Hair can be a good biomarker of occupational exposure to mercury vapor: Simulated experiments and field data analysis

Generally, urine mercury (U-Hg) is widely used for assessment of inorganic mercury (I-Hg) exposure in humans. The reliability of scalp hair as an indicator of mercury vapor exposure is contentious. However, significant correlations were found between hair total mercury (T-Hg) and U-Hg and between hair I-Hg and total gaseous mercury (TGM) in ambient air in our previous studies. Simulated experiments were designed to assess the contribution of direct absorption/adsorption of mercury vapor in the hair. Results indicated that the increases of hair T-Hg concentrations were less than 1 μg/g, which was negligible compared with hair T-Hg concentrations in occupationally exposed workers. The β-mercaptoethanol washing can remove 30% of mercury (Hg) in the exposed hair samples. The inhaled Hg constituted the major fraction (97.4%) of I-Hg exposure for the artisanal Hg mining workers. From the simulated experiments and field data analysis, we can conclude that hair I-Hg can be a useful tool for monitoring occupational exposure to Hg vapor.

► The direct absorption/adsorption of Hg vapor in hair was negligible compared with hair I-Hg in artisanal mining workers.
► The washing styles have significant effects on hair Hg concentrations.
► Hair I-Hg level was significantly correlated with U-Hg in artisanal mining workers and with TGM concentrations.
► Hair can be a good biomarker for estimating exposure to Hg vapor in occupational settings.