Respiratory symptoms and pulmonary function among wood dust-exposed joss stick workers

Health hazards associated with wood dust exposure have been investigated in various industries. This study surveyed wood dust exposure levels and pulmonary effects among joss stick workers. Greater dust concentrations, as measured by six-stage cascade impactors, were observed in work areas where joss sticks were produced and incense was mixed than in other work areas. Total dust concentrations for these two high dust activities ranged from 9.9 to 42.7 mg/m³, and respirable proportions were between 2.0% and 54.6%. Higher dust levels were observed for dry joss stick production methods than for wet production methods. Dust levels for all other performance areas were lower than the permissible exposure level of 10 mg/m³. Although symptoms of cough and phlegm were higher in smoking workers than in nonsmoking workers, the prevalence of respiratory symptoms for exposed workers was not significantly higher than for the controls. The prevalence of pulmonary function deficits and the values of FEF_25% and FEF_75% in the exposed workers were significantly worse than those in the controls. But no difference was found between the male controls and the male exposed workers, the high-exposure group. Respiratory symptoms and pulmonary function also did not show a dose-response trend with the exposure levels estimated by correlation with worker job titles and duration of employment. No suspected case of pneumoconiosis was found from the chest radiographs. These results suggest that wood dust exposure in the joss stick industries might not lead to significant pulmonary damage.     

Clinical laboratory results of vanadium-exposed workers

Vanadium pentoxide exposure and its effect on select hematologic and chemical laboratory tests for workers exposed to 0.2-0.5 mg/m3 vanadium was studied. No association was found between vanadium exposure and the results of laboratory tests. The values of some chemical laboratory tests differed from those of controls. These findings, however, were not considered to be clinically significant because the mean values differed only slightly from each other. Hematologic tests showed no abnormalities when the concentration of vanadium in the factory air was 0.01-0.04 mg/m3.     

炼钒工人的皮炎调查及其病因

本文主要报告对生产钒化合物工人进行皮炎调查的结果。炼钒厂87名接触钒工人皮炎总的患病串为27.6%,各工种患病串范围在20—80%,提示皮炎的发生与接触浓度有一定关系,而对照组28人无皮炎发生。钒酸钠斑贴试验接触组发生和未发生过皮炎的阳性率分别为26%和7%,对照组均为阴性。豚鼠钒酸钠致敏试验结果阳性。皮炎患者外周血淋巴细胞刺激指数为109±57.2,对照93±64。7,P>0.05,致敏豚鼠脾脏淋巴细胞刺激指数(20.3±3.5)明显高于对照(2.2±1.1),P<0.01。结论认为炼钒工人的皮炎与接触钒有关,钒化合物对皮肤的作用可能具有两重性,即原发性刺激作用和致敏作用。     

Acute respiratory symptoms in workers exposed to vanadium-rich fuel-oil ash

BACKGROUND: Occupational exposure to fuel-oil ash, with its high vanadium content, may cause respiratory illness. It is unclear, however, what early acute health effects may occur on the pathway from normal to compromised respiratory function. METHODS: Using a repeated measures design, we studied prospectively 18 boilermakers overhauling an oil-fired boiler and 11 utility worker controls. Subjects completed a respiratory symptom diary five times per day by using a 0-3 scale where 0=symptom not present, 1=mild symptom, 2=moderate symptom, and 3=severe symptom. Daily symptom severity was calculated by using the highest reported score each day for upper and lower respiratory symptoms. Daily symptom frequency was calculated by summing all upper or lower airway symptom reports, then dividing by number of reporting times. Respiratory symptom frequency and severity were analyzed for dose-response relationships with estimated vanadium and PM(10) doses to the lung and upper airway by using robust regression. RESULTS: During the overhaul, 72% of boilermakers reported lower airway symptoms, and 67% reported upper airway symptoms. These percentages were 27 and 36 for controls. Boilermakers had more frequent and more severe upper and lower respiratory symptoms compared to utility workers, and this difference was greatest during interior boiler work. A statistically significant dose-response pattern for frequency and severity of both upper and lower respiratory symptoms was seen with vanadium and PM(10) in the three lower exposure quartiles. However, there was a reversal in the dose-response trend in the highest exposure quartile, reflecting a possible healthy worker effect. CONCLUSIONS: Boilermakers experience more frequent and more severe respiratory symptoms than utility workers. This is most statistically significant during boiler work and is associated with increasing dose estimates of lung and nasal vanadium and PM(10).     

指甲镍含量与接镍水平关系的研究

对某镍业公司不同生产车间空气中镍浓度和工人指甲镍含量进行了测定。共获得空气镍浓度数据５７６个，指甲镍含量数据２４０个。根据生产过程过程和卫生学特征。将所得结果按碎矿压球，电炉转炉、氧化镍焙烧、硫酸镍，汽车修配厂５个观察组进行了分析，看出指甲镍含量与空气镍浓度之间呈现一定的接触水平一反应关系。剔出硫酸镍组数据，仅对镍化合物存在形态相同的其余４个组的进行相关性分析，ｒ＝０．９７２，Ｐ＝０．０２８．本研     

Visual evoked potentials in rotogravure printers exposed to toluene.

Visual evoked potentials (VEPs) from stimulation by checkerboard pattern reversal were examined in 54 rotogravure printers exposed to toluene (all men, aged 22-64 years, duration of exposure 1-41 years). A control group consisted of 46 subjects (23 men and 23 women; aged 22-54 years). Compared with controls the exposed group showed more frequent responses with reduced reproducibility or absence of some waves, or both; the mean P1 wave latency was prolonged and mean amplitudes N1P1 and P1N2 were reduced. The VEPs were abnormal in 24% of workers. The frequency of abnormal VEPs correlated positively with the duration of exposure to toluene and also with the degree of alcohol drinking. No association was found between measurements of VEP and electroencephalogram (EEG) or electromyogram (EMG) examinations. A VEP measurement was made in 78% of the exposed workers two years after the first examination. No statistically significant difference between the two results was found. This suggests a marked stability of the observed VEP changes. These changes can be interpreted as a subclinical sign of dysfunction of the central nervous system (CNS) related to exposure to toluene and also to alcohol consumption.     

Visual evoked potentials in rotogravure printers exposed to toluene

Visual evoked potentials (VEPs) from stimulation by checkerboard pattern reversal were examined in 54 rotogravure printers exposed to toluene (all men, aged 22-64 years, duration of exposure 1-41 years). A control group consisted of 46 subjects (23 men and 23 women; aged 22-54 years). Compared with controls the exposed group showed more frequent responses with reduced reproducibility or absence of some waves, or both; the mean P1 wave latency was prolonged and mean amplitudes N1P1 and P1N2 were reduced. The VEPs were abnormal in 24% of workers. The frequency of abnormal VEPs correlated positively with the duration of exposure to toluene and also with the degree of alcohol drinking. No association was found between measurements of VEP and electroencephalogram (EEG) or electromyogram (EMG) examinations. A VEP measurement was made in 78% of the exposed workers two years after the first examination. No statistically significant difference between the two results was found. This suggests a marked stability of the observed VEP changes. These changes can be interpreted as a subclinical sign of dysfunction of the central nervous system (CNS) related to exposure to toluene and also to alcohol consumption.     

低水平铅暴露对印刷厂工人神经行为的影响评价

为评价低水平铅暴露对神经行为的影响，用世界卫生组织推荐的神经行为核心测试组合（ＮＣＴＢ）方法对２８名印刷厂排字工人和４６名大学三年级学生进行测试。测试项目包括：（１）情感状态，（２）简单反应时，（３）数字跨度，（４）手敏捷度，（５）数字译码，（６）视觉保留。测试结果表明在所有的测试项目中，未见两组间得分有显著性差异。多元逐步回归分析提示在很低暴露水平情况下，铅与神经行为得分间存在联系     

Serum and urinary vanadium of workers processing vanadium pentoxide

Summary Serum and urinary vanadium concentrations were investigated in eight men exposed to vanadium pentoxide dust. The creatinine-adjusted urinary vanadium concentrations were found to correlate with serum vanadium concentrations (r=0.81), but not with the vanadium contents of factory air. The urinary vanadium excretion decreased significantly with the time the workers spent out of exposure. At the beginning of their summer holidays the serum vanadium concentration of the workers was 393 ± 223 (S.D.) nmol/l and the urinary excretion of vanadium 73 ± 50 nmol/mmol of creatinine. Three days after exposure the urinary excretion of vanadium was 46 ± 24 nmol/mmol of creatinine. On the 16th day of their holidays vanadium could be detected in the serum (225 ± 83 nmol/1) and in the urine (48 ± 26 nmol/mmol of creatinine) of the workers. Eight family members of the exposed had less vanadium in urine (32 ± 17 nmol/mmol of creatinine). These results suggest that most of the absorbed vanadium is excreted in the urine within one day after a long-term moderate exposure to vanadium dust.     

Mineral fibres, fibrosis, and asbestos bodies in lung tissue from deceased asbestos cement workers.

Lung tissue from 76 deceased asbestos cement workers (seven with mesothelioma) exposed to chrysotile asbestos and small amounts of amphiboles, has been studied by transmission electron microscopy, together with lung tissue from 96 controls. The exposed workers with mesothelioma had a significantly higher total content of asbestos fibre in the lungs than those without mesothelioma, who in turn, had higher concentrations than the controls (medians 189, 50, and 29 x 10(6) fibres/g (f/g]. Chrysotile was the major type of fibre. The differences were most pronounced for the amphibole fibres (62, 4.7, and 0.15 f/g), especially crocidolite (54, 1.8 and less than 0.001 f/g), but were evident also for tremolite (2.9, less than 0.001, and less than 0.001 f/g) and anthophyllite (1.7, less than 0.001, and less than 0.001 f/g). For amosite, there was no statistically significant difference between lungs from workers with and without mesothelioma; the lungs of workers had, however, higher concentrations than the controls. Strong correlations were found between duration of exposure and content of amphibole fibres in the lungs. Asbestos bodies, counted by light microscopy, were significantly correlated with the amphibole but not with the chrysotile contents. Fibrosis was correlated with the tremolite but not the chrysotile content in lungs from both exposed workers and controls. Overall, similar results were obtained using fibre counts and estimates of mass.     

Prostate-specific antigen and its derivatives in young adults occupationally exposed to quarry pollutants in southeastern Nigeria

To evaluate the level of total prostate-specific antigen (PSA) and effect of duration of exposure to pollutants in quarry workers, 5 mls of blood sample was collected from participants: 72 male quarry workers exposed to quarry pollutants and 72 unexposed controls. PSA estimations were done using the principle of ELISA. Mean total PSA, free PSA, and free-total PSA ratio levels of quarry workers did not differ from those of controls and was below the cutoff for the risk of prostate diseases. Higher mean total PSA and free PSA were observed in workers exposed for > 3 years compared to the unexposed control and workers exposed for ≤ 3 years. Age-adjusted linear regression indicated significant association (R = 0.515; p < .001) between the duration of exposure and total PSA level in quarry workers. This study suggests that longer duration of exposure to the quarry pollutants may elevate PSA level if precautions are not taken to minimize dose of exposure.     

Mineral fibres, fibrosis, and asbestos bodies in lung tissue from deceased asbestos cement workers

Lung tissue from 76 deceased asbestos cement workers (seven with mesothelioma) exposed to chrysotile asbestos and small amounts of amphiboles, has been studied by transmission electron microscopy, together with lung tissue from 96 controls. The exposed workers with mesothelioma had a significantly higher total content of asbestos fibre in the lungs than those without mesothelioma, who in turn, had higher concentrations than the controls (medians 189, 50, and 29 x 10(6) fibres/g (f/g]. Chrysotile was the major type of fibre. The differences were most pronounced for the amphibole fibres (62, 4.7, and 0.15 f/g), especially crocidolite (54, 1.8 and less than 0.001 f/g), but were evident also for tremolite (2.9, less than 0.001, and less than 0.001 f/g) and anthophyllite (1.7, less than 0.001, and less than 0.001 f/g). For amosite, there was no statistically significant difference between lungs from workers with and without mesothelioma; the lungs of workers had, however, higher concentrations than the controls. Strong correlations were found between duration of exposure and content of amphibole fibres in the lungs. Asbestos bodies, counted by light microscopy, were significantly correlated with the amphibole but not with the chrysotile contents. Fibrosis was correlated with the tremolite but not the chrysotile content in lungs from both exposed workers and controls. Overall, similar results were obtained using fibre counts and estimates of mass.     

Serum type III procollagen peptide in asbestos workers: an early indicator of pulmonary fibrosis.

Serum type III procollagen peptide (PIIIP) concentrations were determined in 36 male workers exposed to asbestos fibres in the production of asbestos cement items and in 13 healthy male controls. Mean (SD) PIIIP serum concentrations were 9.3 (1.5) ng/ml (range 7-12) in the controls and 13.7 (3.5)ng/ml (range 7.5-20) in the asbestos workers; the difference was statistically significant (p less than 0.01). The exposed workers were subdivided according to presence or absence of radiological signs of asbestosis and intensity and duration of exposure. PIIIP serum values of workers with asbestos related interstitial fibrosis were the highest of the groups at 14.6 (2.3) ng/ml. In workers with heavy exposure the PIIIP values were significantly related to duration of exposure (r = 0.95; p less than 0.01). PIIIP serum values may be a useful index for the early diagnosis of asbestos induced pulmonary fibrosis and its use should be considered as part of the biological monitoring of exposed workers.     

Serum type III procollagen peptide in asbestos workers: an early indicator of pulmonary fibrosis

Serum type III procollagen peptide (PIIIP) concentrations were determined in 36 male workers exposed to asbestos fibres in the production of asbestos cement items and in 13 healthy male controls. Mean (SD) PIIIP serum concentrations were 9.3 (1.5) ng/ml (range 7-12) in the controls and 13.7 (3.5)ng/ml (range 7.5-20) in the asbestos workers; the difference was statistically significant (p less than 0.01). The exposed workers were subdivided according to presence or absence of radiological signs of asbestosis and intensity and duration of exposure. PIIIP serum values of workers with asbestos related interstitial fibrosis were the highest of the groups at 14.6 (2.3) ng/ml. In workers with heavy exposure the PIIIP values were significantly related to duration of exposure (r = 0.95; p less than 0.01). PIIIP serum values may be a useful index for the early diagnosis of asbestos induced pulmonary fibrosis and its use should be considered as part of the biological monitoring of exposed workers.     

Plasma lipid peroxides among workers exposed to silica or asbestos dusts

Plasma malondialdehyde (MDA) (an indicator of lipid peroxidation) was determined in random samples of workers (age range 25-60 years) exposed to silica dust (n = 31, mean exposure duration 21.3 +/- 8.3 years) or asbestos dust (n = 59, mean exposure duration 15.6 +/- 4.5 years) and in 52 age-matched healthy male controls. MDA levels of both exposed groups were significantly higher than that of the controls and were significantly higher among workers exposed to asbestos than among those exposed to silica dusts. Neither age nor smoking was related to MDA levels among both controls and exposed workers; among the latter group MDA was not significantly correlated with duration of exposure. Mean MDA levels of exposed workers with radiographic signs of lung fibrosis or pleural thickening and of those without such signs were not significantly different, except in the case of asbestos-exposed workers where it was significantly less than that of those without such signs. Differences between mean durations of dust exposure of workers with radiographic signs of lung fibrosis and those without such signs were statistically insignificant. The results suggest the possible involvement of lipid peroxidation on exposure to silica or asbestos dusts in humans and possible development of antioxidant mechanism(s) on prolonged dust exposure and support the opinion that development of pneumoconiosis depends on susceptibility factor(s).     

Early health effects and biological monitoring in persons occupationally exposed to tetraethyl lead

Summary Dependent on the level of occupational exposure to tetraethyl lead, the occurrence of early signs of toxicity and the urinary excretion of triethyl lead, diethyl lead and total lead compounds were investigated. This was done in the following cohorts in the province of Hubei, China: 277 workers at gasoline depots exposed to gasoline, 36 traffic policemen exposed to automobile ex haust and 342 public office workers (virtually non-exposed controls). Mean external tetraethyl lead exposure concentrations were 84.8 g/m³ (as Pb) for the gasoline depot workers, 5.2 g/m³ for traffic police and 1.1 g/m³ for the controls. No significant subclin organic lead toxicity were found in the group of traffic policemen compared with the controls. In the cohort of gasoline workers, however, there was a statistical increase (vs controls) in the frequency of appearance of tremor and of sinus bradycardia. When the cohort of gasoline workers was divided into subgroups of different ranges of exposure, dose-dependence was noted. In general, the urinary excretion of triethyl lead was very low compared to that of diethyl lead, which appears to be a sensitive and specific indicator of exposure to tetraethyl lead; total lead excretion did not correlate well with actual external tetraethyl lead exposure. On the basis of these data it seems that current occupational exposure limits for tetraethyl lead are inadequate and need to be revised. In addition, a biological limit, based on urinary diethyl lead excretion, may be proposed.This paper summarizes data of a thesis (Zhang 1993) submitted to the Medical Faculty of the Heinrich-Heine-Universität Düsseldorf, in partial fulfilment of the requirements for the doctoral degree     

Small airways function in workers exposed to piperazine

Summary An N₂ wash-out technique was used to estimate the small airways function in 22 male workers, exposed to the asthma-inducing amine piperazine, and in 22 referent subjects, with similar smoking habits and age. The volume of trapped gas (VTG) was determined before and after a bronchial provocation with an aerosol of 0.25 ml 0.01% metacholine solution. No difference in VTG was observed between the piperazine-exposed workers and the referent subjects, either before or after the metacholine provocation. This indicates that a time-weighted average (TWA) exposure of about 0.1 mg piperazine/m³ does not cause small airways disease in non-asthmatic workers. Further, age and smoking habits were significantly associated with VTG.     

FEBRILE EPISODES IN WELDERS: RELATIONSHIP TO OCCUPATIONAL EXPOSURE AND SMOKING HABITS

Twenty-seven welders and a control group of 27 workers not engaged in welding were interviewed at nine factories to assess the incidence of metal-fume fever over a six-month period. Twenty-two welders had one or more febrile episodes over the six-month period, compared with 12 in the control group. There were 32 episodes in the welding group, and 22 in the controls. However, much of the difference between the groups was in the number of episodes of more than three days duration, that is, longer than the duration of typical metal-fume fever. Analysis of the figures relating to short-term episodes (three days or less in duration), suggested that the joint effects of smoking and welding increase a worker's susceptibility to short-term fever. This apparently synergistic effect, when viewed against similar findings for smoking and asbestos dust exposure and for smoking and radioactive mine-dust exposure, underscores the oft-overlooked interplay of aetiologic factors in producing unexpectedly large changes in disease risk.     

钒化合物对作业工人神经行为功能影响

目的探讨接触钒化合物对工人神经行为功能的损害作用及表现特征。方法采用WHO推荐的神经行为测试组合(NCTB)对暴露组和对照组做测试,其中接钒工人193人,对照组273人。结果①暴露组代表消极情感的"紧张-焦虑"、"抑郁-沮丧"、"愤怒-敌意"、"疲劳-惰性"、"困惑-迷茫"得分均高于对照组,代表积极情感的"有力-好动"得分低于对照组,差异有统计学意义(P﹤0.05)。②顺背数字、圣地安娜提转敏捷度、数字译码、视觉保留、目标追踪,均是暴露组得分低于对照组(P﹤0.05)。③简单反应时两组间差异无统计学意义(P﹥0.05)。结论钒作业工人神经行为功能测试差于对照组工人,表现在消极情绪增加、积极情绪降低,视觉记忆力下降、运动速度减慢、运动稳定性下降,提示钒接触有可能造成神经行为功能的损害。     

Blood superoxide dismutase and plasma malondialdehyde among workers exposed to asbestos

Blood superoxide dismutase (SOD) and plasma malondialdehyde (MDA) (an indicator of lipid peroxidation [LPO]) were determined in 97 randomly selected asbestos exposed workers (age range: 25–60 years, mean duration of exposures 19.8 ± 8.3 years) and in 42 healthy male controls. MDA, SOD, and MDA/SOD ratio in asbestos exposed workers were significantly higher than in controls. Among both the controls and exposed workers neither age nor smoking was related to SOD or MDA levels. SOD was significantly positively correlated with MDA among the exposed workers. Such correlation was not observed among the controls. SOD but not MDA was significantly positively correlated with the duration of exposure to asbestos. Mean levels of SOD or MDA in exposed workers with radiographic signs of lung fibrosis or pleural thickening did not differ significantly from those without such signs. The results confirm the possible involvement of LPO and development of anti-oxidant mechanism(s) of prolonged exposure to asbestos in humans. However, SOD seems not to be the essential anti-asbestos-induced LPO. Relation between these factors and lung fibrosis is still unclear.