Variations in elemental concentrations of toxic metals in beard samples measured over twelve years, a case study

Abstract Beard samples were collected every day from a single person (55 [at start] to 66- [at end] years old) over a 12-year period. Beard hair samples were analyzed by particle induced X-ray emission (PIXE) to determine variations in concentrations of aluminum, chromium, arsenic, mercury and lead over the sampling period. Only mercury showed a gentle upward trend with age, and a significant increase of 20–30% was observed. This fact was consistent with the results of our previous studies on more than 1250 hairs collected from healthy people. It was also found that concentrations of many toxic elements tended to be higher in summer than in winter, except for chromium. In particular, arsenic and mercury concentrations significantly increased in summer. Their concentrations in the winter dropped to less than 50% and 86% of those in the summer, respectively. These seasonal changes can be attributed to changes in the ingestion of season-specific foods, such as marine products. These findings indicate that beard analyses are a powerful tool for evaluating the exposure to toxic-element.