Metal exposure from additive manufacturing and its effect on the nasal lavage fluid proteome - a pilot study

Maria Assenhöj,Pål Graff,Bijar Ghafouri,Stefan A Ljunggren,Liam J Ward

doi:10.1371/journal.pone.0256746

Abstract

The use of metal additive manufacturing (AM) is steadily increasing and is an emerging concern regarding occupational exposure. In this study, non-invasive sampled nasal lavage fluid (NLF) from the upper airways was collected from metal AM operators at the beginning and end of a workweek during two consecutive years with preventive interventions in the occupational setting in-between (n = 5 year 1, n = 9 year 2). During year one, NLF was also collected from welders (n = 6) from the same company to get a comparison with a traditional manufacturing technique with known exposure and health risks. The samples were investigated using untargeted proteomics, as well as using multi-immunoassay to analyze a panel of 71 inflammatory protein markers. NLF in AM operators from year 1 showed decreased levels of Immunoglobulin J and WAP four-disulfide core domain protein 2 and increased levels of Golgi membrane protein 1, Uteroglobin and Protein S100-A6 at the end of the workweek. At year two, after preventive interventions, there were no significant differences at the end of the workweek. In welders, Annexin A1 and Protein S100-A6 were increased at the end of the workweek. The analysis of 71 inflammatory biomarkers showed no significant differences between the beginning and the end of workweek year 1 in AM operators. We identified several proteins of interest in the AM operators that could serve as possible markers for exposure in future studies with a larger cohort for validation.

Highlights

Additive manufacturing (AM) is a name given to techniques that produce components from the bottom up, often by creating them layer by layer [1]
We found that the AM operators had a trend of higher metal concentrations in their urine and metals on their hands that were reduced after preventive interventions by the company, including powder-handling routines, ventilation, and personal protection equipment (PPE)
Symptoms from eyes or upper airways were reported with cases of irritated, stuffy, or runny nose in AM operators year 2 and Welders year 1 (n = 2 and n = 3, respectively), blood-mixed nasal mucus/nosebleeds in AM operators year 1 and year 2 (n = 1 and n = 2, respectively), and irritated, itchy or stingy eyes in AM operators year 2 (n = 3)

Summary

Introduction

Additive manufacturing (AM) is a name given to techniques that produce components from the bottom up, often by creating them layer by layer [1]. Several of the constituting metals are known to pose a health risk in other occupational settings. This includes that cobalt exposure decrease the lung function in hard metal workers [5] while nickel can cause lung diseases including asthma and damage the nasal cavity [6]. Exposure-related lung function decline has been observed in steel workers exposed to a mix of cobalt, nickel, and chromium dust [8]. Welders constitute a large group of operators exposed to a mix of metals and have increased risk for lung diseases [9,10] and cardiovascular disease [11]. Some of the metals generated in AM are in the nanoscale range and may constitute special risks to human health, similar to what has been shown for welders [12]

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Discussion

Conclusion