Manganese exposure assessment: The use of human toenails as a biomarker of exposure for welders

• Main Author: Ward, Eric James
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01.01.2013
• Subjects: Environmental Health; Occupational health; Occupational safety
• ISBN: 1303618265; 9781303618260

Numerous studies have shown that workers who are exposed to manganese from an occupational source, such as welding, at high levels, experience neurological health effects. Currently, there is no established biomarker for manganese exposure. The objective of this study was to evaluate the hypothesis that an individual's human toenail manganese concentration is reflective of an individual's manganese exposure from welding and dietary sources, and is a valid and reproducible biomarker of manganese exposure. In order to evaluate the hypothesis, toenail specimens from twelve welders and nineteen controls right and left feet were collected and analyzed using Inductively Coupled Plasma Mass Spectrometry (ICPMS) for manganese and iron. An exposure model was developed for this study to estimate the respirable manganese inhaled for specific time frames for each individual based on respirable air sampling and the individual's work history. Additionally, this study examined the effects of age, race, diet, smoking, and the ratio of manganese to iron intake have on toenail manganese concentration in welders and controls. This study was able to show that toenail manganese and iron concentrations were not significantly different in the right and left feet. This study was also able to show that exposure to manganese from welding fume is reflected in toenail manganese concentrations. Based on the results produced in this study, toenail manganese is a valid biomarker of exposure.