Personal and area exposure assessment at a stainless steel fabrication facility: an evaluation of inhalable, time-resolved PM_10, and bioavailable airborne metals

Abstract

This study describes a comprehensive exposure assessment in a stainless steel welding facility, measuring personal inhalable PM and metals, time-resolved PM₁₀ area metals, and the bioavailable fraction of area inhalable metals. Eighteen participants wore personal inhalable samplers for two, nonconsecutive shifts. Area inhalable samplers and a time-resolved PM₁₀ X-ray fluorescence spectrometer were used in different work areas each sampling day. Inhalable and bioavailable metals were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). Median exposures to chromium, nickel, and manganese across all measured shifts were 66 (range: 13–300) μg/m³, 29 (5.7–132) μg/m³, and 22 (1.5–119) μg/m³, respectively. Most exposure variation was seen between workers ($0.79<\mathit{ICC}<0.55),$ although cobalt and inhalable PM showed most variation within workers. Manganese was the most bioavailable metal from the inhalable size fraction (16 ± 3%), and chromium and nickel were 1.2 ± 0.08% and 2.6 ± 1.2% bioavailable, respectively. This comprehensive approach to welding-fume exposure assessment can allow for targeted approaches to controlling exposures based not only on individual measurements, but also on metal-specific measures and assessments of bioavailability.

Keywords:

• Bioavailability
• chromium
• exposure
• manganese
• nickel
• particulate matter
• respiratory health
• welding fumes

Acknowledgments

We would also like to thank Cooper Environmental (now Sunset CES Inc.) for their generous loan of the Xact 625i Ambient Continuous Multi-Metals Monitor during our sampling days and students from the Environmental and Occupational Health program at Boise State for their assistance in the field.

Conflict of interest

The authors declare no conflict of interest relating to the material presented in this article.

Additional information

Funding

This research was funded under support from the Johns Hopkins University Education and Research Center for Occupational Safety and Health (ERC). ERC training grant funding comes from the National Institute for Occupational Safety and Health (NIOSH), under Grant No. 5 T42 OH 008428. This project was also funded through NIOSH under Grant No. R21 OH 010661. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention or the Department of Health and Human Services.