Welding, soldering, and brazing workers are a critical part of the US workforce, with over 574, 000 employees in 2020. Unfortunately, these workers are frequently exposed to welding fumes that contain metallic particles such as chromium, copper, manganese, iron, and nickel, which can lead to serious adverse health effects such as lung disease, Parkinson-like symptoms, and metal fume fever. However, the dose-response of different metals in a chronic exposure setting is not fully understood. Therefore, the development of a biomarker to assess chronic exposure is critical for assessing potential health risks. This study aims to investigate the use of toenail metal concentrations as biomarkers for chronic exposure to metals.
The main insight of this study is the significant association between metal concentrations in welding fumes and toenails, demonstrating the potential of toenail metal levels as biomarkers for chronic metal exposure. By analyzing metal concentrations in both welding fumes and toenails, the research found that welders had significantly higher metal levels compared to controls. As a results of receiver operating characteristic (ROC) curves plots, the most distinguishing biomarker was toenail Mn concentration to distinguish between welders and controls, with an impressive area under the curve (AUC) of 0.87 followed by iron (Fe), zinc (Zn), chromium (Cr), and copper (Cu) concentrations. These findings provide valuable insights into their potential as biomarkers for corresponding metal exposures and have important implications for occupational health monitoring and risk assessment in industries where metal exposure is prevalent.