Alterations in welding process voltage affect the generation of ultrafine particles, fume composition, and pulmonary toxicity

Abstract

The goal was to determine if increasing welding voltage changes the physico-chemical properties of the fume and influences lung responses. Rats inhaled 40 mg/m³ (3 h/day × 3 days) of stainless steel (SS) welding fume generated at a standard voltage setting of 25 V (regular SS) or at a higher voltage (high voltage SS) of 30 V. Particle morphology, size and composition were characterized. Bronchoalveolar lavage was performed at different times after exposures to assess lung injury. Fumes collected from either of the welding conditions appeared as chain-like agglomerates of nanometer-sized primary particles. High voltage SS welding produced a greater number of ultrafine-sized particles. Fume generated by high voltage SS welding was higher in manganese. Pulmonary toxicity was more substantial and persisted longer after exposure to the regular SS fume. In summary, a modest raise in welding voltage affected fume size and elemental composition and altered the temporal lung toxicity profile.

Keywords::

• Welding fume
• inhalation
• lung burden
• nanoparticles
• pulmonary toxicity

Acknowledgements

The authors thank Amy Moseley, Jared Cumpston and Donny Leonard from the inhalation exposure team for their expert technical assistance during the project, grant number: NIOSH IA 97-04-05M12. The authors also thank the National Toxicology Program for additional support during the development of the welding fume generator and exposure system.

Disclaimer: The findings and conclusions of this paper have not been formally disseminated by NIOSH and should not be construed to represent any agency determination or policy.

Declaration of interest: Funding for the project was provided by the National Institute for Occupational Safety and Health (NIOSH, NIOSH IA 97-04-05M12) and the National Occupational Research Agenda (NORA). The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.