Erythrocyte antioxidant system and serum ceruloplasmin levels in welders

Summary The erythrocyte antioxidant system (superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione) and serum ceruloplasmin were studied in workers chronically exposed to welding fumes and gases, which are thought to be oxidant pollutants. Fifty-four healthy men using two electric arc welding processes (manual metal arc on stainless steel and mild steel, and metal inert gas on mild steel) were studied. The possible effects of cigarette smoking were also considered. The erythrocyte antioxidant system was in the normal range for all welders. Serum ceruloplasmin was significantly enhanced only in smoking welders and higher in manual metal arc than in metal inert gas welders, suggesting that the increase is related to the severity of the oxidant threat, which is more stressful for the workers using the manual metal arc technique because of the presence of stainless steel particles in the fumes. Although cigarette smoking alone did not increase serum ceruloplasmin levels, it affected the response to oxidant stress in welders.     

Respiratory symptoms and pulmonary function among welders working with aluminum, stainless steel and railroad tracks

Sixty-four aluminum welders, 46 stainless steel welders, and 149 railroad track welders were investigated regarding respiratory symptoms and pulmonary function (forced vital capacity and forced expiratory volume in 1 s). Referents consisted of nonwelding industrial workers and railroad workers. All groups of welders showed a higher frequency of chronic bronchitis symptoms than their respective referents. Respiratory symptoms were related to ozone concentrations in welders working with aluminum. In stainless steel and railroad track welders respiratory symptoms were related to chromium exposure rather than to total particle exposure. The pulmonary function was not affected in any of the welding groups studied.     

Respiratory impairment and metal exposure in a group of 68 industrial welders

A group of 68 currently employed welders were examined who were exposed to welding fumes either for the whole or for at least half the working day and who used at least two welding processes, which were mainly manual metal arc welding and metal active gas welding, but also metal and tungsten inert gas welding, or oxyacetylene welding. The welders were classified into 3 groups according to the class of materials used, i.e.: 1) only mild and stainless steel; 2) mild and stainless steel and other metals; 3) only other metals. Chronic bronchitis symptoms were observed in 22% of the subjects; signs of suspected radiological fibrosis were present in 18%, initial signs of radiological fibrosis in 4%. Small airway disease was prevalent in the smokers (28 smokers versus 2 nonsmokers); one worker had an obstructive syndrome and another a restrictive syndrome (both were smokers). There was a good correlation between years of exposure and: 1) MEF25 in non-smokers; 2) urinary cobalt in the whole group. There was also a correlation between smoking and FEV1, MEF50, MEF25, PaO2 and urinary cadmium. Serum copper was higher in workers exposed full time than in those exposed part time. Urinary chromium and cobalt and serum copper were high in steel welders, lower in welders using steel and other metals and low in welders using other metals. Urinary chromium was similar in smokers and non-smokers. Serum zinc was found to be of little use for biological monitoring of welders. Urinary chromium was studied for one week in 10 full-time exposed steel welders. The difference between the chromium values at the end of the workshift and those at the beginning was small (low current exposure); the chromium values at the end of the workshift were not uniform in the whole group (different past exposure levels).     

Pulmonary function abnormalities and airway irritation symptoms of metal fumes exposure on automobile spot welders

BACKGROUND: Spot or resistance welding has been considered less hazardous than other types of welding. Automobile manufacturing is a major industry in Taiwan. Spot and arc welding are common processes in this industry. The respiratory effects on automobile spot welders exposed to metal fumes are investigated. METHODS: The cohort consisted of 41 male auto-body spot welders, 76 male arc welders, 71 male office workers, and 59 assemblers without welding exposure. Inductivity Coupled Plasma Mass Spectrophotometer (ICP-MS) was applied to detect metals' (zinc, copper, nickel) levels in the post-shift urine samples. Demographic data, work history, smoking status, and respiratory tract irritation symptoms were gathered by a standard self-administered questionnaire. Pulmonary function tests were also performed. RESULTS: There were significantly higher values for average urine metals' (zinc, copper, nickel) levels in spot welders and arc welders than in the non-welding controls. There were 4 out of 23 (17.4%) abnormal forced vital capacity (FVC) among the high-exposed spot welders, 2 out of 18 (11.1%) among the low-exposed spot welders, and 6 out of 130 (4.6%) non-welding-exposed workers. There was a significant linear trend between spot welding exposure and the prevalence of restrictive airway abnormalities (P = 0.036) after adjusting for other factors. There were 9 out of 23 (39.1%) abnormal peak expiratory flow rate (PEFR) among high-exposed spot welders, 5 out of 18 (27.8%) among the low-exposed spot welders, and 28 out of 130 (21.5%) non-welding-exposed workers. There was a borderline significant linear trend between spot welding exposure and the prevalence of obstructive lung function abnormalities (P = 0.084) after adjusting for other factors. There was also a significant dose-response relationship of airway irritation symptoms (cough, phlegm, chronic bronchitis) among the spot welders. Arc welders with high exposure status also had a significant risk of obstructive lung abnormalities (PEFR reduction). There was also a significant dose-response relationship of airway irritation symptoms (cough, phlegm, chest tightness, and chronic bronchitis) among the arc welders. CONCLUSIONS: These findings suggest that restrictive and obstructive lung abnormalities, and airway irritation symptoms are associated with spot and arc welding exposures.     

上海市宝山区焊接作业场所中电焊烟尘和锰及其无机化合物浓度调查

目的了解上海市宝山区焊接作业场所中电焊烟尘、锰及其无机化合物浓度情况。方法以个体采样方法采集电焊烟尘和锰及其无机化合物,分别采用滤膜称重法和火焰原子吸收光谱法分别进行检测。结果分别对91名焊工和47名焊工进行电焊烟尘和锰及其无机化合物个体采样,结果 28人(30.8%)电焊烟尘时间加权平均(TWA)浓度超过国家职业接触限值,14人(29.8%)锰及其化合物浓度超过国家职业接触限值。CO2气保焊组电焊烟尘TWA均值为5.22 mg/m3,是其他焊接组TWA均值的2.8倍,锰及其无机化合物TWA均值为0.221 mg/m3,是其他焊接组TWA均值的2.7倍。结论 CO2气保焊岗位电焊烟尘、锰及其无机化合物职业危害都较严重。工厂企业应加强职业卫生管理,改善工作环境,为焊工配备有效的个人防护用品,以保障工人身体健康。     

Lung-retained contaminants,urinary chromium and nickel among stainless steel welders

Summary The magnetic method of measuring the amount of lung retained contaminants as well as urinary chromium and nickel determinations have been performed among 83 stainless steel (SS) welders who have used matural metal arc (MMA) and tungsten inert gas (TIG) welding techniques. The welders were divided into four groups according to the time percentage used for MMA welding. Only exposure to MMA/SS welding fumes resulted in clearly elevated chromium concentrations in the urine, the correlation coefficient between the values of urinary chromium and MMA/SS percentage being very significant (P < 0.001). Among the smokers the urinary chromium values were increased (P < 0.05) perhaps owing to contaminated cigarettes. In many workplaces the urinary chromium values of several welders exceeded the value of 30 g/l which is the recommended reference value in Finland. Owing to the solubility properties of nickel compounds in SS welding fumes urinary nickel concentrations were only slightly elevated among MMA/SS welders, and therefore, the urinary nickel determinations do not reflect the level of exposure to nickel compounds. The measured average remanent magnetic field of the chest area correlated well (P < 0.01) with the use of the MMA technique. A very significant correlation (P < 0.001) existed between the average remanent magnetic fields of the chest and the urinary chromium values of MMA/SS welders.     

Lung function and clinical findings in a cross-sectional study of arc welders

Summary An epidemiological, cross-sectional study was conducted in order to assess non-neoplasic effects on the lung due to chronic exposure to arc welding fumes and gases. The study involved 346 arc welders and 214 control workers from a factory producing industrial vehicles. These workers (welders and controls) had never been exposed to asbestos. Respiratory impairments were evaluated by using a standardized questionnaire, a clinical examination, chest radiophotography and several lung function tests (spirometry, bronchial challenge test to acetylcholine, CO transfer tests according to the breath-holding and the steady-state methods, N₂ washout test). The only significant differences between the welders overall compared to the controls were a slightly higher bronchial hyper-reactivity to acetylcholine and a lower lung diffusing capacity for CO in the welders. However, non-specific, radiologic abnormalities (reticulation, micronodulation) and obstructive signs were more frequent in the most exposed welders (welding inside tanks) than in welders working in well ventilated workplaces. The nature of the metal welded (mild-steel, stainless steel, aluminium) did not seem to have an influence on respiratory impairments. In the mild-steel welders, respiratory symptoms (dyspnoea, recurrent bronchitis) and obstructive signs were more frequent in the welders using a manual process than in the welders involved with the semi-automatic process (MIG). For all the workers (welders and controls), smoking had a markedly adverse effect on respiratory symptoms and lung function. Moreover, smoking seemed to interact with welding since CO lung transfer was more impaired in smoking welders than in smoking controls.     

Neurobehavioral performance in aluminum welders

METHODS: Twenty aluminum welders (mean age 33 years; range 21-52), who had been exposed to aluminum for an average of 8.1 years (range 2-21), were tested for tremor and reaction time and screened for neuropsychiatric symptoms in a cross-sectional study. The welders' median urinary aluminum concentration was 1.5 micromol/L (range 0. 7-4.8). Aluminum in air, measured inside the respiratory protection, was 0.9 mg/m(3) (range 0.6-3.8). The welders were compared with twenty construction workers matched for age. RESULTS: Welders reported more symptoms than referents did (median 2 vs. 1; P=0.047). Although the welders as a group performed better than the referents on a tremor test, years of exposure, but not age, was predictive of poorer performance. The welders' reaction times were rapid by clinical standards (mean simple reaction time (SRT): 221 milliseconds; mean continuous performance test (CPT): 364 milliseconds). Although, as a group, they performed better than the referents, there was a statistically significant relation between longer reaction times and aluminum in air (air-Al). CONCLUSIONS: The relations between hand steadiness and years exposed, and between reaction time and air-Al, could indicate slight effects from exposure to aluminum. The possibility of selection of workers with high manual skills into welding work and a possible job-related training effect, might partly serve to explain the good performance among the welders.     

Semen quality in welders exposed to radiant heat.

Several studies suggest that welding is detrimental to the male reproductive system. Welding fume and radiant heat are of interest as possible causal factors. This study investigates semen quality and sex hormone concentrations among 17 manual metal arc alloyed steel welders with a moderate exposure to radiant heat (globe temperature ranging from 31.1 degrees to 44.8 degrees C), but without substantial exposure to welding fume toxicants. During exposure to heat the skin temperature in the groin increased on average by 1.4 degrees C (SE +/- 0.72 degrees C). Sperm count and motile sperm count were non-significantly reduced among welders in comparison with two different reference groups. Within the group of welders the proportion of sperm with normal shape declined significantly after six weeks of exposure to heat and increased after a break in exposure. Sperm count and sperm concentration had the same pattern of intraindividual change in relation to exposure to radiant heat, but the changes were not statistically significant. No consistent changes in concentrations of sex hormones were found. The welders investigated were more exposed to radiant heat than welders in general. The results suggest that the study group of welders experienced a reversible decrease in semen quality, most likely caused by a moderate exposure to radiant heat (about five hours a day through several weeks). It remains to be established if even lower levels of exposure to radiant heat in the general population of welders has any impact on semen quality and fertility.     

Semen quality in welders exposed to radiant heat.

Several studies suggest that welding is detrimental to the male reproductive system. Welding fume and radiant heat are of interest as possible causal factors. This study investigates semen quality and sex hormone concentrations among 17 manual metal arc alloyed steel welders with a moderate exposure to radiant heat (globe temperature ranging from 31.1 degrees to 44.8 degrees C), but without substantial exposure to welding fume toxicants. During exposure to heat the skin temperature in the groin increased on average by 1.4 degrees C (SE +/- 0.72 degrees C). Sperm count and motile sperm count were non-significantly reduced among welders in comparison with two different reference groups. Within the group of welders the proportion of sperm with normal shape declined significantly after six weeks of exposure to heat and increased after a break in exposure. Sperm count and sperm concentration had the same pattern of intraindividual change in relation to exposure to radiant heat, but the changes were not statistically significant. No consistent changes in concentrations of sex hormones were found. The welders investigated were more exposed to radiant heat than welders in general. The results suggest that the study group of welders experienced a reversible decrease in semen quality, most likely caused by a moderate exposure to radiant heat (about five hours a day through several weeks). It remains to be established if even lower levels of exposure to radiant heat in the general population of welders has any impact on semen quality and fertility.     

The potential hazardous effect of exposure to iron dust in Egyptian smoking and nonsmoking welders

Exposure to iron dust and welding fumes is widespread and may increase the risk of lung inflammation. The aim of this study was to identify associations between exposure to iron/welding fumes and the levels of inflammatory parameters and allergic mediators among 120 Egyptian men. Forty nonsmoking and 40 smoking Egyptian welders as well as 40 healthy volunteers who were never exposed to welding fumes and were nonsmoking were enrolled in the study. Peak expiratory flow rates (PEFR) assessed at the end of the shift of work on working days revealed an impairment in lung function, with the smoking workers showing the worse results, followed by nonsmoking workers, as compared to healthy volunteers. Moreover, the results of the present study showed a significant increase in serum iron and immunoglobulin E, as well as plasma thiobarbaturic acid reactive substances, C-reactive protein, tumor necrosis factor-alpha, haptoglobin, interleukin-2, interleukin-6 and interleukin-23 histamine, lactate dehydrogenase isoenzyme-3, and calcitonin. In addition, the results revealed significant decrease in plasma α-1-antitrypsin and serum transferrin, as well as blood activities of antioxidant enzymes: catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase (as compared with control group). However, there was a nonsignificant change in arginase and α-L-fucosidase in smoking and nonsmoking welders exposed to iron dust and welding fumes. In conclusion, occupational exposure to iron dust and welding fumes increases lung inflammation risk among Egyptian blacksmith workers, a condition that worsens with smoking.     

Short-term respiratory function changes in relation to workshift welding fume exposures

Summary The forced vital capacity (FVC), the forced expiratory volume in one second (FEV₁) and the transfer factor for the lung (TL) were measured before and after the 8-h work shift in groups of welders and non-welder controls in a shipyard. For each subject, full-shift average concentrations of welding fume constituents were evaluated. On the average, the lung function indices in both groups of welders and controls decreased from morning through afternoon. The welders demonstrated more reduction in the indices than the control group. In general, there was no significant association between the acute changes in the lung function and the daily amount of exposure to welding fume constituents or the welding environmental factors. However, the overall difference of mean diurnal variations in TL between the groups working under different ventilation condition was significant (P<0.01). On the average, welders who did not use any ventilation system showed maximum reductin in TL value. Acute reduction of FEV₁ was positively correlated (P<0.05) with the levels of iron oxide produced during welding.     

Chronic effects of welding exposure on pulmonary function tests and respiratory symptoms.

OBJECTIVES--The respiratory effects of exposure to welding fumes have been investigated in numerous studies; but results of these studies have not been consistent. The aim of the present study was to investigate the respiratory effects of welding exposure in a large group of manual are welders exposed primarily to mild steel welding processes in confined spaces without respiratory protection. METHODS--Respiratory symptoms and spirometry were studied in 110 welders and 55 controls. The welders and controls were of similar average age and height; smoking habits of the groups were similar. Chest x ray films were taken to exclude people with radiological abnormalities that may influence pulmonary function tests. Welders were grouped according to smoking habits and duration of employment (< 20 years or > 20 years). RESULTS--No gross radiological abnormalities were found. Respiratory symptoms and chronic bronchitis were more prevalent in welders (P < 0.05). Welders who were smokers showed a higher frequency of chronic bronchitis than controls who smoked (P < 0.05). No significant difference in the occurrence of chronic bronchitis was found between welders who smoked and welders who were non-smokers or exsmokers. Compared with the controls, forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow (PEF), and maximum midexpiratory flow (MMEF) were significantly lower in welders (mean values of FVC for welders and controls were 86.06 (25.74) and 96.40 (13.03); and values for FEV1 were 87.54 (13.70) and 95.36 (12.40) respectively; P < 0.01). There was no significant difference in pulmonary function tests between welders who were non-smokers and controls who were non-smokers; whereas FVC, FEV1, PEF, and MMEF were significantly lower in welders who smoked than controls who smoked (P < 0.01). There were no significant differences in pulmonary function tests and occurrence of chronic bronchitis between welders with more or less than 20 years at work. CONCLUSION--Welders working in conditions of inadequate ventilation, have increased risk of chronic bronchitis and impairment of pulmonary function.     

Urinary β2 microglobulin in workers exposed to arc welding fumes

Welding is a process in which two or more metals are attached by the use of heat and, in some cases, pressure. Direct exposure and inhalation of welding fumes causes acute and chronic side effects in humans. Kidney damage is one of these important side effects. β(2) microglobulin is an 11.8 kilodalton protein and levels increase in the case of some inflammatory and viral diseases, or kidney malfunction and autoimmune diseases. In this study measurements of β(2) microglobulin were used as a criterion for assessing effects on the kidneys of workers exposed to welding fumes. The study population were electric arc welders in an industrial plant in Tehran, Iran. For control we selected workers who did not have any exposure to welding fumes. Both groups were selected on the basis of a questionnaire and the consideration of criteria for inclusion and exclusion. In the end 50 cases and 50 controls were chosen. A urine sample was collected from all participants and urinary pH was set to between 6-8 using NaOH (1M). Sample transportation to the laboratory complied with the related standards. The samples were assessed using the ORG 5BM kit. For quantitative assessment of β(2) microglobulin we used the Enzyme-linked Immunosorbent Assay (ELISA) method. The ages of the welders ranged from 21 to 48 years (mean=30.5 ± 5.9 yrs) and of controls from 23 to 56 years (mean=31.8 ± 5.9 yrs). Mean employment duration was 7.86 ± 5.01 years (range 2 to 27 years) for welders. Mean β(2) microglobulin level was 0.10 ± 0.096 μg/ml in welders and 0.11 ± 0.06 in controls. This difference was not statistically significant (P=0.381). In conclusion we don't find that exposure to electric arc welding fumes cause a significant change in urinary β(2) microglobulin compared to the control group.     

Lung function in Pakistani welding workers

Our objective was to study the effects of welding fumes and their duration of exposure on lung function. This was a matched case-control cross-sectional study of spirometry in 50 nonsmoking manual metal arc welders who work without the benefit of welding fume control ventilation or respiratory protective devices. Welding workers, with exposures longer than 9 years, showed a significant reduction in spirometry (forced expiratory volume in one second [FEV1], FEV1/forced vital capacity [FVC%], and peak expiratory flow [PEF]) relative to controls. Lung function in nonsmoking welding workers is impaired and stratification of results shows a dose-effect of years of welding on lung function. This effect primarily shows an obstructive pattern of airways disease. Preventive measures in developing countries have to be adopted to avert long-term lung damage in welders.     

Exposure and urinary excretion of aluminum during welding

The exposure and urinary excretion of aluminum was studied among three previously unexposed volunteers and six welders exposed to welding fumes containing aluminum. The aluminum concentrations in air and urine were determined. The urinary aluminum concentrations rose rapidly in volunteers exposed only for 1 d and returned to the preexposure levels with an estimated half-time of about 8 h. The welders were monitored for one workweek. During the subsequent weekend a decrease in the urinary concentrations occurred in the three welders exposed for two years or less, but such a decrease was not observed among welders exposed for more than 15 years. The urinary concentrations of aluminum were dependent partly on the level of current exposure and partly on the duration of exposure. The data suggest that welders exposed to welding fumes containing aluminum may retain some of the inhaled metal fume for extended periods of time.     

电焊作业对工人心血管功能的影响

目的探讨电焊对男性作业工人心血管功能的影响。方法选择135名男性电焊工人及138名无职业接触的管理岗位人员(对照组)为对象,检测心电图和血压,测定尿锰含量和血清心肌酶谱:肌酸激酶(CK)及其同工酶(CK-MB)、天冬氨酸转氨酶(AST)、α-羟丁酸脱氢酶(α-HBD)和乳酸脱氢酶(LDH)。结果接触组尿锰含量显著高于对照组,接触组血清CK、α-HBD和LDH水平显著升高(P0.05);舒张压降低,心电图异常率增高(P0.05)。结论电焊对作业工人的心血管功能有一定影响。     

不锈钢电焊烟尘对工人尿铬、尿NAG和尿δ－ALA的影响

以尿铬、Ｎ－乙酰－β－Ｄ氨基葡萄糖苷酶（ＮＡＧ）和δ－氨基乙酰丙酸（δ－ＡＬＡ）作为不锈钢电焊烟尘接触者早期职业性损害指标，探讨了各指标间关系及铬的尿廓清生物半减期（ＢＨＴ）。结果表明，接触组工人班后尿铬与电焊烟尘浓度、班前与班后尿ＮＡＧ活力、ＮＡＧ活力与尿δ－ＡＬＡ、班后尿铬与尿δ－ＡＬＡ等均呈显著正相关（Ｐ＜０．０５）。按毒物代谢动力学公式推算，铬的尿廓清ＢＨＴ约为５０ｈ左右。认为尿铬、ＮＡＧ、δ－ＡＬＡ可作为对电焊工生物学监测的同类指标。     

Asthma,lung function,and bronchial responsiveness in welders

The incidence of asthma was compared in welders welding in stainless steel (SS) or mild steel (MS). The study was comprised of welders who had been welding for at least 6 months during the preceding 10 year period in four companies, but who had not been welding occupationally prior to this time. The inclusion criteria were met by 42 SS welders with a total welding time of 196 years. Sixteen of these had left work, six because of airway symptoms. Eighty-five MS welders with a total welding time of 403 years were included. Forty-eight of these had left work, 10 citing airway symptoms as a main reason for leaving work, according to responses in a mailed questionnaire. Ex-welders with airway symptoms were in some cases further investigated with spirometry and bronchial provocation tests. In other cases, medical records gave a clear diagnosis. In addition, bronchial responsiveness and lung function were measured and airway symptoms were recorded in presently active welders. Twenty-three of the 26 active SS steel welders and 23 of the 37 active MS steel welders were examined, together with a reference group of 26 (out of 30 invited) vehicle assemblers. There was no difference in the incidence of welding-associated asthma (5% for SS, 7% for MS welders per 1,000 welding-years). Bronchial responsiveness and lung function in active welders was normal and did not differ between MS and SS welders or between welders and a reference group of vehicle fitters. Welders had a significantly higher prevalence of airway symptoms as compared to vehicle fitters.     

Pulmonary X-ray and functional findings in electric-arc welders

Summary 37 arc welders were examined; 23 of them had worked for part of the time inside closed cisterns under some of the most hazardous working conditions in Prague where MAC for inert dust was greatly exceeded. Radiographic pulmonary alterations were found in 30 of the subjects. These findings mostly belonged to category 1, type s, t, p (according to ILO classification, 1971); only 4 welders from the high-risk group had developed nodulation type m, n, category 2 after an average of 25 years of welding.Statistical comparison of 22 arc welders displaying positive X-ray findings but without chronic bronchitis with a control group of 20 persons of comparable age who were normal in a cardiopulmonary respect revealed no significant differences in lung function.