Acute respiratory effects of exposure to stainless steel and mild steel welding fumes

Oxidative stress status of Turkish welders

Welding, a fabrication process that joins metals or thermoplastics by causing coalescence, is indispensable in modern society and ubiquitous in industry. Welding generates fumes that contain several metals and gases that comprise fine and ultrafine particles with the potential for adverse effects. Although health risks of welders have been evaluated in different populations, occupational exposure to welding fumes is still considered to be an important health problem, especially in developing countries. The aim of this study was to investigate the effects of welding fume exposure on important oxidative stress parameters such as superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), total glutathione (GSH), glutathione peroxidase (GPx), malondialdehyde (MDA), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in Turkish welders (n = 48). The influence of confounding factors such as age, smoking habits, alcohol consumption, and duration of exposure on the studied parameters was also analyzed. In our study, significant decreases in the levels of GSH and activities of CAT, SOD, and GPx and significant increases of MDA, 8-OHdG levels and GR activity were found in the workers compared to the controls. There was a negative correlation between GSH levels and alcohol usage. Also, older workers (≥35 years) had significantly higher GR levels than younger workers. But smoking and alcohol usage, duration of exposure, and utilization of protective measures had no significant effect on the studied parameters in the workers. These results indicate that occupational exposure to welding fumes appears to induce oxidative stress and oxidative DNA damage.

Welding Fumes, a Risk Factor for Lung Diseases

(1) Background: Welding fumes (WFs) are composed of fine and ultrafine particles, which may reach the distal airways and represent a risk factor for respiratory diseases. (2) Methods: In vitro and in vivo studies to understand WFs pathogenesis were selected. Epidemiological studies, original articles, review, and meta-analysis to examine solely respiratory disease in welders were included. A systematic literature search, using PubMed, National Institute for Occupational Safety and Health Technical Information Center (NIOSHTIC), and Web of Science databases, was performed. (3) Results: Dose, time of exposure, and composition of WFs affect lung injury. Inflammation, lung defense suppression, oxidative stress, DNA damage, and genotoxic effects were observed after exposure both to mild and stainless steel WFs. (4) Conclusions: The detection of lung diseases associated with specific occupational exposure is crucial as complete avoidance or reduction of the exposure is difficult to achieve. Further studies in the area of particle research may aid the understanding of mechanisms involved in welding-related lung disease and to expand knowledge in welding-related cardiovascular diseases.

Health Risk of Occupational Exposure in Welding Processes II. Immunological Effects

Many of epidemiological studies have certified the relationship between welding and various forms of health damages. In our study we performed an immunological research within a group of twenty men, working in the risky environment of manufacturing of stainless steel constructions (11 welders and 9 grinders, average age was 31 years, 55 % of smokers, average time period in welding occupational exposure was 8 years). The exposed group of men was compared with a group of healthy blood donors, marked as the control group (people with various types of employment, living in same locality as a people from exposed group). People within the control group were not occupationally exposed to harmful chemical compounds (from 30 to 100 men were chosen for the individual immune parameters, average age of the whole group was 38 years, 40 % of smokers). When compared with the control group, the exposed group of welders and grinders showed higher level of C3 complement (p<0.001), orosomucoid (p<0.05), beta-2–microglobulin (p<0.001), neopterin (p<0.001) and all fagocytic cells (p<0.001). On the contrary, in the group of exposed people decreased values of IgA (p<0.001), IgG (p<0.001), IgM (p<0.001), transferin (p<0.001), alpha-1–antitrypsin (p<0.001), alpha-2–macroglobulin (p<0.001), haptoglobulin (p<0.001) and ceruloplasmin (p<0.05) were found. Some of these changes were characteristic for the exposed group. They could be considered as precursors of biological markers of effect for given type of exposure.

Exposure to heavy metals alters the surface topology of alveolar macrophages and induces respiratory dysfunction among Indian metal arc-welders

BACKGROUND

Despite the available clinico-epidemiological evidence of heavy metal-associated respiratory health hazards among metal arc-welders, experimental confirmation of such an association is lacking.

METHODS

In this study, we recruited 15 metal arc-welders and 10 referent workers without direct exposure. We assessed respiratory health through a questionnaire and spirometry; estimated manganese, nickel and cadmium levels in blood, urine and induced sputum; performed differential counts of sputum leucocytes and measured plasma malondialdehyde (MDA). We used atomic force and scanning electron microscopy to assess the physical property of the alveolar macrophages (AMs) obtained from induced sputum and analysed cell surface deposition of heavy metals using energy dispersion X-ray analysis (EDX). Sputum cellular DNA damage was assessed by DNA-laddering assay.

RESULTS

There was a higher body burden of manganese and nickel in the metal arc-welders than the referents. Among major spirometric indices, only the forced mid-expiratory flow rates (FEF_25-75) were reduced in the welders compared with the referents (63.4 ± 14.7 vs. 89.2 ± 26.7, p < 0.01); this reduction was associated with both heavy metal levels (β: -41.8, 95% CI: -78.5% to -5.1%) and plasma MDA (-0.37; -0.68 to -0.06). In metal arc-welders, significant physical and morphological changes were observed in AMs through microscopic evaluation while EDX analyses demonstrated higher deposition of heavy metals on the AM cell surface than the referents. We also observed a higher degree of DNA damage in the sputum cells of the exposed workers than the referents.

CONCLUSION

Heavy metal exposure-induced adverse respiratory effects among metal arc-welders are mediated through haematological and cytological interactions.

Dose-response of Cotton Dust Exposure with Lung Function among Textile Workers: MultiTex Study in Karachi, Pakistan

BACKGROUND

Cotton dust exposure among textile mill workers lead to impaired lung function. However, only few studies have investigated the dose-response relationship between cotton dust and lung function.

OBJECTIVE

To determine the dose-response relationship between cotton dust exposure and lung function among textile workers.

METHODS

This cross-sectional survey was conducted from January to March 2016 and included 303 adult male textile workers from spinning and weaving sections of 5 mills in Karachi, Pakistan. We collected data through a translated version of the American Thoracic Society respiratory questionnaire (ATS-DLD-78A) and using spirometry. Mill-level airborne cotton dust was measured over an 8-12-hour shift through UCB-PATS (University of California, Berkeley-Particle, and Temperature Monitoring System). Multiple linear regression was used to determine the association between cotton dust exposure and lung function assessed through the 3 indices: forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), and their ratio (FEV1/FVC).

RESULTS

The mean age of the workers was 32.5 (SD 10.5) years. The mean spirometry indices expressed in percent predicted values were FEV1 82.6 (SD 14.0); FVC 90.3 (14.7), and FEV1/FVC 94.9 (10.5). The median cotton dust concentration was 0.61 (IQR 0.2 to 1.3) mg/m3. The frequency of respiratory symptoms was 15% for cough, 20% for phlegm, and 20% for wheezing. After adjustment for covariates, every mg/m3 increase in dust concentration was associated with 5.4% decline in FEV1.

CONCLUSION

This study quantifies the exposure-dependent relationship between cotton dust and lung function; which has implications for regulations and standards in the textile industry in Pakistan and similar cotton-processing countries.

The time-dependent health and biochemical effects in rats exposed to stainless steel welding dust and its soluble form

Welding processes that generate fumes containing toxic metals, such as hexavalent chromium (Cr(VI)), manganese (Mn), and nickel (Ni), have been implicated in lung injury, inflammation, and lung tumor promotion in animal models. The principal objective of this study was to determine the dynamics of toxic effects of inhalation exposure to morphologically rated welding dust from stainless steel welding and its soluble form in TSE System with a dynamic airflow. We assessed the pulmonary toxicity of welding dust in Wistar rats exposed to 60.0 mg/m³ of respirable-size welding dust (mean diameter 1.17 µm) for 2 weeks (6 h/day, 5 days/week); the aerosols were generated in the nose-only exposure chambers (NOEC). An additional aim included the study of the effect of betaine supplementation on oxidative deterioration in rat lung during 2 weeks of exposure to welding dust or water-soluble dust form. The animals were divided into eight groups (n = 8 per group): control, dust, betaine, betaine + dust, soluble-form dust, soluble-form dust + betaine, saline and saline + betaine groups. Rats were euthanized 1 or 2 weeks after the last exposure for assessment of pulmonary toxicity. Differential cell counts, total protein concentrations and cellular enzyme (lactate dehydrogenase-LDH) activities were determined in bronchoalveolar lavage (BAL) fluid, and corticosterone and thiobarbituric acid reactive substances (TBARS) concentrations were assessed in serum. The increase in polymorphonuclear (PMN) leukocytes in BAL fluid (a cytological index of inflammatory responses of the lung) is believed to reflect pulmonary toxicity of heavy metals. Biomarkers of toxicity assessed in bronchoalveolar fluids indicate that the level of the toxic effect depends mainly on the solubility of studied metal compounds; biomarkers that showed treatment effects included: total cell, neutrophil and lymphocyte counts, total protein concentrations, and cellular enzyme (lactate dehydrogenase) activity. Betaine supplementation at 250 mg/kg/day in all study rats groups attenuated stress indices, and corticosterone and TBARS serum levels, and simultaneously stimulated increase of polymorphonuclear cells in BALF of rats. The study confirmed deleterious effect of transitory metals and particles during experimental inhalation exposure to welding dusts, evidenced in the lungs and brain by increased levels of total protein, higher cellular influx, rise of LDH in BALF, elevated TBARS and increased corticosterone in serum of rats. Our result confirm also the hypothesis about the effect of the welding dusts on the oxidative stress responsible for disturbed systemic homeostasis and impairment of calcium regulation.

Association between personal exposure to ambient metals and respiratory disease in Italian adolescents: a cross-sectional study

Background

Release of ambient metals during ferroalloy production may be an important source of environmental exposure for nearby communities and exposure to these metals has been linked to adverse respiratory outcomes. We sought to characterize the association between personal air levels of metals and respiratory health in Italian adolescents living in communities with historic and current ferroalloy activity.

Methods

As part of a study in the industrial province of Brescia, Italy, 410 adolescents aged 11–14 years were recruited. Participants were enrolled from three different communities with varying manganese (Mn) levels: Bagnolo Mella which has current ferroalloy activity, Valcamonica, which has historic ferroalloy activity and Garda Lake which has no history of ferroalloy activity. Particulate matter <10 μm in diameter (PM₁₀) was collected for 24 h in filters using personal sampling. Mn, nickel (Ni), zinc (Zn), chromium (Cr) and iron (Fe) were measured in filters using x-ray fluorescence. Data on respiratory health was collected through questionnaire. Data for 280 adolescents were analyzed using a modified Poisson regression, and risk ratios were calculated for an interquartile (IQR) range increase in each pollutant.

Results

In adjusted models including PM₁₀ as a co-pollutant, we found significant associations between concentrations of Mn (RR: 1.09, 95 % CI [1.00, 1.18] per 42 ng/m³ increase), Ni (RR: 1.11, 95 % CI [1.03, 1.21] per 4 ng/m³ increase) and Cr (RR: 1.08, 95 % CI [1.06, 1.11] per 9 ng/m³ increase) and parental report of asthma. We also found significant associations between increased Mn and Ni and increased risk of asthma medication use in the past 12 months (RR: 1.13, 95 % CI [1.04, 1.29] and (RR: 1.13, 95 % CI [1.01, 1.27] respectively).

Conclusions

Our findings suggest that exposure to ambient Mn, Ni and Cr may be associated with adverse respiratory outcomes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0173-9) contains supplementary material, which is available to authorized users.

Comparative microscopic study of human and rat lungs after overexposure to welding fume

Welding is a common industrial process used to join metals and generates complex aerosols of potentially hazardous metal fumes and gases. Most long-time welders experience some type of respiratory disorder during their time of employment. The use of animal models and the ability to control the welding fume exposure in toxicology studies have been helpful in developing a better understanding of how welding fumes affect health. There are no studies that have performed a side-by-side comparison of the pulmonary responses from an animal toxicology welding fume study with the lung responses associated with chronic exposure to welding fume by a career welder. In this study, post-mortem lung tissue was donated from a long-time welder with a well-characterized work background and a history of extensive welding fume exposure. To simulate a long-term welding exposure in an animal model, Sprague-Dawley rats were treated once a week for 28 weeks by intratracheal instillation with 2mg of a stainless steel, hard-surfacing welding fume. Lung tissues from the welder and the welding fume-treated rats were examined by light and electron microscopy. Pathological analysis of lung tissue collected from the welder demonstrated inflammatory cell influx and significant pulmonary injury. The poor and deteriorating lung condition observed in the welder examined in this study was likely due to exposure to very high levels of potentially toxic metal fumes and gases for a significant number of years due to work in confined spaces. The lung toxicity profile for the rats treated with welding fume was similar. For tissue samples from both the welder and treated rats, welding particle accumulations deposited and persisted in lung structures and were easily visualized using light microscopic techniques. Agglomerates of deposited welding particles mostly were observed within lung cells, particularly alveolar macrophages. Analysis of individual particles within the agglomerates showed that these particles were metal complexes with iron, chromium, and nickel being the most common metals present. In conclusion, long-term exposure to specific welding fume can lead to serious chronic lung disease characterized by significant particle deposition and persistence as demonstrated in both a human case study and rat model. Not only were the lung responses similar in the human and rat lungs, as evidenced by inflammatory cell influx and pulmonary disease, but the composition of individual welding particles and agglomerations in situ was comparable.

Assessment of the biological effects of welding fumes emitted from metal inert gas welding processes of aluminium and zinc-plated materials in humans

The aim of this study was to investigate biological effects and potential health risks due to two different metal-inert-gas (MIG) welding fumes (MIG welding of aluminium and MIG soldering of zinc coated steel) in healthy humans. In a threefold cross-over design study 12 male subjects were exposed to three different exposure scenarios. Exposures were performed under controlled conditions in the Aachener Workplace Simulation Laboratory (AWSL). On three different days the subjects were either exposed to filtered ambient air, to welding fumes from MIG welding of aluminium, or to fumes from MIG soldering of zinc coated materials. Exposure was performed for 6 h and the average fume concentration was 2.5 mg m(-3). Before, directly after, 1 day after, and 7 days after exposure spirometric and impulse oscillometric measurements were performed, exhaled breath condensate (EBC) was collected and blood samples were taken and analyzed for inflammatory markers. During MIG welding of aluminium high ozone concentrations (up to 250 μg m(-3)) were observed, whereas ozone was negligible for MIG soldering. For MIG soldering, concentrations of high-sensitivity CRP (hsCRP) and factor VIII were significantly increased but remained mostly within the normal range. The concentration of neutrophils increased in tendency. For MIG welding of aluminium, the lung function showed significant decreases in Peak Expiratory Flow (PEF) and Mean Expiratory Flow at 75% vital capacity (MEF 75) 7 days after exposure. The concentration of ristocetin cofactor was increased. The observed increase of hsCRP during MIG-soldering can be understood as an indicator for asymptomatic systemic inflammation probably due to zinc (zinc concentration 1.5 mg m(-3)). The change in lung function observed after MIG welding of aluminium may be attributed to ozone inhalation, although the late response (7 days after exposure) is surprising.

Increased metal concentrations in exhaled breath condensate of industrial welders

It was the aim of this study to evaluate the effect of different devices on the metal concentration in exhaled breath condensate (EBC) and to prove whether working conditions in different welding companies result in diverse composition of metallic elements. The influence of two collection devices (ECoScreen, ECoScreen2) on detection of metallic elements in EBC was evaluated in 24 control subjects. Properties of ECoScreen and a frequent use can alter EBC metal content due to contamination from metallic components. ECoScreen2 turned out to be favourable for metal assessment. Concentrations of iron, nickel and chromium in EBC sampled with ECoScreen2 were compared between non-exposed controls and industrial welders. Metal concentrations in EBC were higher in 36 welders recruited from three companies. Exposure to welding fumes could be demonstrated predominantly for increased iron concentrations. Concentrations of iron and nickel differed by working conditions, but chromium could not be detected in EBC.

Comparison of stainless and mild steel welding fumes in generation of reactive oxygen species

Background

Welding fumes consist of a wide range of complex metal oxide particles which can be deposited in all regions of the respiratory tract. The welding aerosol is not homogeneous and is generated mostly from the electrode/wire. Over 390,000 welders were reported in the U.S. in 2008 while over 1 million full-time welders were working worldwide. Many health effects are presently under investigation from exposure to welding fumes. Welding fume pulmonary effects have been associated with bronchitis, metal fume fever, cancer and functional changes in the lung. Our investigation focused on the generation of free radicals and reactive oxygen species from stainless and mild steel welding fumes generated by a gas metal arc robotic welder. An inhalation exposure chamber located at NIOSH was used to collect the welding fume particles.

Results

Our results show that hydroxyl radicals (^.OH) were generated from reactions with H₂O₂ and after exposure to cells. Catalase reduced the generation of ^.OH from exposed cells indicating the involvement of H₂O₂. The welding fume suspension also showed the ability to cause lipid peroxidation, effect O₂ consumption, induce H₂O₂ generation in cells, and cause DNA damage.

Conclusion

Increase in oxidative damage observed in the cellular exposures correlated well with ^.OH generation in size and type of welding fumes, indicating the influence of metal type and transition state on radical production as well as associated damage. Our results demonstrate that both types of welding fumes are able to generate ROS and ROS-related damage over a range of particle sizes; however, the stainless steel fumes consistently showed a significantly higher reactivity and radical generation capacity. The chemical composition of the steel had a significant impact on the ROS generation capacity with the stainless steel containing Cr and Ni causing more damage than the mild steel. Our results suggest that welding fumes may cause acute lung injury. Since type of fume generated, particle size, and elapsed time after generation of the welding exposure are significant factors in radical generation and particle deposition these factors should be considered when developing protective strategies.

Total fume and metal concentrations during welding in selected factories in Jeddah, Saudi Arabia

Welding is a major industrial process used for joining metals. Occupational exposure to welding fumes is a serious occupational health problem all over the world. The degree of risk to welder’s health from fumes depends on composition, concentration, and the length of exposure. The aim of this study was to investigate workers’ welding fume exposure levels in some industries in Jeddah, Saudi Arabia. In each factory, the air in the breathing zone within 0.5 m from welders was sampled during 8-hour shifts. Total particulates, manganese, copper, and molybdenum concentrations of welding fumes were determined. Mean values of eight-hour average particulate concentrations measured during welding at the welders breathing zone were 6.3 mg/m³ (Factory 1), 5.3 mg/m³ (Factory 2), 11.3 mg/m³ (Factory 3), 6.8 mg/m³ (Factory 4), 4.7 mg/m³ (Factory 5), and 3.0 mg/m³ (Factory 6). Mean values of airborne manganese, copper, and molybdenum levels measured during welding were in the range of 0.010 mg/m³–0.477 mg/m³, 0.001 mg/m³–0.080 mg/m³ and 0.001 mg/m³–0.058 mg/m³ respectively. Mean values of calculated equivalent exposure values were: 1.50 (Factory 1), 1.56 (Factory 2), 5.14 (Factory 3), 2.21 (Factory 4), 2.89 (Factory 5), and 1.20 (Factory 6). The welders in factories 1, 2, 3, and 4 were exposed to welding fume concentration above the SASO limit value, which may increase the risk of respiratory health problems.

Cement dust exposure and acute lung function: a cross shift study

Background

Few studies have been carried out on acute effects of cement dust exposure. This study is conducted to investigate the associations between current "total" dust exposure and acute respiratory symptoms and respiratory function among cement factory workers.

Methods

A combined cross-sectional and cross-shift study was conducted in Dire Dawa cement factory in Ethiopia. 40 exposed production workers from the crusher and packing sections and 20 controls from the guards were included. Personal "total" dust was measured in the workers' breathing zone and peak expiratory flow (PEF) was measured for all selected workers before and after the shift. When the day shift ended, the acute respiratory symptoms experienced were scored and recorded on a five-point Likert scale using a modified respiratory symptom score questionnaire.

Results

The highest geometric mean dust exposure was found in the crusher section (38.6 mg/m³) followed by the packing section (18.5 mg/m³) and the guards (0.4 mg/m³). The highest prevalence of respiratory symptoms for the high exposed workers was stuffy nose (85%) followed by shortness of breath (47%) and "sneezing" (45%). PEF decreased significantly across the shift in the high exposed group. Multiple linear regression showed a significant negative association between the percentage cross-shift change in PEF and total dust exposure. The number of years of work in high-exposure sections and current smoking were also associated with cross-shift decrease in PEF.

Conclusions

Total cement dust exposure was related to acute respiratory symptoms and acute ventilatory effects. Implementing measures to control dust and providing adequate personal respiratory protective equipment for the production workers are highly recommended.

Spirometry, impulse oscillometry and capnovolumetry in welders and healthy male subjects

BACKGROUND

Welding processes emit fine and ultrafine aerosol particles which are potentially harmful to the lungs of welders. In the past, changes in lung function were mostly determined by conventional spirometry. In this study spirometry was combined with new techniques such as Impulse Oscillometry (IOS) and Capnovolumetry (CVS) in order to assess welding associated changes in lung function.

METHODS

45 Male welders and 24 non-welders were investigated at two time points: before work shift (baseline) and after work shift.

RESULTS

At baseline there were no differences between both study populations in spirometric, IOS, and CVS parameters. However, parameters of the flow-volume curve decreased with increasing long-term welding fume exposure (welding years). Airway resistances measured by IOS increased with welding years. IOS central airway resistance and several parameters of CVS increased during the work shift indicating airway narrowing and more inhomogeneous ventilation.

CONCLUSIONS

In this study it has been shown that welding associated long-term and short-term effects could be detected in a population of welders, although exposure conditions were quite heterogeneous. The parameters of IOS and Capnovolumetry showed effects even more pronounced than conventional lung function parameters. Thus, these techniques may be considered as an additional tool for occupational medicine research.

A study of the bio-accessibility of welding fumes

The respiratory bio-accessibility of a substance is the fraction that is soluble in the respiratory environment and is available for absorption. In the case of respiratory exposure the amount of absorbed substance plays a main role in the biological effects. Extensive bio-accessibility studies have always been an essential requirement for a better understanding of the biological effects of different workplace aerosols, such as welding fumes. Fumes generated using three different welding techniques, manual metal arc (MMA) welding, metal inert gas (MIG) welding, and tungsten inert gas (TIG) welding were investigated in the present study. Each technique was used for stainless steel welding. Welding fumes were collected on PVC membrane filters in batches of 114 using a multiport air sampler. Three different fluids were applied for the solubility study: deionised water and two kinds of lung fluid simulants: lung epithelial lining fluid simulant (Gamble's solution) and artificial lung lining fluid simulant (Hatch's solution). In order to obtain sufficient data to study the tendencies in solubility change with time, seven different leaching periods were used (0.5, 1, 2, 4, 8, 16, 24 h), each of them with three replicates. The effect of dissolution temperature was also studied. The total amounts of selected metals in the three different welding fumes were determined after microwave-assisted digestion with the mixture of aqua regia and hydrofluoric acid. The most obvious observation yielded by the results is that the solubility of individual metals varies greatly depending on the welding technique, the composition of the leaching fluid and leaching time. This study shows that the most reasonable choice as a media for the bio-assessment of solubility might be Hatch's solution by a dissolution time of 24 h.

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.

The effect of inhaled chromium on different exhaled breath condensate biomarkers among chrome-plating workers

Chromium is corrosive, cytotoxic, and carcinogenic for humans and can induce acute and chronic lung tissue toxicity. The aim of this study was to investigate Cr levels in exhaled breath condensate (EBC) of workers exposed to Cr(VI) and to assess their relationship with biochemical changes in the airways by analyzing EBC biomarkers of oxidative stress, namely, hydrogen peroxide (H2O2) and malondialdehyde (MDA). EBC samples were collected from 24 chrome-plating workers employed in a chrome-plating plant both before and after the Friday work shift and before the work shift on the following Monday. Cr-EBC levels increased from the beginning (5.3 microg/L) to the end of Friday (6.4 microg/L) but were considerably lower on Monday morning (2.8 microg/L). A similar trend was observed for H2O2-EBC levels (which increased from 0.36 microM to 0.59 microM on Friday and were 0.19 microM on Monday morning) and MDA-EBC levels (which increased from 8.2 nM to 9.7 nM on Friday and were 6.6 nM on Monday). Cr-EBC levels correlated with those of H2O2-EBC (r = 0.54, p < 0.01) and MDA-EBC (r = 0.59, p < 0.01), as well as with urinary Cr levels (r = 0.25, p < 0.05). The results of this study demonstrate that EBC is a suitable matrix that can be used to investigate both Cr levels and biomarkers of free radical production sampling the epithelial-lining fluid of workers exposed to Cr(VI).

Occupation, smoking, and chronic obstructive respiratory disorders: a cross sectional study in an industrial area of Catalonia, Spain

BACKGROUND

Few studies have investigated the independent effects of occupational exposures and smoking on chronic bronchitis and airflow obstruction. We assessed the association between lifetime occupational exposures and airflow obstruction in a cross-sectional survey in an urban-industrial area of Catalonia, Spain.

METHODS

We interviewed 576 subjects of both sexes aged 20-70 years (response rate 80%) randomly selected from census rolls, using the ATS questionnaire. Forced spirometry was performed by 497 subjects according to ATS normative.

RESULTS

Lifetime occupational exposure to dust, gases or fumes was reported by 52% of the subjects (63% in men, 41% in women). Textile industry was the most frequently reported job in relation to these exposures (39%). Chronic cough, expectoration and wheeze were more prevalent in exposed subjects with odds ratios ranging from 1.7 to 2.0 being highest among never-smokers (2.1 to 4.3). Lung function differences between exposed and unexposed subjects were dependent on duration of exposure, but not on smoking habits. Subjects exposed more than 15 years to dusts, gases or fumes had lower lung function values (FEV1 -80 ml, 95% confidence interval (CI) -186 to 26; MMEF -163 ml, CI -397 to 71; FEV1/FVC ratio -1.7%, CI -3.3 to -0.2) than non-exposed.

CONCLUSION

Chronic bronchitis symptoms and airflow obstruction are associated with occupational exposures in a population with a high employment in the textile industry. Lung function impairment was related to the duration of occupational exposure, being independent of the effect of smoking.

Respiratory health effects related to occupational spray painting and welding

OBJECTIVE

We sought to study respiratory symptoms among automobile assembly workers.

METHODS

In a cross-sectional study, we compared rates of respiratory symptoms and of physician-diagnosed asthma and COPD in painters and welders to those in assembly workers.

RESULTS

Respiratory symptom reporting was significantly increased among welders (odds ratio [OR] = 1.79-2.61) compared with painters or assembly workers, after age, race, and smoking adjustment in multiple logistic regression analyses. Welders also reported significantly more improvement in symptoms on weekends or vacation. However, no significant elevations in adjusted ORs were observed for physician-diagnosed asthma or chronic obstructive pulmonary disease for welders. In contrast, significantly more painters had physician-diagnosed chronic obstructive pulmonary disease (OR = 3.73, 95% confidence interval = 1.27, 11.0).

CONCLUSIONS

Welders and painters in this plant appeared to have increased risk of respiratory health effects compared with assembly workers.

Correlates of oxidative stress and free-radical activity in serum from asymptomatic shipyard welders

RATIONALE

Oxidative stress is believed to play a key role in the development of welding-induced disease.

OBJECTIVES

This study investigated the effects of welding fume exposure on correlates of oxidative stress in the serum of asymptomatic shipyard welders.

METHODS

Blood samples from 197 male welders and 150 unexposed male office workers were analyzed for manganese and lead. Serum was assayed for protein, albumin, total antioxidant status (TAS), manganese superoxide dismutase (Mn-SOD), aconitase, glutathione peroxidase (GPx), heat shock protein 70, isoprostane, and reactive oxygen species, using electron spin resonance and chemiluminescence. Comparisons between welders and control subjects on biomarkers of oxidative stress were made, and evaluated for the effects of age and smoking. Associations between blood levels of manganese and lead and biomarkers were also explored.

RESULTS

Welding was associated with increases in serum protein, GPx, aconitase, TAS, and isoprostane levels compared with control subjects. These group differences were not altered by age or smoking. In welders and control subjects, age was significantly associated with changes in albumin, TAS, chemiluminescence, GPx, and Mn-SOD. In welders and control subjects, smoking resulted in a decrease in GPx, and in a significant interaction between smoking and chemiluminescence. There were significant correlations between manganese levels in welders' blood and chemiluminescence, GPx, and Mn-SOD, and between lead levels and albumin, TAS, GPx, and Mn-SOD.

CONCLUSIONS

These results document that exposure to welding can cause changes in serum biomarkers of oxidative stress that may be valuable in clinical monitoring of disease development and in assessing whether further reduction of worker exposures is needed.

Respiratory effects from work-related exposure to welding fumes in Hamadan, Iran

The authors studied respiratory symptoms and lung function among welders at welding workshops, and among nonwelders, in Hamadan, Iran. They used a questionnaire to record demographic data, smoking habits, and respiratory symptoms. The authors measured pulmonary functions with subjects standing upright. They collected metal fume samples from the respiratory zone of workers and analyzed the samples by atomic absorption spectroscopy. The concentrations of iron and manganese were higher than threshold limit values. The prevalence of asthma and clinical symptoms was higher in welders than nonwelders. Also, bronchitis was more common among welders (17.45%) than among nonwelders (2.56%). The average respiratory function values of welders were lower than those of nonwelders, with a significant difference between the means (p < 0.001 for all terms). The results of this study also strongly suggest a synergistic relationship between the effects of smoking and welding exposure.

Pulmonary responses to welding fumes: role of metal constituents

It is estimated that more than 1 million workers worldwide perform some type of welding as part of their work duties. Epidemiology studies have shown that a large number of welders experience some type of respiratory illness. Respiratory effects seen in full-time welders have included bronchitis, siderosis, asthma, and a possible increase in the incidence of lung cancer. Pulmonary infections are increased in terms of severity, duration, and frequency among welders. Inhalation exposure to welding fumes may vary due to differences in the materials used and methods employed. The chemical properties of welding fumes can be quite complex. Most welding materials are alloy mixtures of metals characterized by different steels that may contain iron, manganese, chromium, and nickel. Animal studies have indicated that the presence and combination of different metal constituents is an important determinant in the potential pneumotoxic responses associated with welding fumes. Animal models have demonstrated that stainless steel (SS) welding fumes, which contain significant levels of nickel and chromium, induce more lung injury and inflammation, and are retained in the lungs longer than mild steel (MS) welding fumes, which contain mostly iron. In addition, SS fumes generated from welding processes using fluxes to protect the resulting weld contain elevated levels of soluble metals, which may affect respiratory health. Recent animal studies have indicated that the lung injury and inflammation induced by SS welding fumes that contain water-soluble metals are dependent on both the soluble and insoluble fractions of the fume. This article reviews the role that metals play in the pulmonary effects associated with welding fume exposure in workers and laboratory animals.

Pulmonary effects of welding fumes: review of worker and experimental animal studies

BACKGROUND

Approximately one million workers worldwide perform welding as part of their work duties. Electric arc welding processes produce metal fumes and gases which may be harmful to exposed workers.

METHODS

This review summarizes human and animals studies which have examined the effect of welding fume exposure on respiratory health. An extensive search of the scientific and occupational health literature was performed, acquiring published articles which examined the effects of welding on all aspects of worker and laboratory animal health. The databases accessed included PubMed, Ovid, NIOSHTIC, and TOXNET.

RESULTS

Pulmonary effects observed in full-time welders have included metal fume fever, airway irritation, lung function changes, susceptibility to pulmonary infection, and a possible increase in the incidence of lung cancer. Although limited in most cases, animal studies have tended to support the findings from epidemiologic studies.

CONCLUSIONS

Despite the numerous studies on welding fumes, incomplete information still exists regarding the causality and possible underlying mechanisms associated with welding fume inhalation and pulmonary disease. The use of animal models and the ability to control the welding fume exposure in toxicology studies could be utilized in an attempt to develop a better understanding of how welding fumes affect pulmonary health.