[Mercury concentration in gray hair].

Scalp hair sample were collected from 20 gray-haired males and 7 gray-haired females. Two hair samples, one each of dark hair and gray hair, obtained from each individual were selectively analysed for organic and inorganic mercury concentrations. The following finding were made: 1) In both sexes, total and organic mercury concentrations were significantly higher in gray hair than in dark hair but no difference was observed between dark hair and gray hair for the concentration of inorganic mercury. 2) For males, no significant differences between dark hair and gray hair were found for total, organic or inorganic mercury concentrations. On the other hand, gray hair had significantly higher levels of total, organic and inorganic mercury concentrations than dark hair in females. 3) When comparison was made between the sexes, total, organic and inorganic mercury concentrations were significantly higher in males than in females for dark hair. For gray hair, however, significantly higher levels of total and organic mercury concentrations, but not of inorganic mercury concentrations, were found in males. 4) The proportion of inorganic mercury to total mercury was higher in females than in males for both dark and gray hair. It was also higher in gray hair than in dark hair for females.