Welding generates complex aerosols of hazardous metal fumes. Animal models and the ability to control the welding fume (WF) exposure have helped in developing an understanding of how WF affects health. There are no studies that have performed a side-by-side comparison of the pulmonary responses from an animal toxicology study with the lung responses associated with WF exposure by a welder. Post-mortem lung tissue was donated from a long-time welder with a history of extensive WF exposure. To simulate long-term WF exposure in an animal model, Sprague- Dawley rats were treated for 28 weeks by intratracheal instillation with 2 mg of WF. Lung tissues from the welder and treated rats were examined by enhanced-darkfield light microscopy and electron microscopy. Pathological analysis of lung tissue from the welder demonstrated inflammatory cell influx and pulmonary alveolar proteinosis, likely due to long-term exposure to potentially toxic metals. The lung toxicity profile for the treated rats was similar. Aggregates of deposited welding particles were easily visualized, persisted in macrophages, and were composed of Fe, Cr, and Ni. In summary, long-term exposure to specific WF can lead to serious chronic lung disease characterized by significant particle persistence as demonstrated in both a human case study and rat model. Not only were lung responses the same, but the WF composition in situ was similar.
Welding; Aerosols; Metal-fumes; Metallic-fumes; Fumes; Hazards; Exposure-levels; Risk-factors; Animals; Pulmonary-system; Pulmonary-system-disorders; Pulmonary-function; Respiration; Respiratory-system-disorders; Models; Laboratory-animals; Microscopic-analysis; Analytical-processes; Lung; Lung-tissue