents used as glue diluents were mainly acetone, ethylacetate, dichloromethane and methyl ethyl ketone. The results suggest that solvent exposure in shoe factories has changed compared with data reported about 10 years ago. Biological monitoring of shoe factory workers should measure exposures to the specific solvents found in each factory, especially acetone, cyclohexane, ethylacetate and methyl ethyl ketone.     

Prevalence of self-reported health complaints among shoe workers of small workshop exposed to organic solvents in Hebron City, West Bank: a cross-sectional survey

The study was conducted to estimate the prevalences of neurological disorders and mucous membrane irritation complaints among workers of shoe workshops in Hebron City, in particular to measure the associations between the occurrence of symptoms indicating polyneuropathy among workers and exposure to organic solvents in the glueing tasks. A group of 103 male workers from 30 workshops, exposed to organic solvents for more than one year were recruited to the study during the years 1996-1997. A validated Swedish neuropsychiatric questionnaire which contained questions on neurological and mucous irritation symptoms was used. Prevalence ratios were used as an indicator for relative risk. The overall prevalence of painful tingling of limbs (used as indicator of polyneuropathy) was high among the workshop workers (40%) and was significantly associated with long term exposure to organic solvents in glueing tasks (PR 2.8: 95% CI 1.0-8.3). Moderate associations were seen in other tasks. Headache and mental irritability did not show any association with organic solvent exposure in the workshop tasks. Breathing difficulty showed a moderate non-significant association with long term exposure to organic solvents (72 months) in cleaning tasks (1.9,0.7-4.8), while sore eyes also showed a moderate non-significant association with exposure to organic solvents for 25-72 months in the glueing tasks. Long term exposure to n-hexane (mainly found in the glues) could be the main cause of polyneuropathy among the workers of Hebron shoe workshops. The absence of effective ventilation systems and personal protective equipment might increase the prevalence of polyneuropathy among these workers. In conclusion, glues containing high concentrations of n-hexane are still in use in many shoe workshops in Hebron City (as well as in other developing countries), and long term exposure to n-hexane in glueing compounds could result in polyneuropathy among the workers. However, in the absence of objective measurements our results must be interpreted with caution. Well planned longitudinal studies with objective measures of exposure and disease are important for future research in developing countries.     

Evaluation of combined effect of organic solvents and noise by the upper limit of hearing

To clarify the combined effects of organic solvents and noise on hearing, the upper limit of hearing was measured in 48 male workers exposed to organic solvents and/or noise in a factory producing plastic buttons. Measuring the organic solvent concentrations in working environments and breathing zone air, and the noise level in workplaces were also done. The readings suggested that most exposures to organic solvents and/or noise were within the occupational exposure limits. The prevalence rate of the upper limit of hearing below 75th percentile curve was higher in workers exposed to organic solvents and noise than expected (25 percent) and the other groups, whereas it was about 25 percent in the noise and control groups. The results suggest that the probable combined effects of organic solvents and noise on hearing should be considered even when the exposures are within the occupational exposure limits.     

某鞋厂347例接触混合有机溶剂作业工人肝脏B超检查结果分析

目的 探讨长期低浓度接触混合有机溶剂对制鞋作业工人肝脏的影响。 方法 对生产车间使用甲苯、苯、二氯乙烷、正己烷等混合有机溶剂的某鞋业工厂347名工人(接触组)和工厂无毒物接触史后勤人员321人(对照组)进行肝脏B超检查,比较两组检查结果。 结果 生产车间使用的有机溶剂的时间加权平均浓度均未超过职业接触限值。接触组弥漫性肝回声音改变、肝大的检出率均高于对照组,上述指标在两组间比较,差异均有统计学意义(χ2=27.8、12.5,P<0.05)。将两组各分成6个工龄段,弥漫性肝回声改变的检出率在工龄大于等于2年(4个工龄段)的两组员工间比较,差异均有统计学意义(χ2=8.9、10.2、10.2、10.5,P<0.05),两组的异常检出率均随着工龄的增加而升高。 结论 较长时间接触混合有机溶剂对作业工人肝脏可能存在慢性损害,应注意预防。     

职业性混苯暴露工人神经行为功能改变

利用世界卫生组织（ＷＨＯ）推荐的神经行为核心测试组合（ＮＣＴＢ）对１０３名职业性混苯暴露工人,以及７２名无职业性有害因素接触的同厂工人进行测试。结果发现：暴露组在情感状态（ＰＯＭＳ）、手工敏捷度、数字广度、数字译码、目标追踪等项目得分都低于对照组,其中优势手手工敏捷度、目标追踪两项得分差异具显著性。按车间混苯浓度分为高暴露组和低暴露组,多因素分析发现：高暴露组情感状态（ＰＯＭＳ）中的抑郁－沮丧和有力－好动、数字广度、手工敏捷度（优势手和非优势手）、数字译码、目标追踪等项显著低于对照组和低暴露组。提示混苯暴露使工人神经行为功能表现某些方面的改变,如心情趋于抑郁、缺乏活动性,短时记忆力、理解力、运动速度、协调性等方面表现较差。     

Detailed exposure assessment for a molecular epidemiology study of benzene in two shoe factories in China

OBJECTIVES: We carried out a detailed exposure assessment of benzene and toluene in two shoe factories in Tianjin, China. Our goal was to identify workers with a broad range of benzene exposures, for an epidemiologic study relating exposure to early biologic effects. METHODS: A comprehensive exposure survey program was initiated. Over a period of 16 months, 2783 personal solvent exposure samples were collected in two workplaces from 250 workers. Mixed-effects models were used to identify factors affecting exposure. Principal component analyses (PCA) and subsequent regression analyses on the scores of the identified principal components were used to relate potential co-exposures to various exposure sources present in the workplace. RESULTS: The mean benzene exposure level was 21.86 p.p.m. (10th-90th percentiles 5.23-50.63 p.p.m.) in the smaller shoe factory (factory A) and 3.46 p.p.m. (10th-90th percentiles 0.20-7.00 p.p.m.) in the larger shoe factory (factory B). Within-factory exposure levels differed among job titles and were higher for subjects directly involved in handling glues. In contrast, mean toluene levels were relatively similar in the two factories (factory A, 9.52 p.p.m.; factory B, 15.88 p.p.m.). A seasonal trend was identified for both benzene and toluene in factory B. This could be explained in part by changes in air movement and ventilation patterns occurring during the year. A seasonal trend was not present in the smaller shoe factory, where general ventilation was absent. Supplemental analysis showed that exposure levels to other hydrocarbons were low (< or =5 p.p.m.), less than 5% of their respective ACGIH threshold limit values, and generally comparable in the two factories. PCA showed that co-exposures in factory B could largely be explained by glue sources that were used in distinct areas in the workplace. CONCLUSIONS: We demonstrated the occurrence of a broad range of benzene exposure levels in two shoe manufacturing factories in Tianjin, China. Benzene and toluene exposures were determined in part by the degree of contact with glues, the benzene and toluene content of each glue, air movement and ventilation patterns. The availability of long-term monthly personal monitoring data provides an excellent opportunity to estimate individual exposures at different times during the 1 yr period of observation.     

Renal disorders induced by organic solvents

Organic solvents are a class of chemical substances that are widely used in large volume in various manufacturing plants. Due to their high lipophilicity, organic solvents may produce physicochemical damage to renal glomeruli and tubuli. Many reports have been published abroad, though only a few in Japan, on organic solvent-induced nephropathy such as Goodpasture syndrome, a form of renal damage mediated by anti-basement membrane antibodies. This article reviews the epidemiological studies published in the literature and stresses that organic solvent exposure is one of the etiological factors involved in the development of chronic nephropathy. At present in Japan there are 60,000 patients with terminal renal failure undergoing hemodialysis, 50,000 young men placed under observation each year for abuse of organic solvents, and one million workers exposed to organic solvents in factories. Attention should be focused on the occurrence of renal damage due to organic solvents in Japan.     

不同类型职业病危害因素暴露企业工人的生命质量状况调查

目的 探讨不同类型职业病危害因素暴露企业生产工人的生命质量状况及其影响因素。
方法 采用整群随机抽样, 抽取中山市印刷业、灯饰和电子制造业共6家企业1 484名一线工人为研究对象。采用回顾性调查的方法收集上述6家企业连续3年职业病危害因素定期检测报告, 分析主要职业病危害因素及其暴露水平, 同时采用生命质量测评量表SF-36量表评价一线工人的生命质量。
结果 不同类型企业的有机溶剂检测合格率差异有统计学意义(P < 0.05), 印刷业的有机溶剂检测合格率最低(95.5%); 灯饰制造业粉尘检测合格率和噪声检测合格率最低, 分别为96.3%和69.8%。3种不同制造业工人SF-36量表中生理功能、生理职能、身体疼痛、总体健康、活力、社会功能、情感职能、精神健康8个维度的得分, 差异均有统计学意义(P < 0.01), 均以电子制造业得分最高, 印刷业最低。多重线性回归分析结果显示, 与电子制造业相比, 印刷业和灯饰制造业生产工人生理健康维度与心理健康维度得分均低于电子制造企业(P < 0.01), 提示接触有机溶剂、粉尘和噪声可能是生命质量生理健康维度和心理健康维度的共同影响因素。生理健康维度可能还受经常体育锻炼的影响(P < 0.01)。
结论 不同行业工人的生命质量有所不同, 可能受行业中不同职业病危害因素暴露水平和体育锻炼的影响。
     

Effects of mixed organic solvents on neuromotor functions among workers in Buddhist altar manufacturing factories

To clarify the neuromotor effects of long-term exposure to mixed organic solvents, postural sway and tremor were measured in 62 solvent workers of four Buddhist altar manufacturing factories who had worked for 1-46 (mean 12) yr. By using the passive gas sampler, 8-h time-weighted average concentrations in the workers were estimated to be 0.02-8.7 ppm for toluene, 0.02-7.7 ppm for xylene, 0.02-5.5 ppm for styrene and 0.02-40.5 ppm for n-hexane. Sagittal sway and sway area of the posturography with eyes closed were significantly larger in the solvent workers than in 35 age-matched controls (p<0.05), and there was a significant difference in Romberg quotient of sagittal sway between the two groups (p<0.05). Also, tremor intensities at 1.0-5.9 Hz, 6.0-9.9 Hz and 10.0-13.9 Hz with the right hand, and at 6.0-9.9 Hz with the left hand were significantly stronger in the solvent workers than in the controls. Among the solvent workers, transversal and sagittal sways with eyes open and tremor intensity at 10.0-13.9 Hz were significantly related to toluene exposure (p<0.05), which may have been due to the acute effects of such solvents. These findings suggest that long-term exposure to mixed organic solvents may impair neuromotor functions as measured by postural sway and tremor.     

Hearing loss among workers exposed to moderate concentrations of solvents.

OBJECTIVES: It is known that some industrial organic solvents are ototoxic. This study was aimed at evaluating the hearing effects of a mixture of organic solvents alone or in combination with noise on employees in paint and lacquer enterprises. The concentration of solvents was below the occupational exposure limits (OEL) for most of the subjects. METHODS: Altogether 517 subjects were divided into the following three groups: persons with no risk due to noise or organic solvent exposure at the workplace, workers exposed to organic solvents only, and workers exposed to both organic solvents and noise. RESULTS: The relative risk (RR) of hearing loss in the solvent-only exposure group was significantly increased (RR 4.4 and RR 2.8 for noise exposure of < 80 dB-A and < 85 dB-A, respectively) in a wide range of frequencies (2-8 kHz). No additional risk in the solvent + noise exposure group was found (RR 2.8). Hearing thresholds were significantly poorer in a wide range of frequencies (1-8 kHz) for both groups exposed to solvents, when compared with the reference group. The mean hearing thresholds at frequencies of 2-4 kHz were poorer for workers exposed to solvents + noise than for the solvent-only group; this finding suggests an additional effect for noise. However, there was no correlation between hearing loss and the extent of solvent exposure. CONCLUSIONS: The results indicate that occupational organic solvent exposure at moderate concentrations increases the risk of hearing loss, and the ototoxic effects should be considered when the health effects of exposed workers are monitored.     

Cancer mortality among shoe manufacturing workers: an analysis of two cohorts.

OBJECTIVES: To examine the cancer risk of shoe manufacturing workers and evaluate whether the risk was associated with exposure to leather dust and solvents. METHODS: Data from two historical cohort studies of shoe workers were expanded and analysed in parallel. A total of 4215 shoemakers from England contributing 103 726 person-years at risk and 2008 shoemakers from Florence, Italy, contributing 54,395 person-years at risk were included in the analysis. Exposure to leather dusts and solvents from glues was evaluated on the basis of job title information. Standardised mortality ratios (SMR) were calculated as ratios of observed deaths (Obs) over expected derived from national mortalities. RESULTS: Overall mortality was lower than expected in both cohorts (English cohort: Obs 3314, SMR 81, 95% confidence interval (95% CI) 78-84; Florence cohort: Obs 333, SMR 87, 95% CI 78-97). An increased risk of nasal cancer was found (English cohort: Obs 12, SMR 741; Florence cohort: Obs 1, SMR 909). 10 of the 13 cases occurred among English workers employed in the manufacture of welted boots (SMR 926, 95% CI 444-1703), a sector of the industry thought to have had the highest exposure to leather dust. Mortality from leukaemia was not increased in the English cohort (Obs 16, SMR 89), but was increased in the Florence cohort (Obs 8, SMR 214, 95% CI 92-421); and the highest risk was found among shoe workers in Florence who were first exposed between 1950 and 1959 when exposure to benzene was substantial (Obs 3, SMR 536, 95% CI 111-1566). Some evidence for an excess risk of stomach, bladder, and kidney cancer, as well as multiple myeloma and non-Hodgkin's lymphoma was also found in the Florence cohort only among workers employed in jobs with the highest exposure to solvents. CONCLUSIONS: These findings confirm the associations between exposure to leather dust and nasal cancer and between exposure to benzene and leukaemia in the shoe manufacturing industry and suggest that the risk of other cancers may be increased among workers exposed to solvents or glues.     

Solvent exposures at shoe factories and workshops in Hebron City, West Bank

Exposure to organic solvents has been reported to increase the risks for acute and chronic health effects among shoe industry workers. In developing countries, protection against chemical exposures is often not provided. The study was conducted to identify working conditions and estimate the concentrations of organic solvents used in shoe factories and workshops in Hebron City. Personal interviews containing questions related to personal protective equipment (PPE) were used to identify working conditions, and samples collected from factories and workshops were analyzed using gas chromatography. Geometric means (GMs) were calculated for the solvents. Six major organic solvents were detected in the factories. Acetone (GM = 51.5 mg/m3, GSD = 3.82) was common in gluing tasks. Dichloromethane (GM = 47 mg/m3, GSD = 2.62) was common in cleaning tasks. Heptane, methylethyl ketone, n-hexane, and toluene were common in gluing tasks. Four major organic solvents were detected in the workshops: acetone (GM = 32.3 mg/m:3, GSD = 6.33), toluene (GM = 70.3 mg/m3, GSD = 3.06), n-hexane (GM = 19.4 mg/m3:, GSD = 2.65), and methylethyl ketone (GM = 130 mg/mM3, GSD = 1.5). 81% of the factory workers had never used respiratory protective equipment, and 92% had never used work clothes. 97% of the workers in the workshops had never used respiratory protective equipment, 94% had never worn gloves, and 90% had never used work clothes. Exposures to solvents in the absence of personal Protective equipment, tasks barriers, and mechanical ventilation can adversely affect health.     

Mortality of workers employed in shoe manufacturing: an update

BACKGROUND: In the late 1970s, the National Institute for Occupational Safety and Health identified two shoe manufacturing facilities where workers experienced relatively "pure" exposures to toluene. A mortality study was conducted through December 31, 1982. An original study did not detect elevated leukemia mortality but did detect increased lung cancer mortality. The present study is an update of the mortality of the original cohort. METHODS: The study cohort consisted of workers employed 1 month or more between 1940 and 1979 at two Ohio shoe manufacturing plants. Vital status was ascertained through December 31, 1999. RESULTS: Seven thousand eight hundred twenty eight workers, contributing 300,777 person years, were available for analysis. An excess of lung cancer deaths persisted with additional years of follow-up (SMR = 1.36, 95% confidence interval (CI) = 1.19-1.54). Trend tests did not indicate a positive trend between lung cancer risk and duration of employment. Mortality from leukemia was not significantly elevated in the updated analysis. CONCLUSIONS: Results indicate a possible association between lung cancer mortality and exposure to chronic, low-levels of organic solvents. Although the strength of this conclusion was weakened by the lack of increasing lung cancer risk in relation to duration of employment, other studies have supported this association.     

Use of organic solvents and potential worker exposure in the motor vehicle manufacturing industry

This survey was designed to assist with planning epidemiologic studies of the effects of solvent exposure among motor vehicle manufacturing workers. The objectives were to identify subgroups of workers with solvent exposure, and to evaluate the availability of data for a job-exposure matrix (JEM). Of 65 plants selected, 31 (48%) participated. Participant plants represent all production activities initially included in the survey, and employ 97,655 hourly workers. About 14% of these workers use organic solvents (direct exposure), and 19% work in the proximity of solvent-using operations (indirect exposure). However, only 3% have direct exposure, and 6% have indirect exposure to large-volume (≥ 100 gallons/month)/high-frequency (hourly)-use solvents. The highest solvent exposure prevalence occurs in plants manufacturing engines and power train components and in metal degreasing/cleaning and painting tasks, and entails exposure to petroleum fractions, aromatic hydrocarbons, alcohols, and ketones. A JEM can be developed using plant records on job titles, work histories, production scheduling, and plant engineering, and using the corporate computerized personnel and industrial hygiene databases. However, information on solvent use and on exposure is adequate only for recent time periods. © 1993 Wiley-Liss, Inc.     

Health survey of workers exposed to mixed solvent and ergonomic hazards in footwear and equipment factory workers in Thailand

A cross-sectional health study was performed at four footwear and one equipment factory in Thailand to evaluate the prevalence of chemical- and ergonomic-related symptoms in Thai factory workers and to investigate associations between these symptoms and exposures to organic solvents, isocyanates and ergonomic risks. A 10-page health questionnaire was administered to 1784 workers across the four footwear and equipment factories. A total of 1675 questionnaires were returned, yielding a 94% response rate. The questionnaires asked about age, gender, use of chemicals, use of personal protective equipment and health outcomes. Without exception, the percentages of workers reporting symptoms after being hired were higher than those reporting symptoms before being hired for all the factories. The highest symptom percentages were related to ergonomic stressors. Multiple logistic regression was used to calculate adjusted prevalence odds ratios and 95% confidence intervals. This study showed that adverse health effects experienced by footwear and equipment factory workers are associated with occupational exposures to chemicals (volatile organic solvents and water-based adhesives) and ergonomic hazards.     

Sister chromatid exchanges and micronuclei in peripheral lymphocytes of shoe factory workers exposed to solvents

We examined sister chromatid exchanges (SCEs) and micronuclei (MN; cytokinesis-block method) in cultured peripheral lymphocytes from 52 female workers of two shoe factories and from 36 unexposed age- and sex-matched referents. The factory workers showed an elevated level of urinary hippuric acid, a biomarker of toluene exposure, and workplace air contained high concentrations of various organic solvents such as toluene, gasoline, acetone, and (in one of the plants only) ethylacetate and methylenediphenyl diisocyanate. The shoe factory workers showed a statistically significant higher frequency of micronucleated binucleate lymphocytes in comparison with the referents. This finding agreed with three preliminary MN determinations (each comprising 27-32 shoe workers and 16-20 controls) performed in one of the plants 2-5 years earlier. The shoe factory workers also had a lower average level of blood hemoglobin than the referents. In contrast, no difference was found between the groups in SCE analysis. Smokers showed significantly higher mean frequencies of SCEs per cell and high frequency cells (HFC) than nonsmokers. Aging was associated with increased MN rates and reduced cell proliferation. Polymorphism of the glutathione S-transferase M1 gene (GSTM1) did not affect the individual level of SCEs; but in smoking shoe workers an effect of the occupational exposure on the frequency of micronucleated cells could be seen only in GSTM1 null subjects. The low prevalence of the glutathione S-transferase T1 (GSTT1) null genotype precluded the evaluation of the influence of GSTT1 polymorphism. Our results show that the shoe factory workers have experienced genotoxic exposure, which is manifest as an increase in the frequency of MN, but not of SCEs, in peripheral lymphocytes. The exposures responsible for the MN induction could not be identified with certainty, but exposure to benzene in gasoline and methylenediphenyl diisocyanate may explain some of the findings.     

Dose — response relationship between noise exposure and the risk of occupational injury

Many workers worldwide experience fatality and disability caused by occupational injuries. This study examined the relationship between noise exposure and occupational injuries at factories in Korea. A total of 1790 factories located in northern Gyeonggi Province, Korea was evaluated. The time-weighted average levels of dust and noise exposure were taken from Workplace Exposure Assessment data. Apart occupational injuries, sports events, traffic accidents, and other accidents occurring outside workplaces were excluded. The incidences of occupational injury in each factory were calculated by data from the Korea Workers’ Compensation and Welfare Services. Workplaces were classified according to the incidence of any occupational injuries (incident or nonincident workplaces, respectively). Workplace dust exposure was classified as <1 or ≥1 mg/m³, and noise exposure as <80, 80-89, or >90 dB. Workplaces with high noise exposure were significantly associated with being incident workplaces, whereas workplaces with high dust exposure were not. The odds ratios (95% confidence intervals) derived from a logistic regression model were 1.68 (1.27-2.24) and 3.42 (2.26-5.17) at 80-89 dB and ≥90 dB versus <80 dB. These associations remained significant when in a separate analysis according to high or low dust exposure level. Noise exposure increases the risk of occupational injury in the workplace. Furthermore, the risk of occupational injury increases with noise exposure level in a dose-response relationship. Therefore, strategies for reducing noise exposure level are required to decrease the risk of occupational injury.