A Study of Pulmonary Deposition, and the Elimination of Some Constituent Metals From Welding Fume in Laboratory Animals

Lam, H. F.; Hewitt, Peter J.; Hicks, R.

doi:10.1093/annhyg/21.4.363

Cited by 17 publications

(1 citation statement)

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“…The use of animal models could provide valuable mechanistic understanding of the fate of particles in an intact organism. Animal studies have demonstrated that various metals found in welding fumes are cleared from the lung at substantially different rates (Lam et al 1978;Antonini et al 2010Antonini et al , 2011. For example, whereas more than 80% of total deposited Mn had been cleared by 8 days and nearly all Mn by 21 days (in rats exposed to mild steel fume via inhalation), significant amounts (around 40%) of Fe remained in the lungs at 42 days after exposure (Antonini et al 2011).…”

Section: Discussionmentioning

confidence: 99%

Modelled lung deposition and retention of welding fume particles in occupational scenarios: a comparison to doses used in vitro

2022

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Translating particle dose from in vitro systems to relevant human exposure remains a major challenge for the use of in vitro studies in assessing occupational hazard and risk of particle exposure. This study aimed to model the lung deposition and retention of welding fume particles following occupational scenarios and subsequently compare the lung doses to those used in vitro. We reviewed published welding fume concentrations and size distributions to identify input values simulating real-life exposure scenarios in the multiple path particle dosimetry (MPPD) model. The majority of the particles were reported to be below 0.1 μm and mass concentrations ranged between 0.05 and 45 mg/m3. Following 6-h exposure to 5 mg/m3 with a count median diameter of 50 nm, the tracheobronchial lung dose (0.89 µg/cm2) was found to exceed the in vitro cytotoxic cell dose (0.125 µg/cm2) previously assessed by us in human bronchial epithelial cells (HBEC-3kt). However, the tracheobronchial retention decreased rapidly when no exposure occurred, in contrast to the alveolar retention which builds-up over time and exceeded the in vitro cytotoxic cell dose after 1.5 working week. After 1 year, the tracheobronchial and alveolar retention was estimated to be 1.15 and 2.85 µg/cm2, respectively. Exposure to low-end aerosol concentrations resulted in alveolar retention comparable to cytotoxic in vitro dose in HBEC-3kt after 15–20 years of welding. This study demonstrates the potential of combining real-life exposure data with particle deposition modelling to improve the understanding of in vitro concentrations in the context of human occupational exposure.

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Section: Discussionmentioning

confidence: 99%

Modelled lung deposition and retention of welding fume particles in occupational scenarios: a comparison to doses used in vitro

2022

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An investigation of fibrogenic and other toxic effects of arc‐welding fume particles deposited in the rat lung

Hicks

Al-Shamma

Lam

et al. 1983

J of Applied Toxicology

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Lung burdens of deposited particles from fumes generated by arc-welding were established in rats by single inhalation exposures, repeated intermittent exposure or by intratracheal injection. Fumes from manual metal arc-welding using flux-coated mild-steel rods (MMA-MS) were compared with those from metal inert-gas welding with stainless steel wire (MIG-SS). After initial rapid clearance of deposited material from the lungs, persistent residual deposits remained. Such residues resulting from single inhalation were small and confined mainly to peribronchial accumulations in macrophage clusters. Deposits remaining after repeated inhalation were larger and more widespread. Intratracheal administration (50 mg) established massive residual deposits, giving nodular accumulations in peribronchial, subpleural and perivascular sites, with substantial alveolar parenchymal involvement. Deposits from both types of fumes contained predominantly iron. Particles from stainless steel also contained chromium, but concentrations of this element were low in deposits from MMA-MS fumes. MMA-MS deposits contained silica, probably amorphous. Long-term studies (up to 450 days) attempted to detect evidence of fibrosis resulting from particle burdens. Low-grade collagen fibre layers developed at margins of MMA-MS nodules. Diffuse reticulin fibre networks occurred within MIG-SS aggregates. Tissue hydroxyproline levels were increased (doubled) in lungs with intratracheal burdens of MMA-MS particles, but no significant increases resulted from MIG-SS. The major lesions were nodular aggregates of particle-laden macrophages with giant-cell formation, and alveolar epithelial thickening with atelectasis.

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Pneumoconiotic effects of welding-fume particles from mild and stainless steel deposited in the lung of the rat

et al. 1984

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Rats were exposed to single periods of inhalation of fumes generated by arc welding. Two processes were compared: either manual metal arc (MMA) using flux-coated mild steel (MS) electrodes or metal inert-gas (MIG) welding with stainless steel (SS). Widespread but small deposits of fume particles were cleared effectively from alveoli and airways. Peribronchial and subpleural aggregates of particle-laden macrophages remained. More massive and persistent lung-burdens were established by intratracheal administration of suspensions of fume-particles (10 mg and 50 mg, single doses). Initial pneumonitis was attributed to irritant gases or soluble toxic components of particles. MIG-SS particle deposits were more persistent and lesions more severe, inhibition of phagocytosis or clearance and damage to epithelial cells being associated with possible toxic effects in macrophages. Both types of particle caused alveolar epithelial thickening, with proliferation of granular pneumocytes and exudation of lamellar material. Foam cells appeared in alveoli. Long-term effects (80-300 days) involved formation of nodular aggregates of particle-laden macrophages. Giant cells were formed. Nodules containing MIG-SS material were irregular and surrounded by collapsed and thickened epithelium. Soluble chromium or nickel constituents are cited as probable active agents producing effects resembling those of cytotoxic non-fibrogenic dusts, e.g., soluble silicas . MMA-MS particles produced low-grade fibrotic ( collagenised ) changes.

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A Study of Pulmonary Deposition, and the Elimination of Some Constituent Metals From Welding Fume in Laboratory Animals

Cited by 17 publications

References 0 publications

Modelled lung deposition and retention of welding fume particles in occupational scenarios: a comparison to doses used in vitro

Modelled lung deposition and retention of welding fume particles in occupational scenarios: a comparison to doses used in vitro

An investigation of fibrogenic and other toxic effects of arc‐welding fume particles deposited in the rat lung

Pneumoconiotic effects of welding-fume particles from mild and stainless steel deposited in the lung of the rat

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