Peter Brand

Biological effect markers in exhaled breath condensate and biomonitoring in welders: impact of smoking and protection equipment

PurposeThe objective of this study was to investigate the effect of welding as well as the impact of smoking and protection measures on biological effect markers in exhaled breath condensate. Additionally, biomonitoring of chromium, aluminium and nickel in urine was performed to quantify internal exposure.MethodsExhaled breath condensate (EBC) and urine samples of 45 male welders and 24 male non-exposed control subjects were collected on Friday pre-shift and after 8xa0h of work post-shift. In EBC, biological effect markers such as malondialdehyde, nitrite, nitrate, 3-nitrotyrosine, tyrosine, hydroxyproline, proline, H2O2 and pH-value were measured while aluminium, nickel, and chromium were measured in the urine samples.ResultsAlthough internal exposure to aluminium, nickel and chromium in this study was low, welders showed significantly increased concentrations of all these parameters at baseline compared to non-exposed controls. Moreover, welders had higher nitrate concentrations in EBC at baseline and after shift. Nitrate concentration was considerably lower after shift if personal protection equipment was used. H2O2 was increased only when subjects smoked during shift.ConclusionIt has been shown that welding-associated long-term and short-term health effects could be detected in a population of welders. The results also showed that using personal protection equipment is of high importance and H2O2 may be an effect marker associated with smoking rather than with welding fumes, while nitrate in EBC seems to be sensitive to welding fume exposure.

Number Size Distribution of Fine and Ultrafine Fume Particles From Various Welding Processes

Studies in the field of environmental epidemiology indicate that for the adverse effect of inhaled particles not only particle mass is crucial but also particle size is. Ultrafine particles with diameters below 100 nm are of special interest since these particles have high surface area to mass ratio and have properties which differ from those of larger particles. In this paper, particle size distributions of various welding and joining techniques were measured close to the welding process using a fast mobility particle sizer (FMPS). It turned out that welding processes with high mass emission rates (manual metal arc welding, metal active gas welding, metal inert gas welding, metal inert gas soldering, and laser welding) show mainly agglomerated particles with diameters above 100 nm and only few particles in the size range below 50 nm (10 to 15%). Welding processes with low mass emission rates (tungsten inert gas welding and resistance spot welding) emit predominantly ultrafine particles with diameters well below 100 nm. This finding can be explained by considerably faster agglomeration processes in welding processes with high mass emission rates. Although mass emission is low for tungsten inert gas welding and resistance spot welding, due to the low particle size of the fume, these processes cannot be labeled as toxicologically irrelevant and should be further investigated.

Internal exposure, effect monitoring, and lung function in welders after acute short-term exposure to welding fumes from different welding processes.

Objective: In this study, the effect of short-term exposure to welding fumes emitted by different welding techniques on workers was investigated. Methods: In a 3-fold crossover study, six welders used three different welding techniques for 3 hours. Before and after welding, blood and urine samples were collected to perform biomonitoring of metals. Breath condensate was collected to assess inflammatory reactions, and lung function measurements were performed. Results: Welding led to a significant increase of chromium and nickel in blood and urine and of nitrate and nitrite in exhaled breath condensate. These increases were higher for manual metal arc welding with alloyed material (MAW-a). Several lung function parameters decreased after welding. This decrease was significantly higher after MAW-a. Conclusions: In respect to biological effects, MAW-a seems to be more important than other welding techniques.

Inter-reader variability in chest radiography and HRCT for the early detection of asbestos-related lung and pleural abnormalities in a cohort of 636 asbestos-exposed subjects

PurposeTo compare inter-reader variability of chest X-ray and high resolution computed tomography (HRCT) scans of formerly asbestos-exposed employees over a 4-year period.MethodsIn this longitudinal study, 636 formerly asbestos-exposed persons were annually examined with chest radiographs and HRCT scans. Ten observer pairs classified the radiographs and HRCT scans, using the ILO classification and a custom-made CT classification. Inter-observer variability was calculated using the κ-coefficient.ResultsDespite all expectations, HRCT inter-reader variability according to asbestos-related lung or pleura alterations at an early stage did not turn out to be better than X-ray inter-reader variability. Substantial inter-observer agreement was found for pleural calcifications (κX-rayxa0=xa00.63; κCTxa0=xa00.64). Averaging over κ led to fair inter-observer agreement of both methods (κX-rayxa0=xa00.36; κCTxa0=xa00.34).ConclusionsHigh resolution computed tomography scans are superior to X-rays in detecting lung alterations after asbestos exposure and are supposedly easier to interpret. Nevertheless, inter-observer variability did not differ between the two methods in this study. This was probably due to the only discrete asbestos-related lung or pleura alterations of this cohort and to the unfamiliar CT classification sheet, which was revised on the basis of the presented results.

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.

Exposure of healthy subjects with emissions from a gas metal arc welding process: part 1—exposure technique and external exposure

BackgroundStudies concerning welding fume–related adverse health effects in welders are hampered by the heterogeneity of workplace situations, resulting in complex and non-standardized exposure conditions.MethodsIn order to carry out welding fume exposure studies under controlled and standardized conditions, the Aachen Workplace Simulation Laboratory was developed. This laboratory consists of an emission room, in which welding fume is produced, and an exposure room in which human subjects are exposed to these fumes. Both rooms are connected by a ventilation system which allows the welding fume concentration to be regulated. Particle mass concentration was measured with a TEOM microbalance and the particle number-size distribution using a Grimm SMPS device.ResultsIn a study, which is the subject of this paper, it has been shown that welding fume concentration can easily be regulated between 1 and about 3xa0mgxa0m−3. The chosen concentration can be kept constant for more than 8xa0h. However, transport of the particles from the emission room into the exposure room leads to a change in particle size distribution, which is probably due to coagulation of the fraction of smallest particles.ConclusionThe Aachen Workplace Simulation Laboratory is suitable for controlled exposure studies with human subjects.

Effects of formoterol and tiotropium bromide on mucus clearance in patients with COPD.

BACKGROUNDnLung mucociliary clearance is impaired in patients with chronic obstructive pulmonary disease (COPD). Treatment guidelines recommend that patients with COPD receive maintenance therapy with long-acting beta-agonists and anticholinergic agents.nnnMETHODSnTwenty-four patients with mild to moderate COPD received formoterol (12 μg, twice daily from Turbuhaler® dry powder inhaler (DPI)) or tiotropium (18 μg, once daily from Handihaler® DPI) for 14 days. They also received single doses of formoterol, tiotropium, salbutamol (200 μg) and placebo. A radioaerosol technique was used to assess the effects on mucus clearance of 14 days treatment with formoterol or tiotropium, as well as single doses of these drugs.nnnRESULTSnThe 4 h whole lung retention of radioaerosol was significantly higher after 14 days treatment with tiotropium (P = 0.016), but not after 14 days treatment with formoterol. However, patients bronchodilated after 14 days treatment with both drugs, so that the deposited radioaerosol may have had an increased distance to travel in order to be cleared by mucociliary action. A single dose of formoterol enhanced radioaerosol clearance significantly compared to other single dose treatments (P < 0.05).nnnCONCLUSIONnFormoterol (12 μg) enhances mucus clearance in patients with mild to moderate COPD when given as a single dose, and may do so when given for 14 days. Studies of longer duration would be needed in order to assess the effects of the study drugs on mucus clearance when they are used for long-term maintenance therapy.

Experimental exposure of healthy subjects with emissions from a gas metal arc welding process—part II: biomonitoring of chromium and nickel

ObjectivesThe objective of this study was to investigate whether there is a relationship between the external exposure dose of chromium and nickel caused by a metal active gas welding process with a solid high-alloyed steel welding wire and inner exposure of subjects. In order to perform welding fume exposure under controlled and standardized conditions, the investigations were conducted in the “Aachen Workplace Simulation Laboratory”.MethodsTo perform biological monitoring of chromium and nickel, blood and urine samples of 12 healthy male non-smokers who never worked as welders were collected before and after a 6-h exposure to ambient air (0xa0mg/m3) and to welding fumes of a metal active gas welding process once with a concentration of the welding fume of 1xa0mg/m3 and once with a concentration of 2.5xa0mg/m3.ResultsAlthough the internal exposure to chromium and nickel in this study was comparatively low, the subjects showed significantly increased concentrations of these metals in urine after exposure to welding fume compared to the values at baseline. Moreover, the observed increase was significantly dose dependent for both of the substances.ConclusionFor the biological monitoring of chromium and nickel in urine of subjects exposed to welding fumes, a dependency on exposure dose was seen under standardized conditions after a single exposure over a period of 6xa0h. Thus, this study contributes to a better understanding of the relationship between ambient and biological exposures from welding fumes and provides a good basis for evaluating future biological threshold values for these metals in welding occupation.

Relationship between welding fume concentration and systemic inflammation after controlled exposure of human subjects with welding fumes from metal inert gas brazing of zinc-coated materials.

Objectives:It has been shown that exposure of subjects to emissions from a metal inert gas (MIG) brazing process of zinc-coated material led to an increase of high-sensitivity C-reactive protein (hsCRP) in the blood. In this study, the no-observed-effect level (NOEL) for such emissions was assessed. Methods:Twelve healthy subjects were exposed for 6 hours to different concentrations of MIG brazing fumes under controlled conditions. High-sensitivity C-reactive protein was measured in the blood. Results:For welding fumes containing 1.20 and 1.50 mg m−3 zinc, high-sensitivity C-reactive protein was increased the day after exposure. For 0.90 mg m−3 zinc, no increase was detected. Conclusions:These data indicate that the no-observed-effect level for emissions from a MIG brazing process of zinc-coated material in respect to systemic inflammation is found for welding fumes with zinc concentrations between 0.90 and 1.20 mg m−3.

Exposure of healthy subjects with emissions from a gas metal arc welding process: part 3--biological effect markers and lung function.

BackgroundMetal active gas welding (MAG) is a widely-used welding technique resulting in high emissions of welding fume particles. This study investigated whether short-term exposure to these fume particles results in changes in lung function and early stages of inflammatory reactions.MethodsTwelve healthy, young male subjects were exposed to MAG fumes for 6xa0h with three different exposure concentrations in a three-fold cross-over study design. Exposure was performed in the “Aachen Workplace Simulation Laboratory” under controlled conditions with constant fume concentration. Fume concentrations were 0, 1, and 2.5xa0mgxa0m−3 in randomized order. Before and after each exposure, spirometry, and impulse oscillometry were performed and breath condensate samples were collected in order to quantify inflammatory markers like Nitrate, Nitrite, Nitrotyrosine, Hydroxyprolin and Malondialdehyde.ResultsA significant dependency on the exposure concentration could not be established for any of the endpoint parameters.ConclusionIn healthy, young subjects neither changes in spirometry nor changes in inflammatory markers measured in exhaled breath condensate could be detected after short-term exposure.